Prevalence and prediction of sexually transmitted diseases among sex workers in Cameroon

The aim of the study was to determine the prevalence of sexually transmitted diseases (STDs), describe the frequency of genitourinary symptoms and signs, and to assess the accuracy of clinical diagnoses of STD in a cohort of Cameroonian sex workers. Physical examinations were conducted on 1233 sex workers in Yaoundé and Douala, Cameroon. Symptoms experienced within the 14 days prior to examination were collected. Women were tested for gonorrhoea, chlamydia infection, and trichomoniasis. Doctors' clinical impressions were compared with laboratory tests. Prevalence of cervical infection and trichomoniasis was 20%. A high percentage of abnormal signs and symptoms was found in this cohort. Clinical diagnosis for cervicitis and trichomoniasis had low sensitivities (<50%) while specificity remained high (>65%). In conclusion STDs are common among sex workers in Cameroon. Clinical diagnosis was not an accurate predictor of infection at the individual level in this population at risk of STD.

Various types of HIV mixed infections in Cameroon

In order to assess the incidence of HIV mixed infection as well as to clarify the molecular epidemiology of HIV in central Africa, we investigated 43 HIVs obtained from 211 Cameroonian AC, ARC, and AIDS patients in 1994 and 1995. Part of the pol region and part of the env region were phylogenetically analyzed. The genotypes observed were varied: of 43 specimens, 28 (65%) were subtype A, 1 (2%) was subtype B, 2 (5%) were subtype D, 3 (7%) were subtype F, and 2 (5%) were group O. Of the remaining 7 specimens, 3 were mixed infections with HIV-1 subtypes A and C, HIV-1 subtypes C and F, and HIV-2 subtype A and HIV-1 subtype A; 1 was a mixed infection with HIV-1 subtypes A and D and the highly divergent group O (triple infection); another 3 appeared to consist of mosaic genomes (A/G, A/E, and B/A recombinant). These data show that various types of mixed infection, such as between different subtypes of HIV-1 group M, between HIV-1 and HIV-2, and even between HIV-1 groups O and M, were confirmed at a rather high frequency (approximately 10%). The mixed infection is particularly significant where there is a greater variety of HIV-1 subtypes circulating, since it results in new genetic diversity generated by intersubtype recombination.

Characteristics associated with prevalent HIV infection among a cohort of sex workers in Cameroon

OBJECTIVE

To determine prevalence of HIV infection in a cohort of female sex workers in Cameroon, and to describe characteristics associated with HIV infection in this population.

METHODS

In a cross sectional study, 2260 female sex workers in Cameroon were interviewed and screened for HIV serostatus. A standardised questionnaire was used to collect information on sociodemographic characteristics and sexual and health behaviours.

RESULTS

Seropositive participants (18%) were more likely to be over age 25, have four or more children, live in Yaoundé or Douala for 5 years or less, solicit clients in their homes or on the street, have a low educational level, earn a weekly income of less than $24, and have no other occupation outside of sex work. A logistic regression model of selected sociodemographic characteristics indicated that women at particularly high odds of HIV infection were older, poorer, and new immigrants to their city of residence.

CONCLUSION

This seroprevalence study found a lower HIV prevalence than had been previously reported. Although our results are different, this group is still at much higher risk of HIV infection than the population as a whole.

African origin of GB virus C/hepatitis G virus

Ninety-four GB virus C/hepatitis G virus (GBV-C/ HGV) RNA-positive serum samples were obtained from all over the world. We found that all 15 GBV-C/HGV isolates from the Pygmies and the Bantu in the Central African region had a 12-amino acid indel (i.e. insertion or deletion) in the non-structural protein (NS) 5A region. Phylogenetic analyses of the NS5A region, using GBV-A as an outgroup, showed that these 15 isolates had diverged from the common ancestor much earlier than the remaining isolates, indicating an African origin of GBV-C/HGV.

