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Infectious Diseases and Public Health: AIDS/HIV

Abstract:
Human immunodeficiency virus infection causes Acquired immunodeficiency syndrome. The infection was first discovered in US in the year 1980 and currently the country has a high prevalence with 417 HIV positive individuals for every 100,000 people. Social stigma and discrimination against the affected people is an important factor hindering, public health care efforts, in reaching the patience, providing care and preventing the diseases spread. HIV is comparatively easier to control than other air born infectious diseases and can be prevented by taking suitable precautions. Safe and protected sexual practices and disuse of infected needles and blood can help bring down infection rate in US. The future of HIV prevention faces challenges like developing effective drugs and vaccine and want of public and healthcare cooperation to prevent new infection.
Introduction: Acquired immunodeficiency syndrome (AIDS) is a diseases caused by the human immunodeficiency virus (HIV). More than 1.2 million people are infected in US (Cdc.gov, 2015). According to epidemiological reports, the diseases were first discovered in Los Angeles among 5 homosexual males (Week &Alcamo, 2010). In 1982, the clinical criteria for confirming an AIDS diagnosis were formulated. The common finding in this disease is a general collapse of the patient’s immune system, making him/her susceptible to all kind opportunistic infection. Five years from then, 10,000 new cases were reported in the US (Week &Alcamo, 2010). Very soon the US government began to realize that AIDS was becoming an epidemic in the country and the need to stop the epidemic. Huge funds and ambitious initiatives in identifying a cause and effective treatment for this new disease was undertaken by the government and non-government run research labs. Though the virus was identified in 1985, the cure for this disease is absent (Week &Alcamo, 2010).
According to the University of California San Francisco, the current diagnostic criteria for AIDS includes, less than 200 CD4+ T cells per cubic millimeter of blood and presence of one or more diseases from the list of 24 opportunistic infections published by the Centers for Disease Control and Prevention (CDC) (Ucsfhealth.org 2015). Not all the listed opportunistic infection occur in patients and few of them are even rare. The most common infections in AIDS patients are tuberculosis, chlamydial pneumonia, septicemia, toxoplasmosis, cytomegalovirus infection and Kaposi’s sarcoma (Cdc.gov, 2015). A number of tests are now available, to effectively diagnose AIDS and HIV. ELISA test is used to detect the virus in the blood. To accurately confirm a negative test in this method, one needs to repeat the test after a month or two and still remain negative to the test (Ucsfhealth.org 2015). FDA has approved a home test kit, which can be used by the patients themselves to test for the presence of HIV in any body fluid (Ucsfhealth.org 2015). RT-PCR based methods help to determine the viral load in the blood (Ucsfhealth.org 2015). Different clinical course and susceptibility are noticed among people infected with HIV. Not all people with HIV infection develop AIDS. The reason for this is poorly understood. The HLA haplotype of a person is found to affect the course of diseases progression. People with the HLA –B8 haplotype have fast progression of the diseases while people with HLA-B27 have non progressive or slowly progressive diseases.
Human Immunodeficiency Virus (HIV): HIV is a retrovirus (Dalgleish & Weiss, 1999). The virus enters the cell by a series of step which involves- i. interaction of the viral coat protein with the cell surface receptor and entry into virus core particle into host cell, ii. the RNA genome of the virus is then copied by a viral reverse transcriptase to a double stranded DNA, iii. the DNA then enters the nucleus of the cells, where a viral protein called integrase covalently links the viral DNA to cellular DNA creating a provirus (Dalgleish & Weiss, 1999). This provirus is then transcribed and translated by the host cell machinery to give rise to new viral genome and proteins. HIV belongs to the genus Lentivirus. HIV-1 and HIV-2 are reported in human(Crandall, 1999). The virus’s ability to multiple in the cells depend on the both the host and viral molecules (DNA, RNA and protein). CD4+ receptor seen in T lymphocyte, macrophage and dendritic cells help in virus attachment and entry into the cells and hence these cells are main targets for the virus infection (Dalgleish & Weiss, 1999) . Two proteins namely the tat and the rev are very important for the survival of the virus in the cell. tat helps in virus transcription while, rev acts to regulate expression of viral protein (Crandall, 1999). A high level of genetic variability is noticed, since the virus genome was first sequence in 1985. These variations have been the major hindrance for the development of vaccine, and drugs to control AIDS. The highest variation is noticed in the envelop protein namely gag and env. The genetic variability in the patients can also affects the course of diseases. (Crandall, 1999)
Surveillance: According to 2010 CDC estimates, 1.2 billion people above the age of 13 have HIV infection in US. The rate of new infection every year is estimated to be around 50,000. According to the 2008 census data, 417.5/100000 population were diagnosed with HIV. In 2012, 47,989 were diagnosed with HIV infection and 27,928 people were diagnosed with AIDS. The number of people who died with AIDS diagnosis in the year 2011 was 13,834. Southern states in US have the highest infection rate. Washington DC has a very high incidence rate and accounts for 2% of total HIV infection. The other states with notably high incidence include Miami, New Orleans, Baton Rouge, and Jackson, Miss. Women account for 20% of the infection. Blacks make only 12% of the US population, but account for 44% of HIV infection in the country. (Cdc.gov, 2015). Fig1: gives the level of infection among different susceptible groups. Infection rate is high among male homosexual men, followed by heterosexual and injection drug users (Cdc.gov, 2015). Looking at the trend in AIDS; in the 1980’s, the time between infection with HIV and the occurrence of AIDS was predictable; however, this predictability has decreased, since 1996. The