Electropherotypes and G-Types of Group A Rotaviruses Detected in Children with Diarrhea in Lagos, Nigeria

Approximately over 500,000 children die annually due to severe dehydrating diarrhea caused by rotaviruses. This work investigated rotavirus infection among children less than 5 years with diarrhea in Lagos and determined the circulating electropherotypes and genotypes of the virus isolates. Three hundred and two ( ) stool samples from children below 60 months were collected from different hospitals and health care centers in Lagos and subjected to enzyme immunoassay (EIA) to determine the presence of Group A rotavirus, RT-PCR to determine the G-types, and polyacrylamide gel electrophoresis (PAGE) to determine the electropherotypes. The results show that 60.3% of the samples showed distinct rotavirus RNA migration pattern, having long electropherotypes (55.3%) of seven variations dominating over the short electropherotypes (44.5%). Six different G-types were detected (G1, G2, G3, G4, G9, and G12). Serotypes G1 and G12 showed long electropherotypic pattern while G2, G3, and G9 exhibited either short or long electropherotype. All G4 detected show short electropherotypic pattern. In conclusion, information on the genomic diversity and RNA electropherotypes of rotaviruses detected in children with diarrhea in Lagos is reported in this study. 1. Introduction Rotavirus gastroenteritis is the major cause of morbidity and mortality among infants and young children in both developed and developing countries [1, 2]. It is estimated that 130 million children develop rotavirus-related diarrhoea each year with 18 million of them experiencing moderate to severe dehydration, resulting in over 520,000 deaths, with 85% of these deaths occurring in low-income countries [3, 4]. The mature virus particles are icosahedral, nonenveloped, measure 100？nm in diameter, and consist of a double-stranded RNA (dsRNA) in the family Reoviridae. It has a distinct morphologic appearance by negative-stain electron microscopy [5]. The viral capsid is triple layered; the inner layer (core) contains the virus genome, which comprises 11 segments of double-stranded RNA, each coding for products that are either structural viral proteins (VP) or nonstructural proteins (NSP). The segmented genome of rotavirus readily reassorts during coinfection, a property that has been used in developing vaccines and undoubtedly plays a role in virus evolution [6]. Studies on the electrophoretic migration patterns of viral genomic dsRNA segments (electropherotyping) have allowed for the classification of rotaviruses into two major groups, the long (L) and the short (S) electropherotypes [7]. Six of these dsRNA