Epidemiology of rotavirus and astrovirus infections in children in Northwestern Nigeria

Background: Recent estimates attribute 527 000 deaths in children less than five years of age to rotavirus diarrhea annually, with 145 000 occurring in sub-Saharan Africa. Human astroviruses have been identified as one of the most frequent causes of infantile diarrhea, second in incidence only to rotavirus. This study was conducted to determine the prevalence of rotavirus and astrovirus and also to establish the circulating strains of rotavirus in a community in Nigeria where most diarrheic patients do not visit clinics or health care centers. Methods: A total of 154 stool samples (134 diarrheic and 20 non-diarrheic) were collected from infants and young children less than 5 years of age from January-March 2002. Samples were obtained by house-to-house visit in randomly selected districts in Zaria, Northwestern Nigeria. The samples were screened for rotavirus and astrovirus antigens using commercially available Enzyme Linked Immunosorbent Assay (ELISA) kits. All positive group A rotavirus samples were further subjected to VP6 sub-group ELISA, Polyacrylamide gel electrophoresis (PAGE) to determine their RNA electropherotypes and Reverse transcription polymerase chain reaction (RT-PCR) to determine their VP7 and VP4 genotypes. Results: Rotavirus and astrovirus antigens were detected in 9% (12) and 5% (7) of the 134 diarrheic stool samples respectively. No viral antigen was detected in the non-diarrheic stools. Rotavirus infection was more common in younger children than astrovirus infection. VP6 sub-group II specificity (58.3%), long RNA electropherotypes (41.6%), VP7 genotype G1 (33.3%) and VP4 genotype P [6] (33.3%) were the most common strains in circulation at that time in the community. Of significance is the fact that a large proportion of the rotavirus strains in circulation could not be assigned either a VP6 subgroup or RNA electrophoretic pattern probably as a result of low viral load. Conclusion: In this community-based study, rotavirus and astrovirus were significantly associated with diarrhea. However, the prevalence of rotavirus infection among children appears to be low while that of astrovirus falls in the range seen in hospital-based studies around the continent

Electropherotypes and Subgroups of Group A Rotaviruses Circulating among Diarrhoeic Children in Kano; Nigeria

Background: It is estimated that about 600?000 children die annually as a result of severe dehydrating diarrhea caused by rotaviruses. The virus is a double stranded RNA (dsRNA) virus with 11 segments. Group A rotaviruses show a characteristic 4-2-3-2 pattern following electrophoresis. The VP6 subgroups; I and II exist. This work was carried out to study the prevalence of rotavirus infection among children 0-5 years with diarrhea in Kano; and to determine the circulating subgroups and electropherotypes and of the rotavirus isolates. Methods: Two hundred and eighteen stool specimens from children 0-60 months (198 diarrheic and 20 non-diarrheic) were collected from different hospitals and health care centers in Kano and subjected to group A rotavirus enzyme linked immunosorbent assay (ELISA) to determine presence of group A rotavirus; subgroup ELISA to determine the VP6 subgroups and polyacrylamide gel electrophoresis (PAGE) to determine the electropherotypes present. Results: The long electropherotypes (47.05) of four variations dominated over the short electropherotype (17.64). About 11.76of the isolates were of mixed infection. Dominance of subgroup II (45) over subgroup I (25); and the presence of both subgroups I and II (10) and neither subgroup I nor II (15) was observed in this study. Conclusion: Information on the genomic diversity of the RNA electropherotypes in this region; Kano; is reported in this study

Prevalence des antigenes d'adenovirus chez les enfants atteints de diarrhee aigue

Les diarrhees virales constituent une cause majeure de morbidite et de mortalite infantiles dans le monde entier. Les virus impliques sont; d'apres la litterature; les rotavirus; les astrovirus; les adenovirus enteriques et les calicivirus. Une etude epidemiologique retrospective a ete menee dans le centre-est tunisien : six-cent trente-huit selles ont ete prelevees a partir d'enfants de moins de 5 ans se presentant dans un service de soins hospitaliers du centre-est tunisien pour diarrhee aigue entre octobre 2002 et septembre 2005. Tous les prelevements ont ete testes par technique immunoenzymatique commercialise pour la detection d'antigenes specifiques des adenovirus. Les prelevements positifs en antigenes d'adenovirus ont par la suite ete testes par une technique ELISA permettant la mise en evidence specifique des adenovirus enteriques de l'espece F appartenant aux types 40 et 41. Les adenovirus ont ete detectes dans 6des selles testees par ELISA. Parmi les selles positives en adenovirus; 57(20/35) etaient positives en adenovirus F types 40/41. Parallelement a la diarrhee; les signes cliniques les plus frequemment retrouves chez les enfants hospitalises positifs en adenovirus etaient les vomissements (89) et la fievre (53); associes dans 32des cas a des signes respiratoires. Les adenovirus enteriques semblent jouer un role non negligeable dans les diarrhees infantiles en Tunisie. La mise a disposition de methodes de diagnostic simples et efficaces dans les laboratoires hospitaliers pourrait ameliorer la prise en charge des malades en reduisant l'instauration d'antibiotherapies inutiles

Atypical rotavirus identified from young children with diarrhoea in South Africa.

The study was undertaken for antigenic characterization of rotavirus strains isolated from South African children. During July 1996-July 1997, an epidemiological surveillance of rotavirus-associated gastroenteritis was carried out in Pretoria and Gauteng provinces. In total, 1,229 diarrhoeal faecal samples were collected from a pathology laboratory. Of 389 (32%) rotavirus strains detected, most (97%) were group A rotaviruses by serological assay. However, 12 rotavirus strains identified did not apparently carry the common group A-specific antigen as determined by both commercial and monoclonal antibody-based ELISAs. Electrophoretic analysis of the viral RNA genome revealed that these strains shared a common electropherotype and that this resembled the group A rotavirus constellation of RNA segments. Furthermore, the conserved terminal sequences of the group A VP6 and VP7 genes could not be targeted by standard reverse transcriptase-polymerase chain reaction with a routine set of primers to the VP6 or VP7 genes. These strains present an interesting phenotypic variation of the recognized rotaviruses and warrant further characterization.