The World Health Organization reported two cases of a rare virus in an eastern Indian state on Thursday.

Since the infection was first detected in humans in 1998, there have been sporadic new outbreaks across the so-called Nipah Belt.

Two cases of deadly Nipah virus reported in India, prompt increase in airport screenings to prevent spread and virus outbreak. Here's what to know.

An outbreak of the deadly Nipah virus in India has put many countries in Asia on high alert, given the fatality rate in humans can be between 40% and 75%. Several countries, including Thailand, Malaysia and Singapore,

Severe cases can lead to brain swelling, or encephalitis, where symptoms can include confusion, drowsiness and seizures.

Two nurses in eastern India have been infected with the Nipah virus, prompting quarantines, expanded testing and heightened surveillance.