
                               AIDS Overview

        Acquired immune deficiency syndrome, or AIDS, is a  recently
        recognized disease.  It is said to be caused by the  immuno-
        deficiency virus (HIV), which attacks selected cells in  the
        immune system.  However, AIDS is not present in all cases of
        HIV  and HIV is not present in all cases of AIDS,  thus  HIV
        fails the classic Koch Test as the cause of AIDS.

        These cellular defects may not appear for years.  They lead,
        however,  to  a severe suppression of  the  immune  system's
        ability  to resist harmful organisms.  This leaves the  body
        open to invasion by infections, which are then called oppor-
        tunistic  diseases, and to the development of  unusual  can-
        cers. The virus also tends to reach certain brain cells  and
        cause   neuropsychiatric  abnormalities,  or   psychological
        disturbances.

        Since  the first AIDS cases were reported in  1981,  through
        mid-1993 more than 315,000 AIDS cases and more than  194,000
        deaths have been reported in the United States. This is only
        a small portion of the HIV infection as it is guessed that 1
        to  1.5 million Americans had been infected with  the  virus
        through  the  early  1990s.  Curiously, only  25%  of  those
        infected suffer the disease.  25% show some symptoms and 50%
        are not affected.

        Although the vast majority of documented cases have occurred
        in the United States, AIDS cases have also been reported  in
        208  countries worldwide.  Sub-Saharan Africa in  particular
        appears to suffer a heavy burden of this illness.

        No  cure or vaccine now exists for AIDS.  Many of those  in-
        fected with HIV may not even be aware that they carry it and
        can spread the virus.  Combating it is a major challenge  to
        biomedical scientists and health-care providers.  HIV infec-
        tion and AIDS are the most publicized public health problems
        worldwide.

                             Definition of AIDS

        The U.S. Center For Disease Control has established criteria
        for defining cases of AIDS that are based on T4 cell  count,
        the  presence  of opportunistic diseases, and  other  condi-
        tions.  The  opportunistic diseases are generally  the  most
        prominent  and life-threatening clinical  manifestations  of
        AIDS.  It is now recognized, however, that  neuropsychiatric
        manifestations  of HIV infection of the brain are also  com-
        mon.   Other complications of HIV infection  include  fever,
        diarrhea, severe weight loss, and swollen lymph nodes.

        When  HIV-infected persons experience some of  the  symptoms
        but  do not meet full criteria for AIDS, they are given  the
        diagnosis  of  AIDS-related  complex, or ARC.   There  is  a
        controversy  that  ARC and HIV  infection  without  symptoms
        should  not be viewed as distinct entities but,  rather,  as
        stages of an irreversible progression toward AIDS, but  some
        of the infected have carried the virus without affect for 13
        years.

                           Historical Background

        In  the  late 1970s, certain rare cancers and a  variety  of
        serious  infections were recognized to be occurring  in  in-
        creasing numbers of previously healthy persons.  Strikingly,
        these were disorders that would hardly ever threaten persons
        with  normally  functioning immune systems.  First  formally
        described  in  1981, AIDS was observed predominantly  to  be
        affecting homosexual and bisexual men. Soon intravenous drug
        users,  hemophiliacs, and recipients of  blood  transfusions
        were seen as being at increased risk for disease as well. It
        was also observed that sexual partners of persons with  AIDS
        could contract the disease.

        Further study of AIDS patients revealed marked depletion  of
        certain  white  blood cells, called  T4  lymphocytes.  These
        cells play a crucial role in coordinating the body's  immune
        defenses  against invading organisms.  It was presumed  that
        this  defect in AIDS patients was acquired in a common  man-
        ner.

        In 1983, a virus that attacks T4 cells was discovered by Dr.
        Luc Montagnier of the French Pastuer Institute.  He sent  it
        to Dr. Robert Gallo at the U.S. National Institute of Health
        as  a laboratory curiosity and Dr. Gallo declared it  to  be
        the cause of AIDS!

