Concurrent sexual partnerships and HIV prevalence in five urban communities of sub-Saharan Africa

OBJECTIVE

To estimate parameters of concurrent sexual partnerships in five urban populations in sub-Saharan Africa and to assess their association with levels of HIV infection and other sexually transmitted infections (STI).

METHODS

Data were obtained from a multicentre study of factors which determine the differences in rate of spread of HIV in five African cities. Consenting participants were interviewed on sexual behaviour and at four of the five sites also provided a blood and a urine sample for testing for HIV and other STI. Data on sexual behaviour included the number of partnerships in the 12 months preceding the interview as well as the dates of the start and end of each partnership. Summary indices of concurrent sexual partnerships -- some of which were taken from the literature, while others were newly developed -- were computed for each city and compared to HIV and STI prevalence rates.

RESULTS

A total of 1819 adults aged 15--49 years were interviewed in Dakar (Senegal), 2116 in Cotonou (Benin), 2089 in Yaoundé (Cameroon), 1889 in Kisumu (Kenya) and 1730 in Ndola (Zambia). Prevalence rates of HIV infection were 3.4% for Cotonou, 5.9% for Yaoundé, 25.9% for Kisumu and 28.4% for Ndola, and around 1% for Dakar. The estimated fraction of sexual partnerships that were concurrent at the time of interview (index k) was relatively high in Yaoundé (0.98), intermediate in Kisumu (0.44) and Cotonou (0.33) and low in Ndola (0.26) and in Dakar (0.18). An individual indicator of concurrency (iic) was developed which depends neither on the number of partners nor on the length of the partnerships and estimates the individual propensity to keep (positive values) or to dissolve (negative values) on-going partnership before engaging in another one. This measure iic did not discriminate between cities with high HIV infection levels and cities with low HIV infection levels. In addition, iic did not differ significantly between HIV-infected and uninfected people in the four cities where data on HIV status were collected.

CONCLUSION

We could not find evidence that concurrent sexual partnerships were a major determinant of the rate of spread of HIV in five cities in sub-Saharan Africa. HIV epidemics are the result of many factors, behavioural as well as biological, of which concurrent sexual partnerships are only one.

Decreased fertility among HIV-1-infected women attending antenatal clinics in three African cities

Population HIV prevalence estimates rely heavily on sentinel surveillance in antenatal clinics (ANCs), but because HIV reduces fertility, these estimates are biased. To aid interpretation of such data, we estimated HIV-associated fertility reduction among pregnant women in ANCs in Yaoundé (Cameroon), Kisumu (Kenya), and Ndola (Zambia). Data collection followed existing HIV sentinel surveillance procedures as far as possible. HIV prevalence among the women was 5.5% in Yaoundé, 30.6% in Kisumu, and 27.3% in Ndola. The birth interval was prolonged in HIV-positive multiparous women compared with HIV-negative multiparous women in all three sites: adjusted hazard ratios of pregnancy were 0.84 (95% confidence interval [CI]: 0.62-1.1) in Yaoundé, 0.82 (95% CI: 0.70-0.96) in Kisumu, and 0.74 (95% CI: 0.61-0.90) in Ndola, implying estimated reductions in the risk of pregnancy in HIV-positive women of between 16% and 26%. For primiparous women, the interval between sexual debut and birth was longer in HIV-positive women than in HIV-negative women in all sites, although the association was lost in Ndola after adjusting for age and other factors. Consistent results in different study sites help in the development of standard methods for improving ANC-based surveillance estimates of HIV prevalence. These may be easier to devise for multiparous women than for primiparous women.

Operational performance of an STD control programme in Mwanza Region, Tanzania

OBJECTIVES

To describe important details of the design and operational features of the Mwanza sexually transmitted diseases (STD) control programme. To assess the feasibility of the intervention, the distribution of STD syndromes observed, the clinical effectiveness of syndromic STD case management, the utilisation of STD services by the population, and the quality of syndromic STD services delivered at rural health units.

