Friday, May 15, 2020

Lab Culturing Escherichia Coli Involving Cav1.2,...

Lab 4: Culturing Escherichia coli involving Cav1.2, Connexin 43, and N-Cadherin By: Zachary Siou EGRB 491 Due: 2/28/17 Introduction Voltage gated channels are necessary components of life processes, in many organisms. One in particular, is the calcium voltage gated ion channel. Often lodged within the phospholipid bilayer, the imbalance of the calcium, or, the inside vs outside concentration, creates a gradient. The channel proteins often undergo conformations, states that which allow or block calcium ions from passing through. As ions move inside the cell, this creates a depolarization, or surge in the voltage. Clinically, this is associated with the heart and how it allows the heart to contract, which can be read in the†¦show more content†¦For example, Connexin 43 has an effect on cell proliferation, particularly in the testes, which aid in the development of sperm cells [2]. They form a network that provides an environment to foster proper growth and development. Again, this is widely expressed in cases of tumor growth in the area. Figure 1 [2]: The role of tubules in cell proliferation and di fferentiation of sperm cells. N-cadherin is a protein encoded by the CDH2 gene. It interacts with the cellular cytoskeleton, and is often involved in cardiac muscle, as well as certain cancers. Being calcium dependent, it helps to maintain cellular structure and integrity. For example, it plays a role in trans-endothelial migration, which involves cell-cell adhesion [3]. The endothelial layer contains many different fibers, as well as pathways that allow attachment for the cadherin protein. Some cancer cells can eventually pass through the endothelium, causing the cancer to become malignant and spread. Cadherins in this case can be used to identify and track the spread of the cells, and further identify common routes of travel through the human vasculature. Figure 2 [3]: The role of cadherin and catenin in the binding of cancer cells to the endothelium. Procedure The experiment was divided over the span of six days. For this procedure, Cav1.2 will be mainly referred to. On a Thursday, start with clean test tubes, the Luria broth, and either the Cav1.2, Connexin 43, or N-Cadherin (if a

Wednesday, May 6, 2020

The Population Of The United States - 1670 Words

The population of the United States is ever evolving. According to the United States Census Bureau, the United States will become a â€Å"majority-minority† population by the year 2060 (Colby Ortman, 2015, p. 9). In this ever changing society, we are still seeing a small margin of minorities choosing to become teachers. In fact, the teacher-student diversity gap is growing every year. On top of a lack of minority educators in the field, there is also a lack of proper preparation for white teachers who are working in diverse classrooms. In our transforming society, we need highly informed and diverse teachers who will embrace and encourage cultural diversity. In order to understand the implications of this paper, we must first define multiculturalism. The Dictionary of Multicultural Education defines multiculturalism in the following way: â€Å"Multiculturalism is a movement that assumes the gender, ethnic, racial, and cultural diversity of a pluralistic society should be reflected in all of its institutionalized structures but especially in educational institutions, including the staff, norms and values, curriculum, and student body† (p. 182). Some sources suggest that schools need to hire more minority teachers, while others believe that white teachers need to be better prepared to address their diverse classrooms. Overall, there is a strong support for multiculturalism in education among these sources. Although teachers and educational professionals agree that it is a keyShow MoreRelatedThe Population Of The United States1633 Words   |  7 PagesIn the United States, the overall population is getting older with many Americans living into their 70s, 80s, and beyond. The nation is now and will be confronted with the challenge of preparing to meet the financial demands of a continually aging population. The proportion of the population aged 65 years and older is expected to increase from 12.4% in 2000 to 19.6% in 2030; this is an increase to about 72 million. The number of persons aged 80 years and older is expected to increase from 9.3 millionRead MoreThe Population Of The United States1479 Words   |  6 PagesAs the population of the United States grows, one thing is apparent: minorities are overtaking the Caucasian population (which is bound to become a minority before 2100). The increase of the population of minorities in the United States will produce mixed-race persons, who not only have two sets of DNA from two different persons of different races, but two sets of culture. Sometimes, this can cause a clash of ideologies, which can lead to an individual being raised multi-culturally; one may growRead MoreThe Population Of The United States1537 Words   |  7 PagesAs the population of the United States continues to become more diverse, healthcare providers should eï ¬â‚¬ectively communicate with each patient regardless of their culture, nationality, religion or socioeconomic status. Nurses and other providers should be delivering patient centered care that is culturally competent. â€Å"Culture also includes the integrated pattern of thoughts, communications, actions, customs, beliefs, v alues, and institutions associated, wholly or partially, with racial, ethnic, orRead MoreThe Population Of The United States900 Words   |  4 Pages With the continual increase in the elder population, whether or not an aging population is beneficial to society has become widely debatable. While many believe that this top-heavy type of population distribution poses a colossal obstacle in terms of economic development in the long run, others maintain that it is a testament to the development of a society. Given that a high proportion of elderly citizens puts immense pressure on the working force and would be a burden on the healthcareRead MoreThe Aging Population Of The United States1269 Words   |  6 PagesIntroduction Demographic of the elderly in the United States. The recent growth in the number of older adults in the United States is unusual in the history of America. The anticipation of the elderly population (65+) by the year 2050 will be almost 89million people, or greater than the population of the elderly in the year 2010 (CDC 2013). The older dependency ratio is anticipated to increase suddenly from 2010 as the post-World War II baby boomers reach the older age. The olderRead MorePopulation Aging Of The United States933 Words   |  4 PagesPopulation Aging This demographic trend deflects on the stabilization; decline and fall in the United Sates rates in fertility since the generation of the baby boom are given birth. More importantly this demographic trend speculates on the secular increase in the life expectancy and entry of the large baby boom cohort joining in to the normal projected age of retirement that is between 2010 and 2030. The census bureau expects arise of the share population over 65 after the 21st decade short pauseRead MoreThe Homeless Population Of The United States1393 Words   |  6 PagesThe homeless populations are among the most vulnerable populations in the United States. In today’s society, the homeless population consists of every age group, sex, religion, family type, and ethnic group. Families, children, and adults who are homeless suffer many adverse effects from living in shelters and on the streets, and approximately twenty six percent of homeless individuals suffer from severe mental illness (Sta nhope, 2014). This paper focuses on the homeless population of all age groupsRead MoreThe United States Prison Population1808 Words   |  8 Pages The United States prison population has grown tremendously from approximately 500,000 to 2.3 million people in just three decades. We (U.S) spend almost $70 billion annually to place adults in prison and jails, to confine youth in detention centers, and to supervise 7.3 million individuals on probation and parole. California has the largest prison population in the country, with more than 170,000 individuals behind bars. In Los Angeles, more than half of current parolees live in neighborhoods thatRead MoreJewish Population And The United States2957 Words   |  12 Pagesthe Jewish population, referring only to people whose religion is Jewish, totals at about 1.8% of the entire U.S. adult population, which is 4.2 million people (Chapter 1, 2013). When looking at the Jewish population of the U.S. (through association of religion or cult ure) the populace is estimated at between 5.5 and 6 million, making the U.S. the second largest home to the Jewish population, the first being Israel (Sherwin, n.d.). When comparing this data to the 1957 Current Population Survey, isRead MoreWorking With Marginalized Populations Of The United States928 Words   |  4 Pagesmarginalized populations. I also hope to make connections with fellow social workers that share similar passions and values. Population #1: Refugees/Immigrants: Refugees and immigrants have a specific set of needs that differ from other families. Oftentimes they suffer from a lack of resources and do not fully understand the culture that they live in. I would like to work with this population because I have experience in helping refugee/immigrant families succeed in the United States, while helping

