April and May are the months when bats that carry the virus will spread it to humans
Kerala can be hit by Nipah again in 2020 as long as public health measures are being taken to prevent further epidemic and consequent morbidity and mortality, experts say.
“The Nipah virus infection can return so long as virus harbouring bats are there in the country/region,” Dr B Ekbal, a public health activist and currently a member at the Kerala State Planning Board, told The Lede.
According to him, Nipah, like a number of such other infections, spread from animals to human beings and are described as zoonotic diseases.
“Better knowledge about the epidemiology of such diseases may help us to prevent the occurrence of such infections in future,” added Dr Ekbal.
During 2018 May, the Nipah outbreak in Kerala had claimed 17 lives and studies by the National Institute of Virology had concluded that the virus was first transmitted from fruit bats identified as Pteropus spp.
And this year again, during the first week of June, a patient was isolated after his blood samples tested positive for the Nipah virus.
However, timely medical attention had saved his life. About 330 people were put under observation list. And this week, 47 were relieved as none of them showed any distinct symptoms of infection after the 21 days of the incubation period.
When asked why the outbreak is happening between April and June, Dr Ekbal said that usually, the bats discharge the virus from their body during the reproductive period which falls in April and May.
Confirming Dr Ekbal’s findings, Dr A Jayakumaran Nair, Head of Department of Biotechnology at Kerala University, said that it may be associated with the breeding time of bats and also ripening time or harvesting time of certain fruits.
According to the World Health Organisation, fruit bats of the family Pteropodidae – particularly species belonging to the Pteropus genus – are the natural hosts for Nipah virus.
“There is no apparent disease in fruit bats. It is assumed that the geographic distribution of Henipaviruses overlaps with that of Pteropus category. This hypothesis was reinforced with the evidence of Henipavirus infection in Pteropus bats from Australia, Bangladesh, Cambodia, China, India, Indonesia, Madagascar, Malaysia, Papua New Guinea, Thailand, and Timor-Leste,” the WHO says.
According to Dr Ekbal, wanton deforestation and such other onslaught on nature need to be curtailed to avoid repetition of Nipah outbreak.
“Currently health agencies promote a One Health Approach that recognises that the health of human beings is connected to the health of animals. And hence doctors and epidemiologists will have to work in unison with veterinarians and ecologists,” Dr Ekbal added.
‘One Health' is an approach to designing and implementing programmes, policies, legislation, and research in which multiple sectors communicate and work together to achieve better public health outcomes.
The areas of work in which a One Health approach is particularly relevant include food safety, the control of zoonoses (diseases that can spread between animals and humans, such as flu, rabies and Rift Valley Fever), and combating antibiotic resistance (when bacteria change after being exposed to antibiotics and become more difficult to treat).
Nipah is a zoonotic disease, as mentioned earlier.
Dr Ekbal also hoped that anti-virals to treat such viral infections and vaccines that can prevent viral infections will be developed soon.
Currently, there are 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.
In a recent interview with The Lede, Dr Christopher C Broder, Professor, and Chair of the Department of Microbiology at the Uniformed Services University of the Health Sciences in the United States, the founder of ‘wonder drug’ used to treat Nipah virus infection had said that recovery chances of Nipah virus-infected patient are uncertain.
This antibody was brought to Kerala from Australia to treat the patient found infected with the Nipah virus as well as others who have been exposed to the patient in 2018 and this year too.