Slim disease: a new disease in Uganda and its association with HTLV-III infection

Malabsorption, malnutrition and HIV disease

The small intestine is a major target in HIV infection. Chronic diarrhoeal disease associated with malabsorption is the principal clinical manifestation of such infection. Reduced intestinal immunity and opportunistic enteric infections play a major role in clinical disease, but an enteropathy induced by HIV per se has also been implicated. The immunopathology of reduced intestinal immunity and its progression during HIV infection is poorly understood. HIV genome and proteins have been detected reproducibly in cells of the lamina propria resembling macrophages, but direct epithelial infection with HIV is controversial. Another factor which may contribute to diarrhoea is autonomic neuropathy within the jejunum. Small intestinal disease causes malabsorption of fat and disaccharides and may contribute to the weight loss seen in advancing HIV infection. However, malnutrition seen in HIV infection is multifactorial and may occur as a constitutional sign of infection in the absence of overt intestinal disease. Reduced food intake does not appear to be a causative factor in the weight loss in constitutionally well stage IV patients and there is some evidence that release of cytokines (TNF alpha/cachectin) into plasma or locally into tissue may mediate such events. The response of HIV-infected individuals to nutritional support is variable, but it is becoming increasingly apparent that the response is limited by the presence of severe systemic infection. However, aggressive nutrition is an important therapeutic mode which should be offered to all HIV-infected patients.

The clinical and parasitological presentation of Plasmodium falciparum malaria in Uganda is unaffected by HIV-1 infection

The relation between Plasmodium falciparum malaria and symptomatic human immunodeficiency virus 1 (HIV-1) infection was investigated in paediatric and adult patients in Kampala, Uganda, from 1987 to 1989. Both infections contributed largely to hospital morbidity. Of 1527 clinically suspicious in-patients, 61% were positive for HIV-1 infection. 52% of patients with positive HIV-1 serology fulfilled the World Health Organization clinical case definition for acquired immune deficiency syndrome (AIDS) in Africa. No association could be found between HIV-1 infection and malaria either in paediatrics or in adults. P. falciparum parasitaemia was present in 18% of all patients and no differences in prevalence of malaria infection or in parasite density could be demonstrated between HIV-1 positive and HIV-1 negative patients. The comparison of clinical symptoms showed typical differences in AIDS-related morbidity but no difference in malaria-specific morbidity. Also, the response to malaria treatment was the same in HIV-1 positive and HIV-1 negative patients. P. falciparum malaria does not appear to act as an opportunistic agent in AIDS patients in Uganda.

Intestinal microsporidiosis as a cause of diarrhea in human immunodeficiency virus-infected patients: a report of 20 cases

Chronic diarrhea accompanied by weight loss is a common and often debilitating problem associated with human immunodeficiency virus (HIV) infection. Enterocytozoon bieneusi, a newly identified species of the phylum of protozoa, Microspora, has been reported associated with chronic diarrhea and wasting in 11 acquired immunodeficiency syndrome (AIDS) patients in the United States, Europe, and Africa. Diagnosis has been based solely on the ultrastructural identification of this small, intracellular parasite in bowel biopsies. Seventy-one small bowel biopsies from 67 homosexual AIDS and AIDS-related complex patients with chronic diarrhea and with no pathogens identified by light microscopy on paraffin sections, were embedded in plastic and studied by light and transmission electron microscopy. Enterocytozoon bieneusi microsporidiosis was diagnosed by electron microscopy in 20 (22 biopsies) of the patients. More jejunal biopsies (16 of 36) were positive than duodenal biopsies (six of 35). Parasites and spores were clearly visible at the light microscopic level in the semi-thin plastic sections from 17 and 21 of the biopsies, respectively. In retrospect, parasites could be identified by light microscopy in standard hematoxylin and eosin-stained paraffin sections. Infection was confined to enterocytes covering the villi, especially the tips, and was associated with villous atrophy and cell degeneration, necrosis, and sloughing. Release of spores into the bowel lumen was evident. Colorectal biopsies from two of the patients with small bowel microsporidiosis were negative for microsporidia. Enterocytozoon bieneusi infection of the small bowel may be an important cause of diarrhea in HIV-infected persons.

