Thursday, September 14, 2023

Kerala: Media Reports 5th Confirmed Nipah Case - Awaiting Test Results On 11 Others


Nipah, a henipavirus carried by fruit bats in Southeast Asia and the Indian Subcontinent (see map above), was first identified 25 years ago after a large outbreak in Malaysia spread first from bat(s) to pigs - and then from pigs to humans - eventually infecting at least 265 people, killing 105 (see Lessons from the Nipah virus outbreak in Malaysia).

Human-to-human transmission has been reported - as in India in 2018 (see Nipah Transmission In Kerala Outbreak) - where we saw apparently robust household and nosocomial transmission of the virus in Southern India, eventually infecting 19 people.

Recent outbreaks in India have highlighted the risks of a seeing a large urban outbreak of Nipah - similar to what we saw with Ebola in West Africa in 2014-2015 (see Enhancing preparation for large Nipah outbreaks beyond Bangladesh: Preventing a tragedy like Ebola in West Africa by Halsie Donaldson, Daniel Lucey).

In the 2013 paper The pandemic potential of Nipah virus by Stephen P. Luby, the author wrote (bolding mine):

Characteristics of Nipah virus that increase its risk of becoming a global pandemic include: humans are already susceptible; many strains are capable of limited person-to-person transmission; as an RNA virus, it has an exceptionally high rate of mutation: and that if a human-adapted strain were to infect communities in South Asia, high population densities and global interconnectedness would rapidly spread the infection.

While the Nipah outbreaks we've seen have only demonstrated limited human-to-human transmission, each outbreak provides the virus with additional opportunities to better adapt to humans, and potentially increase its threat. 

In 2018 WHO added Nipah (and other henipaviruses) to their List Of Blueprint Priority Diseases; 8 disease threats in need of urgent accelerated research and development.  

Today the Indian State of Kerala is once again experiencing a Nipah outbreak (see 2021's India MOH: A Fatal Case of Nipah in Kozhikode district of Kerala), with local media reporting 5 confirmed cases, 2 deaths, and at least 11 other tests pending.

Official government releases (from the Indian State govt. of Kerala) have been less specific, and the Press Information Bureau for Kerala Twitter/X account has been silent on the matter, but yesterday the State announced the opening of a crisis center (see below) and released a lengthy statement on recognizing the symptoms of the virus. 

Nipah virus; Things to watch out for

The virus can reach humans either directly from bats or indirectly (fruits bitten by bats, other animals infected by bats, etc.). After an infected person develops symptoms, the disease can be spread to others through contact. Nipah virus does not spread very far through the air. The virus can only be transmitted to people who have close contact with people who have symptoms. N95 masks and other protective equipment can be used to avoid contamination if close contact with the patient is required. In areas where Nipah virus infection is detected, everyone with flu-like symptoms, especially fever with headache, Jenny, pitch-and-pey, cough, and symptoms of shortness of breath or wheezing, and their caregivers, including family members, should wear an N95 mask.

RNA Nipah virus is classified as one of the Henipaviruses in the Paramyxoviridae family, which is one of the viruses. It is primitive and found in bats. ICMR According to the studies conducted, Nipah virus has been detected in bats in different parts of the country including Kerala. Other animals like pigs can also be carriers but there is no evidence of this from India. Once the virus reaches a person, it can be spread to others through contact. Infection control in hospitals is extremely important because the disease can spread to caregivers, healthcare workers, and other patients.


The incubation period is 4 to 14 days after the virus enters the body and symptoms appear. It can sometimes be up to 21 days. Fever may be accompanied by one or more of the following symptoms: headache, jenny, pitch and pe, cough, and symptoms of shortness of breath or wheezing. If you have respiratory symptoms, you are more likely to spread it to others. Nipah disease is characterized by the fact that the symptoms may increase over time, and the risk of spreading the disease may increase as the severity of the disease increases.

Confirmation of disease:

RT PCR of samples from throat and nasal secretions, blood, urine and cerebrospinal fluid. The disease is confirmed by testing.


Antiviral drugs etc. may be effective in patients who can detect the disease early and those whose symptoms are not severe, but the mortality rate is high in the subtype of Nipah virus found in our country. So the best prevention is to prevent more people from getting sick.


Wear a mask, maintain social distancing, and wash hands thoroughly with soap and water with sanitizer/occasionally. Store and use items for the patient's personal needs separately. Those who came in contact with the sick person while he had symptoms, and those who may have come in contact with him, should notify the health department and stay at home for such time as the health department directs, without any contact with the household and others. Contact the health department officials on phone every day and if you have any symptoms, you should seek treatment only through the methods prescribed by the officials. In this way, counseling facilities will be provided to remove the fear of people who are under quarantine at home.

0495 2383100, 0495 2383101, 0495 2384100, 0495 2384101 and 0495 2386100 24 hours query numbers. Those with symptoms should contact the control room.

Last updated on :13-09-2023

Local authorities are taking this outbreak seriously, and have ordered some schools to close, and a ban on some types of public gathering (see notice below).


Kozhikode District Collector A Geetha has ordered the temporary suspension of all public programs scheduled to be held for the next ten days due to the confirmed Nipah virus infection in Kozhikode.

Festivals, church fairs and other such events should be conducted only as ceremonies, avoiding mass participation of the people. Public participation in pre-arranged events such as weddings and receptions should be conducted with a minimum number of people following a minimal protocol. In this regard, the concerned police station should be informed and prior permission should be obtained.

Public gatherings like drama, arts and cultural events and sporting events should be postponed. The police have been directed to take strict action against those spreading fake news regarding Nipah disease. The Collector's order also said that public meetings and public events involving public participation should be postponed.


Four years ago, in PLoS NTDS: Prioritizing Surveillance of Nipah Virus in India, we looked at a study that found 7 species of bats in Kerala carrying Nipah, which makes additional spillovers from bats to humans a perennial concern.

While Nipah is the best known henipavirus, it is joined by an Australian variant called Hendra (see Australia: A Novel Variant Of the Hendra Virus) which has caused more than 40 outbreaks in horses, and a handful of human infections, since it was first identified in 1994.

And just over a year ago we saw the first reports (see NEJM: A Novel Henipavirus With Human Spillover In China) of a phylogenetically distinct henipavirus - dubbed Langya henipavirus (LayV) - which they isolated from the throats of 35 fever patients who reported recent animal exposure.

While this outbreak in Kerala will likely - as we've seen in the past - be quickly contained, it is a reminder that there are more zoonotic threats out there than just H5N1 and COVID, and that we could be blindsided by another black swan event at any time.