Pregnant women and those planning a pregnancy should avoid travel to south Florida because of Zika virus, Canadian health officials say.

The Public Health Agency of Canada recommends that pregnant women and those planning a pregnancy "avoid travel to the area in south Florida and countries with reported mosquito-borne Zika virus," a travel notice on its website says. "All travellers should protect themselves from mosquito bites."

On Monday, health officials in the U.S. also warned pregnant women to avoid traveling to a neighbourhood in Miami after the Florida government said it had identified 10 more cases of Zika caused by the bite of local mosquitoes, bringing the total to 14.

These are the first cases of Zika transmission by local mosquitoes in the continental U.S., according to the U.S. Centers for Disease Control (CDC).

Pregnant women who travelled to the affected area of Florida on or after June 15 should talk to their health-care provider about Zika testing, Dr. Gregory Taylor, Canada's chief public health officer said a teleconference with reporters on Tuesday.

The travel advisory is contained to a small area in Florida, Taylor said. "It could continue to expand or it could just burn itself out."

In total, about four million Canadians visit Florida annually, Taylor said.

There have been no reported cases of individuals infected by mosquitoes in Canada.

So far, six species of Canadian mosquitoes have been tested and none were able to transmit the Zika virus, Taylor said. He called the probability of that occurring extremely low. The research into domestic Canadian mosquitoes continues.

Since Zika can persist in the semen of infected males, health officials strongly recommend men with pregnant partners to use condoms or avoid having sex for the duration of the pregnancy.

The Public Health Agency of Canada also recommends male travellers to consider using condoms or avoid having sex with any partner for six months.

For female travellers planning a pregnancy, it is strongly recommended that you wait at least two months before trying to conceive to ensure that any possible Zika virus infection has cleared your body.

Mosquito control in Florida

Of the 14 people infected by mosquitoes in Florida, two are women and 12 are men. Eight patients showed symptoms of Zika, which can include fever, rash, joint pain and red eyes. The others had no symptoms.

The disease is often so mild that most people don't know they are infected. The main concern surrounds the effects of the virus in a developing baby during pregnancy, Taylor said.

Zika infections in pregnant women can cause severe brain-related birth defects, including extremely small skulls known as microcephaly. The global outbreak has led to more than 1,800 serious defects.

Officials with the CDC said they could not remember another time in the 70-year history of the disease-fighting agency when it told members of the public not to travel someplace in the U.S.

The CDC announced Tuesday it is making available more than $16 million US to states and territories in their fight against the Zika virus, in addition to the $25 million US it allocated in July.

CDC director Dr. Tom Frieden said the warning was dictated by science and not by any concern for Florida's tourism industry. He said it was based on how the U.S. contained previous outbreaks of other diseases carried by the same mosquito.



"There wouldn't be a technical or scientific basis to give a broader recommendation," Frieden said.



Speaking Tuesday morning on ABC's Good Morning America, Frieden said officials were finding it hard to eradicate the mosquito in the affected area.



"It could be that the mosquitoes there are resistant to the insecticide being used," he said, adding that it could take weeks for federal and state officials to figure that out.

He also said mosquito control is difficult.

"This is an unusual neighbourhood, or an emerging neighbourhood," Frieden said. "It's mixed use. It has industrial, business and residential and that makes mosquito control very complex."