Sexually transmitted diseases in men in Mogadishu, Somalia

The prevalence of viral and bacterial sexually transmitted diseases were studied in 101 men attending a dermatovenereal outpatient clinic in Mogadishu. A control group of 103 healthy adult men were included for the serological part of the study. Serological markers of hepatitis B virus (HBV), human immunodeficiency virus (HIV), cytomegalovirus (CMV) and herpes simplex virus (HSV) were studied. All sera were tested for syphilis markers. HBV serum markers were detected in 84% of the men in the study group and 66% of the healthy controls (P less than 0.005). Hepatitis B virus carriers were detected more frequently in the study group than among the controls. Also, 96% of the men in both groups had CMV antibodies and all of them had antibodies to HSV. No sera were found to contain HIV antibodies. The TPHA-positivity was 10% and 3% in the study and control groups respectively, and 5% of the patients had syphilis IgM antibodies. Sexual contact with prostitutes was recorded in 54% and 48% respectively of patients and controls, and such contact was correlated with TPHA-positivity in the study group. Chlamydia trachomatis antigen was detected in urogenital specimens of 14% of the men in the study group and gonococcal culture was positive in 53% of those with urethral discharge.

Human immunodeficiency virus and the gastrointestinal tract

Human immunodeficiency virus (HIV) is a retrovirus infecting CD4 positive cells, causing profound immunosuppression and eventually manifesting clinically as the acquired immunodeficiency syndrome (AIDS). The cells principally infected by HIV are T4 (helper) lymphocytes and macrophages. The eventual loss of helper cell function is the prime reason for immunodeficiency, which renders the individual susceptible to opportunistic infections. Virtually every organ system in the body can be affected clinically during the course of HIV infection. The gastrointestinal tract is a major target and the physiological sequelae are an important cause of morbidity and mortality. The pathophysiology of intestinal infection is not yet fully understood but two main mechanisms have been postulated. The first is reduced intestinal immunity resulting in chronic opportunistic infections, which themselves cause altered intestinal function. The second is that HIV per se affects the intestinal mucosa, causing malfunction. The mechanisms by which the latter occurs are controversial but may result from either direct infection of mucosal epithelial cells or from macrophages within the mucosa. Reports have documented the presence of the HIV genome in both epithelial argentochromaffin cells and macrophages. In addition, profound degeneration of intrinsic jejunal autonomic neurones has been demonstrated but the functional significance of such denervation is as yet unknown. The clinical stage of HIV infection at which intestinal mucosal immunity fails is, by definition, when opportunistic infection occurs (that is, clinical progression to stage 4 disease, namely AIDS) but detailed knowledge of the aetiology of intestinal immune failure is lacking. However, protection of intestinal mucosal surfaces with antibodies against HIV, induced by vaccination using the oral or rectal route, is an area of great interest. The major site of entry of HIV is thought to be via the intestinal tract and thus protection of its surfaces may be crucial in preventing infection.

The impact of AIDS mortality on children's education in Kampala (Uganda)

The socioeconomic impact of the AIDS epidemic in Uganda has been evaluated through carrying out a household survey in central Kampala. A chronic disease with fever and weight loss, occurring mainly in young adult, caused about 1% mortality in 1988 in the area studied. There was a negative relation between being orphaned and access to school education. It is suggested that community-based AIDS patient care activities should put special emphasis on educational support of these children.

Revival of the Ugandan Blood Transfusion System 1989: an example of international cooperation

10 yr of civil war in Uganda had destroyed the Blood Transfusion Service when the government came to power in 1986. AIDS had become recognized as a problem of severe proportion. In 1987, the E.E.C. pledged to rehabilitate the central blood bank. This paper describes the first year of operation from December 1988. Over 5000 units of blood, largely from volunteer donors, were delivered to 19 hospitals. The overall incidence of HIV-1 seropositivity was 14.6% and Hepatitis B surface antigen was 5.5%. The cost was 21.5 ECU (US $25) for each unit of HIV negative, H.B.s.Ag. negative, blood.

