Two Australians were diagnosed with the Zika virus after returning home from travels in the Caribbean, a state health service said on Tuesday, confirming the first cases of the mosquito-borne virus in the country this year, Reuters reported. Officials also said that mosquitos carrying the virus had been detected at Sydney International Airport, but stressed that it was unlikely the virus would establish local transmission given the lack of large numbers of the Aedes Aegypti mosquitos. Confirmation of the Australian cases came just a day after the World Health Organization declared the Zika virus to be an international public health emergency due to its link to underdeveloped brains in some babies. There is no vaccine against the mosquito-borne virus. The New South Wales (NSW) health department said the two Sydney residents were diagnosed with the Zika virus on Friday after returning to Australia from Haiti. Formal diagnosis can take several weeks and the department did not disclose when the couple were tested. It said the pair had mild cases of the virus and had recovered.