Zoonotic diseases: Meat we eat a cause for worry?

THIRUVANANTHAPURAM: The Malayali penchant for meat — red or white — remains unsatiated and the overdependence on animal protein has been soaring every year, with consumption reaching record levels.

So is the case with the emerging zoonotic disease risks associated with the growth of animal agriculture, which is a serious cause for concern.  Though the state has not yet found the  point of origin of recent Nipah incidence or avian influenza, whose outbreak occurs in domestic poultry flocks in the state at regular intervals, the recent shift from primarily cereal staples to a more meat-centred animal agriculture, which is more economical, increases risk factors for the emergence of various zoonotic diseases in Kerala than any other place.

According to experts, intensively caged animal rearing plays a critical role as intermediate hosts by bringing animal viruses, which will normally have little contact with alternative hosts, into close contact with people. In the past, animals or birds were raised in backyard farms where the transmission of pathogens was relatively low.

But the industrialisation of animal agriculture, where thousands of animals are confined to crammed enclosures or bringing several hundred truck loads of cattle flouting all norms, posesa a major threat as these practices create a situation where viruses or bacteria pass serially through many hosts, potentially generating novel viral strains with the ability to infect people, say experts.

They have also pointed out the transition of low pathogenic avian influenza to highly pathogenic avian influenza through mutations. And the chances of such mutations are very high in commercial animal rearing sites or unscientific cattle movements involving thousands of  confined animals.

Vijaya Kumar, former joint commissioner, Health (livestock), at the Centre, told TNIE, “There are risks associated with the commercial rearing of animals or birds. But we cannot imagine a scenario without giving emphasis to animal agriculture or animal protein. When traditional agriculture suffered huge losses, it was the profitable animal husbandry that supported the farmers amid the crashes. There are three major migratory pathways in India where we cannot do anything to check the arrival of migratory birds.”
“The only solution is to keep up the strict vigil and ensure close surveillance apart from adopting scientific practices in animal agriculture. Kerala is capable of implementing such enforcement measures more strictly than any other state,” he added.

Risk at hand

As part of the meat industry, pigs, broiler chicken, egg-laying  hens and ducks are reared intensively in cages, while livestock are still kept largely in the open 

Keeping large number of animals in limited spaces poses a high risk of development of zoonotic pathogens with the potential to infect people 

Farms with more animals have a potentially high viral load

Rearing of animals in cages plays a crucial role in transmission of zoonotic viruses, and increases chances of transmission among one another and people

Through proper vigil and surveillance, we can lessen the severity of virus transmission. But, it’s not possible to eliminate epidemics fully 

A major link between animal farming and new viral pathogens is the contact with wildlife

In recent years, avian influenza or bird flu (H5N1 strain) outbreaks have been reported in Kerala in 2014, 2020 and 2021. An H5N8 outbreak was reported at Kuttanad in Alappuzha in 2016 

Nipah outbreak was reported in Kozhikode in 2018, in Ernakulam in 2019 and Kozhikode in 2021.

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