[Aetiology of AFB negative pneumonias in hospitalized HIV patients in Dakar]. / Étiologie des pneumonies BAAR négatives chez les patients infectés par le VIH hospitalisés à Dakar (étude ANRS 1260).

A prospective study was carried out in two tertiary hospitals in Dakar to determine the main causes of sputum acid-fast bacillus (AFB) smear-negative pneumonia in HIV-infected patients. All clinical and microbiological records were reviewed by experts. Seventy patients were finally enrolled. Most of them were hospitalized at an advanced stage of AIDS. The median CD4 cell count was 62/mm(3) and the median body mass index (BMC) was 18 kg/m(2). Thirty-one patients (44 %) were known as seropositive for HIV infection prior to admission. Radiological opacities were localized in 70 % of patients and diffuse in 21 %. Fiberoptic bronchoscopy was performed in 50 patients (71 %). A definite or probable diagnosis was obtained in 55 patients (79 %). Bacterial pneumonia (usually due to Enterobacteriaceae and Pseudomonas aeruginosa), tuberculosis, Pneumocystis pneumoniae and other causes (Kaposi's sarcoma, atypical mycobacteria) were diagnosed in 67 %, 24 %, 5 %, and 13 % of these patients respectively. In conclusion, pneumonia of bacterial origin and tuberculosis can be incriminated in the majority of cases of AFB negative pneumonia observed in HIV patients in Dakar.

Mobility and the spread of human immunodeficiency virus into rural areas of West Africa.

BACKGROUND: In eastern and southern Africa, the human immunodeficiency virus (HIV) epidemic appeared first in urban centres and then spread to rural areas. Its overall prevalence is lower in West Africa, with the highest levels still found in cities. Rural areas are also threatened, however, because of the population's high mobility. We conducted a study in three different communities with contrasting infection levels to understand the epidemiology of HIV infection in rural West Africa. METHOD: A comparative cross-sectional study using a standardized questionnaire and biological tests was conducted among samples in two rural communities of Senegal (Niakhar and Bandafassi, 866 and 952 adults, respectively) and a rural community of Guinea-Bissau (Caio, 1416 adults). We compared the distribution of population characteristics and analysed risk factors for HIV infection in Caio at the individual level. RESULTS: The level of HIV infection was very low in Niakhar (0.3%) and Bandafassi (0.0%), but 10.5% of the adults in Caio were infected, mostly with HIV type 2 (HIV-2). Mobility was very prevalent in all sites. Short-term mobility was found to be a risk factor for HIV infection among men in Caio (adjusted odds ratio (aOR) = 2.06; 95% CI: 1.06-3.99). Women from Caio who reported casual sex in a city during the past 12 months were much more likely to be infected with HIV (aOR = 5.61 95% CI: 1.56-20.15). Short-term mobility was associated with risk behaviours at all sites. CONCLUSIONS: Mobility appears to be a key factor for HIV spread in rural areas of West Africa, because population movement enables the virus to disseminate and also because of the particularly risky behaviours of those who are mobile. More prevention efforts should be directed at migrants from rural areas who travel to cities with substantial levels of HIV infection.

Ordinary and opportunistic enteropathogens associated with diarrhea in Senegalese adults in relation to human immunodeficiency virus serostatus.

