ACQUIRED IMMUNODEFICIENCY SYNDROME (HIV infection, AIDS)

ACQUIRED IMMUNODEFICIENCYSYNDROME (HIV infection, AIDS)

Globally, AIDS caused an estimated 3.1 million deaths in 2003 (2.5–3.5 million)

The epidemic has continued growing, with

estimates of 5 million new infections (4.2–5.8 million) and 2.5 million children (2.1–2.9 million) living with HIV/AIDS.

Identification

Emergence was in 1981 of a cluster of diseases associated with loss of cellular immunity in adults who had no obvious reason for presenting such immune deficiencies.

Within several weeks to several months after infection with HIV, many persons develop an acute self-limited mononucleosis-like illness lasting for a week or two. They may then be free of clinical signs or symptoms for months or years before other clinical manifestations develop.

AIDS Associated Disease Categories1. Gastrointestinal: Cause most of illness and

death of late AIDS.

Symptoms:

Diarrhea

Wasting (extreme weight loss)

Abdominal pain

Infections of the mouth and esophagus.

Pathogens: Candida albicans,

cytomegalovirus, Microsporidia, and

Cryptosporidia.

AIDS Associated Disease Categories2. Respiratory: 70% of AIDS patients develop

serious respiratory problems.

Partial list of respiratory problems associated with

AIDS:

Bronchitis

Pneumonia

Tuberculosis

Lung cancer

Sinusitis

Pneumonitis

AIDS Associated Disease Categories3. Neurological: Opportunistic diseases and

tumors of central nervous system.

Symptoms many include: Headaches,

peripheral nerve problems, and AIDS

dementia complex (Memory loss, motor

problems, difficulty concentration, and

paralysis).

AIDS Associated Disease Categories4. Skin Disorders: 90% of AIDS patients

develop skin or mucous membrane disorders. Kaposi’s sarcoma

1/3 male AIDS patients develop KS Most common type of cancer in AIDS patients

Herpes zoster (shingles) Herpes simplex Thrush Invasive cervical carcinoma

5. Eye Infections: 50-75% patients develop eye conditions. CMV retinitis Conjunctivitis Dry eye syndrome

Extensive tumor lesions of Kaposis’s sarcoma in AIDS patient.Source: AIDS, 1997

Infectious agent

Human immunodeficiency virus (HIV), Retrovirus. Two serologically and geographically distinct

types with similar epidemiological characteristics, HIV-1 and HIV-2, have been identified.

The pathogenicity of HIV-2 may be lower than that of HIV-1

lower rates of mother-to-child transmission for HIV-2.

Structure of the Human Immunodeficiency Virus HIV is a Retrovirus

Occurrence

AIDS was first recognized as a distinct clinical entity in 1981;, however, isolated cases appear to have occurred during the 1970s and even earlier in several areas (Africa, Europe, Haiti, USA).

Of the estimated 40 million persons (34–46 million) living with HIV infection or AIDS (HIV/AIDS) worldwide in 2003, the largest elements were estimated at 25–28.2 million in sub-Saharan Africa, 4.6–8.2 million in south and southeastern Asia, 13–1.9 million in Latin America and 800 000–1 million in North America.

People Living with HIV/AIDS by End of 2001North America

950,000

Latin America1.5 million

Western Europe560,000

East Europe & Central Asia1’000,000

Sub-Saharan Africa28.5 million

North Africa & Middle East

500,000

Australia & New Zealand15,000

South/South East Asia5.6 million

East Asia & Pacific1’000,000

Total: 40 million people

Caribbean420,000

HIV-1 is the most prevalent HIV type throughout the world;

HIV-2 has been found in Africa

Reservoir

Humans. HIV is thought to have recently

evolved from chimpanzee viruses.

Mode of transmission

Person to person transmission through unprotected (heterosexual or homosexual) intercourse;

Contact of abraded skin or mucosa with body secretions such as blood, CSF or semen;

The use of HIV-contaminated needles and syringes, including sharing by intravenous drug users; transfusion of infected blood or its components

Mode of transmission (cont.)

Transplantation of HIV-infected tissues or organs.

The presence of a concurrent sexually transmitted disease, especially an ulcerative one, can facilitate HIV transmission.

Unprotected intercourse (no condom— unprotected sex) with many concurrent or overlapping sexual partners.


HIV can be transmitted from mother to child (MTCT or vertical transmission).

From 15% to 35% of infants born to HIV-positive mothers are infected through placental processes at birth.

HIV-infected women can transmit infection to their infants through breastfeeding and this can account for up to half of mother-to-child HIV transmission.

Giving pregnant women antiretrovirals such as zidovudine results in a marked reduction of MTCT.


After direct exposure of health care workers to HIV-infected blood through injury with needles and other sharp objects, the rate of seroconversion is less than 0.5%, much lower than the risk of hepatitis B virus infection after similar exposures (about 25%).

Unsafe injections may account for up to 5% of transmission.


While the virus has occasionally been found in saliva, tears, urine and bronchial secretions, transmission after contact with these secretions has not been reported.

No laboratory or epidemiological evidence

suggests that biting insects have transmitted HIV infection.

