Progress made in fighting deadly virus spread by pigs and bats
July 6, 2005
According to two new reports in Nature and Proceedings of the National Academy of Sciences, scientists have made an important breakthrough in the effort to fight the deadly Nipah virus which killed more than 100 people in 1999. The outbreak, which also resulted in the culling in 1 million pigs across Malaysia, was later traced to fruit bats.
The teams of scientists lead by Dr. Benhur Lee and Christopher Broder found that the virus infects cells by attaching to a cell receptor, a kind of chemical doorway, called Ephrin-B2. Ephrin-B2 is found on brain cells and cells lining blood vessels and is important in nervous system development and the growth of blood vessels in human and animal embryos. The scientists hope their findings can be used to find a way to defend against the virus, which is not only dangerous to humans and livestock but may have potential as a biological weapon.
Nipah virus was only discovered in 1999 and is part of a new genus of zoonotic viruses related to the Hendra virus, which infected horses and killed two people in Australia in 1994. Nipah virus spreads to humans through contact with infectious animals, usually pigs. Scientists eventually indirectly tied the 1999 outbreak to massive forest fires in southeast Asia.
Fruit bats known as flying foxes are the natural hosts of both Nipah and Hendra viruses. Flying foxes generally live deep in the rainforests of the region feeding off nectar and fruit of canopy trees. During 1997-1998, el Nino brought dry conditions to the region that, when coupled with land-clearing for agriculture, lead to extensive forest fires and a haze that shrouded much of southeast Asia for months. The smoke from the fires and drought reduced the amount of fruit available to fruit bats which, in turn, moved into orchards, some of which were near pig farms. Pigs consumed the contaminated fruit dropped by fruit bats and later spread the virus to humans.
This article used information from Nature, Proceedings of the National Academy of Sciences, Reuters, The Straits Times, and the World Health Organization