Reactivity of a new HIV-1 group O third generation A-HIV-1/-2 assay with an unusual HIV-1 seroconversion panel and HIV-1 group O/group M subtyped samples

It was shown previously that about 97% of the anti-HIV-1 group O strain-positive samples were detected by crossreaction with native HIV-1 gp160 (Van Binsbergen et al., Evaluation of a new third generation anti-HIV-1/anti-HIV-2 assay with increased sensitivity for HIV-1 group O, J. Virol. Methods 60 (1996) 131-137). Fourteen out of 17 new anti-HIV-1 group O positive samples, selected with the Enzygnost HIV-1/2 plus assay, were already reactive when tested with HIV-1 gp160. When tested by the Vironostika HIV Uni-Form II plus O microELISA all 17 samples were reactive, demonstrating the necessity to implement an HIV-1 group O-specific antigen in the assay. On the other hand, it was surprisingly found that 40 out of 43 (93%) of anti-HIV-1 group M-positive samples, belonging to strain A, B, C, D, E or F, were detected by crossreaction with the HIV-1 group O (strain ANT70) synthetic peptide incorporated in the Vironostika HIV Uni-Form II plus O. Only HIV-1 subtype D-positive samples did not react with this peptide, presumably because of the presence of a histidine residue in the immunodominant region of HIV-1 subtype D gp41. Both crossreactions make the Vironostika HIV Uni-Form II plus O microELISA also sensitive for anti-HIV-1-positive samples originating from different geographical regions and resulting from different HIV-1 subtype infections. With an unusual seroconversion panel in which p24 Ag was present persistently, many anti-HIV-1/-2 assays produce alternating positive/negative results in anti-HIV antibody-positive bleeds. It was shown that the use of viral p24 and gp160 in a direct sandwich, allowing detection of anti-HIV IgG and IgM, explains the identification of all anti-HIV-positive bleeds by the Vironostika HIV Uni-Form II plus O. The high sensitivity of the plus O assay was confirmed with clinical samples of a so-called anti-HIV-1 low titer panel. The specificity of the Vironostika HIV Uni-Form II plus O determined in five blood transfusion centers, based on 135070 tests, was 99.97%.

Diagnostic challenges for rapid human immunodeficiency virus assays. Performance using HIV-1 group O, HIV-1 group M, and HIV-2 samples

OBJECTIVE

We sought to determine the ability of seven rapid assays for human immunodeficiency virus (HIV) to detect antibodies in a panel of sera from individuals infected with different types and groups of HIV.

STUDY DESIGN/METHODS

Sixty-eight well-characterized samples, including HIV-1 group O (24), several HIV-1 group M clades (21), HIV-1/2 (10), HIV-2 (10), and samples with indeterminate results (3), were tested by the following rapid HIV assays: HIV-Spot, HIVCHEK System 3, A/Q Rapid HIV, Genie II HIV-1/HIV-2, Quix HIV-1-2-O, ImmunoComb II HIV-1+2 BiSpot, and the Serodia HIV-1+2.

RESULTS

All tests successfully detected the HIV-1 group M clades and the HIV-1/2-positive samples. Of the HIV-2 stand-alone samples, four tests missed the same sample, and three tests missed another sample. Of the HIV-1 group O samples, four samples were missed by at least one test, and another sample was missed by three tests. The sensitivity of the seven rapid assays in detecting each group of sera was between 83% and 100%, with only one test having a sensitivity of 100% for all groups of sera. Three samples proved to be problematic because they were misclassified by more than one assay.

CONCLUSIONS

The performance of rapid HIV assays is variable when testing sera from individuals infected with HIV-1 group O and HIV-2.

[Cytologic aspects of cervical smears in optic microscopy in HIV seropositive women in Yaounde-Cameroon (Central Africa)]

Cytologic aspects of cervical smears in HIV seropositive women in Yaounde-Cameroon (Central Africa). The aim of this study was to present the cytologic aspects of cervical smears performed on HIV seropositive Cameroonian women and analysed by light microscope. Seropositive women (case group) and seronegative women (control group) had cervical smears which were stained by the Papanicolaou Method and analysed by light microscope. For the 65 seropositive women, there were: 62 inflammatory smears (95.5%), 2 normal (3%) and 1 low grade squamous intra-epithelial lesion (1.5%). The 50 seronegative women had: 35 inflammatory smears (70%), 13 normal (26%) and 2 low grade squamous intra-epithelial lesion (4%). In both groups, inflammatory smears were predominant. They were more frequent in seropositive women. There was no significant difference between the percentage of squamous intra-epithelial lesions in seropositive women (1.5%) and seronegative women (4%). We were unable to detect, in Cameroonian seropositive women, any specific lesions on cervical smears predictive of HIV infection without serology.

