Efficacy of antimalarial chemoprophylaxis among French residents travelling to Africa.

Controversy exists about which antimalarial chemoprophylaxis regimen should be used among travellers to Africa: the WHO and other experts recommend the use of mefloquine throughout sub-Saharan Africa, whereas French experts still support the combination of chloroquine and proguanil in most of West Africa (the so-called zone 2 countries). In this case-control study based at a travel clinic, we examined the compliance with antimalarial chemoprophylaxis and its efficacy among travellers to tropical areas. Cases were patients with Plasmodium falciparum malaria (n = 131). Controls were patients who had a negative malaria film (n = 158). Of all controls, only 36 (22.8%) were adequately protected (i.e. compliant with an adapted regimen of chemoprophylaxis). In zone 2 countries, the efficacy of the combined chloroquine and proguanil was 58% (95% CI 22-78%) for all users, but increased to 100% (95% CI 89-100%) for compliant users. In zone 3 countries, the efficacy of mefloquine was 90% (95% CI 51-98%) and 100% (95% CI 58-100%) for all users and compliant users, respectively.

Evidence of changes in sexual behaviours among male factory workers in Ethiopia.

OBJECTIVE: To assess changes in sexual behaviours among male factory workers in Ethiopia. DESIGN: Open cohort studies in two factories near Addis Ababa. DATA AND METHODS: At intake and biannual follow-up visits, data were collected on sexual behaviours including casual sex, sex with commercial sex workers (CSW), condom use, and history of sexually transmitted diseases (STDs) as indicated by genital discharge and genital ulcer. Health education, HIV testing, and counselling were offered to all participants. RESULTS: Between February 1997 and December 1999, 1124 males were enrolled in the two cohort studies. At intake, the prevalence of casual sex in the past year, sex with CSWs, condom use with the last casual partner, history of genital discharge in the past 5 years, and history of genital ulcer in the past 5 years were 9.7, 43.4, 38.8 (Akaki site only), 10.6 and 2.1%, respectively. At the Wonji site, the intake prevalence of casual sex, sex with CSW, and history of genital discharge decreased significantly by calendar year between 1997 and 1999. At both sites combined, between the first and the fourth follow-up visits, there was a decline in the proportion of males reporting recent casual sex (from 17.5 to 3.5%, < 0.001), sex with CSWs (from 11.2 to 0.75%, < 0.001), and genital discharge (from 2.1 to 0.6%, = 0.004). CONCLUSION: There was a decline over time in risky sexual behaviours reported by cohort participants. Part of this decline occurred independently of cohort interventions.

Recombination of HIV type 1C (C'/C") in Ethiopia: possible link of EthHIV-1C' to subtype C sequences from the high-prevalence epidemics in India and Southern Africa.

The magnitude and complexity of the HIV-1 genetic diversity are major challenges for vaccine development. Investigation of the genotypes circulating in areas of high incidence, as well as their interactions, will be a milestone in the development of an efficacious vaccine. Because HIV-1 subtype C (HIV-1C) is responsible for most of the 36 million infections worldwide we investigated the HIV-1C strains circulating in Ethiopia in a retrospective, cross-sectional study. Serum samples from HIV-1-positive individuals were collected in seven Ethiopian cities and towns. Nucleotide sequences of the gag, pol, and env genes were analyzed. We performed phylogenetic analysis by the neighbor-joining and maximum-likelihood methods with sequences from 30 isolates, and we determined recombination by the bootscanning method as implemented in the SIMPLOT program. Sequence analyses of a 2600-nucleotide fragment (including the gag gene, the protease, and the 5' half of reverse transcriptase of the pol gene) and the corresponding V1V2/C2V3 envelope regions confirmed that two distinct HIV-1C genotypes (C' and C") are cocirculating in Ethiopia, as shown previously by the analysis of the C2V3 envelope region. We have identified intrasubtype recombination between the two HIV-1C genotypes, C' and C", with 6 of the 30 (20%) analyzed viruses being recombinants. The C' sequences were phylogenetically linked to the fast spreading viruses in India and southern Africa. Furthermore, all the recombinant viruses shared the C' V1V3 region of the envelope, suggesting that the prevalence of viruses with the C' envelope is increasing compared to the C" envelope. The possibility that viruses with a C' envelope have a biological advantage over the viruses with a C" envelope should be further investigated in biological and epidemiological studies.

Nine-year trends in HIV-1 prevalence among visa applicants in Urban Ethiopia.

A retrospective study was conducted to examine trends in HIV-1 prevalence among visa applicants between the years 1993 to 2001 in Urban Ethiopia. A total of 63,869 visa applicants were screened during these nine years period. The majority of them (79.5%) were females. Their mean age was 31.6 and 25.7 years for males and females, respectively. HIV-1 prevalence ranged from 6.8% in 1993 to 10.4% in 1997 (test for trend: p<0.001), while it seems stabilized at around 11% after 1997. The overall period prevalence was 9.5%. The peak prevalence was documented in the age group 25-29 for females (12.1%) while it was in the age group 30-34 for males (11.4%). This study, therefore, confirms the severity of the HIV-1 epidemic in the country. Visa applicants can be used as a sentinel population for monitoring trends in HIV-1 prevalence in the country, although additional socio-demographic information would be useful for better interpretation of such data.