OBJECTIVES: A survey was conducted in Dakar, Senegal, to identify major types and prevalences of bacteria, parasites, fungi, and Rotaviruses associated with diarrhea in relation to human immunodeficiency virus (HIV) serostatus with the goal to provide guidance to physicians for case management. METHODS: Etiologic agents were identified in a case control study: cases were HIV-infected patients with diarrhea (HIV+ D+) and HIV seronegative patients with diarrhea (HIV D+); controls were HIV-infected patients without diarrhea (HIV+ D ) and seronegative controls without diarrhea (HID D ). Ordinary enteric pathogens were identified by conventional methods. Different Escherichia coli pathotypes were characterized by polymerase chain reaction (PCR), identification of HEp-2 cell adherence pattern, Sereny test, GM1-ELISA, and the suckling mouse assay. Opportunistic parasites, such as Cryptosporidium and Microsporidium, were identified by the Kinyoun method and trichromic stain of Weber, respectively. Rotaviruses were identified with a commercial latex agglutination kit. Antimicrobial susceptibility testing was carried out by the disk diffusion method. RESULTS: Among the 594 patients examined, 158 were HIV+ D+, 121 were HIV2 D+, 160 were HIV+ D , and 155 were HIV D . The main etiologies of diarrhea were different according to HIV serostatus of patients. In immunocompetent adults the main causes of diarrhea were Shigella sp (12.4%), Entamoeba histolytica(10.7%), Salmonella enterica (6.6%), and Giardia (4.9%). In the immunocompromised host the more frequent pathogens were enteroaggregative E. coli (19.6%), Microsporidium (9.4%), Cryptosporidium sp (8.2%), Rotavirus (8.2%), Shigella sp (7.6%), Candida albicans (7.6%), E. histolytica (5.1%), S. enterica (4.4%), and Isospora belli (4.4%). Also, Blastocystis hominis has to be considered as an opportunistic parasite, because it was identified only in HIV-infected patients, with higher prevalence in adults with diarrhea (2.5% in HIV+ D+ patients; 0.6% in HIV+ D patients). High level of asymptomatic carriage of Ascaris lumbricoides and Trichuris trichiura and some cases of multiple infections were observed. Fungi, Cryptosporidium sp and Microsporidium sp, were often identified in patients with low CD4 counts (range, 79 250 cells/mL). Independently from HIV-serostatus, CD4 count was lower in diarrheic persons, suggesting that diarrhea is a debilitating illness and that effective management of diarrhea can prevent immunosuppression. Isolated enteropathogenic strains displayed high resistance to most antibiotics used in Senegal for treating diarrhea (ampicillin, tetracycline, cotrimoxazole); they were susceptible to amikacin, gentamicin, and norfloxacin. CONCLUSION: These epidemiologic data suggest that guidelines for the management of diarrhea during HIV infection in Dakar should be updated.

Low and stable HIV infection rates in Senegal: natural course of the epidemic or evidence for success of prevention?

OBJECTIVES: To document the level of HIV infection in Senegal and also to review evidence of the impact of efforts in prevention, developed by the National AIDS Control Programme and the Civil Society, on the level of the HIV epidemic. METHODS: Research, compilation and critical review of all relevant data on HIV and sexually transmission diseases (STDs) epidemiology, sexual behaviour, and the efforts in prevention developed in Senegal. RESULTS: From 1989 to 1996, the levels of HIV infection estimated in four sentinel urban regions remained stable at around 1.2% in the population of pregnant women, and at 3% in male STD patients. It had increased to 19% in female sex workers. A strong political and community commitment led to an early response to the HIV/AIDS epidemic that has been extended since 1986. Blood transfusion safety was established at the start of the HIV epidemic. The level of knowledge of preventive practices relating to HIV/AIDS among the general population exceeded 90% in the early 1990s. From 1991 to 1996, a 30% to 66% decrease of the STD prevalence rates was observed in pregnant women and sex workers in Dakar. In 1997, 33% of men aged 15-49 years in Dakar reported having had sex with non-regular partners. Among them 67% reported condom use. CONCLUSIONS: It is not possible to know what the course of the HIV epidemic in Senegal would have taken in the absence of efforts at prevention. Certainly, several factors that pre-dated the occurrence of AIDS in Senegal laid the groundwork for a positive response. However, data from a number of sources do reveal the successfulness of efforts in prevention. From available data, Senegal can rightfully claim to have contained the spread of HIV by intervening early and comprehensively to increase knowledge and awareness of HIV/AIDS and to promote safe sexual behaviour.

V3 serotyping of HIV-1 infection: correlation with genotyping and limitations.

