Cultivation of buffalo green monkey kidney cells persistently infected with hepatitis A virus.

Studies were carried out to determine the effect of prolongation of incubation periods, cocultivation with normal buffalo green monkey kidney (BGMK) cells and different concentrations of foetal calf serum (FCS) on the production of hepatitis A virus (HAV) by BGMK cell line persistently infected with HAV strain HM175. HAV could be detected from week 1 onwards. However, maintenance of cultures beyond this period was found to yield substantially higher quantities of virus. Cocultivation of persistently infected cells with normal BGMK cells also improved the antigen yields. Different concentrations of FCS did not show any effect on the amount of virus produced. The cell line was maintained up to 46 passages during which there was continuous production of HAV in the cells and release of small amounts of virus in the culture supernatants. Cell associated and cell free viral particles were found to be infectious. Supernatant derived virus was a highly suitable inoculum for infecting other susceptible cell lines. Persistently infected BGMK cell line appears to be a reliable and economical source to derive HAV in adequate amounts for diagnostic and research purposes.

Hepatitis E virus infection in pregnant rhesus monkeys.

Ten non-pregnant female monkeys and four pregnant monkeys (all Macaca mulatta) in the last third of their gestation period were infected intravenously with the stool sample of a patient with hepatitis E virus infection (immuno-electronmicroscopy positive for hepatitis E virus). Four more non-pregnant monkeys were inoculated with a lower dose (less number of virus particles by IEM) of a stool sample collected on a different day from the same patient. The average incubation period as evidenced by the rise of serum alanine transferase in the non-pregnant monkeys, was 36.4 +/- 4.9 days. The dose of the virus did not affect the incubation period. Two of the pregnant monkeys had incubation periods of 9 and 13 days respectively. They delivered healthy babies on 40th and 53rd day respectively after inoculation. At the age of 11 months, both babies were negative for anti-HEV antibodies. One monkey which delivered a healthy baby on the 2nd day after inoculation had incubation period of 36 days. The baby of this monkey was anti-HEV positive at the age of 11 months. The incubation period was 41 days in the fourth monkey which delivered a macerated foetus on the 36th day after infection. No fatality was recorded in the infected monkeys. Bile samples collected from all monkeys showed strong signals in nested polymerase chain reaction (PCR). It seems that the incubation period in pregnant monkeys was determined by the state of pregnancy.