Low prevalence of oral mucosal lesions in HIV-1 seropositive African women

In Nairobi (Kenya) 334 women prostitutes of whom 80.5% were HIV-1 positive, were examined for oral mucosal lesions; 15.6% of seropositive, and 4.6% of seronegative, women had oral mucosal lesions, predominantly oral candidiasis. In the seropositives, 8.6% had erythematous, 1.1% had hyperplastic candidiasis, and 0.4% had hairly leukoplakia as the only oral lesions; 0.4% had a combination of erythematous and hyperplastic candidiasis, and 1.5% had combinations of pseudomembranous and erythematous candidiasis in the presence of hairly leukoplakia. Of the 211 seropositive women for whom we knew the first date on which a positive serologic test was obtained, the likelihood of developing an oral mucosal lesion was found to be dependent on the duration of seropositivity. The low incidence of oral mucosal lesions in this population may be due to the relatively recent acquisition of HIV-1 infection.

Interleukin-1-induced anorexia in the rat. Influence of prostaglandins

The anorexia associated with acute and chronic inflammatory or infectious conditions is poorly understood. Our objectives were to explore the anorexigenic effects of interleukin-1 (IL-1) in the rat. Recombinant human (rh) IL-1 beta, murine (rm) IL-1 alpha and to a lesser extent rhIL-1 alpha significantly reduced food intake at greater than or equal to 4.0 micrograms/kg i.p. but not at lower doses, in young (200-250 g) meal-fed rats on chow diets. The anorexic effect appears to be mediated by prostaglandins since pretreatment with ibuprofen completely blocked it, and a fish oil based diet abolished it, in comparison to corn oil or chow diets. Fish oil feeding also decreased basal and IL-1 stimulated prostaglandin E2 production by tissues in vitro (liver, brain, peritoneal macrophages) and in the whole body. Constant intravenous infusions of lower doses of IL-1 also diminished food intake, though intravenous boluses did not (reflecting rapid renal clearance). Chronic daily administration of IL-1 caused persistent inhibition of food intake for 7-17 d in chow and corn oil fed rats, but had no effect in fish oil fed rats. There was an attenuation of the effect (tachyphylaxis) after 7 d in corn oil and chow fed rats, but slowed weight gain and lower final weights were observed after 17-32 d of daily IL-1. Old (18-20 mo Fisher 344) rats showed less sensitivity to IL-1 induced anorexia. In conclusion, IL-1 is anorexigenic in the rat, but this is influenced by the structural form of IL-1, the route and chronicity of administration, the source of dietary fat, and the age of the animal. The ability of prior fat intake to influence the anorexic response to IL-1 represents a novel nutrient-nutrient interaction with potential therapeutic implications.

Cryptosporidiosis in children of eastern India

Cryptosporidium infection was found in association with acute diarrhoeal disease in ten patients (13%) of a total of 77 children below the age of 8 years admitted over a period of 1 year to Bhubaneswar Capital Hospital, Orissa state, India. Contrary to another report from South India, there were no asymptomatic cryptosporidium oocyst excretors detected either in the matched control group of 42 children without diarrhoea or in a group of 113 healthy school children investigated. A clustering of seven cases occurred in the months of the rainy season and of three cases in the winter months. Nine out of 63 children (14.3%) below the age of 2 years were infected. Seven of the ten infected children were significantly below their expected weight-for-age, but the mean weight-for-age did not differ from those of the uninfected children. The possible epidemiological factors in the transmission of cryptosporidium are discussed.

Non-traumatic coma in Zambia

A series of 170 patients with non-traumatic coma seen over a 16-month period is reported. The Glasgow coma scale significantly correlated with outcome (P less than 0.001). The diagnosis was also important in determining outcome. Hospital mortality was lowest in patients with cerebral malaria (22.7%), eclamptic coma (36.4%), and organophosphorous poisoning (30.4%). A diagnostic approach to non-traumatic coma is outlined and the management of the different causes is discussed. Most hospitals in tropical Africa should be able to diagnose up to 90% of cases with non-traumatic coma and simple therapy is likely to be effective in the majority of cases.