Envelope sequence variability and serologic characterization of HIV type 1 group O isolates from equatorial guinea

Four sera from Equatorial Guinea (EG) suspected to contain antibody against HIV-1 group O-related viruses were identified on the basis of unusual and differential serologic reactivity in selected commercial assays and Western blot. Degenerate primers, designed from HIV-1 group O published sequences, were used to PCR amplify envelope (env) gene sequences from the suspect EG sera. A complete envelope gene sequence from each serum was determined from the overlapping env gene fragments. Analysis (PHYLIP package of programs) of Env amino acid sequences (translated from nucleotide sequences) indicated that the amino acid sequences obtained from EG sera clustered more closely with HIV Env sequences of group O compared to group M. The amino acid sequences at the octameric tip of the V3 loop were either RIGPLAWY (one isolate), RIGPMAWY (two isolates), or GLGPLAVY (one isolate). The V3 tip tetrameric sequence GPLA is represented only once in the 1995 HIV (Los Alamos) database, but was present in two of our group O-related EG samples. The gp41 immunodominant regions (IDR) protein sequences were identical for sequences from three of the sera, RLLALETLIQNQQLLNLWGCKGR(K)L(I)VCYTSVK(T)W, whereas sequence from the fourth serum contained three changes as noted in parentheses. IDR sequences derived from EG sera were unique compared to those reported for other HIV-1 group O isolate ANT70, VAU, or MVP5180. Antibody in each EG serum directed against the IDR could be detected using synthetic peptides comprising sequences from the ANT70 or MVP5180 IDRs, but were most reactive against the sequences derived from the samples themselves. Little or no serologic reactivity was detected when EG sera were reacted against peptides comprising the IDR of HIV-1 group M (subtype B consensus) or HIV-2 (consensus).

Diversity of the immunodominant epitope of gp41 of HIV-1 subtype O and its validity for antibody detection

The immunodominant regions of the gp41 from 13 HIV-1 subtype O strains from Cameroon, 11 from France and one from Germany were sequenced. The amino acid sequences were compared to those of the 3 published HIV-1 subtype O isolates, ANT70, MVP-5180 and VAU. All HIV-1 subtype O isolates had a very conserved amino acid sequence in this region and showed a subtype O specific structure. Within the cysteine loop there was a positive charge of two basic amino acids, arginine and lysine. Only two strains (CM.6778 and CM.8161) showed an acidic amino acid in this loop. None of the isolates showed the same amino acid sequence in this immunodominant region. A 25 residue peptide from the immunodominant domain of gp41 of the MVP-5180 strain was synthesized, cycled to form the cysteine-loop and coated to microtiter plates. Antibody binding was detected by indirect ELISA using an enzyme labeled anti-human IgG. Out of 111 anti-HIV-1 positive specimens, collected mainly from Cameroonian HIV infected patients, only 10 were not reactive in this assay. The 42 anti-HIV-1 subtype O positive specimens gave all a reaction above cut off. Despite the diversity found in the amino acid sequences within the 25 isolates a peptide-based indirect ELISA representing the immunodominant epitope of the strain MVP-5180 successfully detected all the anti-HIV-O sera so far tested, pointing to the importance of adding such a peptide for correct identification of HIV-1 subtype O infected patients, while some assays without HIV-O specific antigens partially fail to detect all anti-HIV-O specimens.

Prevalence and phylogenetic analysis of HTLV-I isolates in Cameroon, including those of the Baka Pygmy

Our previous analysis of an HTLV-I isolate (CMR229) from a Cameroonian Pygmy demonstrated that the isolate is distinct from typical HTLV-Is of the "Central African group," which has a close similarity to HTLV-I-related simian viruses (STLV-I) in Africa. In this study, we analyzed six new HTLV-Is from Cameroon consisting of three isolates from the Pygmy and three from the Bantu to examine further the genetic features of HTLV-I in Cameroon, especially in the Pygmy. A phylogenetic tree based on the long terminal repeats (LTR) region showed that all the new HTLV-Is belong to the Central African group. On the other hand, an env-based analysis of CMR229 confirmed the previous finding derived from LTR-based analysis that CMR229 has a similarity to African STLV-Is, but is distinct from the typical Central African group of HTLV-I. This suggests that multiple interspecies transmissions from non-human primates to humans have occurred in Central Africa, resulting in the presence of two distinct HTLV-I strains in this area. In addition, it seems likely that the Pygmy harbors the heterogeneous HTLV-I strains from which the main HTLV-I population spread into the Bantu.