HIV-1 V3 serotyping is a classification of immunodeficiency viruses based on antibody binding to V3 peptides that allows obtaining information on circulating subtypes that could be important for population-based epidemiologic studies. Recently, several laboratories have developed V3 enzyme-immunoassays (EIAs) using V3 peptides of subtypes A to E. In the present study, the utility of including additional peptides of subtypes F to H to the EIA was evaluated on a panel of 203 well-characterized serum samples from patients with diverse geographic origins (22 countries) and known HIV-1 genotype (79 A, 61 B, 21 C, 7 D, 7 E, 21 F, 6 G, 1 H). The results indicate a high predictive value (ppv) for serotypes B (> or =0.86), D (1) and E (0.88), and confirm the difficulty of predicting genotype A or C based on serotype A or C. Results also indicate that inclusion of the F peptide in the V3 EIAs may be useful (ppv = 0.61), but introduction of peptides G and H failed to demonstrate significant sensitivity or specificity for these subtypes. Correlation between serotyping and amino-acid sequences of the V3 region from 103 samples allowed the identification of key amino-acids that appear essential for subtype-specific seroreactivity.

Geographic variation in viral load among hepatitis B carriers with differing risks of hepatocellular carcinoma.

The risk of hepatocellular carcinoma (HCC) varies significantly among hepatitis B virus (HBV) carriers from different geographic regions. We compared serological markers of HBV infection in adult male carriers from Haimen City, China and Senegal, West Africa, where the prevalence of chronic infection is similar. HCC mortality among HBV carriers is much higher in Haimen City than it is in Senegal (age-standardized rate, 878 versus 68 per l0(5) person-years). A dramatic difference was observed when HBV DNA levels in serum were assessed among carriers by Southern blot. In the Senegalese group (n = 289), 14.5% were HBV DNA positive by Southern blot in their 20s, and this percentage declined in each subsequent decade of age to 3.3, 2.9, and 0% thereafter. In the Chinese group (n = 285), a higher prevalence of HBV DNA positivity and a less consistent reduction were seen; 29.4% were positive in their 20s, and 30.2, 23.6, and 20.6%, respectively, were positive in each subsequent decade of age. Among 102 male Asian-American HBV carriers, the prevalence of HBV DNA positivity was intermediate between the Chinese and Senegalese populations (36.8, 10.7, 3.0, and 4.6% in each subsequent decade of age). Viral titers were similar among those who were HBV DNA positive in all three populations [median value, 10(7) virions/ml (range, 10(6)-10(9) virions/ml)]. The presence of HBV DNA in serum was positively associated with serum glutathione S-transferase, a marker of liver damage. These findings suggest that the more prolonged maintenance of productive virus infection in the Chinese carriers compared with the Senegalese carriers may explain their higher risk of HCC. This profound difference in the natural history of chronic infection may be due to earlier age of infection in China or to as yet unknown environmental or genetic factors.

Diversity of antibody binding to V3 peptides representing consensus sequences of HIV type 1 genotypes A to E: an approach for HIV type 1 serological subtyping.

