By Richard Ewart
Vanuatu health officials have for the first time confirmed cases of the rare mosquito-borne zika virus.
Zika is the "milder brother" of dengue fever, head of the World Health Organisation (WHO) in Vanuatu Jacob Kool said.
The two illnesses share similar symptoms of fever, aching joints and rash.
Although there were no recorded deaths from zika, health officials warned it can cause "very explosive outbreaks".
Like dengue fever, there is no cure for the zika virus.
The WHO advises prevention through using mosquito nets, protective clothing and insect repellent, and removing breeding sites.
Dr Kool told ABC's Pacific Beat removing sites was "going to be very challenging" following the devastation caused by Cyclone Pam, which killed at least 11 people last month.
"Breeding sites could be any cracked coconut, for example, and there's a lot of debris like that — things that collect water where mosquitoes can breed," he said.
Zika 'a very strange story'
Zika was first discovered in 1947 in Rhesus Monkeys in Uganda's Zika forest.
"Zika is a very strange story ... it had caused only about 20 known human cases until 2007, when there was suddenly 6,000 cases on the island of Yap in the North Pacific," Dr Kool said.
The symptoms usually last four to seven days.
The mild symptoms and similarity to other illnesses may have been the reason for the low number of confirmed cases.
"In hindsight, we think zika has always been confused for dengue in many countries," Dr Kool said.
"So zika virus may have been around and always misdiagnosed for dengue."
In the aftermath of Cyclone Pam, medical teams reported several cases of pink eye to the WHO.
"Pink eye, or red eye, is also a common symptom of zika virus. So I wouldn't be surprised if those cases were zika virus as well," Dr Kool said.
- Australian Broadcasting Corporation
- © ABC