Evaluation of a quantitative double ELISA strategy for confirmation and differentiation of HIV infection

The current HIV pandemic is complicated by the spread of distinct types and subtypes of HIV. The currently used conventional diagnostic tests have shown limitations in the detection of antibodies against all HIV-1 subtypes, as demonstrated by recent identification of HIV-1 subtype O. To evaluate quantitatively the diagnostic potential of a double ELISA strategy for the detection and partial differentiation of HIV-1, HIV-1 subtype O and HIV-2 infections blood samples were examined at five different test centers: Blantyre, Malawi; Abidjan and Daloa, Ivory Coast; Yaoundé, Cameroon; Munich, Germany. All tests results, including ELISA extinction values and Western blot profiles, were forwarded to Munich for final interpretation. An indirect anti-HIV-1/2 ELISA and a competitive anti-HIV-1 ELISA were used in combination for the initial screening of blood specimens. All anti-HIV positive and anti-HIV negative samples were subjected to immunoblot analysis. Independent of the diversity of the extinction profiles, and of the test manufacturer, the quantitative evaluation of the ELISA extinction values could define two extinction areas with a 100% predictive value for HIV-1 seropositivity and HIV seronegativity; extinction values > 2 by the indirect ELISA and < 0.2 by the competitive ELISA for an anti-HIV-1 subtype A to I positive result; extinction values < 0.2 by the indirect ELISA and > 1.0 by the competitive ELISA for an anti-HIV negative result. Additionally, the quantitative evaluation of the extinction profile provides partial information on the HIV-1 subtype as far as the distinction in group M and group O is concerned. In conclusion, the quantitative evaluation of this double ELISA strategy can reduce the number of blood specimens that require additional confirmatory testing in developing countries and can be superior to the immunoblot method during early seroconversion.

Detection of genetically diverse human immunodeficiency virus type 1 group M and O isolates by PCR

A panel of 136 genetically diverse group M and 5 group O adult isolates from outside the United States and Europe were evaluated by PCR with the Roche AMPLICOR HIV-1 test, a modified version of the AMPLICOR HIV-1 test, and a new primer pair/probe system. Detection of some of these isolates was less efficient with the AMPLICOR HIV-1 test; however, the assay was significantly improved by reducing the sample input and lowering the annealing temperature. The new primer pair/probe set detected 140 of 141 isolates, including the 5 group O isolates that were not detected with either of the AMPLICOR HIV-1 test formats.

Molecular analyses of HIV-1 group O and HIV-2 variants from Africa

Genetic variation among HIV isolates creates challenges for their detection by serologic and genetic techniques. To characterize the sequence variation and its correlation to serologic diversity of HIV-1 Group O and HIV-2 isolates, samples were identified by differential reactivity in selected commercial and research assays. Analysis of sera from Equatorial Guinea (EG) led to identification of 4 HIV-1 Group O variants. Viral RNA, extracted from these samples was used to PCR amplify overlapping sequences of the entire envelope gene using multiple primer pairs. Sequence analysis indicated that the V3 loop nucleotide and protein sequences aligned more closely with HIVANT70 compared to other Group O sequences. The amino acid sequences at the octameric tip of the V3 loop were RIGPLAWY, RIGPMAWY, or GLGPLAVY. The tetrameric tip GPLA is represented only once in the published 1994 HIV database (Los Alamos) but was present in 2 of 4 of EG samples. The immuno-dominant region (IDR) sequences derived from EG sera were unique in that none of the sequences were completely homologous to other HIV-1 group O variants. Further, the HIV-1 group O sequence variation could be correlated with differential serologic reactivity using IDR peptides. Compared to HIV-1, the sequence information on HIV-2 isolates is relatively limited, though the HIV-2 isolates also show genetic variation similar to HIV-1. To further establish a correlation between the genetic diversity and serologic detection of HIV-2, plasma samples from Western Africa were evaluated. Eight samples were selected based on weak serologic reactivity to env proteins. PCR amplification and sequence analysis of the gag, env V3 loop, and env IDR regions indicated that the samples could be classified as subtypes A (4 samples), B (3 samples) and D (1 sample). Across the subtypes, there was conservation in the IDR region of the sequence WGCAFRQVCHT. This region is absolutely conserved among the majority of currently known HIV-2 and related SIV viruses (1994 HIV database). One subtype B sample had a unique sequence immediately adjacent to the IDR, however, this did not change the serologic detection using a HIV-2 IDR specific monoclonal antibody.

