AIDS

Human Immunodeficiency Virus (HIV):

General Properties:

~ HIV is a RNA virus belongs to the Retroviridae & belongs to the lentivirus subgroup of retro virus.

~ Has double copy of the genome (diploid).

~ Possess reverse transcriptase enzyme.

~ Has envelope.

~ Surface antigen- glycoprotein 120, glydcoprotein 41.

~ Incubation period-6 months to years or more ( Causes slow virus infection)

~ Both HIV-1 and HIV-2 causes AIDS, But HIV is found worldwide, whereas HIV-2 is found primarily in West Africa.

~ HIV infects and kills helper T cell, resulting in the loss of cell mediated immunity, and causes opportunistic infection. Other cells e.g. macrophages and monocytes have CD4 proteins on their surface can be infected also.

  

AIDS (Acquired Immunodeficiency Syndrome)

 Epidemiology:

The Acquired Immunodeficiency Syndrome (AIDS) was first recognized in 1981 and isolated in 1983. The viruses (HIV-1, 2) almost originated from closely related African primate viruses, simian immunodeficiency viruses (SIVs). Sequence analysis has led to the estimate that HIV-1 was introduced into humans in the early 1930s. Science 1981 AIDS has grown to be the second leading cause of diseases in the world and also the leading cause of death in Africa counting 20% death.

In 2004, the World Health Organization estimated there were 39.4 million people living with AIDS, where 4.9 million infection and 3.1 million death. The cumulative death toll science the epidemic began is over 20 million; the vast majority of cases occurring in sub Saharan Africa where over 13 million children have been orphaned. In Botswana South Africa, Swaziland and Zimbabwe 25-40% of adults are infected, with rates of 5-15% in most other sub Saharan African countries. About 64% of all persons with HIV live in sub-Saharan Africa, with South Africa accounting for one third of AIDS deaths globally. Since 2002, the steepest increases have been seen in East Asia (50%), largely epidemic occurring in china, and in Eastern Europe and Central Asia (40%) and dangerously increasing in the Ukraine, Latvia and Russia now also have been seen in Vietnam, Thailand, Cambodia, Nepal and Myanmar.

Mode of Transmission:

Vertical transmission:

· Older gestational age

· Prolonged rupture of membranes

· Chorioamnionitis

· Fetal trauma (e.g. scalp electrodes)

· Lower birth weight

· Vaginal vs elective caesarean delivery

· No peripartum prophylaxis

· First-born twin

Sexual transmission:

· Sexually transmitted infections (STIs), especially genital ulcers

· Cervical ectopy

· Receptive vs insertive anal sex

· Rectal or vaginal trauma

· Menstruation

· Male-male vs heterosexual sex

· Non-circumcised

· Increased number of partners

Injection drug use transmission:

· Sharing equipment

· Frequency of use

· Linked commercial sex

· Lower income

· Intravenous use

· Cocaine use

· Incarceration

Breastfeeding:

· Longer duration feeding

· Lower parity

· Younger age

· Mastitis

Occupational transmission:

· Deep injury

· Visible blood on device

· Previous arterial or venous device siting

Clinical Feature:

Early (acute) clinical feature (begins after 2-4 weeks of infection):

o Fever

o Lethargy

o Sore Throat

o Diarrhea

o Generalized lymphadenopathy

o Maculopapular rash on the trunk, arms and legs ( but sparing the palm and sole)

o Lekopenia occurs, but the number of CD4 cells is usually normal, high level of veremia occurs

Antibodies to HIV typically appear 10-14 days after infection.

Intermediate stage:

AIDS related complex (ARC)

o Persistent fever

o Fatigue

o Weight loss

o Generalized lymphadenopathy

Late stage:

Late stage of HIV infection is AIDS. Patient develops opportunistic infection by both pathogenic and non
pathogenic organisms.

Some opportunistic infection with their agents is given below……….

Site of infection	Diseases	Causative organisms
Lung	Pneumonia Tuberculosis	Pneumocystis carinni, Cytomeghalovirus. Mycobacterium tuberculosis
Mouth	Thrush Hairy Leukoplakia Ulceration	Candida albicans Epstein-barr virus Herpes simplex virus-1, Histoplasma capsulatum
Esophagus	Thrush Esophagitis	Candida albicans Cytomeghalovirus, Herpes simplex virus-1
Intestinal tract	Diarrhea	Salmonella, Shigella, Giardia
Central nervous system	Meningitis Brain abscess Progressive multifocalleuko encephlopathy	Cryptococcus neoformans Toxoplasma gonndii
Eye	Retinitis	Cytomeghalovirus,
Skin	Kaposi’s sarcoma Zoster Subcutaneous nodule	Human herpesvirus-8 Varicella-zoster virus Cryptococcus neoformans
Reteculoendoth-elial system	Lymphadenopathy or spenomeghaly	Mycobacterium avium complex, Epstein-barr virus

Treatment of HIV infection (AIDS):

          A. Current treatment of choice;

Regimen consisting of two-necleoside inhibitor (Zidouvudine & lamivudine)- this combination is known as HAART [highly active antiretroviral therapy]

        B. In addition to nucleoside inhibitor there are non-nucleoside reverse transcriptase inhibitors that are effective against HIV- Nevirpine (viramune) , delavirdine(rescriptor) & efavirenz (Sustiva).

       C. Protease inhibitor: Saquinvir (Invirase), ritonavir (Norvir), nelfinavir (viracept) & indinavir (vrixivan)

 Prevention Of AIDS:

>Avoidance of promiscuity & anal intercourse

> Use of condom

> Screening of blood & blood products

>Use of disposable syringe & needles

> Interruption of perinatal transmission by screening women of child bearing age.

>Counseling of persons found to be antibody positive

>Education about the mode of transmission & how to avoid infecting others & how to protect themselves.