AIDS: methodological problems in studying its prevention and spread

This paper outlines some problems in conducting AIDS research in developing countries, discusses the impact of the socio-cultural setting on study efforts, and emphasizes the need for adopting methodological approaches that are highly sensitive to the environment. The importance of seeing AIDS as a disease that affects humans not merely biologically, but also socially--in terms of their conceptions of sexual behavior and their belief systems of disease, illness and sickness--is considered. The potential of scientists to disregard this facet in the study of AIDS is stressed. The imperatives for interdisciplinary collaboration between the medical and social scientists are examined to argue that without combining research agendas, significant variables will be ignored in the search for ways to control AIDS. Special attention is given to the limitations of several methods that are employed by medical and social science researchers, including research designs, sampling, data collection and analysis, to suggest that with AIDS research these may be difficult to operationalize. The ethical implications of some of these are weighed. The interaction of economic and political conditions of the context with research activity is explored. Suggestions are given which take cognizance of the fact that it is human beings and Third World conditions, as well as the complexities of HIV and AIDS, that make AIDS research so problematic.

HIV infection in developing countries

Shortly after the first reports on the acquired immunodeficiency syndrome (AIDS) in the United States, it became clear that the disease was also particularly frequent in Haitians living in North America (Pitcheniket at., 1983; Curranet al., 1985) and in Africans seen in Europe for medical care (Katlamaet al., 1984; Clumecket al., 1984). Subsequently, surveys in Haiti and in Central Africa confirmed the occurrence of epidemic foci of AIDS in these areas (Papeet al., 1983; Malebrancheet al., 1983; Piotet al., 1984; Van de Perreet al., 1984).

Acquired immunodeficiency syndrome and human immunodeficiency virus infection in Bujumbura, Burundi

In the first seroepidemiological survey in Burundi in 1984, only 59 acquired immunodeficiency syndrome (AIDS) cases were recognized. We report here clinical surveillance of AIDS cases in the 4 hospitals in Bujumbura during a 4-month period in 1986. The project was combined with a seroprevalence study of pregnant women in the 6 dispensaries in Bujumbura. 258 AIDS patients were recorded. 16% of the 925 pregnant women were seropositive for human immunodeficiency virus (HIV). The clinical characteristics of 120 adult AIDS patients were similar to those reported in Kinshasa or Kigali. From demographic findings we presume that the major mode of HIV transmission in Bujumbura is by sexual contact. The results of this study formed the starting point of prevention activities against AIDS in Burundi.

Human immunodeficiency virus infection among employees in an African hospital

To define the prevalence and course of human immunodeficiency virus (HIV) infection, we examined prospectively a cohort of 2002 adult hospital workers in Kinshasa, Zaire. From 1984 to 1986 the prevalence of HIV infection increased from 6.4 percent to 8.7 percent. Over the two years there was a cumulative incidence of new HIV infection of 3.2 percent. The prevalence was higher among women (16.9 percent) and men (9.3 percent) under the age of 30 than among women (9.0 percent) and men (6.2 percent) over 30. Prevalence rates were similar among physicians (5.6 percent), laboratory workers (2.9 percent), and clerical workers (7.9 percent), but they were higher among female nurses (11.4 percent) and manual workers (11.8 percent). Despite marked differences in the intensity of nosocomial exposure, female nurses had similar infection rates on the female internal medicine ward (9.9 percent), in pediatrics (10.8 percent), and in the delivery room (10.7 percent). The attributable risk of HIV infection from a transfusion was 5.9 percent. Neither medical injections nor scarification was a risk factor for HIV infection. Of the 101 seropositive asymptomatic employees in the 1984 survey, 16 percent had AIDS-related complex, 3 percent had AIDS, and 12 percent had died of AIDS by 1986. Previous studies have revealed a seroprevalence of 8.4 percent among women attending an antenatal clinic near the hospital in 1984 and 1986, and of 5.8 percent (in 1984) and 6.5 percent (in 1986) among men donating blood at the hospital's blood bank. We conclude that there is a continuing high prevalence of HIV infection among hospital workers in Kinshasa, Zaire, which appears to be representative of that in the community and not nosocomial.

