With anxiety rising about mosquito-borne JEV in the area, The Town & Country Journal reached out to Andrew Taylor-Robinson, Professor of Microbiology & Immunology at Vin University in Vietnam, one of the world leaders in mosquito-borne diseases, to ask some questions. The questions raised to the specialist arose during a conversation with local man Clive Robertson, who hit the internet searching for answers whilst his wife spent a month in hospital.
Dr Taylor-Robinson, who has 35 years of experience in research into immunology and microbiology, particularly on mosquito-transmitted infection diseases, was not surprised the border towns have been the source of JEV transmission recently. However, whether feral pigs or fruit bats can spread the disease, he says is “complicated” and not fully understood.
“Pigs and water birds are crucial for maintaining the chain of infection”, and pigs in particular are a “significant amplifying host” because they “can develop high levels of viremia (high virus concentrations in the blood), which allows them to infect blood-feeding mosquitos efficiently.”
Water birds transmitted in the wild is “inconclusive, but it has been shown experimentally in at least one study”.
The clustering of the disease is different in Vietnam where pigs co-exist with favourable mosquito habitats like rice paddies and wetlands.
“However, in Australia, the specific combinations…are not well understood” and “may not provide the same transmission pathways that exist in other regions where JEV is endemic.”
The mortality rate, too, can vary, based on geography and demographics. The range of fatalities can be as low as “0.3 percent to as high as 60 percent in different settings” with mortality rates of about 9 percent are common in younger age groups. Generally, the mortality rate of JEV is “concerningly high”, Professor Taylor Robinson told the paper.
Avoidance of mosquitoes and eliminating environmental factors that welcome mosquitoes is the best way for people to avoid the disease other than vaccination.
“Outbreaks of JEV, particularly in novel locations such as southeast Queensland and Northern NSW, necessitate immediate public health responses, including consideration of mass vaccination among community members in the local vicinity of an outbreak.”
Two vaccines are available and both “significantly” reduce the incidence of disease. One vaccine has a live virus and the other an inactivated one. The inactivated vaccine “induces strong immunogenic responses” whereas the live vaccine “has also been shown to provide immunity over an extended period, which is critical in region where the disease is endemic (not yet in Australia). Boost doses may be recommended for continued protection”. Both vaccines have “favourable safety profiles.”
Dr Taylor-Robinson provided four scientific papers on JEV. If you are interested in the research, please contact me on Voneiff.journo@gmail.com and I'll forward them to you.