Evaluation of a new third generation anti-HIV-1/anti-HIV-2 assay with increased sensitivity for HIV-1 group O

Although the HIV-1 group O virus found in two persons of Cameroonian origin has been described in 1990 (De Leys et al., 1990), sera from group O infected individuals became available only recently. Several studies showed that some of the anti-HIV-1/HIV-2 screening tests failed to detect all of these samples (Loussert-Ajaka et al., 1994; Simon et al., 1994; Schable et al., 1994; Gürtler et al., 1995). In the current version of an anti-HIV-1/anti-HIV-2 screening assay, namely the Vironostika HIV Uni-Form II, an HIV-O specific peptide was introduced in order to improve HIV-1 group O reactivity. The peptide was derived from the immunodominant region of HIV-1 group O gp41 strain ANT70. All 30 anti-HIV-1 group O sera were detected by the so-called plus O assay, while 29 samples of this panel were positive the current assay. The sensitivity of the plus O assay for anti-HIV-1 and anti-HIV-2 positive samples is identical to that of the reference test without HIV-1 group O peptide. The clinical specificity of the HIV Uni-Form II plus O assay is improved to > or = 99.92% by an adjustment of the coat concentration of HIV-1 p24 (to avoid false positive p24 only reactions) without affecting sensitivity of the assay. The specific reaction of an HIV-1 group O specific rabbit serum for quality control purposes is presented.

HIV-1 subtype O: epidemiology, pathogenesis, diagnosis, and perspectives of the evolution of HIV

HIV-1 subtype O is a new HIV variant originating in the West-Central African region, with highest prevalences in countries such as Cameroon, Equatorial Guinea and Gabon. Detection of antibodies to HIV-1 subtype O can pose problems in unmodified ELISA tests, and confirmation of anti-HIV-1 subtype O in immunoblot may give false negative results in some specimens. Nucleic acid-based assays designed for HIV-1 detection do not amplify or detect sequences from HIV-1 subtype O. In their env sequences, HIV-1 subtype O strains show a higher heterogeneity than the classical HIV-1 subtypes, leading to the conclusion that HIV-1 subtype O has been introduced into the human population only recently. Further, unidentified subtypes are also likely to exist.

Childhood leukemia is still a deadly disease in Yaounde, Cameroon: a report of 14 cases

In the Pediatric Unit of the University Teaching Hospital Center of Yaounde, 58 of 2,900 (2%) hospitalized children aged 0 to 15 years who had a malignancy were studied. Fourteen (24.1%) had acute leukemia based on morphologic and cytochemical studies. Acute lymphoblastic leukemia was encountered in 11 of these patients (78.6%). The male to female ratio was 1.3 to 1. Nine of the 11 children (64.3%) were 5 years of age or younger. Eleven (78.6%) died of disease progression and its complications.

Nonoxynol-9 use, genital ulcers, and HIV infection in a cohort of sex workers

OBJECTIVES

To measure the associations between use of nonoxynol-9 (N-9) and incidence of genital ulcers, and incident ulcers and HIV seroconversion.

METHODS

In a study of barrier contraceptive use and HIV infection, 273 female sex workers used condoms and 100 mg N-9 suppositories, and recorded sexual activity on coital logs. Genital ulcers were diagnosed clinically at monthly clinic visits. HIV infection was diagnosed by ELISA and Western blot. We calculated ulcer incidence rates by level of N-9 use. A nested matched case-control analysis assessed the effect of ulcers on HIV acquisition.

RESULTS

More frequent N-9 use was not associated with genital ulcers and may have been protective against the lesions. Ulceration was not a strong risk factor for HIV acquisition in this study (odds ratio 1.1; 95% confidence interval 0.3-3.5).

CONCLUSIONS

Frequent use of N-9 can cause genital irritation and ulceration. Ulcers, in turn, may be risk factors for HIV acquisition. This study, however, did not find an association between N-9 use and ulcers, nor between ulcers and HIV. There is probably a threshold of N-9 use frequency or dose below which the risk of ulceration is minimal. Ulcers due to infectious causes may have been prevented by N-9 use in this cohort.