Cytoplasmic assembly and accumulation of human immunodeficiency virus types 1 and 2 in recombinant human colony-stimulating factor-1-treated human monocytes: an ultrastructural study

Recombinant human colony-stimulating factor-1-treated human peripheral blood-derived monocytes-macrophages are efficient host cells for recovery of the human immunodeficiency virus (HIV) from blood leukocytes of patients with acquired immunodeficiency syndrome. These cells can be maintained as viable monolayers for intervals exceeding 3 months. Infection with HIV resulted in virus-induced cytopathic effects, accompanied by relatively high levels of released progeny virus, followed by a prolonged low-level release of virus from morphologically normal cells. In both acutely and chronically infected monocytes, viral particles were seen budding into and accumulating within cytoplasmic vacuoles. The number of intravacuolar virions far exceeded those associated with the plasma membrane, especially in the chronic phase, and were concentrated in the perinuclear Golgi zone. In many instances, the vacuoles were identified as Golgi elements. Fusion of virus-laden vacuoles with primary lysosomes were rare. The pattern of cytoplasmic assembly of virus was observed with both HIV types 1 and 2 and in brain macrophages of an individual with acquired immunodeficiency syndrome encephalopathy. Immunoglobulin-coated gold beads added to acutely infected cultures were segregated from the vacuoles containing virus; relatively few beads and viral particles colocalized. The assembly of HIV virions within vacuoles of macrophages is in contrast to the exclusive surface assembly of HIV by T lymphocytes. Intracytoplasmic virus hidden from immune surveillance in monocytes-macrophages may explain, in part, the persistence of HIV in the infected human host.

Nosocomial transmission of HIV in Africa: what tribute is paid to contaminated blood transfusions and medical injections?

We reviewed the published data on the possible impact of medical injections and blood transfusions on the spread of human immunodeficiency virus (HIV) in Africa. We also compared these results to our experience in Rwanda, central Africa. The importance of medical injections in the epidemic of HIV infection seems to differ from one area to another. The excess of injections experienced by HIV seropositive subjects in Zaire could be secondary to the parenteral treatment of early HIV-related illness or to the treatment of sexually transmitted diseases, rather than being the cause of HIV infection, as suggested by Rwandese studies. In contrast, blood transfusions have been shown to represent an important source of nosocomial HIV infection in many African countries. Effective and relatively inexpensive measures to diminish the iatrogenic spread of HIV infection in developing countries are summarized.

Antibody to the AIDS virus in Kaposi's sarcoma in Nigeria

The present study has investigated whether Kaposi's sarcoma (KS) in Nigeria is associated with infection with the AIDS virus variously called human T-cell lymphotropic virus type III (HTLV-III), lymphadenopathy/AIDS virus (LAV), and AIDS-associated retrovirus (ARV). Serum samples from 40 KS patients, 30 patients with malignant melanoma of the foot (contemporaneous controls), and 50 normal nontumour-bearing controls were tested for anti-AIDS virus antibody by enzyme-linked immunosorbent assay (ELISA). The assay consistently and reproducibly failed to show seropositivity in all the patients and controls. These results show that Kaposi's sarcoma in Nigeria is not associated with infection with the AIDS virus and that the virus is not endemic in this region.

Human immunodeficiency virus infection in childhood

Acquired immunodeficiency syndrome is associated with considerable morbidity in infants and children. It is caused by human immunodeficiency virus (HIV) which can be transmitted vertically from mother to infant early in pregnancy. Transmission might also occur via breast milk. Although the exact transmission rate of HIV from mother to infant is not known, HIV can become a major threat to child survival. This threat is already present in Africa where high seroprevalences have been reported among infants and young children. Transmission via blood products is decreasing due to reliable methods of screening donors for HIV antibody. Where these tests are not available, parenteral transmission will increase the incidence of HIV infection. The clinical picture of HIV infection in children presents with failure to thrive, pulmonary interstitial pneumonitis, hepatosplenomegaly and recurrent bacterial infections. These are common manifestations of diseases prevalent in children in Africa where malnutrition and recurrent parasitic infections already cause immunosuppression. Recognition of the syndrome is therefore difficult. There is no available cure for HIV infection. Supportive treatment and relief of pain and suffering are the only means of management at present. Prevention of spread of the illness to infants and young children is therefore of paramount importance.