METHODS

The intervention was integrated into rural primary healthcare (PHC) units. It comprised improved STD case management using the syndromic approach, facilitated by a regional programme office which ensured the training of health workers, a reliable supply of effective drugs, and regular support supervision. Five studies were performed to evaluate operational performance: (i) a survey of register books to collect data on patients presenting with STDs and reproductive tract infections (RTIs) to rural health units with improved STD services, (ii) a survey of register books from health units in communities without improved services, (iii) a survey of register books from referral clinics, (iv) a home based cross sectional study of STD patients who did not return to the intervention health units for follow up, (v) a cross sectional survey of reported STD treatment seeking behaviour in a random cohort of 8845 adults served by rural health units.

RESULTS

During the 2 years of the Mwanza trial, 12,895 STD syndromes were treated at the 25 intervention health units. The most common syndromes were urethral discharge (67%) and genital ulcers (26%) in men and vaginal discharge (50%), lower abdominal tenderness (33%), and genital ulcers (13%) in women. Clinical treatment effectiveness was high in patients from whom complete follow up data were available, reaching between 81% and 98% after first line treatment and 97%-99% after first, second, and third line treatment. Only 26% of patients referred to higher levels of health care had presented to their referral institutions. During the trial period, data from the cohort showed that 12.8% of men and 8.6% of women in the intervention communities experienced at least one STD syndrome. Based on various approaches, utilisation of the improved health units by symptomatic STD patients in these communities was estimated at between 50% and 75%. During the first 6 months of intervention attendance at intervention units increased by 53%. Thereafter, the average attendance rate was about 25% higher than in comparison communities. Home visits to 367 non-returners revealed that 89% had been free of symptoms after treatment, but 28% became symptomatic again within 3 months of treatment. 100% of these patients reported that they had received treatment, but only 74% had been examined, only 57% had been given health education, and only 30% were offered condoms. Patients did not fully recall which treatment they had been given, but possibly only 63% had been treated exactly according to guidelines.

CONCLUSIONS

This study demonstrated that it is feasible to integrate effective STD services into the existing PHC structure of a developing country. Improved services attract more patients, but additional educational efforts are needed to further improve treatment seeking behaviour. Furthermore, clear treatment guidelines, a reliable drug supply system, and regular supervision are critical. All efforts should be made to treat patients on the spot, without delay, as referral to higher levels of care led to a high number of dropouts. The syndromic approach to STD control should be supported by at least one reference clinic and laboratory per country to ensure monitoring of prevalent aetiologies, of the development of bacterial resistance, and of the effectiveness of the syndromic algorithms in use.

High prevalence of trichomoniasis in rural men in Mwanza, Tanzania: results from a population based study

OBJECTIVES

To measure the prevalence of urethral infections including trichomoniasis in rural Tanzanian men, to assess the prevalence of symptoms and signs among men with Trichomonas vaginalis, and to analyse the risk factors for trichomoniasis.

DESIGN

A cross sectional study of 1004 men aged 15-54 years in a rural community in north west Tanzania.

METHODS

Participants were interviewed about sexual behaviour and symptoms of sexually transmitted diseases. First fraction urine samples and urethral swabs were collected and used to test for T vaginalis by wet preparation and culture, Neisseria gonorrhoeae by culture, Chlamydia trachomatis by ligase chain reaction and non-specific urethritis by Gram stain. Urine was also tested for the presence of leucocytes using a leucocyte esterase dipstick. Men were re-interviewed 2 weeks later to document new symptoms and signs of urethritis.

RESULTS

Complete laboratory results were available on 980 men. One in four men had laboratory evidence of urethritis. T vaginalis was found in 109 individuals (11%), gonorrhoea in eight (0.8%), and chlamydial infection in 15 (1.5%). Over 50% of men with urethritis were asymptomatic. The prevalence of signs and symptoms was similar among men with T vaginalis alone compared with men with other urethral infections. The sensitivity and specificity of the leucocyte esterase dipstick (LED) test for detecting T vaginalis were 80% and 48% respectively in symptomatic men and 60% and 68% in asymptomatic men. Factors associated with trichomoniasis included religion, type of employment, and marital status.

