The Bangladesh Institute of Epidemiology, Disease Control and Research (IEDCR) has reported a total of nine human Nipah virus cases this year as of Feb. 2015. Of the nine cases, health officials report six fatalities, or a 67% case-fatality rate.

Pteropus  fruit bat Image/Video Screen Shot
Pteropus fruit bat
Image/Video Screen Shot

These cases are from 6 different districts. The districts are: Nilphamari, Ponchoghor, Faridpur, Magura, Naugaon, Rajbari. Median age of the Nipah cases 13 years (Range: 2 to 45 years). 5 (56%) were male.

One cluster was identified in Naugaon, consists of three Nipah encephalitis cases, according to the IEDCR. Of these two are laboratory confirmed cases. Numbers of isolated cases are 6.

According to the World Health Organization (WHO), in the Bangladesh and India outbreaks, consumption of fruits or fruit products (e.g. raw date palm juice) contaminated with urine or saliva from infected fruitbats was the most likely source of infection. Fruit bats of the family Pteropodidae – particularly species belonging to the Pteropus genus – are the natural hosts for Nipah virus. There is no apparent disease in fruit bats.

In more recent outbreaks of the disease, person-to-person transmission has been seen in Bangladesh and India.

Related: What is Nipah virus?

The disease in humans can range from asymptomatic infection to fatal encephalitis. Encephalitis and seizures occur in severe cases, progressing to coma within 24 to 48 hours.

The case fatality rate is estimated at 40% to 75%; however, this rate can vary by outbreak depending on local capabilities for surveillance investigations, according to the WHO.

Those who survive acute encephalitis make a full recovery, but around 20% are left with residualneurological consequences such as persistent convulsions and personality changes.

There is no treatment or vaccine available for either people or animals.

Nipah virus was first detected in Malaysia in 1998 but at present Bangladesh, a hotspot for infectious diseases, is the only country in the world that reports the disease.

Related: The World’s Deadliest Viruses