HIV (Human Immunodeficiency Virus) & AIDS
AIDS (Acquired Immune Deficiency Syndrome) is caused by the HIV (Human Immunodeficiency Virus) and is the last stage of the infection which causes severe damage to the immune system.
Modes of HIV/AIDS transmission
1.Sexual intercourse: HIV is in the semen and vaginal fluid hence having sex with an infected person is a mode of transmission.
2.Blood transmission: If a drug abuser uses contaminated syringes or needles and inject into themselves or contaminated equipment during piercing and tattooing, they can get infected. Similarly if healthcare workers have a needle stick incidents from an infected person they may contract the disease. Transfusion of contaminated blood products and organs will result in HIV too however it has greatly been reduced as the blood products are regularly screened for such infectious diseases since the 1980s.
3.Mother to child: During pregnancy, due to the shared blood circulation, the infant maybe born with HIV. Also HIV is found in breast milk, if infected mothers breastfeed their child they can transmit the virus to them.
HIV is NOT transmitted by…
HIV is not transmitted by day to day contacts at work, home or social events. HIV is not an airborne or food borne virus and it cannot live for long outside the body.
HIV is NOT transmitted by:
1.Casual hugging, , shaking hands, casual kiss, touching door knobs or items touched by infected person or through pets.
2.Sharing of toilet seats and utensils.
3.Mosquitoes and other insects
4.Participation in any form of sports
5.Sharing of food and dishes. Even if the food is contaminated with mall amount of HIV infected blood/semen fluid and consumed, there is no risk of contracting HIV. This is because HIV virus does not live long outside the body. Exposure to the heat from cooking, the air and the stomach acid would have destroyed the virus. By far, CDC has no reports on HIV infection through consumption of food with contamination.
Clinical signs and symptoms of HIV/AIDS
Patients infected with HIV will eventually develop AIDS. Even when a HIV person has no symptoms, they can transmit the virus to others.
The acute retroviral syndrome is when the patient develops flu-like symptoms after contracting the virus. This acute infection phase may last from 1 to 8 weeks. The will experience fever, sore throat, enlarged lymph nodes and some rash similar to a Flu episode. During this phase, there is high viral load and the patient is highly infectious.
After the acute infection phase, the patients may not have any symptoms for months to ten years. This is called the asymptomatic stage. During this stage, the immune system weakens, the CD$ cell count decreases and the viral load increases. Patients are prone to opportunistic infections.
AIDS: when the immune system is severely damaged to cause opportunistic infections, the person is considered to have AIDS. The CD4 T cell count of less than 200/microlitre is diagnoistic of AIDS. AIDS defining illnesses will be discussed below. As the immune system weakens, patients may experience fatigue, weight loss, chronic diarrhea, anorexia, night sweats, persistent lymph nodes as well as contract infection more easily than normal people.
Common AIDS defining infections/diseases
HIV patients’ immune system weakens with time and subsequently the CD4 cells dropped. CD4 cells are a type of T Cells. T cells are cells of the immune system. There are a number of opportunistic infections and cancers that are related to HIV/AIDS. These infections are very uncommon in normal people with normal immune system hence if they are present then AIDS maybe diagnosed in people who have it. The infections/cancers highly associated with AIDS/HIV include:
1.Candidiasis of esophagus, trachea, bronchus or lungs: It is an infection caused by a species of the yeast Candida.
2.Coccidiodomycosis infection other than lungs: A disease due to a fungus called Coccidioides immitis.
3. Cryptococcosis infection other than lungs: An infection caused by a yeast-like fungus, typically Cryptococcus neoformans, found in soil and bird feces.
4. Cryptosporidosis: An intestinal infection characterized by diarrhea caused by a microscopic parasite, Cryptosporidium parvum.
5.Cytomegalovirus CMV of any organ other than spleen, liver or lymph nodes: A group of viruses in the family Herpes Virus infecting humans and other animals, many of these viruses having special affinity for salivary glands, and causing enlargement of cells of various organs and development of characteristic inclusions (owl eye) in the cytoplasm or nucleus.
6. Herpes Simplex infection: Patients will present with mouth ulcers more than 1 month, bronchitis, pneumonitis and esophagitis.
7.Histoplasmosis infections other than lungs: A disease caused by the fungus Histoplasma capsulatum.
8.HIV/AIDS dementia: HIV and AIDS will cause cognition dysfunction and malfunctioning of motor skills affecting the patient’s daily activities and job.
9. HIV associated wasting: There will be unintentional weight loss > 10%, longstanding diarrhea (more than 2 times daily for more than 1 month), long term weakness and also fever for more than 1 month.
