Human rotavirus group a serotypes causing gastroenteritis in children less than 5 years and HIV-infected adults in Viwandani slum, Nairobi.

BACKGROUND: Rotavirus remains a leading cause of acute gastroenteritis in children worldwide with an estimated 2000 deaths each day in developing countries. Due to HIV/AIDS scourge in Kenya, it is possible that rotavirus-related gastroenteritis has been aggravated in adults. The Global Alliance for Immunizations has ranked rotavirus infection a priority for vaccine, and, to ensure its success, there is a need to document the local strain(s) circulating in different regions. METHODS: A cross-sectional study was conducted to document human rotavirus group A serotypes in children below 5 years and HIV-infected adults in Viwandani slum in Nairobi, Kenya. A total of 260 (128 from children and 132 from HIV infected adults) fecal specimen samples were analyzed from August 2012 to July 2013. Screening for rotavirus was done by antigen based enzyme immune-sorbent assay (ELISA), Polyacrylamide gel electrophoresis (PAGE) was used to detect rotavirus electropherotypes and finally genotyping was done by RT-PCR using genotype-specific primer sets targeting VP4 and VP7 genes. RESULTS: Rotavirus was detected in 23% and 8% of children and adult, respectively. Prevalence was high in children of < 2 years and adults of > 48 years. Long electropherotypes accounted for 80% and 60% while short electropherotypes accounted for 20% and 40% in children and adult, respectively. The common globally distributed strains, G1 and G3, accounted for 60% detections while the unusual G9 strain accounted for 80% infection in adults. G1P[8] was the common genotypic combination in children, accounting for 40% infection, whereas G9 [P8] accounted for 60% of the infections in adults. CONCLUSION: This study shows the existence of strain diversity between rotavirus circulating in children and adults within this study group. It further shows that as currently constituted, the 2 vaccines recommended for rotavirus would cover the circulating strain in Viwandani slum. Finally, there is a need for continuous rotavirus strain surveillance in children and a further focus on HIV infected adults.

Measles trends and vaccine effectiveness in Nairobi, Kenya.

OBJECTIVES: To determine morbidity and mortality from measles and to estimate measles vaccine effectiveness among children hospitalised with measles in two hospitals in Nairobi. DESIGN: A review of hospital records (index cards). SETTING: Kenyatta National Hospital and Mbagathi District Hospitals covering the years 1996-2000. METHOD: A review of index cards for measles morbility and mortality was undertaken in the two hospitals. Measles data at the Kenya Expanded Programme on Immunisation covering both hospitals was analysed for vaccine effectiveness. RESULTS: The incidence of measles was unusually high in 1998 between July and November (monthly range 130-305), reflecting on the occurrence of an outbreak at that time. There was no definite monthly incidence trend of measles in 1996,1997, 1999 and 2000. The median age of cases was 13 months (range 0-420 months) for Kenyatta hospital and 18 months (range 1-336 months) for Mbagathi Hospital. Significantly, 29.8% of all cases were aged below nine months when routine immunisation for measles had not begun. The median number of days spent in hospital were five days (range 0-87 days) for Kenyatta and four days (range 1-13 days) for Mbagathi. The overall case fatality rate was 5.6% and was similar for both males and females. The overall measles vaccine effectiveness among measles cases admitted to Kenyatta and Mbagathi Hospitals was 84.1%. CONCLUSION: The case admissions in Kenyatta and Mbagathi Hospitals suggest measles was prevalent in Nairobi over the latter half decade of the 1990's. Apart from 1998 when there was an outbreak, the seasonality of measles was dampened. The 1998 outbreak suggests a build up of susceptible children the majority of whom were born in the last quarter of 1996. The high mortality may have had to do with the majority of cases presenting late when symptoms were already complicated and severe.