Decline in prevalence of HIV-1 infection and syphilis among young women attending antenatal care clinics in Addis Ababa, Ethiopia: results from sentinel surveillance, 1995-2001.

From 1995 to 2001, five rounds of sentinel surveillance were carried out for young women attending antenatal care clinics at four health centers in Addis Ababa, the capital city of Ethiopia, to monitor trends in the prevalence of HIV infection and syphilis. Serum samples were tested for antibodies to HIV (enzyme-linked immunosorbent assay and Western blotting) and antibodies to Treponema pallidum (T. pallidum hemagglutination assay and rapid plasma reagin test). Prevalence ratios for an increase in one calendar year were estimated using log-binomial models. Between 1995 and 2001, the prevalence of HIV infection among young women (age range, 15-24 years) attending antenatal care clinics in inner city health centers declined from 24.2% to 15.1% (prevalence ratio for an increase in one calendar year, 0.91; 95% confidence interval, 0.87-0.95). No change was observed for older age groups or in outer city health centers. The decline in the prevalence of active syphilis (T. pallidum hemagglutination assay and rapid plasma reagin testing positive for antibodies to T. pallidum) was more pronounced among and also restricted to the young age groups (age range, 15-24 years) in the inner city (from 7.6% in 1995 to 1.3% in 2001; prevalence ratio, 0.69; 95% confidence interval, 0.59-0.80). The declining trends in the prevalence of HIV infection and syphilis among young women attending antenatal care clinics in the inner city are encouraging, but these findings require confirmation in future years and for other population groups.

Evidence of changes in sexual behaviours among male factory workers in Ethiopia.

OBJECTIVE: To assess changes in sexual behaviours among male factory workers in Ethiopia. DESIGN: Open cohort studies in two factories near Addis Ababa. DATA AND METHODS: At intake and biannual follow-up visits, data were collected on sexual behaviours including casual sex, sex with commercial sex workers (CSW), condom use, and history of sexually transmitted diseases (STDs) as indicated by genital discharge and genital ulcer. Health education, HIV testing, and counselling were offered to all participants. RESULTS: Between February 1997 and December 1999, 1124 males were enrolled in the two cohort studies. At intake, the prevalence of casual sex in the past year, sex with CSWs, condom use with the last casual partner, history of genital discharge in the past 5 years, and history of genital ulcer in the past 5 years were 9.7, 43.4, 38.8 (Akaki site only), 10.6 and 2.1%, respectively. At the Wonji site, the intake prevalence of casual sex, sex with CSW, and history of genital discharge decreased significantly by calendar year between 1997 and 1999. At both sites combined, between the first and the fourth follow-up visits, there was a decline in the proportion of males reporting recent causal sex (from 17.5 to 3.5%, P < 0.001), sex with CSWs (from 11.2 to 0.75%, P < 0.001), and genital discharge (from 2.1 to 0.6%, P = 0.004). CONCLUSION: There was a decline over time in risky sexual behaviours reported by cohort participants. Part of this decline occurred independently of cohort interventions.

Higher prevalence of anti-HCV antibodies among HIV-positive compared to HIV-negative inhabitants of Addis Ababa, Ethiopia.

Serum samples (n = 4,593) collected in 1994 as part of a representative household community survey of the population of Addis Ababa who were 0-49 years old were tested for hepatitis C (HCV) antibodies. A third generation ELISA was used for primary screening and a line immunoblot assay for confirmation. HCV antibody prevalence was 0.9% (95% CI, 0.6-1.2%) and higher among HIV-positive compared to HIV-negative individuals (4.5% vs. 0.8%, respectively, P < 0.001). Similar higher prevalence of HCV antibodies was seen among HIV-positive compared to HIV-negative antenatal care attenders (2.9% vs. 0.8%, respectively, P = 0.003, n = 1,725), and sex workers (5.3% vs. 1.3%, respectively, P = 0.02, n = 383). Such association between HCV and HIV infection has not been described previously in Africa. After stratification by HIV status, HCV prevalence among women of the general population was identical to that of sex workers, suggesting that HCV sexual transmission is not common in this population and that HIV infection does not enhance susceptibility to HCV sexual transmission.

Herpes simplex virus type 2 seropositivity among urban adults in Africa: results from two cross-sectional surveys in Addis Ababa, Ethiopia.