10. Isosporiasis: a human intestinal disease caused by the parasite Isospora belli. /this is characterized by diarrhea for more than 1 month.
11. Kaposi Sarcoma: cancer of the skin, lungs, and bowel due to a herpes
12. Lymphoma of the brain
13. Non-Hodgkin’s B cell lymphoma or unknown immunology
14. Disseminated Mycobacterium Avium or Kansasii
15. Disseminated and Primary Mycobacterium Tuberculosis
16. Nocardiosis: a serious infection caused by a fungus-like bacterium that begins in the lungs and can spread to the brain.
17. Pneumocystis Carinii Pneumonia: a fungal lung infection caused by Pneumocystis jiroveci.
18. Progressive Multifocal Leukoencephalopathy: a brain disease caused by a virus called the JC virus that results in a severe decline in mental and physical functions.
19. Salmonella Septicemia (non-typhoid)
20. Strongyloides: infection caused by the threadworm, a genus of small nematode parasites.
21. Toxoplasmosis of internal organ: An infection caused by a single-celled parasite named Toxoplasma gondii that may invade tissues and damage the brain.
There are screening tests available to detect the presence of HIV antibodies, p24 antigen and also the viral nucleic acid. Samples for testing can be obtained from the patient’s blood, saliva, urine, plasma and serum.
HIV antibodies can be tested by EIA (Enzyme ImmunoAssay) or ELISA tests, Particle Agglutination tests and also Chemiluminescent Immunoassay (CIA). The ELISA or EIA tests are the standard tests.
If the screening tests are positive, they should be followed by confirmatory tests: Western Blot, Indirect Immunofluorescence Assay (IFA) or Nucleic Acid Amplification Test (NAAT).
Rapid HIV Tests
Rapid HIV tests are carried out when information is needed to assess the need for prophylaxis treatment in those who have occupational exposure (e.g. needle stick injuries in healthcare), non-occupational exposure (e.g. unprotected sex with HIV/AIDS person) or in pregnant women whose HIV status is unknown. The results will be available in 10-20 minutes.
The rapid tests are used to detect the presence of HIV antibodies from blood, serum, plasma and oral fluid samples. If the result is negative it can be determined as definite negative result. However if the test is done within 3 months from exposure to the virus (window period before seroconversion takes place), HIV testing should be repeated at 3 months post exposure date to confirm that the subject did not contract the virus.
If the rapid HIV test is positive, it should be confirmed again with Western Blot test or IFA (Indirect Immunofluorescence Assay).
Urine and Oral Fluid HIV Tests
Oral fluid can be sent for EIA (Enzyme ImmunoAssay) as a rapid HIV test (OraQuick Advance Test). However the percentage of false positive results from oral fluid tests is higher as compared with blood sample results.
Urine Test Calypte HIV-1is a specialized EIA (Enzyme ImmunoAssay) test that is only done at certain medical centers by physicians. Any positive result should be confirmed again with serological tests.
HIV confirmatory test
Western Blot is the confirmation test for HIV infection. It involves the separation of the virus’ proteins by molecular weight on a polyacrylamide gel which is then transferred onto a solid support. The media is then incubated in the subject’s serum and then the reactivity is read. The result can be POSITIVE, NEGATIVE or INDETERMINATE.
POSITIVE Western Blot test: when 2 of the following bands are present: gp 41, gp 120/160 or p24.
NEGATIVE Western Blot test: when none of the bands (gp 41, gp 120/160 or p24) is present.
INDETERMINATE Western Blot test: when one or more of the bands are present but not enough to meet the positive criteria of Western Blot Test. This can be a result of a true infection that has yet to seroconvert or no infection. Patients who have indeterminate test results should have Western Blot test repeated in 2-4 weeks unless acute HIV infection is suspected.
If a positive EIA (Enzyme ImmunoAssay) test is followed by a positive Western Blot test then it is diagnostic of HIV infection.
If a positive EIA (Enzyme ImmunoAssay) is followed by a negative Western Blot test it is a true negative result unless there is active HIV infection.
Other confirmatory tests like radioimmunoprecipitation assay and indirect IFA (Indirect Immunofluorescence Assay) are hardly used now.
The detection of Proviral DNA via Polymerase Chain Reaction (PCR) Test is only useful in diagnosis of HIV in infants to distinguish active infant infection from passive transfer of maternal antibodies.
Currently there is no cure for AIDS. There are only drugs in the market to control the virus, relief the symptoms and improve the quality of life of patients.