We investigated whether V3-binding assays might be useful to analyze human immunodeficiency virus type 1 (HIV-1) variants in different geographic regions. We showed that strong cross-reactivity between subtype-specific V3 peptides is almost inevitable in standard indirect enzyme-linked immunosorbent assays (EIA), impairing precise serological subtyping. We therefore developed a subtype-specific EIA (HIV-1 SSEIA) that uses the principle of blocking by an excess of peptide in the liquid phase. Using 231 serum samples collected from HIV-1-infected individuals in 10 different geographical areas from 4 continents, we showed that this approach detected the dominant subtype reactivity in more than 97% of the cases. Internal controls (0 and 100% blocking) were used for every sample such that comparative analysis was possible, independent of both the individual humoral response and the time of collection during the course of infection. This was validated by the excellent concordance of the serological profiles of couples and the temporal stability of the serological profile in individuals. The geographical distribution of the various subtypes in the SSEIA was in agreement with the present knowledge of the distribution of the various genotypes. Although the goal of this study was not an extensive seroepidemiological survey, our results showed that the various profiles in most of the regions were relatively homogeneous, but in central Africa there was a large diversity of serological profiles. Cluster analysis identified a limited number of V3 serogroups of serotypes within the HIV-1 group M. Five serogroups, some of them divided into subgroups, were identified and characterized by a mean serological profile. Our data confirmed that subtypes A and C, although being dissimilar genetic subtypes, present conserved antigenic properties in the V3 region, and that the D subtype is probably the most divergent within the group M (B Korber et al., J Virol 1994;68:6730). Cluster analysis showed a clear correlation between position within the dendrogram and geographical origin of the samples. This is further support for the reliability and thereof the usefulness of the SSEIA. This simple methodology may help facilitate the analysis of the distribution of various HIV-1 subtypes circulating in different populations and regions.

No direct relationship between HIV1/2 infection and HHV-6 antibody response in a large-scale European and African trial.

BACKGROUND: Tropism of both human herpesvirus-6 (HHV-6) and human immunodeficiency virus (HIV) for CD4+ lymphocytes, and several studies on HIV enhancer transactivation by HHV-6 have suggested that HHV-6 could be implicated as a cofactor in the progression of HIV infection to AIDS. OBJECTIVES: To determine if there is any relationship between HHV-6 infection and the course of HIV infection. STUDY DESIGN: 527 French and 558 African sera (210 from Senegal, 348 from Ivory Coast) were tested for HHV-6 titers by immunofluorescence assay (IFA). For each country, patients studied were divided into several groups; those with AIDS, those who were HIV-seropositive but symptomless, and HIV-seronegative patients. RESULTS: No statistical difference could be found between HHV-6 prevalences or HHV-6 geometric mean titers obtained for each geographical area in the different HIV-1- and/or HIV-2-positive and HIV-negative groups. HIV patients with clinical manifestations of AIDS did not differ in percent seropositivity or distribution of titers from the HIV-asymptomatic patients or HIV-seronegative patients. CONCLUSION: These findings suggest that there is no correlation between HHV-6 antibodies and HIV seropositivity or with the stage of HIV infection.

Viability of Bordetella pertussis in four suspending solutions at three temperatures.

We studied the survival of Bordetella pertussis in four suspending solutions (Casamino Acids broth, deionized water, phosphate-buffered saline, and serum inositol), subjected to three storage temperatures (4, -20, and -70 degrees C) and two freezing methods (direct freezing and fast-freezing in an ethanol-dry-ice bath). Recovery rates were higher for longer periods for suspensions stored at -70 degrees C than those stored at -20 or 4 degrees C. Serum inositol showed the highest recovery rates for all experimental conditions, followed by Casamino Acids, deionized water, and phosphate-buffered saline. Cell viability was significantly reduced in phosphate-buffered saline suspensions fast-frozen before storage. These results identify optimal conditions for storing B. pertussis cells and are applicable to the collection, transport, and storage of aspirated nasopharyngeal samples for use in the laboratory diagnosis of pertussis.

Prevalence of antibodies to hepatitis C virus among patients with leprosy in several African countries and the Yemen.

The prevalence of anti-HCV was determined in 1,309 leprosy patients and a control group of 1,469 subjects from 6 sub-Saharan African countries and the Yemen. Sera found positive by an initial second generation ELISA were subjected to 3 additional confirmatory tests. The anti-HCV prevalence in leprosy patients (7.1%) was significantly higher than in the control group (2.6%). HCV seroprevalence increased with age in both the control and leprosy groups. No statistically significant difference could be found between anti-HCV prevalence and the several clinical forms of leprosy among patients. The results of this study indicate a high degree of exposure or chronic carriage of hepatitis C among leprosy patients.

[Importance of culture media choice in the isolation of Haemophilus ducreyi. Experience in Senegal]. / Importance du choix d'un milieu de culture dans l'isolement de Haemophilus ducreyi. Expérience du Sénégal.

