Nipah Virus a Rare New Genus - Study...05/28/00

WASHINGTON (Reuters) - The Nipah virus that killed 106 people in Malaysia and Singapore and caused livestock breeders to slaughter more than 1 million pigs in 1999 is a member of a new genus of viruses, researchers said on Friday.

They said it was related to a mysterious virus, since named Hendra virus, that sickened horses and killed two people in Australia in 1994.

The two species of virus make up their own genus, said William Bellini of the U.S. Centers for Disease Control and Prevention (CDC) and colleagues at the University of Malaya Medical Centre in Kuala Lumpar, Malaysia, Australia's Commonwealth Scientific and Industrial Research Organization and elsewhere.

``We suggest that these two viruses are representative of a new genus within the family Paramyxoviridae,'' they wrote in their report, published in Friday's issue of the journal Science.

What the two viruses have in common, they said, is an ability to make people ill. ``Like Hendra virus, Nipah virus is unusual among the paramyxoviruses in its ability to infect and cause potentially fatal disease in a number of host species, including humans,'' they wrote.

Nipah, apparently passed by coughing pigs, can lead to deadly encephalitis in people. It caused more than 265 causes in Malaysia and Singapore in 1998 and 1999.

The researchers did a number of tests to try to identify Nipah and found it did not react with measles virus, herpes, enteroviruses or other strains, but did strongly react with antiserum for Hendra virus from Australia.

``The emergence of Hendra virus in two outbreaks of severe respiratory virus disease in thoroughbred horses in Brisbane and MacKay, Queensland, Australia, in 1994 provided the first glimpse of a zoonotic (animal) paramyxovirus with an expanded host range that includes humans,'' they wrote.

``Under experimental conditions, Hendra virus was shown to infect cats, guinea pigs, horses and fruit bats.''

Genetic analysis confirmed Nipah and Hendra were closely related enough to make up their own genus.

They said experiments suggested bats were the natural host of the Nipah virus but tests have yet to turn up an infected bat. ``Thus, the reservoir of Nipah virus and the source of the virus that initiated the outbreak remain open questions,'' they wrote.

Many animal viruses pass to people -- notably influenza, from pigs and ducks and the HIV virus that causes AIDS from people -- but this family of viruses had not been known to before.