        The virus was given various names: human lymphotropic  virus
        (HTLV)  III,  lymphadenopathy-associated  virus  (LAV),  and
        AIDS-associated  retrovirus  (ARV).  It  is  now  officially
        called human immunodeficiency virus (HIV).  A second  strain
        that has been identified, HIV-2, is thus far relatively rare
        outside of Africa.

        Little  is known about the biological and geographical  ori-
        gins of HIV.  Apparently, however, this is the first time in
        modern history that the virus has spread widely among  human
        beings. Related viruses have been observed in animal popula-
        tions,  such  as certain African monkeys, but these  do  not
        appear to produce disease in humans.

                          The Nature of the Virus

        HIV is an RNA retrovirus.  Viewed in an electron microscope,
        it  has a dense cylindrical core that encases two  molecules
        of  viral RNA genetic material.  A spherical outer  envelope
        surrounds  the core. Like all retroviruses, HIV possesses  a
        special  enzyme, called reverse transcriptase, that is  able
        to make a DNA copy of the viral RNA. This enables the  virus
        to  reverse  the normal flow of genetic information  and  to
        incorporate its viral genes into the genetic material of its
        host.  The  virus  may then remain in a latent  form  for  a
        variable and often lengthy period of time until it is  reac-
        tivated. Further knowledge of the mechanisms and triggers of
        the  activation  process is important to the  efforts  being
        made to control HIV infection.

        A critical step in HIV infection is the binding of the virus
        to  a receptor on the cell it attacks, enabling it  to  gain
        entrance.  Studies  have shown that a molecule  called  CD4,
        which  occurs predominantly on the surface of the  T4  cell,
        serves as this receptor. Although the T4 cell is a major HIV
        target, almost any other cell with the CD4 surface  molecule
        can  become  infected with HIV. Thus blood  cells  known  as
        monocytes  and  macrophages are  very  important  additional
        targets.

                           Modes of Transmission

        Researchers have isolated HIV from a number of body  fluids,
        including blood, semen, saliva, tears, urine,  cerebrospinal
        fluid,  breast  milk, and cervical and  vaginal  secretions.
        Strong evidence indicates, however, that HIV is  transmitted
        only  through  three  primary  routes:  sexual  intercourse,
        whether vaginal or anal, with an infected individual;  expo-
        sure  to infected blood or blood products; and from  an  in-
        fected mother to her child before or during birth.

        At least 97 percent of U.S. AIDS cases have been transmitted
        through  one  of  these routes,  with  transmission  between
        homosexual men accounting for about 60 percent of the cases.
        Heterosexual transmission in the United States accounts  for
        about  7  percent of cases but it is a significant  mode  of
        transmission  in Africa and Asia.  About 24 percent of  AIDS
        cases occur in intravenous drug users exposed to HIV-infect-
        ed  blood  through  shared needles.   Current  practices  of
        screening  blood  donors and testing all donated  blood  and
        plasma for HIV antibodies have reduced the number of cumula-
        tive cases caused by transfusion to about 1 percent.

        The number of new cases of AIDS in women of reproductive age
        is increasing at an alarming rate, but the numbers are still
        relatively small. AIDS has become the leading cause of death
        for women between the ages of 20 and 40 in the major  cities
        of North and South America, Western Europe, and  sub-Saharan
        Africa.  In  the United States, AIDS has hit  hardest  among
        black  and Hispanic women, who represent 17 percent  of  the
        female population but make up 73 percent of women with AIDS.
        AIDS is also having a devastating impact on infant  mortali-
        ty, since over 80 percent of HIV-infected children under the
        age of 13 acquired HIV from their infected mothers.  Between
        24 and 33 percent of children born to infected women develop
        the disease.

        No scientific evidence supports transmission of HIV  through
        ordinary nonsexual contact and one study, which can never be
        repeated,  indicated HIV carriers can live in close  contact
        with  others, such as family members, hugging,  kissing  and
        sharing toothbrushes, without transmitting the virus!   This
        study was done with AIDS patients before HIV had been  iden-
        tified.

        Careful  studies show that despite prolonged household  con-
        tact  with  infected individuals, family  members  have  not
        become  infected,  except  through sex  or  needle  sharing.
        Health-care  workers have been infected with HIV from  expo-
        sure  to  contaminated  blood or  by  accidentally  sticking
        themselves with contaminated needles.

