Epidemiological characteristics of human immunodeficiency virus type-2 infection in Africa

Sexually transmitted diseases in Japanese female commercial sex workers working in massage parlors with cell baths

A cross-sectional study of Japanese female commercial sex workers (FCSWs) working in massage parlors with cell baths (MPCBs) was conducted between July 1999 and December 2001. The study subjects were 171 FCSWs aged from 19 to 36 years. A questionnaire included sexual characteristics in addition to working name and date of birth. We serologically or bacteriologically confirmed the prevalence of HIV-1, HIV-2, hepatitis B virus (HBV), hepatitis C virus (HCV), Chlamydia trachomatis, Neisseria gonorrhoeae, syphilis, and trichomoniasis. There were no differences in the clinical characteristics of FCSWs working in standard-class MPCBs (group A) and those working in expensive-class MPCBs (group B). With respect to sexual characteristics, HIV-1 and HIV-2 were not confirmed in any subjects, but N. gonorrhoeae was detected in 1.2%. Use of condoms was 98.4% in group A and 83.3% in group B ( P < 0.01). No HIV infection and an extremely low prevalence of sexually transmitted diseases (STDs) were recognized in Japanese FCSWs working in standard- and expensive-class MPCBs.

Genetic analysis of HIV type 2 from Ghana and Guinea-Bissau, West Africa

The phylogenetic variability of part of the long terminal repeat (LTR) region of HIV-2 strains isolated in 1995 from five individuals residing in Bissau, the capital city of Guinea-Bissau, and collected from seven persons from Kumasi, Ghana in 1996-1997, was analyzed. All Guinean samples and all but one Ghanaian sample clustered with HIV-2 subtype A. One Ghanaian sample (14%) was classified as HIV-2 subtype B. This study adds to previous reports on HIV-2 subtype distribution in West Africa indicating local prevalence of HIV-2 subtype B in Ivory Coast and neighboring Ghana.

Increased prevalence of retrovirus infections among older women in Africa

Recent studies of HIV-2 have suggested an increased incidence and prevalence among women older than 45 y compared with younger women. We therefore examined whether this phenomenon applied generally to all 3 major retroviruses, HIV-1, HIV-2 and HTLV-I, among women in Africa. We conducted a MedLine search from 1987 to 1997, using the keywords Africa and HIV-1, HIV-2 or HTLV, respectively. Community studies, national surveys and studies on professional cohorts were selected. Age groups > 45/50 y were compared with the age group with the lowest female/male prevalence ratio between 20 and 44 y of age. Thirty-one studies had sufficient data to be included. The female/male odds ratio (OR) for seropositivity was calculated for the old and the young age groups, respectively, providing the ratio of odds ratios: OR (old)/OR (young). Summary ratios for studies of all 3 retroviruses were estimated. In general we found a higher female/male prevalence ratio in the age group over 45/50 y than in the younger age group. For HIV-1 the odds ratio was 1.82 times [95% confidence interval (CI) 1.19-2.79] higher in the old age group than in the young group. For HIV-2 it was 1.97 [95% CI 0.95-4.08], and for HTLV-I it was 2.02 [95% CI 0.99-4.14] times higher. For all 3 viruses combined, the ratio was 1.88 [95% CI 1.36-2.61]. The few incidence studies of HIV-1 and HIV-2 indicated a similar tendency. Since differential mortality is unlikely to explain the pattern, the increase in the HIV-1, HIV-2 and HTLV-I female/male prevalence ratio suggests that older women may have increased exposure or susceptibility to all 3 retrovirus infections.

HIV trends in African blood donors

OBJECTIVES

To assess trends over the last 12 years in HIV-1/HIV-2 seroprevalence among blood donors in African nations and to correlate trends with national AIDS policies, with the purpose of preventing future cases.

METHODS

Using collated data of African seroepidemiologic studies published by the U.S. Bureau of the Census, we established a best-fit linear trend, determined by regression analysis of HIV-1 and HIV-2 seroprevalence values for African blood donors against time, with adjustments for sample size of reported studies.

RESULTS

Among 38 nations with sufficient data, 11 showed increases in HIV-1 seroprevalence, six showed decreases and 21 showed no significant changes. Decreases were seen primarily in nations with a high HIV-1 seroprevalence before 1989 (P<0.001, Chi-square). HIV-2 seroprevalence decreased in all nations where it was tested except Nigeria. There was a moderate correlation between decreases in HIV-1 and HIV-2 seroprevalence values (correlation coefficient = 0.39). No significant correlations between HIV policies and subsequent HIV-1 seroprevalence trends among blood donors and HIV patients were detected.

CONCLUSIONS

A great disparity exists in trends in HIV-1 seroprevalence among African nations. HIV-2 seroprevalence is consistently decreasing throughout most of West Africa, the exception being Nigeria. The absence of any significant correlation between HIV seroprevalence trends and healthcare policies suggests that other factors are more influential than national policy in determining such trends and, by extrapolation, trends in AIDS prevalence.

Rate of decline of percentage CD4+ cells is faster in HIV-1 than in HIV-2 infection

Increasing evidence suggests that the pathogenesis of HIV-1 is different from that of HIV-2. Thus, we have measured, longitudinally at various times over a median follow-up of 2.1 years, the percentage CD4+ cells of 94 patients infected with HIV-1 and 164 patients infected with HIV-2. The pattern of decline of CD4% over time was linear for patients with either infection. Multilevel statistical modeling techniques showed that after stratifying for HIV status, the rate of decline of CD4% was faster among patients who died than among those who survived (difference in rate of decline = 2.34% CD4+ cells/year; p = 0.0002). After stratifying for survival status, the rate of decline was faster and less variable among patients infected with HIV-1 than among patients infected with HIV-2 (difference in rate of decline = 1.12% CD4+ cells/year; p = 0.05). The proportion of patients who showed no fall in CD4+ cells was higher in HIV-2 than in HIV-1 infection (p = 0.026). These data suggest fundamental differences between the two infections, with HIV-1 being more pathogenic resulting in a faster and more homogeneous rate of decline than HIV-2. In HIV-2 infection, disease in many patients progresses slowly, but in some the advance is just as fast as that in HIV-1 infection. The reasons for this marked heterogeneity need elucidation to understand the disease and to target therapeutic interventions against HIV-2 in those most at risk.