Tuesday, May 5, 2020

Diagnosis of Diseases free essay sample

Infection simply means that a germ—virus, bacteria, or parasite—that can cause disease or sickness is present inside a person’s body. An infected person does not necessarily have any symptoms or signs that the virus or bacteria is actually hurting his or her body; they do not necessarily feel sick. A disease means that the infection is actually causing the infected person to feel sick, or to notice something is wrong. For this reason, the term STI—which refers to infection with any germ that can cause an STD, even if the infected person has no symptoms—is a much broader term than STD. The distinction being made, however, is closer to that between a colonization and an infection, rather than between an infection and a disease. Specifically, the term STD refers only to infections that are causing symptoms. Because most of the time people do not know that they are infected with an STD until they start showing symptoms of disease, most people use the term STD, even though the term STI is also appropriate in many cases. Moreover, the term sexually transmissible disease is sometimes used since it is less restrictive in consideration of other factors or means of transmission. For instance, meningitis is transmissible by means of sexual contact but is not labeled as an STI because sexual contact is not the primary vector for the pathogens that cause meningitis. This discrepancy is addressed by the probability of infection by means other than sexual contact. In general, an STI is an infection that has a negligible probability of transmission by means other than sexual contact, but has a realistic means of transmission by sexual contact (more sophisticated means—blood transfusion, sharing of hypodermic needles—are not taken into account). Thus, one may presume that, if a person is infected with an STI, e. g. , chlamydia, gonorrhea, genital herpes, it was transmitted to him/her by means of sexual contact. The diseases on this list are most commonly transmitted solely by sexual activity. Many infectious diseases, including the common cold, influenza, pneumonia, and most others that are transmitted person-to-person can also be transmitted during sexual contact, if one person is infected, due to the close contact involved. However, even though these diseases may be transmitted during sex, they are not considered STDs. Review of literature Laboratory medicine is the base of the modem day health care system. The advance in technology, better understanding of the various disease processes, advancement of medical research and the growing demand for reliable test result has greatly revolutionalized the area of laboratory medicine. Most of the present day laboratories are now equipped with, to a varying degree, sophisticated automated instruments, with test results, which are accurate and reproducible. There is more emphasis on the quality control programs. Today, in larger hospital, major sections of the laboratory are specialized to the extent that they engage specialized staff and perform all the tests relating to their disciplines within the sections. In the smaller hospitals the staff the staff may be required to work in more than one section. It is not unusual for these smaller hospitals not to establish and staff some sections and send the specimens to the other larger institutions. Presently there is no prevailing legislation to check labs. Which do not satisfy the minimum standards and hence do not provide quality results, which is a cause for great concern? The ministry has established and accreditation board to fix some rules and regulations for the small laboratories, which are not even having the recommended instruments and qualified. In this changed scenario organization and management of laboratory services is not only a complicated and complex process but also a great challenge. . Materials Good planning and design to meet the current and foreseeable needs pertaining to personnel, equipments, space and tasks to be performed is very important for establishing and successful laboratory service. The steps in design process are: 1. Preparation Assess the needs, staff requirement; technology (current amp; future) Committee may be formed involving Laboratory staff, architect, medical staff and interior designer. 2. Function * Define the activities that are to be performed. * Consider the flow of the people and material. * Storage: reagents, stationary and equipment spare. * Utilities * Specific needs of each individual section in the laboratory. 3. Schematic design * Structural design * Architectural design System options – like plumbing, electricity, heating, ventilation and air conditioning. * Cost estimation 4. Design development Interior designing – colour, texture, finish, and furnishings. Considerations in Laboratories Design Location of the lab: in a hospital the lab should ideally be located close to the emergency department, OPD intensive care units and operating rooms. The laboratory should be very nearer to the doctor as well as it should be located ver y close to the city. * Space requirement: The lab should be spacious to comfortably house the equipments and laboratory personnel. There should be no hindrance for the movement of the personnel. * The adequate lighting, good ventilation, temperature control (equipments should be kept in AC rooms to increase their life), electrical power (including emergence power/ generations), continuous water supply and good sanitation should be provided to the laboratory. * Noise control in the open labs is achieved by installing a drop ceiling. This in addition can be used for installation of utilities like power cables, computer cables, which add flexibility to the design. Fume hoods and biological safety cabinets are required and should be located way from high traffic areas and doorways. * It is advisable to have movable partitions instead of permanent brick walls between various sections of the lab, as it adds to the flexibility for any future expansion or alterations. The workbenches, used for tasks performed while sitting should be 2. 5 ft in height and those to be used for tasks, which are, performed standing should be 3 ft high. The width of these workbenches should be at least 2’6†. The wood surfaces with acid proofing, smooth cement surfaces. Base cabinets (under the lab counters / work benches are preferred over the suspended cabinets, as they provide 30% extra storage space. * Emergency exit, which opens to the corridor, should be provided. * Separate rests rooms should be provided for the laboratory staff. * Choose the furniture modular furniture (detachable, movable, and foldable), though expensive allows more flexibility. Serology Serology is the scientific study of blood serum and other bodily fluids. In practice, the term usually refers to the diagnostic identification of antibodies in the serum. Such antibodies are typically formed in response to an infection (against a given microorganism), against other foreign proteins (in response, for example, to a mismatched blood transfusion), or to ones own proteins (in instances of autoimmune disease). Serological tests may be performed for diagnostic purposes when an infection is suspected, in rheumatic illnesses, and in many other situations, such as checking an individuals blood type. Serology blood tests help to diagnose patients with certain immune deficiencies associated with the lack of antibodies, such as X-linked agammaglobulinemia. In such cases, tests for antibodies will be consistently negative. There are several serology techniques that can be used depending on the antibodies being studied. These include: ELISA, agglutination, precipitation, complement-fixation, and fluorescent antibodies. Some serological tests are not limited to blood serum, but can also be performed on other bodily fluids such as semen and saliva, which have (roughly) similar properties to serum. Serological tests may also be used forensically, specifically a piece of evidence (e. g. , linking a rapist to a semen sample). SEXUALLY TRANSMITTED DISEASES A sexually transmitted disease (STD), also known as sexually transmitted infection (STI) or venereal disease (VD), is an illness that has a significant probability of transmission between humans or animals by means of human sexual behavior, including vaginal intercourse, oral sex, and anal sex. While in the past, these illnesses have mostly been referred to as STDs or VD, in recent years the term sexually transmitted infection (STI) has been preferred, as it has a broader range of meaning; a person may be infected, and may potentially infect others, without showing signs of disease. Some STIs can also be transmitted via the use of IV drug needles after its use by an infected person, as well as through childbirth or breastfeeding. Sexually transmitted infections have been well known for hundreds of years. * | Classification and