main reasons for this being: the availability of active retroviral therapy. Thus it is now difficult to understand people infected, based on the number of AIDS case. HIV surveillance in US faces challenges like; getting people to volunteer to get themselves tested, and reporting the test to the CDC. Serologic testing algorithm for recent HIV seroconversion (STARHS) is a sero-surveillance initiative by the CDC to differentiate new from old HIV infection. Medical monitoring program is a federal government initiative to collect information from HIV patients. NHBS (National HIV Behavioral Surveillance System) program aims to determine the surveillance among high risk population. National HIV Prevention Program Monitoring and Evaluation (NHM&E) is an initiate by the CDC. Under this initiative CDC has allotted fund for research in HIV/AIDS basic research, it prevention and control. The data generated by the CDC is used for activities like decision making, determining policies, evaluating prevention & control activities and in understanding HIV. (Cdc.gov, 2015).
Figure1: Estimated New HIV Infections in the United States, 2010, for the Most Affected Subpopulations (Cdc.gov, 2015)
*Subpopulations representing 2% or less are not reflected in this chart. Abbreviations: MSM, men who have sex with men; IDU, injection drug user.
Prevention and Control HIV/AIDS: The most common route of getting HIV infection is through sexual intercourse via anal or vaginal route. Sharing infected syringes, needles and transfusion of infected blood are the next common mode of transmission. Transmission through these routes put injection drug users, hemophiliacs and transfusions receivers at high risk for getting the infection. Use of condom, safe sex practices and reducing the number of sexual partners can help to reduce majority of the HIV infection. Using single use-disposable syringes needle and thorough screening of blood for HIV can prevent getting infected from health care facilities. A baby can get the infection from its mother during pregnancy and breast feeding. Blood, semen, pre-seminal fluids, rectal fluids and vaginal fluids of the infected patient carry the virus. One of the biggest hindrances in HIV prevention and control is the stigma and discrimination among AIDS patients which prevents them reporting the infection and causing them to spread infection to others either knowingly or unknowingly. HIV does not spread by shaking hands, hugging, and closed-mouth kissing a person infected with HIV. HIV is also not transmitted from contact with objects such as toilet seats, doorknobs, or dishes used by a person infected with HIV. When compared to early days the hope for HIV people has improved. There are currently 20 antiretroviral drugs in the market for HIV. Tenofovir, Lamivudine, Efavirenz are commonly used retroviral drugs for AIDS. These drugs have to be taken at the right dose and at the right time to avoid resistance and for effective cure. When drug resistance is seen to first line of therapy, only then WHO recommend the second line of therapy, which includes nucleoside reverse-transcriptase inhibitors and a ritonavir-boosted protease inhibitor (PI). Ucsfhealth.org, (2015).
HIV Research: National Institute of Allergy and Infectious Diseases is ardently trying to end AIDS and HIV in US. Many laboratories in NIH and supported work at other universities, medical center are trying to understand the diseases better, develop better prevention, therapy and cure. NIAID research is focusing on areas like: the mechanism by which HIV infects the host, developing HIV vaccines, developing preventive medication, developing topical antimicrobicidals for people who could not use condoms, next generation AIDS/HIV treatment, and behavioural intervention among homosexuals and other people who are very sexually active. Basic research has helped us understand a lot of facts about the diseases like the molecular interaction, replication within the host immune cells and immune response to retroviral infections. Basic research is important to understand targets against which therapeutics and vaccines can be developed. We still need to understand a lot on how virus infects the immune system and how to activate the immune system against the virus. (Niaid.nih.gov, 2015) Recently scientists noticed the HIV’s property to compartmentalize in the brain, CSF and genital track. The virus at these site where often unresponsive to retroviral drugs. (T. Blackard, 2012). Currently there is no vaccine in the market that is effective in HIV prevention and or modifying diseases pathogenesis. The national HIV/AIDS strategy (NHAS) was first released by the White house in 2010. These strategies aim to reduce HIV in high risk population and educate all Americans of the HIV/AIDS threat. Many people in the high risk group like male homosexuals, sex workers, drug addicts and minorities belong to the disenfranchised section of the society, with limited access to health care and a weak social support structure. Medicaid, Ryan white program, AIDS drug assistance programme help to fund treatment of uninsured patients. HOPWA (Housing oppourtunity for people with AIDS) is a federal programme taking care of housing needs of AIDS people. It is the responsibility of public health worker to create awareness and support at individual and community level. The HIV care service needs a multidisciplinary approach involving doctors, nurses, psychotherapist, researchers and social workers to be completely effective. (Aids.gov, 2015).
Conclusion: The efforts of the public health department have contributed significantly in preventing the number of new HIV infections in US. Nevertheless, the future of AIDS control in US faces a number of challenges like: handling the newly infected, preventing increase in new infections, reducing cost and toxicity of existing drug, identify vaccine and better therapeutics. The diseases can be effectively controlled if the public join hands with the countries struggle to end AIDS.

References:

1. Aids.gov,. (2015).Treatment and Care Programs. Retrieved 12 January 2015, from https://www.aids.gov/federal-resources/hiv-aids-programs/treatment-and-care-programs/
2. Cdc.gov,.(2015).CDC – HIV in the United States – Statistics Overview – Statistics Center–HIV/AIDS. Retrieved 10 January 2015,from http://www.cdc.gov/hiv/statistics/ basics/ataglance.htmlCDC.
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