HAART (Highly Active AntiRetroviral Therapy) has been effective in reducing the viral load, preventing the viral replication, improving T cell count and immune system. Even if patients are on HAART, they can still transmit the virus to others through sex and blood. If the patient’s CD4 count can be maintained above 200 cells/mm3, patient’s quality of life will be improved.
A combination of anti-HIV drugs should be used instead of a single drug is used the drug resistance likelihood increases. The available anti-HIV drug groups include:
1.NNRTIs (Non-nucleoside reverse transcriptase inhibitors): these drugs interrupt with the proteins required in replication of the HIV Virus. The drugs in this group include etravirine (Intelence), efavirenz (Sustiva) and nevirapine (Viramune).
2.PIs (Protease Inhibitors): These drugs interfere with protease that is required for replication of HIV virus. The drugs in this group include darunavir (Prezista), fosamprenavir (Lexiva), atazanavir (Reyataz) and ritonavir (Norvir).
3.NRTIs (Nucleoside reverse transcriptase inhibitors): These drugs are dysfunctional building components that the HIV virus requires to duplicate itself. The drugs in this group include Abacavir (Ziagen), and the combination drugs lamivudine and zidovudine (Combivir) and emtricitabine and tenofovir (Truvada).
4.Integrase inhibitors: these drugs act by disrupting the protein Integrase that is required by HIV virus to integrate its genetic material into the CD4cells. Raltegravir (Isentress) is an example of such drug.
5.Entry or fusion inhibitors: Drugs like enfuvirtide (Fuzeon) and maraviroc (Selzentry) block HIV virus entry into CD4 cells.
The choice of medications should be individualised based on virologic efficacy, toxicity of drugs, dosing frequency, drug-drug interactions, resistance testing results, pill burden and also patient's other comorbid conditions.
The US Department of Health and Human Services Panel on Antiretroviral Guidelines for Adults and Adolescents (DHHS ART Guidelines) recommend starting treatment for the following groups of patients who have not been take HAART before:
1.Patients with AIDS defining illnesses or those with CD4 less than 350/µl.
2.Pregnant women with HIV infection.
3.Patients with HIV-associated nephropathy. Starting treatment preserves kidney function and improves survival.
4.HIV patients who have Hepatitis B co-infection.
5.Patients with CD4 count less than 350/µl are strongly recommended to start HAART treatment. For patients with CD4 count between 350-500 /µl are moderately recommended to start HAART treatment. For those patients with CD4 count > 500/µl, treatment is optional.
6.Patients with rapid decrease in CD4 counts (>120 cells/µl/year) or if they have increased risk of other non-AIDS illnesses that increase the patient’s morbidity and mortality.
Common side effects of HAART
2.Nausea and vomiting
4.“Buffalo Hump” (collection of fat at the back) and abdomen
7.Increased levels of cholesterol and sugars and also increased risk in heart diseases.
Treatment failure is due to a multiple factors. Treatment failure refers to suboptimal suppression of HIV virus, failure to achieve or maintain CD4 cell count recovery and clinical disease progression while on treatment.
There are many factors causing treatment failure. They include non-compliance with medications, drug side effects, drug-drug interactions, pre-existing drug resistance to antiviral drug and potency of antiretroviral therapy.
Recommended Vaccinations for HIV infected persons
1.Pneumococcal vaccination every 5-7 years
2.Yearly influenza vaccination
3.Hepatitis B vaccination for those who are not immune
For those patients with CD 4 count less than 200, bactrium can be given as a prophylaxis against pneumocystis jiroveci and toxoplasmosis infections.
Azithomycin, rifabutin and clarithromycin can be given for thos ewith CD 4 count less than 50-75 to protect against Mycobacterium Avium.
Prevention of HIV transmission
1.Avoid drug abuse and sharing of needles and syringes.
2.HIV positive patients should not donate blood, organs and sperms. They should not have unprotected sex with others too.
3.Avoid direct contact with blood from an infected person.
4.Healthcare workers should have proper personal protection equipment when caring for HIV patients to avoid direct contact with their blood and fluids.
5.HIV infected mothers should not breast feed as they can transmit the virus to the baby through milk.
6.HIV infected females who wish to conceive should undergo counseling and consult specialists to reduce risk of transmission to the infants.
7.Avoid unprotected sex, always use a condom. Abstinence is the only way to prevent sexual transmission of HIV. Oral sex is a less risky sexual behavior.
8.If you suspect yourself to have contracted HIV via needle stick injuries or unprotected sex with a HIV person, immediate consult with an infectious disease physician and starting Post Exposure Prophylaxis (PEP) treatment may reduce the chance of infection.
9.HIV infected persons should inform their partners of their IV status and advise them to go for screening tests and treatment if positive.