Human immunodeficiency virus detected in bowel epithelium from patients with gastrointestinal symptoms

Infectious human immunodeficiency virus (HIV) was recovered from two out of four bowel biopsy specimens from acquired immunodeficiency syndrome (AIDS) patients with chronic diarrhoea of unknown aetiology. In-situ hybridisation of biopsy specimens from rectum and duodenum of other AIDS patients with gastrointestinal complaints showed the presence of HIV-infected cells in both the base of the bowel crypts and the lamina propria. The type(s) of epithelial cell(s) infected could not be determined definitively. However, the association of in-situ labelling of HIV RNA in argentaffin staining cells strongly suggests that enterochromaffin cells derived from neural crest tissue are among the target cells. This evidence that HIV can directly infect the bowel raises the possibility that the virus causes some of the gastrointestinal disorders of AIDS patients.

The prevalence of infection with human immunodeficiency virus over a 10-year period in rural Zaire

In 1985 we tested 659 human serum samples, collected in the remote Equateur province of Zaire in 1976, for antibody to human immunodeficiency virus (HIV). Five (0.8 percent) were positive, and HIV was isolated from one of these. Follow-up investigations in 1985 revealed that three of the five seropositive persons had died of illnesses suggestive of acquired immunodeficiency syndrome (AIDS), and two remained healthy but seropositive. In 1986, a serosurvey we conducted using a cluster-sampling technique in the same region showed a seroprevalence of 0.8 percent in 389 randomly selected residents. The seroprevalence in 283 prostitutes was 11 percent. Patients with AIDS were identified in various hospitals in the province. Risk factors for AIDS included a greater than average number of sexual partners and residence outside the area. We believe that the long-term stability of HIV infection in residents of rural Zaire suggests that social change may have promoted the spread of AIDS in Africa.

Sexually transmitted viral infections in various population groups in Mogadishu, Somalia

The prevalence of serum antibodies to human immunodeficiency virus (HIV), herpes simplex virus (HSV), and cytomegalovirus (CMV) and of hepatitis B virus (HBV) markers was investigated in different population groups, including prostitutes, in Mogadishu, Somalia. Hepatitis B surface antigen (HBsAg) was detected in 37% of pregnant women, 4% of neonates, 22% of educated women, and 20% of prostitutes. No significant difference between the groups was observed for HBV. In contrast to figures reported from South East Asia, the prevalence of hepatitis Be antigen (HBeAg) was 18% in prostitutes and only 3% in all other HBsAg positive subjects. The prevalence of antibodies to HSV (100%) and CMV (90%) was very high, but antibodies against HIV were not detected in any of 471 sera. As the routes of transmission for HBV and HIV infections are considered to be similar, HIV will probably spread rapidly in Somalia once this virus has been introduced into the country.

Antiviral therapy in AIDS. Clinical pharmacological properties and therapeutic experience to date

The rapid spread of human immunodeficiency virus (HIV) infections and the grim outcome of these infections have focused interest on the possibilities for medical intervention. The end-stage of these infections, acquired immune deficiency syndrome (AIDS), was first recognised in 1981, and the causative agent isolated in 1983. Already several antiviral drugs have been investigated. One initially promising drug, suramin, was found to have a net harmful effect but another, zidovudine (azidothymidine) has been shown to prolong life in AIDS patients. The properties of these and several other antiviral drugs such as antimoniotungstate (HPA-23), foscarnet (phosphonoformate) ribavirin, dideoxynucleotides, and interferons, are reviewed. The role of immunomodulating modalities such as plasmapheresis, bone marrow transplantation, thymosin, interleukin-2, inosine pranobex (isoprinosine), and cyclosporin are also discussed. None of the currently available drugs hold promise as monotherapy. Through analysis of the experience with these drugs and the increasing knowledge of HIV pathogenesis, new drugs can be designed. It seems increasingly clear that drugs will eventually have to be used in combination in order to reduce toxicity, exploit therapeutic synergy, and reduce the risk of HIV resistance. The theoretical and experimental background for such combinations are currently being elucidated.

