Chapter 12

Hepatitis A Virus

Livia Melo Villar, Luciane A Amado Leon and Vanessa Salete de Paula

Abstract

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.

Total Pages: 309-336 (28)

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