terminology Until the 1990s, STDs were commonly known as venereal diseases  : Veneris is the Latin genitive form of the name Venus, the Roman goddess of love. Social disease was another euphemism. Public health officials originally introduced the term sexually transmitted infection, which clinicians are increasingly using alongside the term sexually transmitted disease in order to distinguish it from the former. According to the Ethiopian Aids Resource Center FAQ, Sometimes the terms STI and STD are used interchangeably. This can be confusing and not always accurate, so it helps first to understand the difference between infection and disease. Infection simply means that a germ—virus, bacteria, or parasite—that can cause disease or sickness is present inside a person’s body. An infected person does not necessarily have any symptoms or signs that the virus or bacteria is actually hurting his or her body; they do not necessarily feel sick. A disease means that the infection is actually causing the infected person to feel sick, or to notice something is wrong. For this reason, the term STI—which refers to infection with any germ that can cause an STD, even if the infected person has no symptoms—is a much broader term than STD. [1] The distinction being made, however, is closer to that between a colonization and an infection, rather than between an infection and a disease. Specifically, the term STD refers only to infections that are causing symptoms. Because most of the time people do not know that they are infected with an STD until they start showing symptoms of disease, most people use the term STD, even though the term STI is also appropriate in many cases. Moreover, the term sexually transmissible disease is sometimes used since it is less restrictive in consideration of other factors or means of transmission. For instance, meningitis is transmissible by means of sexual contact but is not labeled as an STI because sexual contact is not the primary vector for the pathogens that cause meningitis. This discrepancy is addressed by the probability of infection by means other than sexual contact. In general, an STI is an infection that has a negligible probability of transmission by means other than sexual contact, but has a realistic means of transmission by sexual contact (more sophisticated means—blood transfusion, sharing of hypodermic needles—are not taken into account). Thus, one may presume that, if a person is infected with an STI, e. g. , chlamydia, gonorrhea, genital herpes, it was transmitted to him/her by means of sexual contact. The diseases on this list are most commonly transmitted solely by sexual activity. Many infectious diseases, including the common cold, influenza, pneumonia, and most others that are transmitted person-to-person can also be transmitted during sexual contact, if one person is infected, due to the close contact involved. However, even though these diseases may be transmitted during sex, they are not considered STDs. Bacterial * Chancroid (Haemophilus ducreyi) * Chlamydia (Chlamydia trachomatis) * Granuloma inguinale or (Klebsiella granulomatis)   Gonorrhea (Neisseria gonorrhoeae) Syphilis (Treponema pallidum) Fungal * Tinea cruris jock itch maybe sexually transmitted * Candidiasis or yeast Infection Viral Micrograph showing the viral cytopathic effect of herpes (ground glass nuclear inclusions, multi-nucleation). Pap test. Pap stain. * Viral hepatitis (Hepatitis B virus)—saliva, venereal fluids. (Note: Hepatitis A and Hepatitis E are transmitted via the fecal-oral route; Hepatitis C (liver cancer) is rarely sexually transmittable, and the route of transmission of Hepatitis D (only if infected with B) is uncertain, but may include sexual transmission. * Herpes simplex (Herpes simplex virus 1, 2) skin and mucosal, transmissible with or without visible blisters * HIV/ AIDS (Human Immunodeficiency Virus)— venereal fluids * HPV (Human Papilloma Virus)— skin and mucosal contact. High risk types of HPV are known to cause most types of cervical cancer, as well as anal, penile, and vulvar cancer, and genital w arts. * Molluscum contagiosum (molluscum contagiosum virus MCV)—close contact Parasites * Crab louse, colloquially known as crabs (Phthirius pubis) * Scabies (Sarcoptes scabiei) Protozoal * Trichomoniasis (Trichomonas vaginalis) Sexually transmitted enteric infections Various bacterial (Shigella, Campylobacter, or Salmonella), viral (Hepatitis A, Adenoviruses), or parasitic (Giardia or amoeba) pathogens are transmitted by sexual practices that promote anal-oral contamination (fecal-oral). Sharing sex toys without washing or multiple partnered barebacking can promote anal-anal contamination. Although the bacterial pathogens may coexist with or cause proctitis, they usually produce symptoms (diarrhea, fever, bloating, nausea, and abdominal pain) suggesting disease more proximal in the GI tract. Pathophysiology Many STDs are (more easily) transmitted through the mucous membranes of the penis, vulva, rectum, urinary tract and (less often—depending on type of infection)[citation needed] the mouth, throat, respiratory tract and eyes. The visible membrane covering the head of the penis is a mucous membrane, though it produces no mucus (similar to the lips of the mouth). Mucous membranes differ from skin in that they allow certain pathogens into the body Pathogens are also able to pass through breaks or abrasions of the skin, even minute ones. The shaft of the penis is particularly susceptible due to the friction caused during penetrative sex. The primary sources of infection in ascending order are venereal fluids, saliva, mucosal or skin (particularly the penis), infections may also be transmitted from feces, urine and sweat. The amount required to cause infection varies with each pathogen but is always less than you can see with the naked eye. This is one reason that the probability of transmitting many infections is far higher from sex than by more casual means of transmission, such as non-sexual contact—touching, hugging, shaking hands—but it is not the only reason. Although mucous membranes exist in the mouth as in the genitals, many STIs seem to be easier to transmit through oral sex than through deep kissing. According to a safe sex chart, many infections that are easily transmitted from the mouth to the genitals or from the genitals to the mouth, are much harder to transmit from one mouth to another With HIV, genital fluids happen to contain much more of the pathogen than saliva. Some infections labeled as STIs can be transmitted by direct skin contact. Herpes simplex and HPV are both examples. KSHV, on the other hand, may be transmitted by deep-kissing but also when saliva is used as a sexual lubricant. Depending on the STD, a person may still be able to spread the infection if no signs of disease are present. For example, a person is much more likely to spread herpes infection when blisters are present (STD) than when they are absent (STI). However, a person can spread HIV infection (STI) at any time, even if he/she has not developed symptoms of AIDS (STD). All sexual behaviors that involve contact with the bodily fluids of another person should be considered to contain some risk of transmission of sexually transmitted diseases. Most attention has focused on controlling HIV, which causes AIDS, but each STD presents a different situation. As may be noted from the name, sexually transmitted diseases are transmitted from one person to another by certain sexual activities rather than being actually caused by those sexual activities. Bacteria, fungi, protozoa or viruses are still the causative agents. It is not possible to catch any sexually transmitted disease from a sexual activity with a person who is not carrying a disease; conversely, a person who has an STD got it from contact (sexual or otherwise) with someone who had it, or his/her bodily fluids. Some STDs such as HIV can be transmitted from mother to child either during pregnancy or breastfeeding. Although the likelihood of transmitting various diseases by various sexual activities varies a great deal, in general, all sexual activities between two (or more) people should be considered as being a two-way route for the transmission of STDs, i. e. , giving or receiving are both risky although receiving carries a higher risk. Healthcare professionals suggest safer sex, such as the use of condoms, as the most reliable way of decreasing the risk of contracting sexually transmitted diseases during sexual activity, but safer sex should by no means be considered an absolute safeguard. The transfer of and exposure to bodily fluids, such as blood transfusions and other blood products, sharing injection needles, needle-stick injuries (when medical staff are inadvertently jabbed or pricked with needles during medical procedures), sharing tattoo needles, and childbirth are other avenues of transmission. These different means put certain groups, such as medical workers, and haemophiliacs and drug users, particularly at risk. Recent epidemiological studies have investigated the networks that are defined by sexual relationships between individuals, and discovered that the properties of sexual networks are crucial to the spread of sexually