Genetic relatedness of hepatitis A virus isolates during a community‐wide outbreak

Abstract

In 1993-94, a community-wide outbreak of hepatitis A occurred in Stanislaus County, California. Stool specimens collected from a sample of 33 case patients were used to evaluate the duration of hepatitis A virus (HAV) excretion and the genetic relatedness of HAV isolates. Twenty-four percent of the patients had a stool sample positive for HAV antigen by enzyme immunoassay, whereas 91% had at least one stool positive for HAV RNA by RT-PCR amplification. Children were found to excrete low levels of HAV RNA for up to 10 weeks after the onset of symptoms. Analysis of the HAV VP1 amino terminus and VP1/P2A regions showed that a limited number of HAV isolates circulated during the epidemic and the majority of the cases were infected with the same strain.

Presumed common source outbreaks of hepatitis A in an endemic area confirmed by limited sequencing within the VP1 region

“…In this study, we found the amino terminal region of VP1, which is a variable part of the genome, useful for both the detection and characterization of HAV RNA in sera from hepatitis A cases. When using a considerably shorter fragment within this region, the discrimination obtained between HAV strains involved in a community outbreak was, however, less compared to the VP1/ P2A junction [Robertson et al, 2000]. We con®rmed that virus may be present in serum for a longer period during the convalescence of hepatitis A than anticipated previously [Yotsuyanagi et al, 1993;Fujiwara et al, 1997;Bower et al, 2000].…”

“…Most of these strains both from sporadic cases and from the outbreaks in Desamparados and Santa Ana were not related closely to any strain published previously, but constituted discrete, interrelated geographical clusters. With the improvement in sanitation conditions and the consequent increase in the susceptibility of the general population to HAV infection, this type of study will provide essential baseline data for genetic analysis of strains during outbreaks to identify the source of infection as also shown for South Africa and the USA [Taylor, 1997;Robertson et al, 2000]. Previously, sequence analysis of the VP1-2A junction has made it possible to distinguish between strains involved in addict epidemics and in small outbreaks associated with imported cases of hepatitis A [Stene-Johansen et al, 1998].…”

Molecular epidemiology of hepatitis A virus in metropolitan areas in Japan

“…A report from the United States showing that most patients infected in a community-wide outbreak were infected by the same strain supports this hypothesis. 15 In developed countries, a substantial number of patients with hepatitis A acquired HAV through homosexual activity (www.cdc.gov/nciod/diseases/hepatitis/ h96surve.htm). Recent studies using PCR analysis have shown that the fecal excretion of HAV continues even after recovery, 16 which suggests that hepatitis A patients may transmit the virus even after recovery.…”

Foodborne viruses

“…The concentration of virus in stool declines after jaundice appears, although prolonged shedding may occur, particularly among infants and children (reportedly up to 5 months post infection [134,136]). Robertson et al [154] found low levels of HAV RNA in stools from children for up to 10 weeks after the onset of symptoms. Reactivation of viral shedding can occur during relapsing illness.…”

“…The other three genotypes have been found in captive Old World monkeys [179]. Genetically distinct lineages are found in di¡erent geographic regions and among patients in particular risk groups [154,173,174,176,180,181]. The genetic diversity of HAV has been used to verify the occurrence of outbreaks including foodborne [142,153,159,163,167,169] and waterborne outbreaks [160], and to link apparently sporadic cases to recognized foodborne and waterborne outbreaks [167,182].…”