Hepatitis A Virus
Pp. 309-336 (28)
Livia Melo Villar, Luciane A Amado Leon and Vanessa Salete de Paula
Hepatitis A virus (HAV) infection is the most frequent cause of viral
hepatitis worldwide. HAV belongs to the Picornaviridae family in the genus
Hepatovirus. The genome of HAV is a positive-sense single-stranded RNA that is
approximately 7.5 kb in length. In fact, HAV is classified into six genotypes: three
isolated from humans (I–III) and three of simian origin (IV–VI). Worldwide, genotype
I is the most prevalent, particularly subgenotype IA. A diagnosis of hepatitis A can be
performed by detection of anti-HAV IgM and IgG antibodies by enzyme immunoassay
or HAV RNA detection by nested-PCR. Hepatitis A is transmitted principally via the
fecal-oral route, including person-to-person contact and the ingestion of water or food
that is contaminated by the feces of infected individuals. HAV infection is usually selflimited
and benign, with no symptoms, but a severe form of the disease, fulminant
hepatitis, affects approximately 1% of the patients who are hospitalized for hepatitis A.
In Latin America, several seroprevalence studies have demonstrated an
epidemiological shift in HAV infection from high towards intermediate endemicity
levels. In Brazil, a large number of children under five years of age (74.1-90%) have
been found to be susceptible to HAV infection in 3 capitals of the North, Midwest and
Southeast region of Brazil. There is no specific treatment for hepatitis A. Therapy
should be supportive and aimed at maintaining an adequate nutritional balance.
Clinical course, Diagnosis, Epidemiology, Genetic variability,
Genome, Hepatitis A virus, Replication, Transmission, Treatment, Viral structure.
Laboratory of Viral Hepatitis, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Brazil.