Detection of norovirus and sapovirus infection among children with gastroenteritis in Ho Chi Minh City, Vietnam

Abstract

This report describes norovirus (NoV) and sapovirus (SaV) infections in hospitalized children with acute sporadic gastroenteritis in Ho Chi Minh City, Vietnam. Stool specimens collected between December 1999 and November 2000 were examined for NoV and SaV using reverse transcription-PCR and phylogenetic analysis. NoVs were detected in 72 of 448 rotavirus-negative specimens, counted as part of an overall annual detection rate of 5.4% (72 of 1,339 children). This included four NoV genogroup I (GI) strains and 68 NoV GII strains. Only one SaV GI strain was detected in the rotavirus-negative specimens. Over 73% of the NoV sequences belonged to GII/4 (Lordsdale cluster) and were detected in all months except March. We also detected GII/3 strains (Saitama U201 cluster), a naturally occurring recombinant NoV, between January 2000 and March 2000 but not after this period. Other NoV strains belonging to GI/4, GI/8, GII/1, and GII/7 were also detected but were infrequent. In addition, two almost identical NoV GII strains (strains 026 and 0703) collected six months apart were classified into a new genotype that includes the Mc37 strain, which was previously shown to be a recombinant NoV. During this one-year study, the NoV prevailed at the end of the rainy season and the beginning of the dry season. Further epidemiological studies may be necessary to determine whether the GII/4 strains continue to dominant in this region.

Hospitalization due to norovirus and genotypes of rotavirus in pediatric patients, state of Espírito Santo

“…The high prevalence of NoV reported here, contrasts with other reports elsewhere dealing with sporadic cases in hospitalized children, which vary from 5.4% to 30% in pediatric patients (Subekti et al 2002, Oh et al 2003, Hansman et al 2004). Nevertheless, prevalence as high as 48.4% and 53% have also been related (Kirkwood & Bishop 2001, Colomba et al 2007).…”

“…Prevalence of NoV at the beginning of the dry season was previously observed in Vietnam (Hansman et al 2004). In contrast to countries with a temperate climate, the region of the present study does not have a clear variation in temperature.…”

Norovirus Infections in Symptomatic and Asymptomatic Food Handlers in Japan

“…Recently, excretion of norovirus by symptomatic and asymptomatic individuals during a hospital outbreak of gastroenteritis where a GII/4 strain was dominant has been described (6). At present, norovirus GII/4 strains are the most prevalent in many countries (4,8,27,28). What is more, variant GII/4 sequences, i.e., those differing by approximately 5% of amino acids, were speculated to be more virulent and part of the reason for the increased number of infections worldwide (8).…”

“…At present, norovirus GII/4 strains are the most prevalent in many countries (4,8,27,28). What is more, variant GII/4 sequences, i.e., those differing by approximately 5% of amino acids, were speculated to be more virulent and part of the reason for the increased number of infections worldwide (8). Clearly, norovirus GII/4 strains are widespread, although they may not always cause symptoms, which may account for the increased number of infections via a "silent" (that is, asymptomatic) transmission route.…”

“…One emerging characteristic is that strains have been found to persist in one geographical region, only to disappear suddenly (8,10). Seasonal studies have commonly found norovirus outbreaks peaking in the winter periods; however, the incidence rates, detection rates, and overall prevalence rates of infections may differ by country and setting and are likely to be affected by diagnostic techniques.…”