Human group C rotaviruses identified in Kenya.

BACKGROUND: Rotavirus is associated with acute infantile gastro-enteritis in infants and young children worldwide. Rotavirus is associated with the high cases of morbidity and mortality and it is estimated that up to 650,000 deaths in young children occur annually in the less developed countries. Approximately a quarter of these deaths occur in African children yet minimal data exist on the circulating rotavirus strains in Africa. OBJECTIVE: To characterise the circulating rotavirus strains in Kenya. DESIGN: A prospective study to investigate rotavirus infection in infants and young children with acute diarrhoea in different areas of Kenya. Between September 2001 and February 2002, 119 faecal specimens were collected from children aged between 1 and 60 months with acute infantile gastro-enteritis. SETTING: Faecal samples were collected from clinics around Nairobi and its suburbs including Karen, Ngong, Ongata Rongai. SUBJECTS AND METHODS: Faecal samples were collected from 119 infants and young children with diarrhoea and were analysed by commercial ELISA and polyacrylamide gel electrophoresis (SDS-PAGE) to identify possible non-group A rotaviruses. Extraction of any potential rotavirus double-stranded RNA from faeces and characterisation by SDS-PAGE showed the presence of human group C rotaviruses. RESULTS: Examination of these samples with a commercial ELISA assay for the presence of group A rotavirus antigen showed that 13 specimens (11%) were positive. An analysis of all stool specimens was performed by polyacrylamide gel electrophoresis to identify possible non-group A rotaviruses. Extraction of any potential rotavirus double-stranded RNA from faeces and characterisation by SDS-PAGE showed the presence of human group C rotaviruses. CONCLUSION: This is the first report of group C rotaviruses in Kenya. Further studies are underway to continue the surveillance of rotavirus strains in Kenya; as this information will be useful in planning rotavirus vaccine trials in Africa.

The prevalence of anti-phospholipid antibodies in a selected population of Kenyan women and development of a non-human primate model.

The mechanisms by which anti-phospholipid antibodies (aPLs) may induce pregnancy losses, intrauterine growth retardation and pregnancy-induced hypertension are not clearly understood. Moreover, there is a controversy regarding the possible direct effects of these antibodies on the physiology of the placenta since the target antigens of these antibodies are intracellular antigens and are potentially inaccessible to the antibody. Also, controversy exists regarding the usefulness of the treatment regimens currently available. In this study, we present preliminary data on the prevalence of aPLs in a selected population (n = 80) of Kenyan women visiting Kenyatta National Hospital, Nairobi, Kenya for obstetrical complications including recurrent pregnancy losses. Our results showed approximately 13.8% of the patients were positive for anti-cardiolipin antibodies whereas 33.8% were positive for aPS. Additionally, we screened 72 non-human primates for presence of aPLs and our results showed that the olive baboon (Papio anubis) had the highest prevalence rate (52.2%, n = 23). Overall, our results suggest that the olive baboon may be a suitable animal model for studying the mechanism of action of the anti-phospholipid antibody and pregnancy complications associated with aPLs.

Characterisation of retroviral-related antigens expressed in normal baboon placental tissues.

The genomes of all eukaryotes contain multiple copies of DNA sequences that are related to sequences found in infectious retroviruses. Endogenous retroviruses (ERVs) are generally non-pathogenic although they have been implicated in the induction of tumours and immunological disorders. The ERVs have morphological features consistent with type-C retroviral particles and are expressed in normal placental tissue in most mammals. They have antigenic similarity with exogenous retroviruses such as HIV-1 and may have a role to play in the regulation of cellular gene expression, syncytiotrophoblast formation or pregnancy-related immunosuppression. Some of the human endogenous retroviruses have been well-characterised. Among the non-human primates, the baboon endogenous virus (BaEV) is the only endogenous retrovirus so far which has been shown to be effective in vitro. The entire nucleotide sequence of BaEV has been determined. It has been shown to have a chimeric genomic structure of about 8 kb long. BaEV particle expression in placental tissues has been demonstrated using electron microscopy. However, to date, very little work has been done to evaluate the expression of retroviral-related antigens in normal baboon tissues. In this study, mouse polyclonal antibodies were produced against isolated baboon placental ERV particles and characterised using immunohistochemistry and immunoblotting techniques. Most of the anti-BERV antibodies displayed specific immunoperoxidase staining on placental syncytiotrophoblast and cross-reacted with exogenous retroviral proteins on immunoblot analyses. Reverse transcriptase (RTase) activity associated with sucrose gradient-purified placental retroviral-like particles were also demonstrated. These studies indicate that endogenous retroviral particles are expressed in baboon placental villous tissue and suggest retroviral proteins may play an immunomodulatory role at the maternal-foetal interface.