The role of hepatitis E virus in acute sporadic non-A, non-B hepatitis

Hepatitis E virus (HEV) is the cause of enterically transmitted non-A, non-B (NANB) hepatitis. Water-borne epidemics have been reported in many developing countries primarily affecting young and middle-aged adults. To determine the role of HEV in acute sporadic NANB hepatitis, we have studied the profiles of anti-HEV IgG in the sera of patients previously diagnosed for NANB hepatitis. We tested the sera of 53 patients with acute NANB hepatitis and 100 healthy people as a control group for anti-HEV IgG. Thirty-nine of the 53 patients (73.3%) and none of the control group were positive for HEV infection, according to results shown by ELISA. This result suggests that HEV is a common cause of acute sporadic NANB hepatitis in Turkey. Further studies are needed in the other regions to determine the true prevalence of HEV infection in Turkey.

[An experimental infection in lambs by the hepatitis E virus]

Lambs were experimentally infected with a pool of 10% hepatitis E (HE) patient fecal suspension containing HE virus (HEV) isolates Osh-225 and Osh-228 which caused an infection closely resembling experimental HE in primates. Clinical manifestations consisted of acute biochemical and histological hepatitis, virus shedding in feces, the presence of virus-like particles in the peripharyngeal lymph nodes and the contents of small intestine, of HEV RNA in the parenchymal organs of lambs. Susceptibility of lambs to HEV derived from the infected piglets and the possibility of passaging the piglets' HEV in lambs was demonstrated. This passaging led to shortening of the incubation period.

Infectivity titration of a prototype strain of hepatitis E virus in cynomolgus monkeys

The infectivity titer of a standard stock of the SAR-55 strain of hepatitis E virus (HEV) was determined in cynomolgus macaques (Macaca fascicularis) and the effect of dose on the course of the infection was examined by weekly monitoring of alanine aminotransferase (ALT) and anti-HEV levels. Antibody to HEV (anti-HEV) was measured with ELISAs based on ORF-2 recombinant antigens consisting of either a 55 kDa region expressed in insect cells or shorter regions expressed as fusion proteins in bacteria. The ELISA based on the 55 kDa antigen was generally more sensitive. The infectivity titer of SAR-55 was 10(6) cynomolgus 50% infectious doses per gram of feces. The infectivity titer corresponded to the HEV genome titer of the inoculum as determined by reverse transcriptase-polymerase chain reaction (RT-PCR). Anti-HEV IgM was detected in only a portion of the animals that had an anti-HEV IgG response. Biochemical evidence of hepatitis was most prominent in animals that were inoculated with the higher concentrations of virus and the incubation period to seroconversion was prolonged in animals that received the lower doses.

Hepatitis viruses: changing patterns of human disease

Viral hepatitis is a disease of antiquity, but evidence for more than one etiologic agent has been recognized only since the 1940s, when two viruses (hepatitis A virus and hepatitis B virus) were thought to account for all disease. In the past 20 years, three additional hepatitis agents (hepatitis C virus, hepatitis D virus, and hepatitis E virus) have been discovered, and there is evidence for at least one additional virus. Each of the five recognized hepatitis viruses belongs to a different virus family, and each has a unique epidemiology. The medical impact of these viruses on society has been strongly influenced by changes in human ecology. This has resulted in some cases in diminished disease and in others in increases in the incidence of disease.

An epidemic outbreak of hepatitis E in Yangon of Myanmar: antibody assay and animal transmission of the virus

An epidemic outbreak of hepatitis E occurred in an army recruit camp of Yangon, Myanmar, in October 1989. One hundred and eleven patients among 600 residents were hospitalized. As high as 83.7% of these patients were positive for the acute phase antibody against hepatitis E virus by an enzyme-linked immunosorbent assay developed in our laboratory. Also, 30.6% of 49 symptom-free residents examined were positive for the antibody. We prepared a stool extract from six patients and inoculated it into 10 rhesus monkeys for a series of three sub-passages. All of them developed acute biochemical hepatitis along with an elevation of antibody levels. A rechallenge with viruses of the present outbreak failed to provoke hepatitis in two monkeys that had previously recovered from acute hepatitis caused by an isolate of sporadic hepatitis E of the same area. Similarly, the rechallenge of the sporadic strain did not induce hepatitis in two monkeys that had been previously infected with the epidemic virus. These data suggested that the subjects would obtain neutralizing antibodies against the hepatitis E virus once infected, and many adult inhabitants of the endemic area had no protective antibodies and were still susceptible to hepatitis E infection.