A low proportion of HBeAg among HBsAg-positive pregnant women with known HIV status could suggest low perinatal transmission of HBV in Cameroon

<p>Abstract</p> <p>Background</p> <p>Transmission of hepatitis B virus (HBV) from HBV-positive mothers to their infants is common and usually occurs when the mother is hepatitis B e antigen (HBeAg) positive and/or has a high HBV DNA load. In this study, we determined the prevalence of hepatitis B surface antigen (HBsAg) and HBeAg among pregnant women with known HIV status.</p> <p>Findings</p> <p>A total of 650 pregnant women with a mean age of 26.2 years including 301 HIV-positives and 349 HIV-negatives were screened for HBsAg (Monolisa AgHBs Plus Biorad, France). Among the HBsAg-positives, HBeAg and anti-HBe were tested (Monolisa Ag HBe Plus Biorad, France). Overall, 51 (7.85%) were positive for HBsAg. The prevalence of HBsAg was not statistically different between HIV-positive and HIV-negative pregnant women [28/301 (9.3%) vs 23/349 (6.59%); p = 0.2]. None of the 45 HBsAg-positive samples was reactive for HBeAg.</p> <p>Conclusions</p> <p>Our study indicates a high prevalence of HBsAg with very low proportion of HBeAg in Cameroonian pregnant women. Since perinatal transmission of HBV is mostly effective when the mother is also HBeAg-positive, our data could suggest that perinatal transmissions play a minor role in HBV prevalence in Cameroon. In line with previous African studies, these findings further suggests that horizontal transmission could be the most common mechanism of HBV infections in Cameroon.</p

Access to Mutualistic Endosymbiotic Microbes: An Underappreciated Benefit of Group Living

The original publication is available at www.springerlink.com A central question in behavioral ecology has been why animals live in groups. Previous theories about the evolution of sociality focused on the potential benefits of decreased risk of predation, increased foraging or feeding efficiency, and mutual aid in defending resources and/or rearing offspring. This paper argues that access to mutualistic endosymbiotic microbes is an underappreciated benefit of group living and sets out to reinvigorate Troyer’s hypothesis that the need to obtain cellulolytic microbes from conspecifics influenced the evolution of social behavior in herbivores and to extend it to nonherbivores. This extension is necessary because the benefits of endosymbionts are not limited to nutrition; endosymbionts also help protect their hosts from pathogens. When hosts must obtain endosymbionts from conspecifics, they are forced to interact. Thus, complex forms of sociality may be more likely to evolve when hosts must repeatedly obtain endosymbionts from conspecifics than when endosymbionts can be obtained either directly from the environment, are vertically transmitted, or when repeated inoculations are not necessary. Observations from a variety of taxa are consistent with the ideas that individuals benefit from group living by gaining access to endosymbionts and the complexity of social behavior is associated with the mode of acquisition of endosymbionts. Ways to test this theory include (a) experiments designed to examine the effects of endosymbionts on host fitness and how endosymbionts are obtained and (b) using phylogenetic analyses to examine endosymbiont-host coevolution with the goal of determining the relationship between the mode of endosymbiont acquisition and host sociality