Nipah: A killer virus

Nipah virus (NiV) is member of the genus Henipavirus in the family Paramyxoviridae. NiV disease is a zoonotic disease characterized by fever, constitutional symptoms, and encephalitis, sometimes accompanied by respiratory illness. The name "Nipah virus" originated from Sungai Nipah (Nipah River Village). A Nipah virus disease outbreak was reported from Kozhikode district of Kerala, India on 19 May 2018. This is the first NiV outbreak in South India. As of 28 May, there are 14 deaths, 16 confirmed cases and 12 suspected cases. Transmission of the NiV disease occurred from direct contact with sick pigs or their contaminated tissues also via respiratory droplets, contact with throat or nasal secretions from the pigs, or contact with the tissue of a sick animal. Consumption of fruits or fruit products (e.g. raw date palm juice) contaminated with urine or saliva from infected fruit bats was the most likely source of infection. Limited human to human transmission of NiV has also been reported among family and care givers of infected NiV patients. In Siliguri, India, transmission of the virus was also reported within a health-care setting (nosocomial), where 75% of cases occurred among hospital staff or visitors. This infection can occur in humans without showing any symptoms. However, it is essential for people to look out for influenza-like symptoms. Fever, sore throat, headaches, vomiting and muscle pain (myalgia) are some of the common signs. The infection progresses to acute respiratory infection (mild to severe) causing interference in breathing. During this phase, people experience atypical pneumonia and acute respiratory distress, which further leads to severe problems (fatal encephalitis). Initially develop influenza-like symptoms of fever, headaches, myalgia (muscle pain), vomiting and sore throat, followed by dizziness, drowsiness, altered consciousness, and neurological signs that indicate acute encephalitis. Some people can also experience atypical pneumonia and severe respiratory problems, including acute respiratory distress. Encephalitis and seizures occur in severe cases, progressing to coma within 24 to 48 hours. The incubation period (interval from infection to the onset of symptoms) is believed to range from 4 to 18 days. However, an incubation period as long as 45 days has been reported. BSL 2 facilities are sufficient if the virus can be first inactivated during specimen collection. Laboratory diagnosis of NiV includes serology, histopathology, Polymerase Chain Reaction (PCR) and virus isolation. Serum Neutralization Test, Enzyme Linked Immunosorbent Assay (ELISA), Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) are used for laboratory confirmation. The 2018 review of the WHO list of Blueprint priority diseases indicates that there is an urgent need for accelerated research and development for the Nipah virus.