KOZHIKODE: Kerala’s northern districts, particularly Kozhikode and Malappuram, are once again under the grip of a Nipah virus outbreak. The new case, reported in September, comes only two months after a school boy tragically succumbed to the virus infection in Malappuram. The frequent recurrence of Nipah cases in these districts has raised concerns, with the region being flagged for repeated outbreaks over the past six years. Making matters worse, the root cause behind this alarming trend remains unidentified.
Experts have highlighted the role of Pteropus fruit bats, the known carriers of the Nipah virus, as a key factor in the virus’s recurrence in the region. However, these bats are not unique to Malabar and are found across India.
Kerala’s efficient healthcare system, equipped with robust diagnostic capabilities, has made it possible to identify Nipah cases more quickly which may explain the higher detection rates here compared to other regions where the virus might go unnoticed.
Dr Anoop Kumar A S, director of critical care at Aster MIMS, Kozhikode, who has been instrumental in tracing early cases of Nipah, said the virus is primarily transmitted from infected bats to humans, followed by human-to-human transmission. Fruit bats throughout India are known to harbour the Nipah virus, with reports confirming its presence in bats across every Indian state, aside from parts of Kashmir. However, there is no conclusive scientific data to determine if bats in Kerala carry a higher viral load compared to those in other regions.
Comparative research on virus concentration in bats from different areas is lacking. As a result, the higher number of identified cases in Kerala is likely due to increased vigilance and more extensive testing. Meanwhile, symptoms of the disease have evolved over the years. While early outbreaks presented with encephalitis, recent cases have exhibited pneumonia, a condition often mistaken for more common illnesses and thus overlooked.
He emphasised that early detection is key to containing the virus. Dr Kumar also called for event-based surveillance to detect signals or clusters within hospitals and communities, a strategy crucial for mitigating fatalities.
Environmental factors, such as deforestation and urbanisation, have also contributed to these outbreaks, said environmental activist and scientist Santhosh G. The disruption of bat habitats through human activities has increased contact between humans and bats, heightening the risk of zoonotic spillover events like Nipah. A study published in the European Medical Journal underlines the need for preventive measures and systematic monitoring of bat populations to avoid future outbreaks.
While Kerala’s healthcare system has demonstrated a remarkable capacity to detect and respond to outbreaks, the recurring Nipah outbreaks highlight the need for further research into the virus’s transmission dynamics.