BACKGROUND: Although several surveys investigating the epidemiology of herpes simplex virus type 2 (HSV-2) infection using type-specific immunologic assays have been carried out in Africa, none has examined the risk factors for HSV-2 infection in a representative sample from an urban adult population. GOALS: To estimate the prevalence of HSV-2 infection in the adult population of Addis Ababa, Ethiopia, and to identify risk factors for HSV-2 infection. STUDY DESIGN: Two cross-sectional surveys, one community-based (June to September 1996, n = 506) and one factory-based (February to November 1997, n = 657), were conducted. Samples were tested for HSV-2 immunoglobulin G antibodies using type-specific enzyme-linked immunoassays (ELISA). RESULTS: In the community-based survey, HSV-2 prevalence increased with age until 25 years, then leveled off at 50% in both genders. The same independent predictors of HSV-2 infection were identified in both genders: older age, higher lifetime number of sexual partners, positive HIV serology, and positive Treponema pallidum hemagglutination serology. CONCLUSIONS: This study confirmed the high prevalence of HSV-2 infection among adults in an African urban population and its association with HIV infection. Prevention of HSV-2 and other sexually transmitted infections through partner reduction and condom use should be encouraged.

Decline in prevalence of HIV-1 infection and syphilis among young women attending antenatal care clinics in Addis Ababa, Ethiopia: results from sentinel surveillance, 1995-2001.

From 1995 to 2001, five rounds of sentinel surveillance were carried out for young women attending antenatal care clinics at four health centers in Addis Ababa, the capital city of Ethiopia, to monitor trends in the prevalence of HIV infection and syphilis. Serum samples were tested for antibodies to HIV (enzyme-linked immunosorbent assay and Western blotting) and antibodies to Treponema pallidum (T. pallidum hemagglutination assay and rapid plasma reagin test). Prevalence ratios for an increase in one calendar year were estimated using log-binomial models. Between 1995 and 2001, the prevalence of HIV infection among young women (age range, 15-24 years) attending antenatal care clinics in inner city health centers declined from 24.2% to 15.1% (prevalence ratio for an increase in one calendar year, 0.91; 95% confidence interval, 0.87-0.95). No change was observed for older age groups or in outer city health centers. The decline in the prevalence of active syphilis (T. pallidum hemagglutination assay and rapid plasma reagin testing positive for antibodies to T. pallidum) was more pronounced among and also restricted to the young age groups (age range, 15-24 years) in the inner city (from 7.6% in 1995 to 1.3% in 2001; prevalence ratio, 0.69; 95% confidence interval, 0.59-0.80). The declining trends in the prevalence of HIV infection and syphilis among young women attending antenatal care clinics in the inner city are encouraging, but these findings require confirmation in future years and for other population groups.

Immunophenotyping of blood lymphocytes at birth, during childhood, and during adulthood in HIV-1-uninfected Ethiopians.

To obtain more insight into blood lymphocyte subpopulations of Ethiopians, we studied the immunologic profile of children and neonates and compared these data with those obtained from adults. Peripheral blood mononuclear cells (PBMCs) and cord blood mononuclear cells (CBMCs) were collected from 137 HIV-1-uninfected subjects aged 0 (cord blood) up to 40 years. Lymphocyte subsets (T, B, and NK cells, CD4+ and CD8+ T cells) were determined and T cell activation (CD38 and HLA-DR) and differentiation (CD45RO and CD27) markers were measured on CD4+ and CD8+ T cells. The absolute number and percentage values of most lymphocyte subpopulations differed substantially with age. Neonates and children were found to have significantly higher CD4+ T cell counts compared to adults. The median absolute CD4 count at birth was comparable to those reported for Caucasians. At birth 97% of the CD4+ T cells were naîve and this proportion significantly declined to 14.2% during adulthood. In addition, activation of both CD4+ and CD8+ T cells, as determined by the double expression of HLA-DR and CD38, was observed in children under the age of 16 and adults, but not in neonates. A more differentiated phenotype (CD27-) was observed in adults compared to children for both CD4+ and CD8+ T cells. The immune alterations including the remarkably low CD4 count with highly depleted naîve phenotype and a persistently activated immune system seen in adult Ethiopians are not apparent at birth, but rather develop over time.

Primary HIV-1 subtype C infection in Ethiopia.

Between 1997 and 2001, 1624 Ethiopian factory workers were enrolled in prospective HIV-1 cohorts in Ethiopia, at Akaki and Wonji towns. HIV-1 seroprevalence at intake was 11.8% (Akaki) and 7.1% (Wonji). HIV-1 incidence was .75 per 100 person-years (Akaki) and .35 per 100 person-years (Wonji). During follow up, CD4 T-cell counts remained significantly lower and CD8 T-cell counts significantly higher in Ethiopian seroconverters compared with Dutch seroconverters. Viral loads were lower in Ethiopian seroconverters versus Dutch seroconverters in the first months after seroconversion, subsequently increasing to similar levels. All 20 Ethiopian seroconverters were infected with HIV-1 subtype C (15 with sub-cluster C' and 5 with sub-cluster C). Viral loads were higher in sub-cluster C'-infected Ethiopian seroconverters. One subject demonstrated a window period of at least 204 days, combined with a high preseroconversion viral load and no decline of CD4 T cells over a follow-up period of at least 3 years.