HIV Transmission in United States and Rest of the World

Drugs Against HIV Reverse Transcriptase Inhibitors:

Competitive enzyme inhibitors. Example: AZT, ddI, ddC.

Protease Inhibitors: Inhibit the viral proteases. Prevent viral maturation.

Problem with individual drug treatments: Resistance.

Drug combinations: A combination of: One or two reverse transcriptase inhibitors One or two protease inhibitors.

Drug cocktails have been very effective in suppressing HIV replication and prolonging the life of HIV infected individuals, but long term effectiveness is not clear.

Incubation period

Variable. Although the time from infection to the

development of detectable antibodies is generally 1–3 months, the time from HIV infection to diagnosis of AIDS has an observed range of less than 1 year to 15 years or longer.

The median incubation period in infected infants is shorter than in adults.

Period of Communicability

Not known precisely; begins early after onset of HIV infection and presumably extends throughout life.

Infectivity during the first months is considered to be high; it increases with viral load, with worsening clinical status and with the presence of other STIs.

Susceptibility

The presence of other STIs, especially if ulcerative, increases susceptibility, as may the fact of not being circumcised for males, a factor possibly related to the general level of penile hygiene.

Interactions between HIV and other infectious disease agents

Mycobacterium tuberculosis infection:

Persons with latent tuberculous infection who are also infected with HIV develop clinical tuberculosis at an increased rate, with a lifetime risk of developing tuberculosis that is multiplied by a factor of 6–8.

This interaction has resulted in a parallel pandemic of tuberculosis.

in some urban sub-Saharan African populations where 10%–15% of the adult population have dual infection (Mycobacterium tuberculosis and HIV),

Other adverse interactions with HIV infection include pneumococcal infection, non-Typhi salmonellosis, falciparum malaria and visceral leishmaniasis.

Methods of control

A. Preventive measures: HIV/AIDS prevention programs can be

effective only with full community and political commitment to change and/or reduce high HIV-risk behaviours.

Methods of control (cont.)

Public and school health education must stress that having multiple and especially concurrent and/or overlapping sexual partners or sharing drug paraphernalia both increase the risk of HIV infection.


The only absolutely sure way to avoid infection through sex is to abstain from sexual intercourse or to engage in mutually monogamous sexual intercourse only with someone known.

In other situations, latex condoms must be used correctly every time a person has sexual intercourse.


Expansion of facilities for treating drug users reduces HIV transmission.

HIV testing and counselling is an important

intervention for raising awareness of HIV status, promoting behavioural change and diagnosing HIV infection. HIV testing and counselling can be undertaken for: a) persons who are ill or involved in high-risk behaviours, b) attenders at antenatal clinics, to diagnose maternal

infection and prevent vertical transmission; c) couple counselling (marital or premarital); d) anonymous and/or confidential HIV counselling and

testing for the “worried well”.


All pregnant women must be counselled about HIV early in pregnancy and encouraged to undertake an HIV test as a routine part of standard antenatal care.

Those found to be HIV-positive take a course of ARV treatment, to reduce the risk of their infant being infected.


All donated units of blood must be tested for HIV antibody; only donations testing negative can be used.

People who have engaged in behaviours that place them at increased risk of HIV infection should not donate plasma, blood, organs for transplantation, tissue or cells (including semen for artificial insemination).

Only clotting factor products that have been screened and treated to inactivate HIV must be used.


Care must be taken in handling, using and disposing of needles or other sharp instruments.

Health care workers should wear latex gloves, eye protection and other personal protective equipment in order to avoid contact with blood or with fluids.


WHO recommends immunization of asymptomatic HIVinfected children with the EPI vaccines; those who are symptomatic should not receive BCG vaccine.

Live Measles-Mumps-Rubella and polio vaccines are recommended for all HIV-infected children.

B. Control of patient, contacts and the immediate environment:

1) Report to local health authority: Official reporting of AIDS cases is obligatory in most countries.

Official reporting of HIV infections is required in some areas, Class 2

2) Isolation: Isolation of the HIV-positive person is unnecessary, ineffective and unjustified.

Universal precautions apply to all hospitalized patients.

3) Concurrent disinfection: Of equipment contaminated with blood or body fluids and with excretions and secretions visibly contaminated with blood and body fluids by using bleach solution or germicides

4) Quarantine: Not applicable.

5) Immunization of contacts: Not applicable.

6) Notification of contacts and source of infection: The infected patient should ensure notification of sexual and needlesharing partners whenever possible.

Management

AIDS must be managed as a chronic disease; antiretroviral treatment is complex, involving a combination of drugs: resistance will rapidly appear if a single drug is used.

The drugs are toxic and treatment must be

lifelong.

In addition; treatment of other additional associated conditions

C. Epidemic measures: HIV is currently pandemic, with large numbers of infections reported in the Africa, the Americas, southeastern Asia, and Europe.

D. Disaster implications: Emergency personnel should follow the same universal precautions as health workers.

International measures: The United Nations Joint Programme on HIV/AIDS (UNAIDS), which coordinates UN activities, and WHO do not endorse measures such as requirements for AIDS or HIV examinations for foreign travellers prior to entry.

Thank You

ACQUIRED IMMUNODEFICIENCY SYNDROME (HIV infection, AIDS)

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