A comprehensive study on the Nipah virus outbreak in Kerala has found that only the index case was infected in the community from fruit bats, but all other remaining cases were due to the transmission of the virus in three hospitals in Kozhikode district.
The research report, titled ‘Outbreak Investigation of Nipah Virus Disease in Kerala’, was recently published in the Journal of Infectious Diseases, brought out by Infectious Diseases Society of America. The study, done by Dr G Arunkumar of Manipal Centre for Virus Research, was supported by the Indian Council of Medical Research under the Ministry of Health and Family Welfare.
The outbreak of the Nipah virus, a highly fatal emerging zoonotic virus, was reported in Kozhikode district during May-June this year. There had been 23 suspected cases of the disease. However, the laboratory could only confirm 18 cases, apart from the index case.
The outbreak had 17 reported deaths. The samples of the index case, 27-year-old Muhammed Sabith, were not sent for testing for Nipah virus.
The report said the fatality rate of outbreak in Kozhikode was 91 per cent. The WHO has put the fatality rate of Nipah in the estimated range between 40 to 75 per cent. The report said the human-to-human transmission pattern of Nipah is consistent with that of two earlier outbreaks in West Bengal – Siliguri (2001) and Nadia (2007). It says, “Only the index case was infected in the community. All remaining cases were due to nosocomial (taking place in a hospital or acquired in a hospital) transmission in 3 different hospitals.”
When contacted, Dr Arunkumar said, “The transmission of Nipah in Kerala called for effective implementation of infection control mechanism in hospitals in the state. All hospitals should be made to strictly follow an infectious control practices…”
He said the chances of another outbreak of Nipah in Kerala is rare.