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

The virus has a fatality rate ranging from 40 per cent to 75 per cent, according to health experts. There is currently no approved vaccine or cure, making early containment and monitoring critical.

The adenovirus is a new strain that attacks the respiratory system, eyes, kidneys and, other organs seemingly in minutes — with no cure yet available.

Nipah virus has a death rate ranging from 45 to 75 per cent, and there is no vaccine or medical treatment available for animals or humans.