Genital ulcerations typify one of the major reasons clients seek STD consultation in developing countries. The usual etiologies are syphilis, chancroid and herpes. The ideal diagnostic approach is to undertake complete laboratory examination that are rarely possible in structure destitute of laboratory analysis possibilities which is the case for most of the STD transmission agents. Chancroid is caused by Haemophilus ducreyi, a short Gram negative bacteria. The bacteriological diagnosis is based on direct examination, isolation and identification of the bacteria. The nutritive exigence of the bacteria required 3 medium of isolation (PPLO base Pasteur), GC base (GIBCO) and Muller Hinton base (Becton & Dickinson, with "chocolate" agar) have been tested from the chancre samples of 108 male patients who had a median age of 31 years. Direct exams were positive in 66 cases (61%) and culture exams positive in 53 cases (49%). The Muller Hinton base with "chocolate" agar produced the best results and seems to be the medium of choice for isolated strains in Senegal. The culture mediums currently used in Europe are apparently inappropriate for the germ culture in Senegal. We have also observed that all the isolated strains were producers of beta-lactamase. Antibiotic treatment before the sample swab is taken seems to have an inhibiting effect on the culture. Direct examination with a sensibility of 94.3% and a specificity of 70.9% remains sufficient in routine presumptive diagnosis in endemic areas.

High antigenic cross-reactivity of the V3 consensus sequences of HIV-1 gp120.

The principal neutralization determinant (PND) of the human immunodeficiency virus type 1 (HIV-1) is located within the variable V3 region of the external envelope protein gp120. Although it is recognized that V3 sequences induce antibody response with restricted neutralization activity in vitro, we observed that the V3 consensus sequences representing North American/European and African isolates were highly cross-reactive, binding 94 and 77%, respectively, of sera collected from HIV-1 individuals originating from various parts of the world. Even HIV-1-positive sera from some East African residents, infected by strains whose V3 loop sequences are undoubtedly distinct from the North American/European consensus V3 loop sequence, reacted better to the V3 North American/European consensus peptide than to African-specific V3 sequences. Results indicate that the V3 consensus sequences represent the best candidates for optimal cross-reactivity with a wide variety of strains. Furthermore, using immunoassays for antibodies to prototype-specific V3 sequences, it is shown that HIV-1 strains related to the MN group are prevalent in West Africa, indicating either a West African origin of the MN-related viruses or more probably an introduction of this group of viruses through European/North American contacts.

Temporary expatriation is related to HIV-1 infection in rural Senegal.

OBJECTIVES: To assess temporary expatriation as a risk factor for HIV infection in a rural area of Senegal and to examine the transmission of HIV from expatriates to their families. DESIGN: Cross-sectional study in identified expatriates and in a representative cluster sample of the general population from the same geographical area in northern Senegal. METHODS: In 1989, a survey (including questionnaire and serological tests for HIV-1 and HIV-2) was conducted in all expatriates currently living in 11 villages in northern Senegal and spouses of all expatriates (present or not) from this area ('expatriate' group, n = 258). In parallel, a cluster sample of 600 adults was drawn from eight villages of the same area, of whom 414 were selected as the control group since they and their spouses had not travelled outside Senegal in the last 10 years. RESULTS: In the 'expatriate' group, sera from 39 subjects were confirmed as HIV-positive by Western blot [17 out of 63 men (27.0%) and 22 out of 195 women (11.3%)]. Of these subjects, 33 were infected by HIV-1, four by HIV-2 and two had a dual HIV-1/2 profile. In contrast, only two subjects (one man and one woman) from the control group were infected by HIV-2 and none by HIV-1. In men, HIV-1 seroprevalence was associated with age < 40 years [odds ratio (OR), 7.4; P = 0.03] and previous sexually transmitted disease (STD) symptoms (OR, 13.5; P = 0.03), whereas the risk factors in women were age < 25 years (OR, 3.7; P = 0.04), being a widow (OR, 30.4; P < 0.01) and presence of sexual activity over the last 2 years (OR, 21.3; P < 0.01). CONCLUSIONS: Penetration of HIV-1 infection in a country where HIV-2 is endemic shows that the HIV-1 epidemic is currently spreading to rural West Africa. Migrant workers appear to play a major role in this epidemic.

