Kerala reports multiple primary Nipah cases for first time

Thiruvananthapuram: Even though Kerala has reported Nipah cases seven times since the state reported its first case in 2018, this is for the first time multiple primary cases have been detected simultaneously. A primary case refers to an infection directly transmitted from the natural source, such as fruit bats to humans, whereas secondary cases occur when the virus spreads from person to person. The state health department has issued alerts in Palakkad, Malappuram, Kozhikode, Kannur, Wayanad and Thrissur districts, advising extensive vigilance. Experts have also called for caution in other districts as well. Until last year, each outbreak in Kerala began with a single primary case, followed by secondary infections through human contact.

The health specialist points out that the extensive reporting of multiple primary cases simultaneously in various regions indicates the chances of the virus getting widespread. Research findings on how the Nipah virus spreads is forthcoming.

According to the health department, though the virus variant detected in Kerala is genetically similar to the strain found in Bangladesh, there is no evidence that it originated from there. Genetic sequencing suggests that the virus has been present in bat populations in Kerala earlier itself but was only identified in humans in 2018.

Researchers have not yet found final results that the Nipah virus has been spread from fruit eating bats. It is also important to find out whether there is a carrier of virus between humans and bats. Five research teams, including the Indian Council of Medical Research (ICMR), are conducting field studies in the affected districts. Experts believe that Nipah cases are detected during the period from May to September, when bats are most active in mating and breeding, and also this is the fruit blooming time period in Kerala.

Most of the departments have failed to set up proper monitoring and preventive measures, not just against Nipah but also with other zoonotic diseases such as monkeypox, which can affect similar wildlife species.

Doctors have been advised to test patients presenting with symptoms similar to meningitis, such as severe headache, dizziness, nausea or sudden shortness of breath.

Last year, Kerala recorded nearly 100 cases and 33 deaths from Acute Encephalitis Syndrome (AES), primarily caused by the Japanese encephalitis virus.

The majority of cases have been reported from districts such as Palakkad (39 cases), Malappuram (35 cases), and Wayanad (15 cases), which is unusual. Furthermore, cases have also been detected in districts like Kozhikode, Kannur, and Kasaragod. The presence of the Nipah virus can be confirmed by testing samples collected from these areas as well. Meanwhile, cases of Acute Encephalitis Syndrome (AES) reported in Thiruvananthapuram and Kollam are suspected to have other causes, such as Japanese encephalitis.