transmitted diseases. In particular, assortative mixing between people with large numbers of sexual partners seems to be an important factor. It is possible to be an asymptomatic carrier of sexually transmitted diseases. In particular, sexually transmitted diseases in women often cause the serious condition of pelvic inflammatory disease. Prevention Main article: Safe sex Prevention is key in addressing incurable STIs, such as HIV amp; herpes. The most effective way to prevent sexual transmission of STIs is to avoid contact of body parts or fluids which can lead to transfer with an infected partner. No contact minimizes risk. Not all sexual activities involve contact: cybersex, phonesex or masturbation from a distance are methods of avoiding contact. Proper use of condoms reduces contact and risk. Ideally, both partners should get tested for STIs before initiating sexual contact, or before resuming contact if a partner engaged in contact with someone else. Many infections are not detectable immediately after exposure, so enough time must be allowed between possible exposures and testing for the tests to be accurate. Certain STIs, particularly certain persistent viruses like HPV, may be impossible to detect with current medical procedures. Many diseases that establish permanent infections can so occupy the immune system that other diseases become more easily transmitted. The innate immune system led by defensins against HIV can prevent transmission of HIV when viral counts are very low, but if busy with other viruses or overwhelmed, HIV can establish itself. Certain viral STIs also greatly increase the risk of death for HIV infected patients. Vaccines Vaccines are available that protect against some viral STIs, such as Hepatitis B and some types of HPV. Vaccination before initiation of sexual contact is advised to assure maximal protection. Condoms Condoms only provide protection when used properly as a barrier, and only to and from the area that it covers. Uncovered areas are still susceptible to many STDs. In the case of HIV, sexual transmission routes almost always involve the penis, as HIV cannot spread through unbroken skin, thus properly shielding the insertive penis with a properly worn condom from the vagina and anus effectively stops HIV transmission. An infected fluid to broken skin borne direct transmission of HIV would not be considered sexually transmitted, but can still theoretically occur during sexual contact, this can be avoided simply by not engaging in sexual contact when having open bleeding wounds. Other STDs, even viral infections, can be prevented with the use of latex condoms as a barrier. Some microorganisms and viruses are small enough to pass through the pores in natural skin condoms, but are still too large to pass through latex condoms. Proper usage entails: * Not putting the condom on too tight at the end, and leaving 1. 5  cm (3/4  inch) room at the tip for ejaculation. Putting the condom on snug can and often does lead to failure. * Wearing a condom too loose can defeat the barrier. * Avoiding inverting, spilling a condom once worn, whether it has ejaculate in it or not, even for a second. Avoiding condoms made of substances other than latex or polyurethane, as they dont protect against HIV. * Avoiding the use of oil based lubricants (or anything with oil in it) with latex condoms, as oil can eat holes into them. * Using flavored condoms for oral sex only, as the sugar in the flavoring can lead to yeast infections if used to penetrate. Not following the first fiv e guidelines above perpetuates the common misconception that condoms arent tested or designed properly. In order to best protect oneself and the partner from STIs, the old condom and its contents should be assumed to be still infectious. Therefore the old condom must be properly disposed of. A new condom should be used for each act of intercourse, as multiple usage increases the chance of breakage, defeating the primary purpose as a barrier. Nonoxynol-9 Nonoxynol-9 a vaginal microbicide was hoped to decrease STD rates. Trials however have found it ineffective. Diagnosis STI tests may test for a single infection, or consist of a number of individual tests for any of a wide range of STIs, including tests for syphilis, trichomonas, gonorrhea, chlamydia, herpes, hepatitis and HIV tests. No procedure tests for all infectious agents. STI tests may be used for a number of reasons: * as a diagnostic test to determine the cause of symptoms or illness * as a screening test to detect asymptomatic or presymptomatic infections * as a check that prospective sexual partners are free of disease before they engage in sex without safer sex precautions (for example, in fluid bonding, or for procreation). * as a check prior to or during pregnancy, to prevent harm to the baby * as a check after birth, to check that the baby has not caught an STI from the mother * to prevent the use of infected donated blood or organs as part of the process of contact tracing from a known infected individual * as part of mass epidemiological surveillance Not all STIs are symptomatic, and symptoms may not appear immediately after infection. In some instances a disease can be carried with no symptoms, which leaves a greater risk of passing the disease on to others. Depending on the disease, some untreated STIs can lead to infertility, chronic pain or even death. Early identification and treatment results in less chance to spread disease, and for some conditions may improve the outcomes of treatment. There is often a window period after initial infection during which an STI test will be negative. During this period the infection may be transmissible. The duration of this period varies depending on the infection and the test. Treatment High risk exposure such as what occurs in rape cases may be treated prophylacticly using antibiotic combinations such as azithromycin, cefixime, and metronidazole. An option for treating partners of patients (index cases) diagnosed with chlamydia or gonorrhea is patient-delivered partner therapy (PDT or PDPT), which is the clinical practice of treating the sex partners of index cases by providing prescriptions or medications to the patient to take to his/her partner without the health care provider first examining the partner. History Prior to the invention of modern medicines, sexually transmitted diseases were generally incurable, and treatment was limited to treating the symptoms of the disease. The first voluntary hospital for venereal diseases was founded in 1746 at London Lock Hospital. Treatment was not always voluntary: in the second half of the 19th century, the Contagious Diseases Act was used to arrest suspected prostitutes. The first effective treatment for a sexually transmitted disease was salvarsan, a treatment for syphilis. With the discovery of antibiotics, a large number of sexually transmitted diseases became easily curable, and this, combined with effective public health campaigns against STDs, led to a public perception during the 1960s and 1970s that they have ceased to be a serious medical threat. During this period, the importance of contact tracing in treating STIs was recognized. By tracing the sexual partners of infected individuals, testing them for infection, treating the infected and tracing their contacts in turn, STI clinics could be very effective at suppressing infections in the general population. In the 1980s, first genital herpes and then AIDS emerged into the public consciousness as sexually transmitted diseases that could not be cured by modern medicine. AIDS in particular has a long asymptomatic period—during which time HIV (the human immunodeficiency virus, which causes AIDS) can replicate and the disease can be transmitted to others—followed by a symptomatic period, which leads rapidly to death unless treated. Recognition that AIDS threatened a global pandemic led to public information campaigns and the development of treatments that allow AIDS to be managed by suppressing the replication of HIV for as long as possible. Contact tracing continues to be an important measure, even when diseases are incurable, as it helps to contain infection. ACQUIRED IMMUNO-DEFICIENCY SYNDROME (AIDS) Acquired immunodeficiency syndrome (AIDS)| Classification and external resources| The Red ribbon is a symbol for solidarity with HIV-positive people and those living with AIDS. | ICD-10| B24. | ICD-9| 042| DiseasesDB| 5938| MedlinePlus| 000594| eMedicine| emerg/253| MeSH| D000163| List of abbreviations used in this articleAIDS: Acquired immune deficiency syndrome HIV: Human immunodeficiency virus CD4+: CD4+ T helper cells CCR5: Chemokine (C-C motif) receptor 5 CDC: Centers for Disease Control and Prevention WHO: World Health Organization PCP: Pneumocystis pneumonia TB: Tuberculosis MTCT: Mother-to-child transmission HAART: Highly active antiretroviral therapy STI/STD: Sexually transmitted infection/disease| Acquired immune deficiency syndrome or acquired immunodeficiency syndrome (AIDS) is a disease of the human immune system caused by the human immunodeficiency virus (HIV). This condition progressively reduces the effectiveness of the immune system and leaves individuals susceptible to opportunistic infections and tumors. HIV is transmitted through direct contact of a mucous membrane or the bloodstream with a bodily fluid containing HIV, such as blood, semen, vaginal fluid, preseminal fluid, and breast milk. This transmission can involve anal, vaginal or oral sex, blood transfusion, contaminated hypodermic needles, exchange between mother and baby during pregnancy, childbirth, breastfeeding or other exposure to one of the above bodily fluids. AIDS is now a pandemic. In 2007, it was estimated that 33. 