Prevalence and risk determinants of human immunodeficiency virus type 2 (HIV-2) and human immunodeficiency virus type 1 (HIV-1) in west African female prostitutes.

The authors studied the prevalence and risk determinants for human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2) in female prostitutes from Dakar (1985-1990), Ziguinchor (1987-1990), and Kaolack (1987-1990), Senegal, West Africa. Each cohort showed a distinct distribution of HIVs: 10.0% HIV-2 and 4.1% HIV-1 in Dakar, 38.1% HIV-2 and 0.4% HIV-1 in Ziguinchor, and 27.4% HIV-2 and 1.3% HIV-1 in Kaolack. In 1,275 female prostitutes from Dakar, increase years of sexual activity and a history of scarification were associated with HIV-2 seropositivity. In contrast, HIV-1 seroprevalence was associated with a shorter duration of prostitution and a history of hospitalization. In 278 female prostitutes from Ziguinchor, HIV-2 seroprevalence was associated with women of Guinea-Bissau nationality and increased years of sexual activity. In 157 female prostitutes from Kaolack, HIV-2 seroprevalence was associated with increased years of sexual activity and a history of never using condoms. The authors also studied the risk determinants for HIV-2 in the 1,280 Senegalese prostitutes pooled from all three sites. Controlling for ethnic group, women from Ziguinchor and Kaolack were more likely to be HIV-2 seropositive as compared with women from the Dakar site. Increased years of sexual activity were associated with HIV-2 seropositivity, while a history of excision and BCG vaccinations decreased the risk of HIV-2 infection.

[Prevalence of Chlamydia trachomatis in genital samples from Abidjan]. / Prévalence de Chlamydia trachomatis dans des prélèvements génitaux à Abidjan.

A study of direct genital swabs achieved in Abidjan, on 116 men and 131 women consulting for urogenital complaints, has revealed that the men show a prevalence of 28.4% Chlamydia trachomatis, and of 18.1% Neisseria gonorrhoeae. Concerning the women the prevalence of the same germs are 13.7% for Chlamydia trachomatis, and 4.6% for Neisseria gonorrhoeae. These results show the importance of Chlamydia trachomatis as a sexually transmitted disease in Abidjan (Côte-d'Ivoire). No differences were observed according to age in the two groups.

[Epidemiological study of HIV seroprevalence in a leprosy patient population in Senegal]. / Etude épidémiologique de la séroprévalence de l'infection par le VIH dans une population hansénienne au Sénégal.

We report the findings of an epidemiological study conducted between June 1989 and February 1990 on a population of leprosy patients in southern Senegal (Bignona major endemic disease sector). Two types of population were studied: patients living in urban areas and inmates of leprosaria. The global HIV seroprevalence (HIV 2 in all cases) of the leprosy-patient population was 1.15% (3/257): 0.8% (1/130) for the urban group and 1.5% (2/127) for the leprosaria. The seroprevalence rate does not differ significantly from that for the control group studied and for blood donors (1/221). The diagnosis of leprosy in the seropositive subjects had been established before 1980. None of them showed any sign of relapse. The immunodepression associated with the presence of HIV was only moderate: it was reflected in a lowering of the CD4 count and of the CD4/CD8 ratio, but with no clinical sign of AIDS.

Site-directed serology using synthetic oligopeptides representing the C-terminus of the external glycoproteins of HIV-1, HIV-2, or SIVmac may distinguish subtypes among primate lentiviruses.

