WA adult diagnosed with Zika virus

A West Australian adult has been diagnosed with Zika virus infection after returning from central America, the Health Department says.

Aedes aegypti mosquitoes, a Zika vector, at the Biomedical Sciences Institute at Sao Paulo University (AAP) Source: AAP

A West Australian adult has been diagnosed with the Zika virus after recently returning from central America.

The WA Health Department said on Friday that it was the second case ever notified in the state, following a single case last year.

Zika virus is transmitted to humans through the bites of infectious Aedes mosquitoes, most commonly Aedes aegypti, the same species that transmits dengue, chikungunya and yellow fever viruses in tropical countries.

Most infected people have no symptoms or experience only a mild illness, but a recent increase in the number of babies born with microcephaly - a small head with abnormal brain development - has been linked to outbreaks of Zika virus in Brazil and other countries.

WA Health chief health officer Tarun Weeramanthri said there was no risk to people who had not recently travelled to a Zika-affected country.

"The Zika infection is only transmitted via Aedes mosquitoes and not by human-to-human contact, except possibly, very rarely, by sexual means," Dr Weeramanthri said.

"Aedes mosquitoes are not found in Western Australia, so there is no recognised risk of the virus spreading here."

Since 2012, 23 cases have been reported in Australia and all were contracted overseas.