Evaluation of a clinical case-definition of acquired immunodeficiency syndrome in Africa

A provisional clinical case-definition for acquired immunodeficiency syndrome (AIDS) developed by the World Health Organisation (WHO) for use in Africa was tested on 174 inpatients at Mama Yemo Hospital, Kinshasa, Zaire. In this hospital population with a 34% infection rate of human immunodeficiency virus (HIV), the clinical case-definition had a specificity of 90%, a sensitivity of 59%, and a predictive value of 74% for HIV seropositivity. These results support the use of the WHO clinical definition for AIDS in Africa. However, since HIV prevalence and disease expression vary, similar evaluations should be carried out in different regions.

Prevalence of human T-lymphotropic retroviruses type III (HIV) and type IV in Ivory Coast

Serological investigations in the Ivory Coast indicate that, despite the rarity of overt acquired immunodeficiency syndrome (AIDS), human immunodeficiency virus (HIV) is widely prevalent. So also is human T-lymphotropic virus type IV (HTLV-IV). The highest rates of HIV and HTLV-IV seropositivity were observed in female prostitutes. These findings suggest that, like HIV, HTLV-IV can be transmitted by heterosexual contact, and that the mobility of prostitutes may be an important factor in spread of the retroviruses in Africa. The incidence of HIV-associated AIDS in the Ivory Coast is likely to rise sharply in the next few years.

HLA studies of endemic African Kaposi's sarcoma patients and matched controls: no association with HLA-DR5

In the search for a genetic factor involved in the etiology of Kaposi's sarcoma, several studies have recently focused on a significantly increased HLA determinant, DR5, as well as a decreased DR3, among patients with both the classical and the AIDS-related form of Kaposi's sarcoma. To test the consistency of this phenomenon, we analysed the frequencies of HLA immunogenetic markers in 23 histologically confirmed Kaposi's sarcoma patients from Central Africa, where this tumor is endemic, and a local sex- and tribe-matched control group. No definite association was observed for any of the HLA antigens, including DR5 and DR3. We were not able to support the hypothesis that the same HLA-associated immune susceptibility factors are involved in all types of Kaposi's sarcoma.

A prevalence study of HIV antibodies in rural Kenya

In order to describe the prevalence of HIV antibodies and AIDS in West Kenya, serological tests, including ELISA, and in some cases immunoblotting, were performed on whole blood collected on filter paper from 603 Kenyans. Serum samples from 55 of these persons underwent the same examinations, and 45 were further examined by immunofluorescence and a commercial ELISA. The majority of the Kenyans examined were residents of a province in West Kenya, while the others were students from other parts of Kenya, predominantly rural areas. Male/female ratio was 62/38. Median age was 18 years (range 0-70). Five Danes with previously demonstrated HIV antibodies, and 10 Danish controls were examined for HIV antibodies in filter paper whole blood, and in serum by ELISA and immunoblotting. The tests carried out on the filter paper blood were found to be reliable. Only one of the examined Kenyans had antibodies to HIV by both ELISA and immunoblotting, representing a prevalence of 0.17% (95% confidence limits: 0.00-0.93%). This low prevalence is not in accord with results previously presented from rural districts in Kenya.