In this study the presence of a highly immunogenic domain located at the C-terminus of the external glycoproteins (EGP) of human and simian immunodeficiency viruses (HIV-1, HIV-2, and SIVMAC) is shown using synthetic oligopeptides as antigens in enzyme immunoassays. This epitope is probably located within the last 13 and 15 residues of the EGP of HIV-1 and HIV-2, respectively. The C terminal epitope of the EGP of SIVMAC may involve residues located more upstream. Among the HIV-2/SIV serotype, we observed that the reactivity to the C-terminal epitope of gp120 was dependent of both species and geographical origin of the samples tested. It seems that this gp 120 C-terminal epitope could distinguish subtypes among the HIV-2/SIV serotype. Further studies, using site-directed enzyme immunoassays with synthetic peptides representing the C-terminus of the EGP derived from a wide variety of HIV2/SIV strains must be performed to confirm this observation. These kinds of assays may constitute important tools for use in seroepidemiological studies and broaden our understanding of the distribution and phylogenetic relationship of primate lentiviruses.

Seroepidemiology of human herpesvirus-6 in pregnant women from different parts of the world.

The prevalence of HHV-6 IgG was studied in 11 different countries across several continents: Morocco, Burkina-Faso, Congo, Ivory Coast, Mali, Niger, Senegal, Togo, Ecuador, Martinique, and France. The study group consisted of 550 pregnant women, representative of the general adult population in each country. Antibodies were detected by immunofluorescence assay on HSB-2 cells infected with HHV-6. Each serum was tested at nine dilutions (1:20 to 1:5,120), sera greater than or equal to 20 being considered positive. For the negative antigen control, we used mock-infected HSB-2 cells. Great differences were seen between separate areas: Morocco showed both low prevalence (20%) and a low geometric mean titer (12), whereas sub-Saharan Africa displayed high prevalences (60% to 90%) and variable geometric mean titers (34 to 229). This study revealed a prevalence of 92% for Ecuador, significantly higher than the prevalence for Martinique (50%), yet both countries had very low antibody titers compared with those found in Africa. The prevalence in France (76%) was similar to previous results from other European countries.

Laboratory diagnosis of HIV-1 and HIV-2 in Africa.

PIP: It is well accepted that HIV is the cause of AIDS and that the virus is distributed widely throughout the world. Being able to diagnose infection with HIV through laboratory tests has done much to facilitate the early recognition of the severity and extent of the AIDS pandemic. Many laboratory techniques exist to detect infection with HIV-1 and HIV-2. In recent years, however, African countries have found it difficult to implement such diagnostic tests because the tests have been either ill-suited or too expensive for the developing country setting. This paper describes many of the HIV laboratory diagnostic techniques currently used in both diagnostic and research settings. The review of techniques is, however, neither all-inclusive nor globally applicable, but intended to be simply a view of available techniques from the African perspective. The opening general section on the detection of HIV-1 and HIV-2 is followed by discussion of screening tests, rapid tests, and confirmatory tests to detect HIV antibodies. Techniques to detect virus include viral isolation, the detection of viral antigen, and PCR. HIV testing algorithms are discussed. The authors stress in closing the importance of the effective laboratory diagnosis of HIV in the prevention and control of HIV/AIDS. Laboratory personnel must be trained, cost-effective laboratory techniques made available for the African setting, and test systems chosen which are best adapted to the prevailing epidemiologic, socioeconomic, and cultural contexts. These latter systems often will differ from the types of diagnostic tests and testing algorithms used in more developed countries.^ieng

[Maternal-infant transmission of the HTLV-1 virus]. / Transmission mère-enfant du virus HTLV-1.

The virus is transmitted horizontally via the bloodstream or sexual intercourse but vertical transmission is also believed to be a major mode of contamination. Between 20 and 25% of children born to seropositive mothers are believed to be infected and more than 90% of mothers whose children are found to be seropositive are themselves infected. If transplacental route appears to be exceptional or poorly documented, transmission by breast-feeding has been proved by virological, experimental and epidemiological arguments and is a major mode of contamination.