Virus fears prompt call for ‘readiness and response’ plan

The WHO has said Botswana, Cape Verde, Comoros and Swaziland are on track to eliminate malaria by...
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Fears a deadly mosquito-borne virus could reach New Zealand have led the government to call for a wide-ranging response plan.

The Ministry for Primary Industries proposal asks for a "readiness and response" plan to the event of Japanese encephalitis virus (JEV), which is carried by mosquitoes.

JEV infects both humans and animals and is a leading cause of human encephalitis and death, especially in children.

"The socio-cultural and economic impacts of a JEV incursion in New Zealand would be significant," the proposal document said.

The World Health Organisation (WHO) has said 24 countries in the WHO southeast Asia and Western Pacific regions have endemic JEV transmission, exposing more than 3billion people to risks of infection. Most JEV infections were mild (fever and headache) or without apparent symptoms, but about one in 250 infections resulted in severe clinical illness and even death, the WHO said.

In most temperate areas of Asia, JEV is transmitted mainly during the warm season, when large epidemics can occur.

University of Otago department of microbiology and immunology Prof Jemma Geoghegan said targeted surveillance would act as a useful early warning system to quickly detect the virus if it were to arrive here.

"This could be regularly testing for the virus or its antibodies in key animal species as well as in mosquitoes."

The proposal document said early evidence of an incursion could come from infected animals and was "likely to precede infection in people, while its spread had already affected parts of Australia".

"Having previously been free of JEV, following an incursion in late 2021, there was rapid spread across all Australian mainland States, and the Northern Territory.

"By the end of the transmission season in 2022/23, 45 human clinical cases and seven deaths had been recorded and resulted in pork production losses equivalent to 3%-6% of annual production with detections in over 80 piggeries.

"Further information regarding potential JEV vectors, hosts and the transmission pathways between them, along with host and vector ecology is required to ensure that the surveillance can provide robust details of presence of the vector/disease in a New Zealand context.

"The aim of this project is to fill knowledge gaps related to JEV incursion and establishment by identifying New Zealand locations that have suitable ecological conditions to allow establishment and amplification of competent mosquito vectors for JEV.

"This project will also determine the predominant vertebrate animal types fed upon by NZ mosquito species across these suitable areas."

Documents obtained by the Otago Daily Times estimated the value of the contract to be about $500,000.

Applications opened on May 21 and close on July 10; the decision to award the three-year contract should occur in late August.