Reactivity of five anti-HIV-1 subtype O specimens with six different anti-HIV screening ELISAs and three immunoblots

Five anti-subtype O specimens were tested by anti-HIV-1/2 screening and confirmatory assays. They can be divided into three specimens, reactive with all ELISAs, independent of the nature of the antigen (recombinant proteins or peptides) and test configuration (indirect ELISA or double antigen/sandwich ELISA). One specimen was not detected by one peptide based ELISA. One specimen was only recognized by two ELISAs and should be considered as a marker sample for the weakness of currently used ELISAs with anti-subtype O. Three different immunoblot assays available commercially detected two of the specimens with a major binding of gp160 and other viral bands, especially the integrase and reverse transcriptase. Another two specimens lacked reactivity with glycoproteins almost completely, but showed some staining with the enzymes of HIV, and would most probably be interpreted as indeterminate. The fifth specimen, which was also missed by most of the ELISAs, had very faint staining of the gp160 and a very weak staining of p24, and would most probably be interpreted as negative. Adaption of currently available tests to anti-subtype O is needed for the future reliability of anti-HIV diagnostic reagents.

Sensitivity of United States HIV antibody tests for detection of HIV-1 group O infections

Infections by highly divergent strains of HIV-1, first detected in central Africa and grouped provisionally as group O, have not been reliably detected by certain European HIV screening tests. Serum specimens from eight probable group O infections from Cameroon were tested by ten HIV assays licensed by the US Food and Drug Administration. All assays based on synthetic peptides or recombinant antigens failed to detect at least one of the infections; assays based on whole-virus lysates performed better. Divergent HIV strains may be undetected by current HIV tests. Thus active surveillance for and characterisation of HIV variants to evaluate and, when necessary, modify current tests is urgently needed.

Gonorrhea as a risk factor for HIV acquisition

OBJECTIVE

The role of gonorrhea in facilitating acquisition of HIV infection has only recently been studied. A previous nested case-control analysis in a cohort of female sex workers in Zaïre found a strong association between HIV seroconversion and prior gonorrheal infection. The objective of this study was to replicate the Zaïre study analysis in a cohort of 273 Cameroonian sex workers to determine whether gonorrhea increased the risk of HIV acquisition, and if the crude association between gonorrheal infection and HIV acquisition was weakened when the level of unprotected coitus was more carefully controlled.

METHODS

We conducted a nested case-control study of initially HIV-1-negative women (n = 273) followed prospectively (with monthly sexually transmitted disease check-ups and 3-monthly HIV-1 serology). As in Zaïre, cases (seroconverters, n = 17) were compared with controls (women who remained HIV-1-negative, n = 68) for incidence of gonorrhea and sexual exposure during the presumed period of HIV-1 acquisition.

RESULTS

The association between gonorrheal infection and subsequent HIV acquisition was stronger in Zaïre than in Cameroon [crude odds ratios (OR), 6.3 versus 2.2]. In both the Zaïre and Cameroon data the crude OR were reduced (6.3 to 4.8, and 2.2 to 1.7, respectively) by controlling for risk factors including a dichotomous variable indicating irregular or no condom use. When this variable was replaced in the Cameroon data with a more precise continuous variable indicating the percentage of unprotected coital acts, the gonorrhea OR was further reduced to 1.4 (95% confidence interval, 0.4-4.9).

CONCLUSION

These results suggest that in the Cameroon cohort, gonorrheal infection did not facilitate HIV acquisition, but that having gonorrhea was a marker for unprotected coitus that facilitated HIV acquisition. The data demonstrate how OR can be overestimated when imprecise dichotomous measures of unprotected coitus are used. Future studies should plan for better control of self-reported condom use.

The use of nonoxynol-9 for protection against cervical gonorrhea

OBJECTIVES

Although condoms are the best defense against sexually transmitted disease, little is known about the effectiveness of female-controlled methods containing nonoxynol-9 as backup protection when condoms are not being used.

