Science and Technology News

Thursday, May 27, 2010

Scientists Model Human Disease Caused by Deadly Nipah Virus

Christen McCluney
Defense Media Activity

Researchers from the Uniformed Services University of the Health Sciences (USU), the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID) and the National Emerging Infectious Diseases Laboratories (NEIDL) have recently found the first successful nonhuman primate model to test the Nipah virus, which will assist in research into how the disease affects humans.

Nipah is an emerging virus that causes severe illness with symptoms that include inflammation of the brain (encephalitis) and/or respiratory diseases. Nipah is closely related to Hendra virus and can cause severe disease in both animals such as pigs, resulting in significant economic losses for farmers, and people.

“It was because of the discovery of Hendra virus in 1994 in Australia that the CDC had reagents available to help identify this new virus, now called Nipah, that was infecting pigs in Malaysia in 1998-99,” Dr. Christopher Broder, USU professor of microbiology said.

In the initial Malaysia outbreak, transmission occurred largely from pigs to people, with pig farmers at high risk. But in more recent outbreaks of Nipah in Bangladesh, many cases have been linked to date palm sap contamination by fruit bats, also known as flying foxes.

Nipah virus has caused about a dozen outbreaks since its identification, and it can infect a wide range of animals and causes severe disease and death in people, making it a public health concern.

The experiments for this study were carried out at the U.S. Army Medical Research Institute of Infectious Diseases which operates a high-level biocontainment laboratory that offers safety and security.

“Without a vaccine or an approved therapeutic, there is nothing you can do to treat it,” Broder said. “The case fatality rate amongst infected people with Hendra and Nipah is greater than 50 percent and in Bangladesh is greater than 75 percent.”

The researchers demonstrated that when exposed to the virus, African Green Monkeys showed signs that were essentially identical to the symptoms humans have when infected by this deadly virus.

The findings from this study will provide a critical framework to test and evaluate potential vaccines and therapeutic measures needed to treat people that come into contact with the virus.

Broder said there are no cases of Nipah in the United States or in North or South America. But researchers are interested in testing bats in South America to see if there are related viruses.

“What we want to show now is whether certain vaccines and therapeutics that we have developed can be administered to monkeys and show protection,” he added. “We have recently reported on the successful application of a therapeutic human monoclonal antibody against Nipah virus in a ferret model of disease, and we are now further testing it in the hopes of its future use in people. We are just in the beginning stages of these important experiments.”

He also added that as a result of this research an antibody therapy could be available within a few years.

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