Two new cases of Zika virus detected in Australia: authorities

Two new cases of the mosquito-borne Zika virus have reportedly been detected in two Australian patients who recently returned to Sydney from the Caribbean, though its unlikely the virus has established local transmission.

The Asia-Pacific has been on high alert for the mosquito-borne virus, currently found in epidemic proportions in the Americans, following the declaration of a global emergency by the World Health Organization on Tuesday.

The yellow fever mosquito driving the Zika outbreak in Brazil - where its been linked to thousands of birth defects in newborns - is found in the tropics in far north of Australia's Queensland state, the area "most likely to get a small outbreak", medical entomologist Dr Cameron Webb told a media briefing in Sydney on Tuesday, noting the mosquito is not present in metropolitan Australia.

"That outbreak won't be caused by infected mosquitos coming back from South America, it will be triggered by travellers coming back infected with the virus," Webb said.

That is exactly what has happened after two New South Wales state residents who recently travelled through the Caribbean returned to Sydney infected with the Zika virus, Fairfax Media reported late on Tuesday.

The NSW health department's director of communicable diseases Dr Vicky Sheppeard, in a statement late Tuesday, confirmed to Xinhua the Zika virus was detected in the two patients last Friday, but said the residents had mild cases of the virus and have since recovered.

The detection of Zika virus in Australia is not new after four cases were diagnosed in NSW in 2014 from people who had recently travelled from the Cook Islands, while an additional case was detected in 2015 from a patient returning form the Solomon Islands, Sheppeard said.

"It is very unlikely that Zika virus established local transmission in NSW as the mosquitoes that spread the infection are not established here - although they are found in some parts of north Queensland," Sheppeard said.

Earlier on Tuesday, Australia's chief medical officer Professor Chris Baggoley urged for calm and stressed the importance of the nation's strong biosecurity system while suggesting pregnant women should reconsider their need to travel.

"As far as Australia goes, we remain in very good shape," Baggoley said.

Authorities in Papua New Guinea - Australia's closest neighbor - have been placed on high alert for the virus after cases were detected in Samoa, Tonga and New Zealand, indicating measures introduced to help combat the spread of Ebola virus can be re-activated if necessary.

"There is a great deal that remains unknown about the Zika virus, but the reports and suspected links to birth defects and neurological problems mean that this threat must be taken very seriously," Papua New Guinea's Prime Minister Peter O'Neill said in a statement.

Tropical regions inadvertently serve as a breeding ground for the mosquito that carries the Zika virus, which can often be mis-diagnosed as dengue fever.

Queensland authorities have called an emergency meeting of infectious disease experts and others this week to ensure the state is well equipped to handle the mosquito-borne illness that will most likely reach the country through the Torres Strait via Papua New Guinea and the South Pacific.

"The advice that I have is Queensland is of no great threat of this virus, but it is spreading," Queensland state Health Minister Cameron Dick told reporters on Tuesday.

"The World Health Organization has now designated it as an international threat, so we need to be prepared in Queensland."

Though the WHO have declared the Zika virus to be a global epidemic, vaccine manufacturers have said a vaccine for wide-scale public use is months, if not years away.

The closest prospect is a consortium that could have a vaccine ready for emergency use by year's end, with the first stage of human testing potentially beginning as early as August, according to its lead developer, Canadian scientists Gary Kobinger.

Current efforts to combat Zika are focused on protecting people from being bitten and on eradicating mosquitoes, a tough task for many parts of the poverty stricken Pacific islands that have been saving water from the El Nino enforced drought, inadvertently providing a breeding ground for the disease spreading insect.