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Japanese Encephalitis Virus in piggeries and other high density animal production facilities

The media is making news about mosquitoes transferring JEV to humans, especially since flooding rains in NSW and Qld. Mosquito transfer of viruses is what happens.

Dengue fever and Ross River fever are recognised and understood by residents in tropical climates and now the Japanese Encephalitis virus is getting publicity. In early March 2022, one person has contracted the virus and died; nine other cases have been recorded across NSW, Qld, Victoria and some in South Australia to date.

Dr Bennet was on the ABC (9 March 2022) and said that outbreaks had been seen in the Torres Strait where vaccination programs are in progress “but not this far south in Australia, so that was certainly alarming” she said.

tiger mosquito

“This virus is transmitted through the bite of an infected mosquito.
But the main way that mosquito gets infected is when it bites a pig with the disease”.

Dr Bennet ABC (9 March 2022)

Dr Bennet was on the ABC (9 March 2022) and said that outbreaks had been seen in the Torres Strait where vaccination programs are in progress “but not this far south in Australia, so that was certainly alarming” she said.

“This virus is transmitted through the bite of an infected mosquito. But the main way that mosquito gets infected is when it bites a pig with the disease”.

Pigs are not necessarily affected but, it is still important to reduce the mosquito breeding opportunities around the piggery as well as killing the adult mosquitoes inside. All to reduce or stop transmission.

PyBo (Natural Pyrethrum Insecticidal Concentrate) is registered for use inside all high density animal production facilities where it can be misted or fogged as often as necessary. To address the blurry distinction between whether the pigs can be inside or outside at the time of a misting/fogging to control adult mosquitoes, we have applied for a Permit to allow animals to be inside at the time of application. This Permit has been received and provisionally accepted and we expect approval is highly likely soon,” he said.

APPROVED : Permit Number – PER92361

Maybe piggeries have higher water use than most animal housing… although horse stables use a lot of water to cool down and wash the animals. All this water runs somewhere and may pond out beyond the concrete… and, mosquito eggs laid on the surface hatch the same or next day; the wrigglers yo-yo up and down for a few days, then the pupal tumblers for another few days before new adults emerge all within say two weeks depending on the climate.

Females need a blood meal for protein for the production of the next rafts of eggs… and if they have had a blood meal from an infected animal and take their next meal from a human, the transfer of the virus occurs.

You could spray some PyBo into the ponds but a better treatment in water is to apply Temephos granules over the surface. (details: David Gray’s Graybait 50 SG).

Better water management is the aim… less, even no ponding will reduce or eliminate breeding. Your Local Council/Shire may cooperate or assist in mosquito control.

Ion Staunton
Entomologist