As Kerala heaves a sigh of relief at how a potential second run of Nipah could be averted through timely detection and control measures, the disease should be seen as an opportunity for developing a clinical algorithm for all emerging viral infections at tertiary-care level, strengthening diagnostic and research capacities and, above all, changing community behaviour.
Bats are the natural reservoirs of not just Nipah but many deadly viral pathogens such as Sars, Ebola and Marburg. While Nipah virus (NiV) infection is self-limiting, with a limited geographic span, changes in the ecosystem and increased international travel can bring any emerging new virulent pathogens home in a matter of hours, say public health experts.
NiV has been isolated in fruit bats (Pteropus/flying fox) wherever they have been tested, even when there are no simultaneous human infections.
“These bats do present a risk, but the probability of direct infections from bats to community is very low or even rare. As we strengthen and expand our surveillance and diagnostic capacity, more cases will in all likelihood be picked up from multiple sites. But not all of these cases will be in clusters nor will every case be a super transmitter,” says G. Arunkumar, director, Manipal Institute of Virology.
“Investment in hospital infection control procedures and strengthening surveillance of acute encephalitis syndrome (AES) of unknown aetiology and Acute Respiratory Distress Syndrome (ARDS) will pay rich dividends in the long run when the threat of epidemics due to new and emerging viral pathogens is distinct and possible,” he says.
In India, the AES surveillance scene changed dramatically between 2000 and 2010, when the long-time focus on Japanese Encephalitis shifted to other dangerous viruses such as Chandipura, West Nile, NiV or herpes simplex viruses which can also cause acute encephalitis.
The realisation that diagnosis of AES cases of unknown aetiology is critical for the early detection of new and lethal pathogens hit Kerala last year, following the first Nipah outbreak.
“It is to expedite early detection and to launch a pre-emptive response against any outbreaks by new and emerging pathogens that outbreak monitoring units have been set up in all medical colleges, post-Nipah. Strengthening infection control protocols in hospital apart, our major activity has been the establishment of a clinical algorithm-based screening protocol for all emerging infections, using molecular diagnostic testing through multiplex PCR platforms. All cases of AES are now tested using multiplex PCR to pinpoint a diagnosis,” says R. Aravind, head of infectious diseases, Government Medical College here.