A virus closely related to polio is causing major outbreaks of hand, foot and mouth disease across the Asia-Pacific region.
In Lancet Neurology and Lancet Infectious Diseases this month, researchers from the UK, Asia and Australia warn that in some cases there are severe neurological complications; and there are fears that Australia is unprepared for an outbreak.
Enterovirus 71 was first identified in California, US, in the 1960s where it caused small outbreaks of hand, foot and mouth and neurological disease.
The virus has become of increasing concern since the late 1990s, researchers say, when regular epidemics starting occurring across the Asia-Pacific region, including one in Taiwan in 1998. That outbreak is thought to have involved millions of people; and 500,000 cases were reported in an outbreak in mainland China.
During an outbreak of the virus, which mostly affects children, the majority of those affected will have mild, self-limiting illness, researchers say, noting there is no effective anti-viral treatment or vaccine.
But a small proportion of those affected will rapidly develop severe and sometimes fatal neurological and systemic complications over days or even hours. These include aseptic meningitis, poliomyelitis-like acute flaccid paralysis and brainstem encephalitis.
No effective treatment available
Clinical microbiologist Professor Peter McMinn, from the University of Sydney — and a co-author of one of the recent papers — says it is likely the virus underwent a crucial genetic change at some point in the mid-1990s which improved the way it transmitted through communities and allowed it to create these large outbreaks.
Australia has already seen outbreaks of enterovirus 71, including one in Perth, Western Australia, in 1999, and in Sydney, NSW, in 2004.
The continent may have been somewhat protected due to the relatively high living standards of most of the community and a geographically disparate population, says McMinn, warning that there is no room for complacency.
Australia still doesn't have a nationally co-ordinated and funded system to monitor the disease.
"My concern is that it could cause a large epidemic and we won't be prepared," he says.
"I think that Australians, particularly parents, should be aware of this disease, it's a disease of great concern to parents in Asia because of the devastating effects in can have on children."
With no effective treatment available for enterovirus 71, the best hope of preventing the disease lies with teams of researchers in the region who are developing a vaccine, he says.
There are many vaccines under investigation and development, including inactivated whole-virus, live attenuated, subviral particle and DNA vaccines.
McMinn noted one vaccine in particular, being developed in China, which is due to enter Phase I clinical trials and could be available within three to four years.
He says he wants to see Australia support regional efforts to develop a vaccine, and would also like to see funding for a national surveillance system to monitor the virus in Australia.