The mosquito-borne virus has recently been discovered in Australian travellers returning from South America.

The Department of Foreign Affairs and Trade has advised travellers to avoid all 22 countries affected by Zika virus, most of which are situated in South and Central America and the Pacific Islands. The World Health Organisation has also warned that Zika virus could spread to all countries in South, Central and North America excluding Canada and Chile.

Infection with the virus is particularly harmful to pregnant women as it can cause brain-damage to their unborn child. According to Brazil’s Health Ministry, the virus has been linked to microcephaly, a deformity which limits infants’ brain growth. WHO has reported there have been almost 4,000 suspected cases of the deformity in Brazil, a figure 30 times higher than that of any single year since 2010.

WHO director-general Margaret Chan has warned that if the epidemic is still going on when Brazil hosts the Olympic Games in August, “pregnant women should either stay away or be obsessive about covering up against mosquito bites”.

Dr Chan concedes that a causal link between Zika infection in pregnancy and microcephaly has not been established, but says “the circumstantial evidence is suggestive and extremely worrisome”.

The no-go list for pregnant women includes Puerto Rico, Brazil, Colombia, El Salvador, French Guiana, Guetemala, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Suriname, Barbados, Bolivia, Ecuador, Guadeloupe, Saint Martin, Guyana, Cape Verde and Samoa.

Although travelling to an affected country will put you at a high risk of contracting this virus, most Australians will be fairly safe in their own backyard. Zika can only be carried by certain species of mosquito, and Australia is home to only one of these; the Aedes aegypti, which is limited to far North Queensland.

Westmead Hospitals virologist Professor Dominic Dwyer told the ABC “it’s a question of being alert but not alarmed.”

“There have been some people who have come back to Australia who’ve had Zika virus infection, but what we haven’t had is evidence of the spread of the infection from one person to another in this country.

“The main mosquito carriers of the virus are not present to any great degree in Australia, except perhaps up in the top end of Queensland,” Professor Dwyer said.

Zika virus is generally considered a mild disease but there is currently no vaccination, cure or treatment, so at this stage it is safest to follow government advice and delay travel to any areas affected by the disease.