2  million people lived with the disease worldwide, and that AIDS killed an estimated 2.   million people, including 330,000 children. [ Over three-quarters of these deaths occurred in sub-Saharan Africa, retarding economic growth and destroying human capital. Genetic research indicates that HIV originated in west-central Africa during the late nineteenth or early twentieth century AIDS was first recognized by the U. S. Centers for Disease Control and Prevention in 1981 and its cause, HIV, identified in the early 1980s Although treatments for AIDS and HIV can slow the course of the disease, there is currently no vaccine or cure. Antiretroviral treatment reduces both the mortality and the morbidity of HIV infection, but these drugs are expensive and routine access to antiretroviral medication is not available in all countries. Due to the difficulty in treating HIV infection, preventing infection is a key aim in controlling the AIDS pandemic, with health organizations promoting safe sex and needle-exchange programmes in attempts to slow the spread of the virus. Main symptoms of AIDS. The symptoms of AIDS are primarily the result of conditions that do not normally develop in individuals with healthy immune systems. Most of these conditions are infections caused by bacteria, viruses, fungi and parasites that are normally controlled by the elements of the immune system that HIV damages. Opportunistic infections are common in people with AIDS. These infections affect nearly every organ system. People with AIDS also have an increased risk of developing various cancers such as Kaposis sarcoma, cervical cancer and cancers of the immune system known as lymphomas. Additionally, people with AIDS often have systemic symptoms of infection like fevers, sweats (particularly at night), swollen glands, chills, weakness, and weight loss. 14][15] The specific opportunistic infections that AIDS patients develop depend in part on the prevalence of these infections in the geographic area in which the patient lives. Pulmonary infections Pneumocystis pneumonia (originally known as Pneumocystis carinii pneumonia, and still abbreviated as PCP, which now stands for Pneumocystis pneumonia) is relatively rare in healthy, immunocompetent people, but common among HIV-infected individuals. It is caused by Pneumocystis jirovecii. Before the advent of effective diagnosis, treatment and routine prophylaxis in Western countries, it was a common immediate cause of death. In developing countries, it is still one of the first indications of AIDS in untested individuals, although it does not generally occur unless the CD4 count is less than 200 cells per  µL of blood. Tuberculosis (TB) is unique among infections associated with HIV because it is transmissible to immunocompetent people via the respiratory route, is not easily treatable once identified, Multidrug resistance is a serious problem. Tuberculosis with HIV co-infection (TB/HIV) is a major world health problem according to the World Health Organization: in 2007, 456,000 deaths among incident TB cases were HIV-positive, a third of all TB deaths and nearly a quarter of the estimated 2 million HIV deaths in that year Even though its incidence has declined because of the use of directly observed therapy and other improved practices in Western countries, this is not the case in developing countries where HIV is most prevalent. In early-stage HIV infection (CD4 count gt;300 cells per  µL), TB typically presents as a pulmonary disease. In advanced HIV infection, TB often presents atypically with extrapulmonary (systemic) disease a common feature. Symptoms are usually constitutional and are not localized to one particular site, often affecting bone marrow, bone, urinary and gastrointestinal tracts, liver, regional lymph nodes, and the central nervous system Gastrointestinal infections Esophagitis is an inflammation of the lining of the lower end of the esophagus (gullet or swallowing tube leading to the stomach). In HIV infected individuals, this is normally due to fungal (candidiasis) or viral (herpes simplex-1 or cytomegalovirus) infections. In rare cases, it could be due to mycobacteria. [20] Unexplained chronic diarrhea in HIV infection is due to many possible causes, including common bacterial (Salmonella, Shigella, Listeria or Campylobacter) and parasitic infections; and uncommon opportunistic infections such as cryptosporidiosis, microsporidiosis, Mycobacterium avium complex (MAC) and viruses,[21] astrovirus, adenovirus, rotavirus and cytomegalovirus, (the latter as a course of colitis). In some cases, diarrhea may be a side effect of several drugs used to treat HIV, or it may simply accompany HIV infection, particularly during primary HIV infection. It may also be a side effect of antibiotics used to treat bacterial causes of diarrhea (common for Clostridium difficile). In the later stages of HIV infection, diarrhea is thought to be a reflection of changes in the way the intestinal tract absorbs nutrients, and may be an important component of HIV-related wasting Neurological and psychiatric involvement HIV infection may lead to a variety of neuropsychiatric sequelae, either by infection of the now susceptible nervous system by organisms, or as a direct consequence of the illness itself. Toxoplasmosis is a disease caused by the single-celled parasite called Toxoplasma gondii; it usually infects the brain, causing toxoplasma encephalitis, but it can also infect and cause disease in the eyes and lungs. Cryptococcal meningitis is an infection of the meninx (the membrane covering the brain and spinal cord) by the fungus Cryptococcus neoformans. It can cause fevers, headache, fatigue, nausea, and vomiting. Patients may also develop seizures and confusion; left untreated, it can be lethal. Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease, in which the gradual destruction of the myelin sheath covering the axons of nerve cells impairs the transmission of nerve impulses. It is caused by a virus called JC virus which occurs in 70% of the population in latent form, causing disease only when the immune system has been severely weakened, as is the case for AIDS patients. It progresses rapidly, usually causing death within months of diagnosis. AIDS dementia complex (ADC) is a metabolic encephalopathy induced by HIV infection and fueled by immune activation of HIV infected brain macrophages and microglia. These cells are productively infected by HIV and secrete neurotoxins of both host and viral origin Specific neurological impairments are manifested by cognitive, behavioral, and motor abnormalities that occur after years of HIV infection and are associated with low CD4+ T cell levels and high plasma viral loads. Prevalence is 10–20% in Western countries but only 1–2% of HIV infections in India. This difference is possibly due to the HIV subtype in India. AIDS related mania is sometimes seen in patients with advanced HIV illness; it presents with more irritability and cognitive impairment and less euphoria than a manic episode associated with true bipolar disorder. Unlike the latter condition, it may have a more chronic course. This syndrome is less often seen with the advent of multi-drug therapy. Tumors and malignancies Kaposis sarcoma Patients with HIV infection have substantially increased incidence of several cancers. This is primarily due to co-infection with an oncogenic DNA virus, especially Epstein-Barr virus (EBV), Kaposis sarcoma-associated herpesvirus (KSHV) (also known as human herpesvirus-8 [HHV-8]), and human papillomavirus (HPV). Kaposis sarcoma (KS) is the most common tumor in HIV-infected patients. The appearance of this tumor in young homosexual men in 1981 was one of the first signals of the AIDS epidemic. Caused by a gammaherpes virus called Kaposis sarcoma-associated herpes virus (KSHV), it often appears as purplish nodules on the skin, but can affect other organs, especially the mouth, gastrointestinal tract, and lungs. High-grade B cell lymphomas such as Burkitts lymphoma, Burkitts-like lymphoma, diffuse large B-cell lymphoma (DLBCL), and primary central nervous system lymphoma present more often in HIV-infected patients. These particular cancers often foreshadow a poor prognosis. Epstein-Barr virus (EBV) or KSHV cause many of these lymphomas. In HIV-infected patients, lymphoma often arises in extranodal sites such as the gastrointestinal tract. When they occur in an HIV-infected patient, KS and aggressive B cell lymphomas confer a diagnosis of AIDS. Invasive cervical cancer in HIV-infected women is also considered AIDS-defining. It is caused by human papillomavirus (HPV). In addition to the AIDS-defining tumors listed above, HIV-infected patients are at increased risk of certain other