METHODS

To assess the extent to which nonoxynol-9 protects women against gonorrhea, a cohort of 303 female sex workers (prostitutes) in Yaounde, Cameroon, were asked to use condoms and suppositories containing nonoxynol-9 at every sexual encounter and to record daily sexual activity and use of condoms and suppositories on coital logs that were reviewed monthly. Evidence of gonorrheal infection was based on a positive gonorrhea culture. Stratified analysis and proportional hazards regression were used to estimate rate ratios.

RESULTS

Forty-one women enrolled in the study were excluded from the current analysis. The estimated incidence of gonorrhea was 6.2 infections per 100 person-months of observation. Incidence rate ratios estimated from proportional hazards regression models controlling for condom use showed that using nonoxynol-9 during acts not protected by condoms reduced the risk of infection.

CONCLUSIONS

Although the protective effect of condoms against sexually transmitted disease is greater than that afforded by nonoxynol-9, using nonoxynol-9 when condoms are not used is a far better strategy in gonorrhea prevention than using no method at all.

A new subtype of human immunodeficiency virus type 1 (MVP-5180) from Cameroon

A new subtype (MVP-5180) of human immunodeficiency virus type 1 (HIV-1) was isolated from a Cameroonian AIDS patient. MVP-5180 was grown in several human T-cell lines and the monocytic U937 line. MVP-5180 DNA could not be amplified by nested primer PCR with conventional env primers and could be only very faintly amplified with gag and pol primers. Most German, Ivoirian, and Malawian anti-HIV-1 sera reacted faintly or moderately with Env proteins in an MVP-5180 immunoblot, whereas some Cameroonian sera reacted strongly. Of HIV-1-infected Cameroonians, 8% were identified by serological methods as infected with MVP-5180; 7% were positive when MVP-5180-specific PCR env primers were used. DNA sequence analysis of MVP-5180 showed that its genetic organization was that of HIV-1, with 65% similarity to HIV-1 and 56% similarity to HIV-2 consensus sequences. The env gene of MVP-5180 had similarities to HIV-1 and HIV-2 of 53 and of 49%, respectively. V3 loop analysis identified a crown of Gly-Pro-Met-Arg by using cloned DNA and Gly-Pro-Leu-Arg by using PCR-amplified DNA, neither of which configuration has been described for other HIV strains. In an analysis of relationships, MVP-5180 occupied a position distant to all other HIV-1 strains, including the chimpanzee simian immunodeficiency virus type 1 SIVcpz and the Uganda virus U455, and closer to the HIV-1/HIV-2 divergence node. MVP-5180, together with another Cameroonian isolate, ANT-70, constitutes a group subtype O of the most divergent HIV-1 isolates yet identified. Characterization of MVP-5180 is important for understanding the natural history of the primate immunodeficiency viruses and for the development of vaccines and diagnostics.

Barrier contraceptive use and HIV infection among high-risk women in Cameroon

OBJECTIVES

To measure the association between spermicide use and HIV infection, adjusting for condom use, and to measure the association between condom use and HIV infection, adjusting for spermicide use.

DESIGN

Prospective study of women using nonoxynol-9 (N-9) spermicides and latex condoms, with up to 12 monthly clinic visits for interviews, examinations and tests, and re-supply.

METHODS

A total of 273 HIV-negative women with multiple sexual partners were enrolled, given latex condoms and N-9 vaginal spermicidal suppositories, and advised to use both every time they had sexual intercourse. Participants recorded data on sexual activity on pictorial coital logs. New HIV infections were detected and confirmed by quarterly enzyme-linked immunosorbent assays and Western blots, respectively.

RESULTS

Nineteen HIV infections occurred during mean follow-up of 8.1 months (an incidence rate of 10.4 infections per 100 women-years). The adjusted HIV rate ratio (RR) was 0.1 [95% confidence interval (CI), 0.1-0.6] for more consistent compared with less consistent spermicide users; and 1.1 (95% CI, 0.4-2.9) for more consistent compared with less consistent condom users. Among the subgroup of experienced condom users, the RR for more versus less consistent condom use was 0.3.

CONCLUSIONS

This is the first epidemiological evidence that N-9 spermicides can reduce the incidence of HIV infection. A more definitive randomized clinical trial is urgently needed.

