A virus believed to be responsible for a string of recent birth defects in Brazil has made another appearance in Canada.

Three Canadians returned home from trips abroad with the Zika virus – two from B.C. and one in Alberta.

Earlier this month, the Public Health Agency of Canada said a B.C. resident who recently travelled to El Salvador had contracted the virus.

The CBC reports the other person from B.C. had returned from Columbia. Both patients have since recovered.

As for the case in Alberta, it’s not yet known in what country they picked up the virus, and their medical status remains unknown.

However, health officials say there is little to no risk to the public. The mosquitoes that carry the virus don’t live in Canada due to the climate, and tranmission from one person to another is rare.

The World Health Organization says it is convening an emergency committee on Monday to decide if the Zika virus outbreak should be declared an international health emergency.

At a special meeting on Thursday, WHO Director-General Dr. Margaret Chan said the virus – which has been linked to birth defects and neurological problems – was “spreading explosively.”

Chan said although there was no definitive proof that Zika was responsible for a spike in the number of babies being born with abnormally small heads in Brazil, “the level of alarm is extremely high.”

WHO last declared an international emergency over the devastating 2014 Ebola outbreak in West Africa, which ended up killing more than 11,000 people.

Zika is native to parts of Africa and Asia and is transmitted to people by the daytime-biting Aedes mosquito. Last year it sparked a massive outbreak in Brazil, with over 270,000 cases so far. The virus has since spread to 20 countries.

The WHO has said that Canada and Chile are the only two countries in the Americas where the virus is not likely to spread.

While Zika generally causes mild symptoms like fever, feeling unwell, a rash, red eyes and joint pain – or in the majority of people, no symptoms at all – in may cause birth defects. The virus is being investigated as a possible cause of small heads and undeveloped brains – microcephaly – in some newborns whose mothers may have been infected while pregnant.

Brazilian officials still say they believe there’s a sharp increase in cases of microcephaly and strongly suspect the Zika virus is to blame. Officials in El Salvador, Colombia and Brazil have suggested women stop getting pregnant until the crisis has passed.