tumors, notably Hodgkins disease, anal and rectal carcinomas, hepatocellular carcinomas, head and neck cancers, and lung cancer. Some of these are causes by viruses, such as Hodgkins disease (EBV), anal/rectal cancers (HPV), head and neck cancers (HPV), and hepatocellular carcinoma (hepatitis B or C). Other contributing factors include exposure to carcinogens (cigarette smoke for lung cancer), or living for years with subtle immune defects. Interestingly, the incidence of many common tumors, such as breast cancer or colon cancer, does not increase in HIV-infected patients. In areas where HAART is extensively used to treat AIDS, the incidence of many AIDS-related malignancies has decreased, but at the same time malignant cancers overall have become the most common cause of death of HIV-infected patients. In recent years, an increasing proportion of these deaths have been from non-AIDS-defining cancers. Other infections AIDS patients often develop opportunistic infections that present with non-specific symptoms, especially low-grade fevers and weight loss. These include opportunistic infection with Mycobacterium avium-intracellulare and cytomegalovirus (CMV). CMV can cause colitis, as described above, and CMV retinitis can cause blindness. Penicilliosis due to Penicillium marneffei is now the third most common opportunistic infection (after extrapulmonary tuberculosis and cryptococcosis) in HIV-positive individuals within the endemic area of Southeast Asia. An infection that often goes unrecognized in AIDS patients is Parvovirus B19. Its main consequence is anemia, which is difficult to distinguish from the effects of antiretroviral drugs used to treat AIDS itself. [ Cause For more details on this topic, see HIV. Scanning electron micrograph of HIV-1, colored green, budding from a cultured lymphocyte. A generalized graph of the relationship between HIV copies (viral load) and CD4 counts over the average course of untreated HIV infection; any particular individuals disease course may vary considerably. CD4+ T Lymphocyte count (cells/mm? )   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   HIV RNA copies per mL of plasma AIDS is the most severe acceleration of infection with HIV. HIV is a retrovirus that primarily infects vital organs of the human immune system such as CD4+ T cells (a subset of T cells), macrophages and dendritic cells. It directly and indirectly destroys CD4+ T cells. Once HIV has killed so many CD4+ T cells that there are fewer than 200 of these cells per microliter ( µL) of blood, cellular immunity is lost. Acute HIV infection progresses over time to clinical latent HIV infection and then to early symptomatic HIV infection and later to AIDS, which is identified either on the basis of the amount of CD4+ T cells remaining in the blood, and/or the presence of certain infections, as noted above. In the absence of antiretroviral therapy, the median time of progression from HIV infection to AIDS is nine to ten years, and the median survival time after developing AIDS is only 9. 2 months. [] However, the rate of clinical disease progression varies widely between individuals, from two weeks up to 20  years. Many factors affect the rate of progression. These include factors that influence the bodys ability to defend against HIV such as the infected persons general immune function. Older people have weaker immune systems, and therefore have a greater risk of rapid disease progression than younger people. Poor access to health care and the existence of coexisting infections such as tuberculosis also may predispose people to faster disease progression. The infected persons genetic inheritance plays an important role and some people are resistant to certain strains of HIV. An example of this is people with the homozygous CCR5-? 2 variation are resistant to infection with certain strains of HIV. [] HIV is genetically variable and exists as different strains, which cause different rates of clinical disease progression. Sexual transmission Sexual transmission occurs with the contact between sexual secretions of one person with the rectal, genital or oral mucous membranes of another. Unprotected sexual acts are riskier for the receptive partner than for the insertive partner, and the risk for transmitting HIV through unprotected anal intercourse is greater than the risk from vaginal intercourse or oral sex. However, oral sex is not entirely safe, as HIV can be transmitted through both insertive and receptive oral sex. Sexual assault greatly increases the risk of HIV transmission as condoms are rarely employed and physical trauma to the vagina or rectum occurs frequently, facilitating the transmission of HIV. Other sexually transmitted infections (STI) increase the risk of HIV transmission and infection, because they cause the disruption of the normal epithelial barrier by genital ulceration and/or microulceration; and by accumulation of pools of HIV-susceptible or HIV-infected cells (lymphocytes and macrophages) in semen and vaginal secretions. Epidemiological studies from sub-Saharan Africa, Europe and North America suggest that genital ulcers, such as those caused by syphilis and/or chancroid, increase the risk of becoming infected with HIV by about fourfold. There is also a significant although lesser increase in risk from STIs such as gonorrhea, chlamydia and trichomoniasis, which all cause local accumulations of lymphocytes and macrophages. Transmission of HIV depends on the infectiousness of the index case and the susceptibility of the uninfected partner. Infectivity seems to vary during the course of illness and is not constant between individuals. An undetectable plasma viral load does not necessarily indicate a low viral load in the seminal liquid or genital secretions. However, each 10-fold increase in the level of HIV in the blood is associated with an 81% increased rate of HIV transmission. Women are more susceptible to HIV-1 infection due to hormonal changes, vaginal microbial ecology and physiology, and a higher prevalence of sexually transmitted diseases. People who have been infected with one strain of HIV can still be infected later on in their lives by other, more virulent strains. Infection is unlikely in a single encounter. High rates of infection have been linked to a pattern of overlapping long-term sexual relationships. This allows the virus to quickly spread to multiple partners who in turn infect their partners. A pattern of serial monogamy or occasional casual encounters is associated with lower rates of infection. HIV spreads readily through heterosexual sex in Africa, but less so elsewhere. One possibility being researched is that schistosomiasis, which affects up to 50% of women in parts of Africa, damages the lining of the vagina. Exposure to blood-borne pathogens CDC poster from 1989 highlighting the threat of AIDS associated with drug use This transmission route is particularly relevant to intravenous drug users, hemophiliacs and recipients of blood transfusions and blood products. Sharing and reusing syringes contaminated with HIV-infected blood represents a major risk for infection with HIV. Needle sharing is the cause of one third of all new HIV-infections in North America, China, and Eastern Europe. The risk of being infected with HIV from a single prick with a needle that has been used on an HIV-infected person is thought to be about 1 in 150 (see table above). Post-exposure prophylaxis with anti-HIV drugs can further reduce this risk. This route can also affect people who give and receive tattoos and piercings. Universal precautions are frequently not followed in both sub-Saharan Africa and much of Asia because of both a shortage of supplies and inadequate training. The WHO estimates that approximately 2. 5% of all HIV infections in sub-Saharan Africa are transmitted through unsafe healthcare injections. Because of this, the United Nations General Assembly has urged the nations of the world to implement precautions to prevent HIV transmission by health workers. The risk of transmitting HIV to blood transfusion recipients is extremely low in developed countries where improved donor selection and HIV screening is performed. However, according to the WHO, the overwhelming majority of the worlds population does not have access to safe blood and between 5% and 10% of the worlds HIV infections come from transfusion of infected blood and blood products. Perinatal transmission The transmission of the virus from the mother to the child can occur in utero during the last weeks of pregnancy and at childbirth. In the absence of treatment, the transmission rate between a mother and her child during pregnancy, labor and delivery is 25%. However, when the mother takes antiretroviral therapy and gives birth by caesarean section, the rate of transmission is just 1%. The risk of infection is influenced by the viral load of the mother at birth, with the higher the viral load, the higher the risk. Breastfeeding also increases the risk of transmission by about 4  %. Misconceptions Main article: HIV and AIDS misconceptions A number of misconceptions have arisen surrounding HIV/AIDS. Three of the most common are that AIDS can spread through casual contact, that sexual intercourse with a virgin