[Short term projections of infection by the human immunodeficiency (HIV) and the acquired immunodeficiency syndrome (AIDS) in Cameroon]

As of December 1991, Cameroon has reported 827 cases of AIDS. The results from the Sentinel Surveillance System show a seroprevalence of 1.3% HIV1 among pregnant women, 2.5% in people attending STD clinic and 3.5% in tuberculosis patients. The World Health Organization projection model was used to make a short term projection of HIV infection and AIDS cases. Results show that the number estimated of HIV infected populations varies between 24 to 45,000 people by the year 1995. Results show also an estimated 8,500 cumulative AIDS cases. Even in a low prevalence country as Cameroon the impact of the HIV epidemic is important and will result in a burden for the health care system.

A short term projection of HIV infection and AIDS cases in Cameroon

By September 1991 Cameroon had reported 650 cases of the acquired immune deficiency syndrome (AIDS). The results from the sentinnel surveillance system showed a seroprevalence of human immunodeficiency virus (HIV)1 of 1.3% among pregnant women, 2.5% in people attending sexually transmitted disease clinics and 3.5% in tuberculosis patients in 1990. The estimated number of persons infected with HIV varies between 10,000 and 30,000. The World Health Organization projection model was used to make a short-term projection of HIV infection and AIDS cases; it indicated that the number of persons infected with HIV will double by the year 1995, with an estimated 8500 AIDS cases. Even in a low prevalence country such as Cameroon, the impact of the HIV epidemic is important and will result in a burden for the health care system.

HIV prevalence in patients with sexually transmitted diseases in Yaounde, (Cameroon) in 1989 and 1990: necessity of an STD control programme

OBJECTIVE

To monitor HIV seroprevalence among STD clinic attenders as part of a sentinel surveillance programme.

DESIGN

Seroepidemiological survey on randomly selected patients.

SETTING

"Elig Essono" STD clinic, Yaounde; from February 1989 to December 1990.

PATIENTS

1161 randomly selected patients.

MAIN OUTCOME MEASURES

HIV and syphilis seroprevalence.

RESULTS

Twenty six of the 1161 patients (2.4%; CI: 95%; 1.5%-3.3%) tested were found to be HIV positive (mostly due to HIV1); 35.4% had antibodies to Treponema pallidum. There was no association between HIV seropositivity and sex, marital status, or educational level. Genital ulcer disease did not correlate with HIV seroprevalence. However, patients with a positive serological test for T pallidum were more likely to have HIV infection (rr = 2.4; 95% CI; from 1.1 to 3.0). Results from 1990 were double those of 1989 (3.3% versus 1.6%, p = 0.02).

CONCLUSIONS

Compared with the findings among the same groups in metropolitan areas of various other African countries, the HIV seroprevalence is still low; this could be due to many reasons, such as the recent introduction of the virus in the country, a different spectrum of STDs, the high level of circumcision of males. HIV infection trends should continue to be monitored among risk groups such as STD patients and control programmes implemented to reduce the rapid spread of AIDS in the country.

HIV and chlamydia infections among prostitutes in Yaoundé, Cameroon

Eleven selected prostitute leaders were recruited who subsequently recruited 157 of their peers, bringing the total to 168. Sera was collected and tested for antibodies to HIV-1 and HIV-2 using a commercial enzyme-linked immunoabsorbent assay (ELISA); positive cases were confirmed by Western Blot (Dupont). A direct immunofluorescent method was performed on smears from the endocervical junction. Twelve of 168 (7.1%) of the women tested were found to be HIV-1 positive; none were found positive for HIV-2. Sixty six of 168 (38.3%) were found to be Chlamydia trachomatis (CT) positive; three cases (1.8%) were found to be positive for both HIV-1 and CT. Prostitutes are a high risk group in Yaoundé for HIV and chlamydia infections. The results in this study may not reflect the seriousness of the situation given the selected population used. Similar studies still need to be carried out. Prostitutes need to be educated about AIDS, other STDs and the use of condoms to protect their clients and themselves.

[HIV-1 serology and carrier state for HBs and HBe in blood donors at Yaounde University Hospital Center, Cameroon]

5,980 blood donors were screened for HIV1 antibodies and Hepatitis B Virus surface antigen (HBs Ag), using the ELISA technique, in the University Teaching Hospital of Yaounde, Cameroon, between January 1988 and May 1989. All HBs Ag positive samples were also screened for HBe Ag. The seroprevalence of HIV1 antibodies was 0.43%; 11.72% of blood donors were found to be HBs Ag positive and, among these, 16.26% were also HBe Ag positive.