                               Clinical Signs

        Following  infection  with HIV, an individual  may  show  no
        symptoms at all or may develop an acute but transient  mono-
        nucleosislike illness. The period between initial  infection
        and  the development of AIDS is currently observed  to  vary
        from about 6 months to 11 years.  Various estimates indicate
        that  somewhere  between 26 to 46 percent  of  the  infected
        individuals  will go on to develop full-blown AIDS within  a
        little more than seven years following infection.  Once AIDS
        develops  the  clinical  course generally  follows  a  rapid
        decline; and most people with AIDS die within three years.

                     Opportunistic Infections and Cancers

        Because  the  T4 cell is involved in almost all  immune  re-
        sponses,  its depletion renders the body highly  susceptible
        to  opportunistic infections and tumorous growths. The  most
        predominant  and  threatening complication  is  Pneumocystis
        carinii  pneumonia, which is frequently the first  infection
        to occur and is the most common cause of death. Other infec-
        tions include the parasites Toxoplasma gondii and Cryptospo-
        ridiosis; fungi such as Candida and Cryptococcus; mycobacte-
        ria such as Mycobacterium avium, intracellulare, and  tuber-
        culosis;  and  viruses such as  cytomegalovirus  and  herpes
        simplex  and zoster.  Increased susceptibility to  bacterial
        infection is noted particularly among children with AIDS.

        Many  AIDS  patients  develop  cancers,  including  Kaposi's
        sarcoma (KS), non-Hodgkin's lymphoma, and Hodgkin's Disease.
        KS  occurs in patients who manifest hardly any  evidence  of
        immunological impairment, indicating that other factors  may
        also  be  at work.  Among the  non-Hodgkin's  lymphomas  are
        immunoblastic  and Burkitt's-type as well as  primary  brain
        lymphomas.  These tumors tend to be unusually aggressive and
        poorly  responsive  to chemotherapy,  particularly  in  AIDS
        patients  who have already experienced opportunistic  infec-
        tions.

                 Other HIV-Related Disorders and Cofactors

        Neuropsychiatric manifestations occur in about 60 percent of
        HIV-infected  persons. It is now well established  that  HIV
        can exist and proliferate within the brain, spinal cord, and
        peripheral  nerves. This results in a broad range  of  symp-
        toms, including meningoencephalitis and dementia.   Evidence
        thus far indicates that circulating HIV-infected blood cells
        of  the  kind called monocytes may be  responsible  for  the
        initiation  of infection in the brain. There is little  evi-
        dence to support direct infection of neuron tissue by HIV.

        Blood-cell  abnormalities  of HIV patients  include  anemia,
        reduced white-blood-cell counts, and platelet  deficiencies.
        Researchers have also been able to show direct infection  of
        bone-marrow  cells,  the  precursors  of  circulating  blood
        cells,  and  the  proliferation of the  virus  within  these
        cells.  Bone marrow may represent an important reservoir  of
        HIV in an infected person and provide a potential  mechanism
        for spreading the virus through the body. Other  HIV-related
        syndromes include nephritis and lung inflammation (pneumoni-
        tis).

        Certain  cofactors appear to play an important role  in  HIV
        infection and AIDS by increasing susceptibility to infection
        and  by  enhancing viral-disease activity.   Other  sexually
        transmitted  diseases  appear to be of  particular  signifi-
        cance.   Damage  to genital skin and  mucous  membranes  may
        facilitate transmission of the virus. In addition, laborato-
        ry studies show that certain other microbes frequently found
        in AIDS patients, such as mycoplasmas, also probably act  as
        cofactors.

                              Treatment of HIV

        Two major avenues are being pursued by biomedical scientists
        in the fight against HIV infection and AIDS. One strategy is
        to develop a vaccine that can induce neutralizing antibodies
        against HIV and protect uninfected individuals if exposed to
        the virus itself. The second approach involves the discovery
        and development of therapeutic agents against HIV  infection
        and AIDS.