CONCLUSIONS

A high prevalence of urethritis was found in men in this community based study. More than half of the urethral infections detected were asymptomatic. The most prevalent pathogen was T vaginalis. Studies are needed on the prevalence of trichomoniasis in men presenting to health services with complaints suggestive of urethritis since treatment for T vaginalis is not included in the syndromic management of urethritis in most countries. The performance of the LED test as a screening test for trichomoniasis was unsatisfactory in both symptomatic and asymptomatic men. Improved screening tests are urgently needed to identify urethral infections that are asymptomatic and which are not covered by current syndromic management algorithms.

Simplified strategy for detection of recombinant human immunodeficiency virus type 1 group M isolates by gag/env heteroduplex mobility assay. Study Group on Heterogeneity of HIV Epidemics in African Cities

We developed a heteroduplex mobility assay in the gag gene (gag HMA) for the identification of group M subtypes A to H. The assay covers the region coding for amino acid 132 of p24 to amino acid 20 of p7 (according to human immunodeficiency virus type 1 [HIV-1] ELI, 460 bp). The gag HMA was compared with sequencing and phylogenetic analysis of an evaluation panel of 79 HIV-1 group M isolates isolated from infected individuals from different geographic regions. Application of gag HMA in combination with env HMA on 252 HIV-1- positive plasma samples from Bénin, Cameroon, Kenya, and Zambia revealed a high prevalence of a variety of intersubtype recombinants in Yaoundé, Cameroon (53.8%); Kisumu, Kenya (26.8%); and Cotonou, Bénin (41%); no recombinants were identified among the samples from Ndola, Zambia. The AG(IbNG) circulating recombinant form, as determined by gag HMA, was found to be the most common intersubtype recombinant in Yaoundé (39.4%) and Cotonou (38.5%). Using a one-tube reverse transcriptase PCR protocol, this gag HMA in combination with env HMA is a useful tool for rapidly monitoring the prevalence of the various genetic subtypes as well as of recombinants of HIV-1. Moreover, this technology can easily be applied in laboratories in developing countries.

AIDS and hospital bed occupancy: an overview

In several countries of sub-Saharan Africa more than 10% of the adult population are infected with HIV, while in large towns such as Kampala, Lusaka, Blantyre, Kigali and Harare this proportion exceeds 25%. One of the most obvious consequences is the increased occupancy of hospital beds by patients with HIV infection, perhaps to the exclusion of patients with other ailments. This paper gives an overview of several hospital occupancy studies.

Epidemiological and molecular characteristics of HIV infection in Gabon, 1986-1994

OBJECTIVE

To describe trends in the prevalence of HIV-1 infection in different populations in Gabon, and the molecular characteristics of circulating HIV strains.

METHODS

Data were collected on HIV prevalence through sentinel surveillance surveys in different populations in Libreville (the capital) and in Franceville. In Libreville, a total of 7082 individuals (hospitalized patients, tuberculosis patients, pregnant women, asymptomatic adults, prisoners) were recruited between 1986 and 1994. In Franceville, we tested 771 pregnant women and 886 healthy asymptomatic adults (1986-1988). Sera were screened for HIV antibodies by enzyme-linked immunosorbent assay (ELISA) and confirmed by Western blot or line immunoassay (LIA). Reactive samples in ELISA were tested for the presence of antibodies to HIV-1 group O viruses by ELISA using V3 peptides from HIV-1 ANT-70 and HIV-1 MVP-5180 followed by confirmation by LIA and a specific Western blot. Seventeen HIV-1 strains were isolated (1988-1993) and a 900 base-pair fragment encoding the env region containing V3, V4, V5 and beginning of gp41 was sequenced and a phylogenetic tree was constructed.

RESULTS

HIV prevalence was relatively low and remained stable (0.7-1.6% in pregnant women, 2.1-2.2% in the general population). The prevalence was also stable among prisoners (2.1-2.6%). Among hospitalized and tuberculosis patients prevalence was higher and increased (1.8-12.7% and 1.5-16.2%, respectively). Only three sera had antibodies to HIV-1 group O. The 17 HIV-1 strains represent six different genetic subtypes including type O.