Variable and conserved neutralization antigens of human immunodeficiency virus

Human immunodeficiency virus type 1 (HIV-1, HTLV-III/LAV), the retrovirus responsible for acquired immune deficiency syndrome (AIDS), shows a high degree of genetic polymorphism, particularly in the env gene. We have examined sera from rabbits and guinea pigs immunized with gp130, a recombinant env glycoprotein, and sera from HIV-1-infected subjects, to test their capacity to neutralize a panel of genetically divergent HIV-1 isolates. The sera raised against recombinant antigen specifically neutralized the virus strain from which the env gene was cloned (HTLV-IIIB), but not an independent isolate (HTLV-IIIRF). One rabbit serum tested on seven isolates cross-neutralized two at lower titres. In contrast, human sera from Britain and Uganda, chosen for ability to neutralize HTLV-IIIRF, cross-neutralized six other HIV-1 isolates. When serum and isolate were derived from the same subject, the serum was in some cases effective at slightly lower concentrations (higher titres). Human complement did not affect neutralization titres. These findings indicate that genetically diverse HIV-1 isolates carry both variable and widely conserved antigenic epitopes for neutralizing antibodies. The identification of shared epitopes may help the development of protective vaccines.

Evidence for heterosexual transmission and clinical manifestations of human immunodeficiency virus infection and related conditions in Lusaka, Zambia

In a hospital-based survey in Lusaka, Zambia, 189 (17.5%) of 1078 subjects had antibodies against the human immunodeficiency virus (HIV). The prevalence of antibodies was low in subjects aged less than 20 or greater than 60 years; in men the peak prevalence (32.9%) occurred in those aged 30-35 years, and in women (24.4%) it occurred in the 20-25 year age-group. There was no significant difference in prevalence by sex after adjusting for age. High educational level was independently associated with HIV seropositivity; the antibody against HIV was found in 18.4% of blood donors and in 19.0% of hospital workers. Among patients the antibody prevalence ranged from 8.7% in antenatal women and 9.3% in orthopaedic patients to 29.2% in those attending sexually transmitted disease (STD) clinics (the prevalence being 37.3% in previous attenders and 22.8% in first-time attenders). Seropositivity rates were higher in patients with an infectious problem (23.4%) than in those without (11.4%, p = 0.0002). Herpes zoster, oral thrush, diarrhoea, tuberculosis, and weight loss were independently correlated with seropositivity. The data strongly suggest that HIV infection is prevalent in Africa and is transmitted heterosexually. The restricted distribution of seropositivity to the sexually active age-groups indicates that the epidemic, at least in this part of Africa, is newly introduced; this has substantial implications for prevention.

Absence of antibodies to the human immunodeficiency virus in sera from Africa prior to 1975

Three different assays for detection of antibodies to the human immunodeficiency virus (HIV) were conducted on 677 sera obtained from 1964 to 1975 from male and female children and adults in Uganda and other countries in Africa. Several sera were collected from individuals with Kaposi sarcoma. No evidence of antibodies to the virus was noted up to 1975. These results strongly suggest that the emergence of HIV in Africa occurred relatively recently. Further studies are required to determine the geographic origin of the acquired immunodeficiency syndrome virus.

A transmission model for AIDS

Mathematical and computer-simulation models of sexually transmitted diseases, which have been used to study gonorrhoea and human papilloma virus transmissions, are applied to the study of AIDS. The problems of adapting the general model to the new problem, within already established principles, are described; and solutions offered. The objective is to predict equilibrium levels for the prevalence and incidence of HTLV-III infection in the U.K. Within the uncertainties of the available information on sexual behaviour in our society, on the risk of transmission and on the natural history of the infection, the model predicts: the infection will be self-sustaining in the heterosexual as in the homosexual population, the equilibrium prevalence of HTLV-III infection may attain 500-800 per 1000 among promiscuous male homosexuals and female prostitutes: 1 to 5 per 1000 among non-promiscuous heterosexual males and females: and 8 to 15 per 1000 overall, these equilibria will be reached in about 10 years among the promiscuous classes, but not for 40 years among the less promiscuous, this implies 20,000 to 40,000 deaths from AIDS per year in the U.K., these estimates will be modified by behaviour changes in the population as a whole, responding to fear of infection and to health-education approaches, but substantial control will depend upon the production of a vaccine and its preferential use in the promiscuous classes.