        At  present no vaccine exists to protect against  infection,
        although  recent advances have led some experts  to  predict
        that  a  vaccine  should be available within  the  next  ten
        years. Obstacles still remain, however, primarily because of
        the variability of the virus itself.  Many different strains
        of HIV exist, and even within a given individual's body  the
        virus can undergo mutations rapidly and easily.  A number of
        candidate  vaccines were in the early phases of  testing  in
        human volunteers by the early 1990s around the world.

        Dramatic  strides were also being made in the  treatment  of
        HIV  infection  and its complications.  Efforts  were  being
        focused  on two major areas: antiviral drugs with  a  direct
        effect against the causative agent; and immunomodulators, or
        substances that act to reconstitute or enhance immune-system
        function.  Efforts  to  develop and  improve  treatments  of
        specific opportunistic infections and tumors are also  being
        made.

        Because  of  the  complex life cycle of  HIV,  however,  the
        successful  development of antiviral and  immune-enhancement
        therapies  represents  an  enormous  scientific   challenge.
        Unlike  most  known  disease-producing  microorganisms,  HIV
        infects the very cells that are intended to lead the  immune
        system's attack against invaders. This makes it  technically
        very  hard to kill the virus without destroying the  already
        threatened immune system. Furthermore, there may be  several
        important reservoirs in the body for HIV that will be diffi-
        cult  to deal with while not causing fundamental  damage  to
        the  host cells involved. For example, macrophage cells  can
        support  HIV replication while harboring the virus from  the
        body's  immune surveillance. Circulating blood cells of  the
        kind called macrophages appear to play an important role  in
        the  propagation of HIV throughout the body,  including  the
        brain.

        In  seeking effective therapies, other important  considera-
        tions  are involved.  Thus, since the brain is an  important
        target of HIV infection, an effective anti-HIV agent  should
        be  able to cross the blood-brain barrier. It would also  be
        desirable  if therapies could be taken orally, since  it  is
        likely  that  AIDS drugs would have to be taken for  a  long
        period  and perhaps a lifetime.

        Dozens  of agents have been tested in humans, but  only  two
        have been licensed by the U.S. Food and Drug  Administration
        (FDA):  azidothymidine (AZT) and dideoxyinosine  (DDI).  AZT
        interferes  with  virus replication and has  been  found  to
        prolong life in some patients, but its ability to delay  the
        onset  of  full-blown AIDS in persons with no  symptoms  has
        been  questioned. AZT's potentially toxic side  effects  may
        preclude  uses  in  many cases. DDI acts  similarly  but  is
        recommended  for those who cannot tolerate AZT.

        Other drugs are in clinical trials. Some drugs are available
        to fight major opportunistic infections. Eye infections  can
        be  treated with ganciclovir or foscarnet, which also  helps
        patients  live longer, while aerosolized pentamidine  fights
        Pneumocystis carinii pneumonia and protects the patient from
        AIDS dementia. The slow process of FDA approval of new  AIDS
        drugs  has developed into a political issue. AIDS  activists
        are demanding that the government speed up authorization  by
        postponing  certain tests comparing efficacy and ability  to
        prolong life until after the drug is on the market. While  a
        faster approval rate may expose patients to unforeseen  side
        effects, activists argue that patients with life-threatening
        diseases  who  have no alternative therapy should  still  be
        entitled to choose these drugs.

                     The Global AIDS Situation Worsens

        According to the World Health Organization (WHO) as of  June
        30, 1993, 718,894 cumulative AIDS cases in adults and  chil-
        dren  have been reported to the Evaluation Unit,  Office  of
        Cooperation with National Programmes, World Health Organiza-
        tion Global Programme on AIDS.
        WHO  estimates  that over 25 million cumulative  AIDS  cases
        have occurred to date. This estimate is based on the  avail-
        able  data on the distribution, spread, and  penetration  of
        HIV throughout the World, and is consistent with the  effect
        of under-diagnosis, underreporting, and delays in  reporting
        of  AIDS  cases. Again as a consequence  of  such  reporting
        biases,  whereas  over 50% of reported AIDS cases  are  from
        developed  countries, about 80% of all estimated AIDS  cases
        are from the developing world.

