Nipah Virus
Description
Nipah Virus
Description: Nipah
Virus: Symptoms, Spread, and Kerala's Recurring Outbreaks Explained. Explore
the Nipah virus, its symptoms, transmission, and the recurring outbreaks in
Kerala, including a change in clinical presentation.
Nipah virus
(NiV) is a zoonotic virus, meaning that it can spread between animals and
people.
Fruit bats,
also called flying foxes, are the animal reservoir for NiV in nature. The Nipah
virus is also known to cause illness in pigs and people.
Symptoms
Infected
people initially develop symptoms including fever, headaches, myalgia (muscle
pain), vomiting and sore throat. This can be 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.
Most people
who survive acute encephalitis make a full recovery, but long term neurologic
conditions have been reported in survivors.
How it spreads?
Infected
fruit bats can spread the disease to people or other animals, such as pigs.
People can become infected if they have close contact with an infected animal
or its body fluids (such as saliva or urine)—this initial spread from an animal
to a person is known as a spillover event. Once it spreads to people, person-to-person
spread of NiV can also occur.
Treatment
There are
currently no drugs or vaccines specific for Nipah virus infection although WHO
has identified Nipah as a priority disease for the WHO Research and Development
Blueprint. Intensive supportive care is recommended to treat severe
respiratory and neurologic complications.
Nipah Virus outbreak in Kerala
Since May
2018 when Kerala reported the first Nipah outbreak in Kozhikode district,
there have been three more outbreaks of Nipah virus including the latest
one in late-August 2023. For reasons still not known, three of the four Nipah
outbreaks in Kerala in 2018, 2021 and 2023 have been in Kozhikode district; the
2019 outbreak was in Ernakulam district.
A survey by
the National Institute of Virology revealed that the Nipah virus is in
circulation among the bat population across nine states and one Union
Territory. Nipah viral antibodies were found in Kerala, Tamil Nadu, Karnataka,
Goa, Maharashtra, Bihar, West Bengal, Assam, Meghalaya and Pondicherry. But why
has Nipah been resurfacing only in Kerala? According to experts, it may have
many explanations. The Nipah virus might have become endemic in the Kerala bat
population. Another cultural reason attributed to Nipah outbreaks is the custom
of drinking fresh toddy or sweet tree sap which may get contaminated by infected
bats. Experts have not ruled out the possibility that Nipah may have remained
undetected in other states.
Clinically, how are the Nipah
symptoms in 2018 different from what you are seeing in 2023?
Majority of the Nipah cases that have been reported from different parts of the world since 1998 have had mainly encephalitis symptoms. Even during the 2018 outbreak in Kerala, all the patients had encephalitis symptoms — they came to the hospital with fever and later developed unconsciousness and neurological issues. This time, the patients have been showing mainly respiratory symptoms and developing severe pneumonia. They did not have many encephalitis symptoms. We developed suspicion only because there was a clustering of cases and a few unusual symptoms. The index case, who died on August 30, had fever, which progressed into severe pneumonia and later multi-organ failure. He had no symptoms of encephalitis. His case was concluded as viral pneumonia, which is very common.
Here is a link to an article on What are Sponge Cities?
