Crisscross migration puts India at high risk, experts say
India has one of the highest incidences of bird flu outbreaks globally because it is under three transnational flight paths for migratory birds, authorities said.
An outbreak of avian influenza has gripped four states, but poses little risk to humans at this stage, officials said, as the Union government put all states on alert to stop its spread and economic impact.
“The current outbreak has been caused by the H5N8 strain, but there are other strains circulating around the world,” said Dr. C Tosh, senior scientist at the Bhopal-based National Institute for High Security Animal Diseases (NIHSAD).
In Kerala, most poultry have been affected, a federal official said, while in Madhya Pradesh and Rajasthan, thousands of crows were affected. In Himachal Pradesh, most migratory birds have fallen ill. Several hundred have died.
“Reports show that the routes of infection are primarily through migratory birds, although cross-contamination cannot be ruled out,” Tosh said.
After confirmation of positive NIHSAD samples, avian influenza has been reported in the following epicenters: Baran, Kota and Jhalawar (Rajasthan), Mandsaur, Indore and Malwa (Madhya Pradesh), Kangra (Himachal Pradesh) and Kottayam and Allapuzha ( Kerala).
Several streams of flight paths of migratory birds cross the skies of the country. India is also a terminal destination for many of those streams, making it a biological hotspot for bird disease, according to Sobhit Pal of the Bombay Natural History Society.
For example, Amur hawks take off from Nagaland, run south and fly over three oceans to South Africa and then to Mongolia.
The feathered aviator travels 22,000 km, exceeding the air distance between Delhi and San Francisco, the longest commercial flight route in the world, by almost 8,000 km. It takes about two months for the bird to make the trip.
Nearly 370 species of birds, from the northern hummingbird to the yellow-rump flycatcher, traverse India from Europe, Russia and Mongolia each year, according to Pal.
This makes bird watchers happy, but it also makes the country vulnerable to bird flu, which has occurred 24 times in every state since the first outbreak in 2004. The last outbreak occurred in 2016, infecting poultry in Delhi, Kerala, Punjab and Madhya Pradesh. Data from the states shows that back then, nearly 400,000 poultry were culled due to the outbreak.
Avian flu also has serious economic impacts. Government records show that almost 400 million rupees were paid to poultry farmers from 2004 to 2016 as compensation for the mass slaughter of birds.
When the poultry business is affected, prices of corn, which is used as feed, tend to plummet, hurting farm incomes, said Abhishek Agrawal of Comtrade, a commodity trading company.
The majority of cases in 2016 were also determined to be H5N8.
“The H5N8 type is highly pathogenic, but it is not known to be easily transmitted to humans,” said a government official on condition of anonymity, citing an update from the World Health Organization (WHO) on India.
All states, particularly those already infected and their neighbors, have been asked to follow biosecurity measures to implement the National Action Plan for the Control and Containment of Avian Influenza, which prescribe adequate sanitation, separation , the use of personal protective equipment, surveillance and sacrifice, among other measures.
The Ministry of Agriculture has said that the National Institute for High Security Animal Diseases, which works in coordination with the World Organization for Animal Health, along with four specialized regional laboratories, is coordinating efforts to contain the outbreak.
The government has not banned poultry for human consumption. All lake bird sanctuaries have been advised to be vigilant.