        In  the developing world, two-thirds of all  estimated  AIDS
        cases  to date are thought to have occurred  in  sub-Saharan
        Africa;  however,  HIV infection trends have been  rapid  in
        South and South-East Asia, with over 1.5 million  cumulative
        HIV  infections  estimated  to have occurred  to  date.  The
        worldwide  total now exceeds 13 million adults  HIV-infected
        since the pandemic's start, with an additional 1 million  or
        more  HIV-infected children. The distribution of  adult  HIV
        infections  in  other regions of the World  is  as  follows:
        Australasia  over  25,000; East Asia and  the  Pacific  over
        25,000; Eastern Europe and Central Asia about 50,000;  Latin
        America  and the Caribbean about 1.5 million;  North  Africa
        and  the Middle East over 75,000; North America over 1  mil-
        lion  infections;  Western Europe about 500,000  HIV  infec-
        tions. The unstable political, social and economic  environ-
        ment  in Eastern Europe and Central Asia suggests  that  the
        evolution  of HIV/AIDS in that part of the World may  poten-
        tially  be rapid; current estimates are based on  relatively
        limited data.

        In the world as a whole, heterosexual intercourse has rapid-
        ly become the dominant mode of transmission of the virus. As
        a result the developing countries already hold as many newly
        infected  women  as men, and some  developed  countries  are
        approaching  equal incidence in men and women where  sex  is
        casually given.  Perinatal transmission, i.e.,  transmission
        of  HIV  from an infected mother to her  unborn  or  newborn
        baby, is showing a corresponding increase. Homosexual trans-
        mission,  on  the other hand, has  remained  significant  in
        North  America, Australasia, and Northern  Europe,  although
        even in these areas heterosexual transmission is showing the
        fastest rate of increase.

        Transmission  through  contaminated blood  transfusions  has
        been  virtually eliminated in industrialized  countries;  in
        developing  countries,  steps  are being  taken  to  prevent
        transfusion-related infections, although much remains to  be
        done and the costs are high. Bloodborne transmission through
        needle  sharing  outside the health care setting is  on  the
        rise  in  a number of groups of drug injectors  in  the  de-
        veloped and developing world.

        The  World Health Organization estimates that in early  1992
        at least 10 to 12 million adults and children worldwide have
        become  infected with HIV since the start of  the  pandemic.
        Among  them, some two million have gone on to  develop  AIDS
        (which occurs ten years on average after the initial  infec-
        tion  with the virus). By the year 2000, WHO estimates  that
        cumulative totals of 30 to 40 million men, women, and  chil-
        dren will have been infected, and 12 to 18 million will have
        developed AIDS.

        Nearly  90% of the projected HIV infections and  AIDS  cases
        for  this decade will occur in the developing countries.  In
        sub-Saharan  Africa, where over six million adults  are  al-
        ready infected, the situation is critical.  As many as  one-
        third  of  pregnant  women attending  some  urban  antenatal
        clinics are HIV-infected, and seropositivity rates this high
        are being seen outside cities as well.

        As a result, WHO now projects that five to ten million  HIV-
        infected  children will have been born by the year 2000.  By
        the  mid-1990s  the  projected increase in  AIDS  deaths  in
        children will begin to cancel out the reduction in mortality
        achieved  by child survival programs over the past two  dec-
        ades.

        In  those  African  countries where the  prevalence  of  HIV
        infection  is  already high, life expectancy at  birth  will
        actually  drop by five to ten percent instead of  rising  by
        20%  by  the year 2000, as was projected in the  absence  of
        AIDS.

        In  Asia, which holds more than half of the world's  popula-
        tion,  the dramatic rise in seroprevalence between 1987  and
        1991 in South and Southeast Asia may well parallel that seen
        in sub-Saharan Africa in the early 1980s, and by the mid  to
        late  1990s more Asians than Africans will be infected  each
        year. As of early 1992, Latin America and the Caribbean were
        estimated to have over one million HIV-infected adults.

