Zika virus is likely to be far more widespread than we imagine, and its full impact on global health may not become apparent for decades, according to a Burnet Institute review commissioned by BMC Medicine.
The commentary led by Professor James Beeson, The global threat of Zika virus to pregnancy: epidemiology, clinical perspectives, mechanisms, and impact focuses on Zika virus’ impact on fetal health.
Transmitted by infected Aedes species mosquitoes, Zika virus has been associated with the increased incidence of serious congenital neurological defects including microcephaly, most notably in Brazil, host nation for the 2016 Olympics.
“What’s been striking to me is the fact that 80 percent of infections are asymptomatic,” study first author, Dr Philippe Boeuf, said.
“The cases that are reported are symptomatic with an impact on fetal health, but we’re probably seeing just the tip of the iceberg.
“There is no accurate, simple diagnostic test, and when you put that together with the high rate of asymptomatic infections, it’s not a good combination.
“There’s an urgent need for a diagnostic.”
Co-author, Associate Professor Heidi Drummer said Zika virus has been known since the 1940s, but it is only in the past five years that explosive outbreaks have occurred in Micronesia and spread eastwards across the Pacific to South America.
“There has actually been an ongoing mutation of the virus over the last 60 years, relatively small changes compared to what you would see in HIV or hepatitis C,” Associate Professor Drummer said.
“But it could be that those mutations have caused it to change the types of disease it causes so that it is more infectious or causes more severe disease symptoms in, particularly, pregnant women in their first trimester.
“Because it is such a new epidemic, it is still not clear whether children who look normal when they are born will go on to have some sorts of abnormalities in their development.
“That is something that I know the people in Micronesia and South America will be monitoring over the next 10 or 20 years, to see what impact potentially it will have on normal babies for their cognitive development. It is a big unknown.”
Associate Professor Drummer said early tests on a Zika vaccine have been promising, but the key to controlling the virus is mosquito control, particularly in resource-constrained communities such as Brazil’s favelas.
She said Australian researchers have a responsibility to join the global research effort and contribute their expertise, not only because the Aedes mosquito is found in northern parts of Australia.
“I do not think just because it is not here we should be saying it is not our problem and a problem for the rest of the world,” Associate Professor Drummer said.
“I think that is where Burnet can have its biggest impact. We have got a global focus and we have particular expertise in pregnancy, virology, cohort studies and point of care diagnostics to make that impact.
“Zika is on our doorstep and we need to support our closest neighbours.”