Differences in epidemiologic and clinical features of Nipah virus encephalitis between the Malaysian and Bangladesh outbreaks

ABSTRACT

Since the initial outbreak of Nipah encephalitis in Malaysia in 1998, the virus has reemerged in Bangladesh and the adjacent Indian state of West Bengal since 2001. To date more than 470 patients have been affected with over 250 fatalities in total. Although the source of the virus is believed to be the Pteropus fruit bats both in Malaysia and Bangladesh, there are also significant epidemiological and clinical differences in the outbreaks occurring in these two regions. Epidemiologically, in the Bangladesh and India outbreaks, bat-to-human transmission through food and animal and human-tohuman transmissions were the predominant modes, the outbreaks were on a smaller scale and they have recurred every year except 2002 and 2006. Clinically, the mortality was higher and respiratory manifestation was more prominent in the Bangladeshi and Indian patients compared with their Malaysian counterparts, which might reflect differences in care and medical practices. There remain however, important differences in clinical manifestations which are likely to be due to some genetic variations in the virus.