        The  brunt of the AIDS pandemic is thus  increasingly  being
        borne  by the developing countries. In parts of  sub-Saharan
        Africa the pandemic's overall social and economic impact  is
        already  enormous  and is bound to become  more  devastating
        still.  The  health  and social  support  infrastructure  is
        inadequate  to  handle the clinical  burden  of  HIV-related
        disease, which includes an upsurge in tuberculosis.

        The deaths of millions of young and middle-aged adults,  who
        include members of social, economic, and political elites as
        well as professional health workers and teachers, could lead
        in some societies to economic disruption and even  political
        turmoil. Through the deaths of young men and women, innumer-
        able  children  and elderly people are  already  being  left
        without support.

        In sub-Saharan Africa alone, 10 to 15 million children  will
        be  orphaned  by  the year 2000 as their  mothers,  or  both
        parents, die of AIDS. A similar scenario can be expected  in
        Asia, Latin America, and other parts of the developing world
        in the first decade of the twenty-first century.

        Prevention is indisputably the most important objective of a
        global  strategy, since it is the only way to avert all  the
        human, social, and economic costs of HIV infection, which is
        lifelong and, in the absence of curative drugs, believed  to
        be ultimately fatal. A universally effective and  affordable
        preventative vaccine is unlikely to be available before  the
        year 2000.

                            Worst Case Scenario

        In June 1992, the Harvard-based Global AIDS Policy Coalition
        issued a worst-case projected figure for the number of world
        adult  HIV  cases  that  disagrees  with  the  World  Health
        Organization's estimates. The report projected that as  many
        as  120 million people will be infected with the AIDS  virus
        by  the year 2000, with a low-end estimate of 40 million  by
        the turn of the century.

                             Understanding AIDS

        The Acquired Immune Deficiency Syndrome, or AIDS, was  first
        reported  in the United States in mid-1981. The  total  AIDS
        cases  in the United States (including U.S. territories)  as
        of June 30, 1993, were 315,390, and of these cases,  194,334
        deaths were reported, says the Center for Disease Control in
        Atlanta.

        AIDS  is  characterized  by a  defect  in  natural  immunity
        against  disease.  People who have AIDS  are  vulnerable  to
        serious  illnesses  which would not be a  threat  to  anyone
        whose immune system was functioning normally. These illness-
        es  are  referred to as "opportunistic" infections  or  dis-
        eases: in AIDS patients the most common of these are Pneumo-
        cystis carinii pneumonia (PCP), a parasitic infection of the
        lungs; and a type of cancer known as Kaposi's sarcoma  (KS).
        Other  opportunistic  infections  include  unusually  severe
        infections  with yeast, cytomegalovirus, herpes  virus,  and
        parasites  such  as  Toxoplasma  or  Cryptosporidia.  Milder
        infections with these organisms do not suggest immune  defi-
        ciency.

        Symptoms  of  full-blown AIDS include  a  persistent  cough,
        fever,  and  difficulty  in  breathing.   Multiple  purplish
        blotches and bumps on the skin may indicate Kaposi's  sarco-
        ma.

        People  infected  with the virus can have a  wide  range  of
        symptoms, from none to mild to severe.  At least a fourth to
        a  half of those infected will develop AIDS within  four  to
        ten  years.  Many experts think the percentage will be  much
        higher, but there is no clinical evidence of this idea.

        The national Centers for Disease Control and Prevention  has
        changed  its AIDS surveillance case definition  for  adoles-
        cents  and adults to include HIV-infected people who have  a
        CD4  T-lymphocyte (a white blood cell) count less  than  200
        cells  per  microliter (a millionth of a liter),  or  a  CD4
        percent  less than 14. A normal adult has 800 to  1,200  CD4
        cells  in a microliter of blood. People with  HIV  infection
        lose  all  of the CD4 cells over time as  their  ability  to
        produce them diminishes.

        Also, CDC added recurrent pneumonia, pulmonary tuberculosis,
        and  invasive cervical cancer in HIV-infected people to  the
        23  clinical conditions in the case definition published  in
        1987.  According  to CDC, the addition of  these  conditions
        reflects their documented or potential importance in the HIV
        epidemic. CDC reports, for instance, that cities with  large
        numbers  of  AIDS cases have had parallel  increases  in  TB
        rates, with the racial, ethnic and age groups most  affected
        by HIV having the greatest increase in TB incidence.

