Nipah virus encephalitis in the Kerala state of India
Amid the risk of a Nipah virus outbreak, India’s southern Kerala state has taken preventive measures, including the closure of schools and offices and declaring containment zones in certain areas. This action comes after the deaths of two individuals from the rare and deadly Nipah virus, which causes brain damage.
Since the fourth outbreak of Nipah virus in 2018, more than 130 people have been tested for the virus. During the 2018 outbreak, at least 21 people died from the disease.
On May 19, 2018, an outbreak of Nipah virus disease (NiV) was reported in the Kozhikode district of Kerala, India, marking the first NiV outbreak in South India. The outbreak affected the districts of Kozhikode and Malappuram, resulting in 17 deaths and 18 confirmed cases as of June 1, 2018. A multidisciplinary team led by the Indian Government’s National Centre for Disease Control (NCDC) responded to the outbreak, with technical support from the World Health Organization (WHO). WHO did not recommend travel or trade restrictions or entry screening related to the NiV outbreak.
This outbreak was the third Nipah virus outbreak in India, with previous occurrences in 2001 and 2007 in West Bengal. A total of 23 cases, including the index case, were identified, with 18 laboratory-confirmed cases. The response to the outbreak was managed by state and central government agencies and was considered a success.
Recognizing the importance of documenting and sharing the experience in Kerala, the state government requested an external review and documentation of the response from WHO. A joint team led by WHO’s South-East Asia Regional Office (SEARO) and Regional Office for the Western Pacific (WCO) conducted the review to understand the response and readiness for future high-threat pathogen outbreaks.
The review focused on three key areas:
- Coordination structure and mechanisms in place during the outbreak.
- Performance of surveillance and interventions, including non-technical support functions.
- Assessment of the reduction of transmission and impact of interventions.
Kerala, known for achieving impressive health outcomes with modest resources, relied on its robust health system to contain the outbreak. The response saw strong leadership and commitment from various levels of Indian health authorities and the private sector.
However, the early stages of the response involved significant improvisation. Technical shortcomings were exacerbated by a relatively inexperienced surveillance workforce that needed further training in field epidemiology and data analysis. Data sharing between India and WHO regarding the outbreak response and its efficiency was limited. There was also a missed opportunity to collect accurate data for a better understanding of Nipah virus disease’s epidemiology, clinical characteristics, and virology, which could have informed timely clinical trials of potential treatment options.
The Nipah outbreak highlighted the ongoing risk of outbreaks in Kerala and the rest of India, emphasizing the need for preparedness. It underscored the importance of annual preparatory work before the traditional Nipah seasons.
Urgent efforts were needed to raise awareness of Nipah virus signs and symptoms among the community and healthcare professionals. Strengthening infection control practices, ensuring the availability of medical supplies and personal protective equipment, and familiarizing hospital staff with standard operating procedures and protocols for incident management were critical steps for future outbreak management. Electronic health reporting and health information management systems were also deemed essential for responding to acute events like Nipah virus outbreaks.
