Detection and Molecular Characterazitation of Rotavirus Strains Isolated from Children Attending Selected Health Facilities in Kiambu District

Abstract

Despite numerous health intervention measures available, severe dehydrating rotavirus diarrhea remainsa major contributor towards childhood mortality particularly in developing countries. Globalrotavirus surveillance is vital towards the development of safe, effective and efficacious vaccinesto control the associated high infection rates. In Kenya, however, there is little corroborateddata on rotavirus epidemiology, burden of disease and strains in circulation. The objectiveof this study was to determine the prevalence and molecular characteristics of rotavirus strainsresponsible for severe gastroenteritis in children in Kiambu District, Kenya. A total of 232 fecal samples were collected between August 2008 and May 2011 from children below 5 yearsold with diarrhea hospitalized at Kiambu District Hospital and Karuri Health Centre. The specimenswere screened for' group A rotavirus using Enzyme Linked Immuno-sorbent Assay (ELISA). RNA from ELISA-positive specimens was separated by polyacrylamide gel electrophoresis (PAGE) to determine rotavirus electropherotypes. Reverse Transcription PolymeraseChain Reaction (RT-PCR) was used to determine rotavirus G and P genotypes. The ELISA screen gave 36.6% positive results for group A rotavirus among the diarrheal cases. Rotaviruswas detected most frequently in infants and young children aged below 2 years with a peakat 6 to 11 months (X2 = 12.162; df = 4; P = 0.016). The virus was found year-round with slightpeaks and valleys in some months (X2 = 96; df =90; P value = 0.313). Of the 85 ELISApositivesamples, 58 (68.1%) gave visible RNA profiles whereas 28 (32.9%) gave invisible profile.Ofthe visible RNA profiles, 92.9%, 5.3% and 1.8% displayed long, short and more than 11RNA segments electropherotypes respectively (X2 = 344.621; df = 1; P = 0.001). Five differentG genotypes were determined in 55 of 85 of the specimens analysed (X2 = 447.48; df = 1;P = 0.001). G1 was predominated among the strains at 44.7%. Other usual global genotypes; G2, G4 and G9 were detected atlO.60/0;,4,.7% and 1.2% respectively. G8, an African-specific strainwas isolated at 8.2%. Three different.P genotypes were determined in 55.3% of the specimensanalysed (X2 = 376.379; df= 1; P'='=U.001).P [8] and P[4] predominated at 28.2% and 25.9% respectively. P[6], an African-specific strain was isolated in one sample. Data generated fromthis study will add crucial information on the burden of the rotavirus disease and genotype distributionin the country. Such information will not only aid in seeking advocacy for rotavirus vaccineintroduction in the country's national immunization programme, but will also help in the evaluationof the efficacy of these vaccines in relation to the rotavirus genotypes in circulation. The heterogeneity and ever-changing epidemiology of rotavirus observed in this and other relatedstudies underscores the need for continued surveillance of rotavirus strains throughout Kenyato ensure that vaccination programmes being advocated for provide optimal protection.