Description of the situation
15 April 1999
Disease Outbreak Reported
While the exact number of encephalitis cases and deaths in Malaysia continues to be tabulated, it is now apparent that the number of cases is no longer increasing, showing that the epidemic is under control. Both Japanese encephalitis virus and a Hendra-like virus (now being designated as Nipah virus) infections have been reported; however, Nipah virus appears to be the predominant pathogen. Cases have almost exclusively occurred in persons in close contact with pigs, especially those working is areas where there is disease in pigs. Pig culling in affected areas is ongoing to control Nipah virus transmission.
Multiple epidemiological studies both in animals and humans are continuing. These include studies to determine the animal species infected by Nipah and to identify the natural reservoir of the virus. Among the studies in humans, emphasis is on the identification of the specific risk factors for infection. Investigators from the United States Centers for Disease Control and Prevention and from other countries, including Australia and Japan, are working with the Malaysian government to conduct these studies.