will cure AIDS, and that HIV can infect only homosexual men and drug users. Other misconceptions are that any act of anal intercourse between gay men can lead to AIDS infection, and that open discussion of homosexuality and HIV in schools will lead to increased rates of homosexuality and AIDS. Pathophysiology | This section may require cleanup to meet Wikipedias quality standards. Please improve this section if you can. April 2008)| The pathophysiology of AIDS is complex, as is the case with all syndromes. [64] Ultimately, HIV causes AIDS by depleting CD4+ T helper lymphocytes. This weakens the immune system and allows opportunistic infections. T lymphocytes are essential to the immune response and without them, the body cannot fight infections or kill cancerous cells. The mechanism of CD4+ T cell depletion differs in the acute and chronic phases. [ During the acute phase, HIV-induced cell lysis and killing of infected cells by cytotoxic T cells accounts for CD4+ T cell depletion, although apoptosis may also be a factor. During the chronic phase, the consequences of generalized immune activation coupled with the gradual loss of the ability of the immune system to generate new T cells appear to account for the slow decline in CD4+ T cell numbers. Although the symptoms of immune deficiency characteristic of AIDS do not appear for years after a person is infected, the bulk of CD4+ T cell loss occurs during the first weeks of infection, especially in the intestinal mucosa, which harbors the majority of the lymphocytes found in the body. The reason for the preferential loss of mucosal CD4+ T cells is that a majority of mucosal CD4+ T cells express the CCR5 coreceptor, whereas a small fraction of CD4+ T cells in the bloodstream do so. ] HIV seeks out and destroys CCR5 expressing CD4+ cells during acute infection. A vigorous immune response eventually controls the infection and initiates the clinically latent phase. However, CD4+ T cells in mucosal tissues remain depleted throughout the infection, although enough remain to initially ward off life-threatening infections. Continuous HIV replication results in a state of generalized immune activation persisting throughout the chronic phase. [ Immune activation, which is reflected by the increased activation state of immune cells and release of proinflammatory cytokines, results from the activity of several HIV gene products and the immune response to ongoing HIV replication. Another cause is the breakdown of the immune surveillance system of the mucosal barrier caused by the depletion of mucosal CD4+ T cells during the acute phase of disease. This results in the systemic exposure of the immune system to microbial components of the gut’s normal flora, which in a healthy person is kept in check by the mucosal immune system. The activation and proliferation of T cells that results from immune activation provides fresh targets for HIV infection. However, direct killing by HIV alone cannot account for the observed depletion of CD4+ T cells since only 0. 01–0. 10% of CD4+ T cells in the blood are infected. A major cause of CD4+ T cell loss appears to result from their heightened susceptibility to apoptosis when the immune system remains activated. Although new T cells are continuously produced by the thymus to replace the ones lost, the regenerative capacity of the thymus is slowly destroyed by direct infection of its thymocytes by HIV. Eventually, the minimal number of CD4+ T cells necessary to maintain a sufficient immune response is lost, leading to AIDS Cells affected The virus, entering through which ever route, acts primarily on the following cells: * Lymphoreticular system: * CD4+ T-Helper cells * Macrophages * Monocytes * B-lymphocytes * Certain endothelial cells * Central nervous system: Microglia of the nervous system * Astrocytes * Oligodendrocytes * Neurones – indirectly by the action of cytokines and the gp-120 The effect The virus has cytopathic effects but how it does it is still not quite clear. It can remain inactive in these cells for long periods, though. This effect is hypothesized to be due to the CD4-gp120 interaction. [70] * The most prominent effect of HIV is its T-helper cell suppression and lys is. The cell is simply killed off or deranged to the point of being function-less (they do not respond to foreign antigens). The infected B-cells can not produce enough antibodies either. Thus the immune system collapses leading to the familiar AIDS complications, like infections and neoplasms (vide supra). * Infection of the cells of the CNS cause acute aseptic meningitis, subacute encephalitis, vacuolar myelopathy and peripheral neuropathy. Later it leads to even AIDS dementia complex. * The CD4-gp120 interaction (see above) is also permissive to other viruses like Cytomegalovirus, Hepatitis virus, Herpes simplex virus, etc. These viruses lead to further cell damage i. e. cytopathy. Molecular basis For details, see: * Structure and genome of HIV * HIV replication cycle * HIV tropism Diagnosis The diagnosis of AIDS in a person infected with HIV is based on the presence of certain signs or symptoms. Since June 5, 1981, many definitions have been developed for epidemiological surveillance such as the Bangui definition and the 1994 expanded World Health Organization AIDS case definition. However, clinical staging of patients was not an intended use for these systems as they are neither sensitive, nor specific. In developing countries, the World Health Organization staging system for HIV infection and disease, using clinical and laboratory data, is used and in developed countries, the Centers for Disease Control (CDC) Classification System is used. WHO disease staging system Main article: WHO Disease Staging System for HIV Infection and Disease In 1990, the World Health Organization (WHO) grouped these infections and conditions together by introducing a staging system for patients infected with HIV-1. An update took place in September 2005. Most of these conditions are opportunistic infections that are easily treatable in healthy people. Stage I: HIV infection is asymptomatic and not categorized as AIDS * Stage II: includes minor mucocutaneous manifestations and recurrent upper respiratory tract infections * Stage III: includes unexplained chronic diarrhea for longer than a month, severe bacterial infections and pulmonary tuberculosis * Stage IV: includes toxoplasmosis of the brain, candidiasis of the esophagus, trachea, bro nchi or lungs and Kaposis sarcoma; these diseases are indicators of AIDS. CDC classification system Main article: CDC Classification System for HIV Infection There are two main definitions for AIDS, both produced by the Centers for Disease Control and Prevention (CDC). The older definition is to referring to AIDS using the diseases that were associated with it, for example, lymphadenopathy, the disease after which the discoverers of HIV originally named the virus. In 1993, the CDC expanded their definition of AIDS to include all HIV positive people with a CD4+ T cell count below 200 per  µL of blood or 14% of all lymphocytes. The majority of new AIDS cases in developed countries use either this definition or the pre-1993 CDC definition. The AIDS diagnosis still stands even if, after treatment, the CD4+ T cell count rises to above 200 per  µL of blood or other AIDS-defining illnesses are cured. HIV test Main article: HIV test Many people are unaware that they are infected with HIV. Less than 1% of the sexually active urban population in Africa has been tested, and this proportion is even lower in rural populations. Furthermore, only 0. 5% of pregnant women attending urban health facilities are counseled, tested or receive their test results. Again, this proportion is even lower in rural health facilitiesTherefore, donor blood and blood products used in medicine and medical research are screened for HIV. HIV tests are usually performed on venous blood. Many laboratories use fourth generation screening tests which detect anti-HIV antibody (IgG and IgM) and the HIV p24 antigen. The detection of HIV antibody or antigen in a patient previously known to be negative is evidence of HIV infection. Individuals whose first specimen indicates evidence of HIV infection will have a repeat test on a second blood sample to confirm the results. The window period (the time between initial infection and the development of detectable antibodies against the infection) can vary since it can take 3–6  months to seroconvert and to test positive. Detection of the virus using polymerase chain reaction (PCR) during the window period is possible, and evidence suggests that an infection may often be detected earlier than when using a fourth generation EIA screening test. Positive results obtained by PCR are confirmed by antibody tests. [] Routinely used HIV tests for infection in neonates and infants (i. e. patients younger than 2 years), born to HIV-positive mothers, have no value because of the presence of maternal antibody to HIV in the childs blood. HIV infection can only be diagnosed by PCR, testing for HIV pro-viral DNA in the childrens lymphocytes. Prevention Estimated per act risk for acquisition of HIV by exposure route | Exposure Route| Estimated infections per 10,000 exposures to an infected source| Blood Transfusion| 9,000[| Childbirth (to child)| 2,500[| Needle-sharing injection drug use| 67| Percutaneous needle stick| 30| Receptive anal intercourse*| 50| Insertive anal intercourse*| 6. | Receptive penile-vaginal intercourse*| 10| Insertive penile-vaginal intercourse*| 5| Receptive oral intercourse* §| 1| Insertive oral intercourse* §| 0. 