Academic journal article Journal of Health Population and Nutrition

Diversity of Human Rotavirus VP6, VP7, and VP4 in Lagos State, Nigeria

Academic journal article Journal of Health Population and Nutrition

Diversity of Human Rotavirus VP6, VP7, and VP4 in Lagos State, Nigeria

Article excerpt

INTRODUCTION

Group A rotavirus is the most important aetiologic agent of severe gastroenteritis in children, aged less than five years, worldwide (1). Incidence of morbidity due to rotavirus-associated disease in young children is similar in developed and developing countries (2,3). The disease is more often severe and fatal in children in developing countries (4). Hence, a rotavirus vaccine would be useful in both developed and particularly developing countries for the prevention of severe disease in young children and reduction in treatment costs (5).

Results of field trials on candidate rotavirus vaccines suggest the need to study the epidemiology of rotavirus strains to formulate an effective rotavirus vaccine, because the immunity induced by candidate rotavirus vaccines is serotype-specific (6). Although several studies have documented that G1-4 are the predominant serotypes causing human disease worldwide (7), G9 serotypes have been rapidly emerging over the past few years in many locations globally (8). These five VP7 (G1-4 and G9) serotypes are incorporated into most vaccines currently being formulated. These were already tested in Europe and the USA (5).

Surveys of VP4 genotypes in several countries found that P[8] genotype was the most predominant P type in circulation (7). P[8] was associated almost always with either G1, G3, or G4, and P[4] was almost always associated with G2 (6). In developing countries, unusual strains have been reported and were most prevalent in some locations, such as Brazil, where G5 serotype was most prevalent (9). In India also, unusual combinations and rare human strains predominate (8).

The Fifth Rotavirus Vaccine Workshop, held at the Centers for Disease Control and Prevention (CDC) in 1995, recommended gathering and sharing data on the incidence, seasonality, and identification of serotypes of circulating rotaviruses (10), aiming at identifying critical needs for a vaccine for these diverse environments.

Serotype epidemiology of rotavirus infection has been reported in limited studies in Nigeria. In one study in Ibadan, only G1 strains were found to be circulating by monoclonal antibody enzyme immunoassay (EIA) for rotavirus serotype (11,12). In a second study, which included specimens from the north and south regions of the country, only strains with VP7 genotype G3 or G1 or G1/G3 [mosaic] viruses were detected by a PCR-based assay (13). In addition, VP4 genotype was determined in rotavirus-positive specimens (14). Surprisingly, the most common VP4 genotype was reported to be P[6], followed by P[8] strains, which are globally more prevalent. In a study conducted in Zaria, northern Nigeria, human rotaviruses with G1 and with G3 of VP7 serotype-specificity circulated at similar levels, and 'mosaic' viruses, which reacted with both G1 and G3 of VP7 monoclonal antibodies, were detected (15).

This study was undertaken to characterize VP7 and VP4 types of Nigerian rotavirus strains in Lagos because of its dynamic nature to determine the most prevalent strains.

This study aimed at extending the knowledge of VP7 serotype epidemiology for Nigeria and encompassed a study in Lagos, Nigeria. The purpose was to know whether the currently-licensed vaccines and those on clinical trials could protect our children, since they may protect less against unusual strains circulating in any country.

MATERIALS AND METHODS

Selection of patients and screening of rotavirus Faecal samples were collected from 287 children, aged less than five years, with acute diarrhoea attending the Gbaja Health Centre of Massey Street Children Hospital (n=106) and the Lagos University Teaching Hospital (n=181), Lagos State, Nigeria, during January 1996-December 1997. All children were seen initially as outpatients, and stool specimens were collected within 24 hours of presentation to the hospitals.

Ten percent suspensions of the sample in phosphate-buffered saline were tested for the presence of group A rotavirus antigen using a commercial enzyme immunoassay (Rotavirus IDEIA[TM], Dako, UK). …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.