Backyard Piggeries, not so Harmless in the context of JE

Dependence on piggeries for livelihoods in resource constrained settings

PiggeriesPatterns of animal husbandry have been altering, with increased water logging – grazing lands remain submerged in water for long periods and large bovines have declined in population. This has pushed marginal farmers and the landless to take up pig farming

Pigs are a major source of livelihood in many rural communities. According to Dom community that rears pigs in eastern Uttar Pradesh, on an average, pigs give birth thrice a year and the litter which comprises roughly 15-18 pigs, fetches a sale price of Rs 3,000 each

Since most pig farms in Asia and particularly India are unorganised in nature, there is increasing risk of disease

Establishing the connection between pigs and JE

PiggeriesJE occurs in most Asian countries such as China, Malaysia, Taiwan and India, since they are the main exporters of pork and are still practising traditional ways of rearing pigs

Communities that rear pigs live usually on the periphery of the village in close proximity to them – living, cooking, eating, sleeping cheek-by-jowl, increasing their vulnerability to infection and disease

Poor levels of awareness regarding hygiene conditions, pig rearing practices and pig management make their homes and surrounding areas a hotbed of viruses, including JE

Living close to pigs increases chances of human infection

PiggeriesRural populations who rear pigs, virtually co-exist with them, increasing the likelihood of human infection

During transmission season, when vector density is abundant, infected mosquitoes transmit infection to human beings as incidental, dead-end hosts in the transmission cycle, due to low and short-lived viraemia

Pigs play an important role in the natural cycle and serve as an amplifier host since they allow manifold virus multiplication without suffering from disease and maintain prolonged viraemia; thus, mosquitoes biting pigs can be dangerous for humans too

The scenario in India

PiggeriesIn India, the population of pigs is reported to be more than 135 million, 31.7% (42.84 million) of which are in Uttar Pradesh
As per the latest 19th Livestock Census by The Department of Animal Husbandry, Dairying and Fisheries, UP has the second largest pig population in the country

Studies from peninsular and eastern parts of India indicate that pigs are the main vertebrate host of JEV and major reservoir of the infection

Because infected pigs act as amplifying hosts, domestic pig rearing is an important risk factor in the transmission of JE to humans

In different parts of the country, 12–44% of the pig population have been found to be positive for JE antibodies, particularly in endemic areas

Transmission of virus from pigs to humans

PiggeriesTransmission of JE is likely to increase in Bangladesh, Cambodia, Indonesia, Laos, Myanmar, North Korea, India and Pakistan because of population growth, intensified rice farming, pig rearing and the lack of vaccination programmes and surveillance The JE virus (JEV) is mainly transmitted by the mosquito Culextritaeniorrhynchus, which prefers to breed in irrigated rice paddies
Clearly, where rice production and pig rearing overlap, the impact on JE transmission is stronger than in areas where both activities are physically separated

Making piggeries “JE-Safe”

Vaccinating pigs: Is a potential strategy to control JE, but is not widely used because the high turnover in pig populations requires annual vaccination of newborn pigs, which is an expensive intervention
Separating pigs: Moving pigs away from human habitation has been successfully demonstrated in countries like Australia but are yet to be proven effective in Indian settings where other animals in human vicinity attract mosquitoes, adding to the complexity

Improving pig shelters: Maintaining hygiene and using nets to prevent mosquitoes from biting pigs to transmit infection

Personal protection gear: Making use of repellants, wearing long-sleeved clothes and introducing bednets

References

http://www.cfsph.iastate.edu/FastFacts/pdfs/japanese_encephalitis_F.pdf
Kumari, 2012 Review of JE in UP, WHO South-East Asia Journal of Public Health Domestic pigs and Japanese Encephalitis Virus Infection, Australia, Emerging Infectious Diseases,
www.cdc.gov/eid





















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