1998–1999 Malaysia Nipah virus outbreak

The 1998–1999 Malaysia Nipah virus outbreak was a Nipah virus outbreak occurring from September 1998 to May 1999 in the states of Perak, Negeri Sembilan and Selangor in Malaysia. A total of 265 cases of acute encephalitis with 105 deaths caused by the virus were reported in the three states throughout the outbreak. The Malaysian health authorities at first thought that Japanese encephalitis (JE) was the cause of the infection. This misunderstanding hampered the deployment of effective measures to prevent the spread, before the disease was identified by a local virologist from the Faculty of Medicine, University of Malaya as a newly discovered agent. It was named Nipah virus (NiV). The disease was as deadly as the Ebola virus disease (EVD), but attacked the brain system instead of the blood vessels. University of Malaya's Faculty of Medicine and the University of Malaya Medical Centre played a major role in serving as a major referral centre for the outbreak, treating majority of the Nipah patients and was instrumental in isolating the novel virus and researched on its features.

This emerging disease caused major losses to both animal and human lives, affecting livestock trade. It also created a significant setback to the swine sector of the animal industry in Malaysia. The country became the origin of the virus, but had no more cases since 1999. Further outbreaks continue to occur in Bangladesh and India.