CONCLUSION

Our data from 1986 to 1994 show a stable and low HIV prevalence in Gabon, and a high genetic diversity of HIV-1 strains. This, also observed in Cameroon, is in contrast to that found elsewhere in Africa. Differences in rate of spread of HIV infection are probably explained by interplay between numerous factors. The role of different HIV subtypes in the dynamics of the HIV epidemic should be examined further.

Why do men with urethritis in Cameroon prefer to seek care in the informal health sector?

OBJECTIVE

To study the impact of cost of treatment for sexually transmitted diseases (STDs) on the preference of men with urethritis to seek care in the informal sector.

SUBJECTS AND METHODS

A random sample of young men from the general population of Yaoundé and Douala, Cameroon, and of employees of a Yaoundé factory underwent a structured interview on the occurrence of STD-related complaints and health seeking behaviour. Men who consulted in the formal sector were compared with men consulting in the informal sector, with regards to cost of medication and level of education.

RESULTS

Sixteen percent of men in the general population and 20% of factory employees reported a history of urethritis in the 12 months preceding the interview. Of the men in the general population 53% had sought care in the formal sector; among the factory employees this proportion was 56%. Men who did not consult in the formal sector spent significantly less on drugs than men who did consult in the formal sector: median cost $14.4 versus $24.0 (p = 0.02) for drugs purchased in pharmacies; median cost $8 versus $32 for drugs purchased in small stores or from acquaintances. Preference for formal health services was associated with higher educational attainment.

CONCLUSION

In large towns in Cameroon the utilisation of formal health services for STD related complaints is low and the high cost of treatment in the formal sector may play an important role in the choice of care option.

Benefits of HIV screening of blood transfusions in Zambia

Blood transfusion continues to be an important route of transmission of HIV in developing countries, especially for young children following the perinatal period. Testing for HIV is costly and reliable donor support for the purchase of test kits is often essential, yet difficult to secure. The costs of screening transfusions for HIV and the financial benefits in terms of savings on treatment costs averted were calculated for a district hospital in Zambia where seroprevalence among donors was 15.9%. Financial benefits exceed costs by a factor of 2.7-3.5. In 1991, 1073 transfusions were given and an estimated 150 cases of transfusion-related AIDS were prevented by screening, of which 59% were in children aged 5 years or under and 31% were in women. The total cost of HIV screening was 3061 pounds ($4745), and the cost per case of HIV infection prevented was 20.40 pounds ($31.62); the cost of this protection for the population served by the hospital was 0.02 pounds ($0.03) per person. An estimated 3625 undiscounted healthy years of life were saved, of which nearly 69% were in children under 6, at a cost of 0.85 pounds ($1.32) per year of life saved. It is essential that financial and political support for HIV screening of blood for transfusion is maintained.

HTLV-I infection among prostitutes and pregnant women in Kinshasa, Zaïre: how important is high-risk sexual behavior?

High-risk sexual behavior as risk factor for human T-cell lymphotropic virus type I (HTLV-I) infection was assessed in cross-sectional studies with 1,183 prostitutes and 1,166 pregnant women in Kinshasa, Zaire. Eighty six (7.3%) prostitutes were positive for HTLV-I. The seroprevalence among prostitutes from the regions along the equator was 12.7%, whereas among prostitutes from the other regions it ranged between 0 and 4.3%. In the prostitutes from the high-prevalence regions, but not in the prostitutes from the low-prevalence regions, HTLV-I infection was associated with increasing age [odds ratio (OR) = 1.1 per year increment], active syphilis (OR = 2.3), and human immunodeficiency virus (HIV) infection (OR = 2.0). Forty three (3.7%) pregnant women were HTLV-I seropositive. Among the women from low-prevalence regions, there was no significant difference in HTLV-I seroprevalence between prostitutes (4.3%) and pregnant women (3.5%). In a group of 409 prostitutes who were observed for a mean duration of 23 months, the incidence of HTLV-I infection was 0.7 per 100 women-years, whereas the incidence of HIV infection was 9.8 per 100 women-years. We conclude that in Kinshasa prostitution per se was not associated with an increased risk of HTLV-I infection.