                          The Expanded Definition

        The  expanded definition went into effect last Jan.  1.  CDC
        estimates  the expanded definition could increase  AIDS  re-
        porting  in 1993 by about 75 percent, possibly resulting  in
        80,000  to 90,000 case reports. Under the  1987  definition,
        50,000  to 60,000 case reports would have been  expected  in
        1993.

        For  a  free  single copy of  "1992  Revised  Classification
        System for HIV Infection and Expanded AIDS Surveillance Case
        Definition  for  Adolescents and Adults,"  contact  the  CDC
        Nationaly AIDS Clearinghouse, P.O. Box 6003, Rockville,  Md.
        20849-6003; telephone (1-800) 458-5231.

        AIDS  is spread by sexual contact, needle sharing,  or  less
        commonly  through  transfused blood or its  components.  The
        risk  of  infection with the virus is  increased  by  having
        multiple sexual partners, either homosexual or heterosexual,
        and sharing of needles among those using illicit drugs.  The
        occurrence  of the syndrome in hemophilia patients and  per-
        sons receiving transfusions provides evidence for  transmis-
        sion  through  blood.  It may be transmitted  from  infected
        mother  to  infant before, during, or  shortly  after  birth
        (probably through breast milk).

        The  AIDS virus can be spread by sexual intercourse  whether
        you  are male or female, heterosexual, bisexual or  homosex-
        ual.  This happens because a person infected with  the  AIDS
        virus  may  have the virus in semen or vaginal  fluids.  The
        virus  can enter the body through the vagina, penis,  rectum
        or  mouth.  Anal intercourse, with or without a  condom,  is
        risky. The rectum is easily injured during anal intercourse.

        Other  sexually  transmitted diseases,  such  as  gonorrhea,
        syphilis,  herpes  and  chlamydia, can  also  be  contracted
        through oral, anal and vaginal intercourse.

        Scientists have discovered how AIDS infects brain cells  and
        have  identified genes that affect the AIDS virus.  But  ef-
        forts  to devise a treatment or vaccine are  complicated  by
        the fact that AIDS is caused by two, perhaps three,  similar
        viruses, and that the virus mutates frequently.

        With  no  cure in sight, prudence could  save  thousands  of
        people in the U.S. who have yet to be exposed to the  virus.
        Their  fate will depend less on science than on the  ability
        of large numbers of human beings to change their behavior in
        the face of growing danger. Experts believe that couples who
        have  had  a totally monogamous relationship  for  the  past
        decade are safe. A negative blood test would be near-certain
        evidence of safety.

        People who should be tested for AIDS include homosexual  men
        and  intravenous drug users, their sex partners, and  anyone
        who has had several sex partners, if their sexual history is
        unknown,  during any one of the last five years. Anyone  who
        tests  positive  should see a physician  immediately  for  a
        medical  evaluation. Persons testing positive should  inform
        their  sex  partners  and should use a  condom  during  sex.
        (NOTE:  According to the U.S. Food and Drug  Administration,
        natural membrane condoms made from lambskin may not  protect
        against the AIDS virus.) They should not donate blood,  body
        organs, other tissue or sperm, nor should they share  tooth-
        brushes,  razors,  or  other implements  that  could  become
        contaminated with blood.

        Information  about where to go for confidential testing  for
        the  presence  of the AIDS virus is provided  by  local  and
        state health departments. There is a National AIDS Hot Line:
        (800) 342-2437 for recorded information about AIDS, or (800)
        433-0366 for specific questions.

        Although condoms greatly reduce the risk of getting an  AIDS
        infection,  they  are not guaranteed to be  100%  effective.
        Considering  that  there  is a 16% chance  of  failing  when
        condoms are used as contraceptives it could also happen that
        a  condom could fail in protecting against AIDS.  The  human
        sperm  is many times larger than the AIDS virus.  One  sperm
        measures  about  3,000  nanometers  (a  nanometer  is   one-
        billionth of a meter) and the AIDS virus is only 100 nanome-
        ters.

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