Mother-to-child transmission of human immunodeficiency virus type 1 in relation to the season in Yaounde, Cameroon

A public health program to prevent mother-to-child transmission (MTCT) of human immunodeficiency virus type 1 (HIV-1) by treatment with nevirapine has been ongoing in Yaounde, Cameroon since January 2000. After 24 months, plasma samples from 119 children born to HIV-1-positive mothers were tested for HIV-1 RNA between six and eight weeks after birth. Thirteen (10.9%) tested positive (95% confidence interval = 5.2-16.7%). Risk factors associated with MTCT in this study were maternal viral load (P < 0.05), low birth weight (chi2 for trend = 8.78, P = 0.01), and birth during the second half of the year. A high correlation was repeatedly observed between rainfall in a given month and the risk of MTCT of HIV-1 in children born three months later (r = 0.634, P < 0.001). Although we cannot rule out other tropical infections related to the rainy season, the role of malaria is highly suspected since the interval of three months we observed between the peaks of rainfall and the rate of transmission is consistent with the Plasmodium life cycle.     

Novel multiplexed HIV/simian immunodeficiency virus antibody detection assay

Like most emerging infectious disease viruses, HIV is also of zoonotic origin. To assess the risk for cross-species transmission of simian immunodeficiency viruses (SIVs) from nonhuman primates to humans in the Democratic Republic of Congo, we collected 330 samples derived from nonhuman primate bushmeat at 3 remote forest sites. SIV prevalences were estimated by using a novel high-throughput assay that included 34 HIV and SIV antigens in a single well. Overall, 19% of nonhuman primate bushmeat was infected with SIVs, and new SIV lineages were identified. Highest SIV prevalences were seen in red-tailed guenons (25%) and Tshuapa red colobus monkeys (24%), representing the most common hunted primate species, thus increasing the likelihood for cross-species transmission. Additional studies are needed to determine whether other SIVs crossed the species barrier. With the newly developed assay, large-scale screening against many antigens is now easier and faster.     

Bilateral anterior dislocation of the shoulders

Bilateral anterior shoulder dislocation is a very rare clinical entity. We report another case of traumatic bilateral anterior dislocation of shoulders. We discuss the mechanism of the dislocation which is unusual and the treatment.     

Human herpesvirus 8 primary infection occurs during childhood in Cameroon, Central Africa

While in the United States and northern Europe, human herpesvirus 8 (HHV-8) appears to be mainly sexually transmitted with primary infection occurring in adulthood, the modes of transmission remain unknown in East and Central Africa, where Kaposi's sarcoma (KS) is a long-standing endemic disease, occurring not only in adults but also in children. The aim of our present study was to determine the prevalence of HHV-8 infection in children from Yaounde, Cameroon, Central Africa. Specific antibodies directed against both latent and lytic HHV-8 antigens were detected and titrated, with an immunofluorescence assay using the KS-1 cell line, in the plasma of 258 children and adolescents, of 32 mother and child pairs and of 189 pregnant women. Two different HHV-8 DNA-specific sequences were searched in the buffy coat by PCR assays. The overall HHV-8 seroprevalence was 27.5% among these children and adolescents. In newborns, seroprevalence reached 46%, reflecting passive transmission of maternal IgG. This was followed by a marked drop. Then, beginning around 4 years of age, a regular increase of HHV-8 antibodies took place, reaching 39% in the 12- to 14-year age group and 48% above 15 years, a rate similar (54.5%) to that observed in pregnant women. PCR detection of HHV-8 sequences was negative in seronegative children and positive in the buffy coat in 17% of HHV-8-seropositive children, reflecting a low viral load in the peripheral blood. Our results establish that in Central Africa HHV-8 infection takes place during childhood by casual routes, in contrast to the sexual transmission observed in adults in northern Europe and the United States. We hypothesize that the lymphadenopathic form of KS seen in African children is related to an early and massive infection by HHV-8 in susceptible individuals.     

Phylogenetic analysis of 49 newly derived HIV-1 group O strains: high viral diversity but no group M-like subtype structure

We assess the genetic relationships between 49 HIV-1 group O strains from 24 and 25 patients living in Cameroon and France, respectively. Strains were sequenced in four genomic regions: gag (p24) and three env regions (C2-V3, gp41, and for 22 C2-gp41). In each of the genomic regions analyzed, the genetic diversity among the group O strains was higher than that exhibited by group M. We characterize three major group O phylogenetic clusters (O:A, O:B, and O:C) that comprised the same virus strains in each of the genomic regions analyzed. The majority of strains cluster in O:A, a cluster previously identified by analysis of pol and env sequences. Group O recombinants were also identified. Importantly, the distinction between these three major group O clades was weak compared to the strong clustering apparent in the global group M phylogenetic tree that led to the identification of subtypes. Thus, these clusters of group O viruses should not be considered as equivalent to the group M subtypes. This difference between the pattern of group O and the global group M diversity, both taking into account the pandemic status of the group M subtypes and the comparatively small number of group O-infected individuals (the majority being from Cameroon), indicates that the group O phylogeny primarily represents viral divergence in the Cameroon region, analogous to group M viral diversity present in the Democratic Republic of Congo.     

In Vitro and In Vivo Human Herpesvirus 8 Infection of Placenta

Herpesvirus infection of placenta may be harmful in pregnancy leading to disorders in fetal growth, premature delivery, miscarriage, or major congenital abnormalities. Although a correlation between human herpesvirus 8 (HHV-8) infection and abortion or low birth weight in children has been suggested, and rare cases of in utero or perinatal HHV-8 transmission have been documented, no direct evidence of HHV-8 infection of placenta has yet been reported. The aim of this study was to evaluate the in vitro and in vivo susceptibility of placental cells to HHV-8 infection. Short-term infection assays were performed on placental chorionic villi isolated from term placentae. Qualitative and quantitative HHV-8 detection were performed by PCR and real-time PCR, and HHV-8 proteins were analyzed by immunohistochemistry. Term placenta samples from HHV-8-seropositive women were analyzed for the presence of HHV-8 DNA and antigens. In vitro infected histocultures showed increasing amounts of HHV-8 DNA in tissues and supernatants; cyto- and syncitiotrophoblasts, as well as endothelial cells, expressed latent and lytic viral antigens. Increased apoptotic phenomena were visualized by the terminal deoxynucleotidyl transferase-mediated deoxyuridine nick end-labeling method in infected histocultures. Ex vivo, HHV-8 DNA and a latent viral antigen were detected in placenta samples from HHV-8-seropositive women. These findings demonstrate that HHV-8, like other human herpesviruses, may infect placental cells in vitro and in vivo, thus providing evidence that this phenomenon might influence vertical transmission and pregnancy outcome in HHV-8-infected women.