5[| * assuming no condom use  § source refers to oral intercourse performed on a man| The three main transmission routes of HIV are sexual contact, exposure to infected body fluids or tissues, and from mother to fetus or child during perinatal period. It is possible to find HIV in the saliva, tears, and urine of infected individuals, but there are no recorded cases of infection b y these secretions, and the risk of infection is negligible. Sexual contact The majority of HIV infections are acquired through unprotected sexual relations between partners, one of whom has HIV. The primary mode of HIV infection worldwide is through sexual contact between members of the opposite sex. During a sexual act, only male or female condoms can reduce the risk of infection with HIV and other STDs. The best evidence to date indicates that typical condom use reduces the risk of heterosexual HIV transmission by approximately 80% over the long-term, though the benefit is likely to be higher if condoms are used correctly on every occasion. The male latex condom, if used correctly without oil-based lubricants, is the single most effective available technology to reduce the sexual transmission of HIV and other sexually transmitted infections. Manufacturers recommend that oil-based lubricants such as petroleum jelly, butter, and lard not be used with latex condoms, because they dissolve the latex, making the condoms porous. If lubrication is desired, manufacturers recommend using water-based lubricants. Oil-based lubricants can be used with polyurethane condoms. Female condoms are commonly made from polyurethane, but are also made from nitrile and latex. They are larger than male condoms and have a stiffened ring-shaped opening with an inner ring designed to be inserted into the vagina keeping the condom in place; inserting the female condom requires squeezing this ring. Female condoms have been shown to be an important HIV prevention strategy by preliminary studies which suggest that overall protected sexual acts increase relative to unprotected sexual acts where female condoms are available. At present, availability of female condoms is very low and the price remains prohibitive for many women. Studies on couples where one partner is infected show that with consistent condom use, HIV infection rates for the uninfected partner are below 1% per year. Prevention strategies are well-known in developed countries, but epidemiological and behavioral studies in Europe and North America suggest that a substantial minority of young people continue to engage in high-risk practices despite HIV/AIDS knowledge, underestimating their own risk of becoming infected with HIV. Randomized controlled trials have shown that male circumcision lowers the risk of HIV infection among heterosexual men by up to 60%. It is expected that this procedure will be actively promoted in many of the countries affected by HIV, although doing so will involve confronting a number of practical, cultural and attitudinal issues. However, programs to encourage condom use, including providing them free to those in poverty, are estimated to be 95 times more cost effective than circumcision at reducing the rate of HIV in sub-Saharan Africa. Some experts fear that a lower perception of vulnerability among circumcised men may result in more sexual risk-taking behavior, thus negating its preventive effects. However, one randomized controlled trial indicated that adult male circumcision was not associated with increased HIV risk behavior. Studies of HIV infection rates among women who have undergone female genital cutting (FGC) have reported mixed results; for details see Female genital cutting#HIV. Exposure to infected body fluids Health care workers can reduce exposure to HIV by employing precautions to reduce the risk of exposure to contaminated blood. These precautions include barriers such as gloves, masks, protective eyeware or shields, and gowns or aprons which prevent exposure of the skin or mucous membranes to blood borne pathogens. Frequent and thorough washing of the skin immediately after being contaminated with blood or other bodily fluids can reduce the chance of infection. Finally, sharp objects like needles, scalpels and glass, are carefully disposed of to prevent needlestick injuries with contaminated items. Since intravenous drug use is an important factor in HIV transmission in developed countries, harm reduction strategies such as needle-exchange programmes are used in attempts to reduce the infections caused by drug abuse. Mother-to-child transmission (MTCT) Current recommendations state that when replacement feeding is acceptable, feasible, affordable, sustainable and safe, HIV-infected mothers should avoid breast-feeding their infant. However, if this is not the case, exclusive breast-feeding is recommended during the first months of life and discontinued as soon as possible. It should be noted that women can breastfeed children who are not their own; see wet nurse. Education, health literacy and cognitive ability The most important way to change risky behavior is health education. Several studies have shown the positive impact of education and health literacy on cautious sex behavior. Education itself does not work, only if it leads to higher health literacy and general cognitive ability. This ability is relevant to understand the relationship between own risky behavior and possible outcomes like HIV-transmission. Treatment See also HIV Treatment and Antiretroviral drug. There is currently no publicly available vaccine for HIV or cure for HIV or AIDS. The only known methods of prevention are based on avoiding exposure to the virus or, failing that, an antiretroviral treatment directly after a highly significant exposure, called post-exposure prophylaxis (PEP). PEP has a very demanding four week schedule of dosage. It also has very unpleasant side effects including diarrhea, malaise, nausea and fatigue. [106] Antiviral therapy Abacavir  Ã¢â‚¬â€œ a nucleoside analog reverse transcriptase inhibitor (NARTI or NRTI) The chemical structure of Abacavir Current treatment for HIV infection consists of highly active antiretroviral therapy, or HAART. This has been highly beneficial to many HIV-infected individuals since its introduction in 1996 when the protease inhibitor-based HAART initially became available. Current optimal HAART options consist of combinations (or cocktails) consisting of at least three drugs belonging to at least two types, or classes, of antiretroviral agents. Typical regimens consist of two nucleoside analogue reverse transcriptase inhibitors (NARTIs or NRTIs) plus either a protease inhibitor or a non-nucleoside reverse transcriptase inhibitor (NNRTI). Because HIV disease progression in children is more rapid than in adults, and laboratory parameters are less predictive of risk for disease progression, particularly for young infants, treatment recommendations are more aggressive for children than for adultsIn developed countries where HAART is available, doctors assess the viral load, CD4 counts, rapidity of CD4 decline and patient readiness while deciding when to recommend initiating treatment Traditionally, treatment has been recommended for otherwise asymptomatic patients when CD4 cell counts fall to 200-250 cells per microliter of blood. However, beginning treatment earlier (at a CD4 level of 350 cells/microliter) may significantly reduce the risk of death Standard goals of HAART include improvement in the patient’s quality of life, reduction in complications, and reduction of HIV viremia below the limit of detection, but it does not cure the patient of HIV nor does it prevent the return, once treatment is stopped, of high blood levels of HIV, often HAART resistant. Moreover, it would take more than the lifetime of an individual to be cleared of HIV infection using HAART. Despite this, many HIV-infected individuals have experienced remarkable improvements in their general health and quality of life, which has led to the plummeting of HIV-associated morbidity and mortality. In the absence of HAART, progression from HIV infection to AIDS occurs at a median of between nine to ten years and the median survival time after developing AIDS is only 9. 2  months. HAART is thought to increase survival time by between 4 and 12  years. For some patients, which can be more than fifty percent of patients, HAART achieves far less than optimal results, due to medication intolerance/side effects, prior ineffective antiretroviral therapy and infection with a drug-resistant strain of HIV. Non-adherence and non-persistence with therapy are the major reasons why some people do not benefit from HAART. The reasons for non-adherence and non-persistence are varied. Major psychosocial issues include poor access to medical care, inadequate social supports, psychiatric disease and drug abuse.