The number of confirmed Zika cases continues to rise in B.C., with 47 people now diagnosed with the virus after travelling including three pregnant women, according to the B.C. Centre for Disease Control.
Zika is a virus that's carried and transmitted by mosquitos in a number of countries, including Mexico, most of Central and South America, and parts of Florida and Texas.
Most people who get Zika have no symptoms, but in pregnant women, infection can cause severe birth defects in a developing fetus, including microcephaly or an abnormally small head.
That's why pregnant women, women who may want to become pregnant and their partners are warned against travelling anywhere with active Zika transmission.
"Pregnant women should really consider seriously whether their travel is necessary," said Dr. Eleni Galanis of the B.C. Centre for Disease Control.
"I think it's very much an individual decision, but to my own patients and to my own family members and if I were pregnant, I would not take that risk."
Hundreds tested in B.C. each month
All of the 47 B.C. Zika cases were acquired while travelling — some in resorts, some off the beaten path and some on extended stays, said Dr. Galanis.
Mexico was the most commonly cited country among the travellers, she said.
Travellers can and should take precautions to avoid getting bitten by mosquitos, such as wearing insect repellant and long-sleeve clothes, especially at dawn and dusk, said Dr. Galanis.
But that might not be enough given the potential for severe complications, she said.
"Even with all the greatest precautions in the world, you probably will get bitten once or twice. So then it's your decision to make about whether or not you want to take that risk."
Each month, the B.C. CDC is seeing between zero and eight new Zika infections, out of the 200-300 tests conducted on returning travellers.
2 Canadian pregnancies with anomalies
Zika does not cause birth defects in all or even most cases.
One U.S. study found birth defects in six per cent of babies born to women with possible Zika infection, Dr. Galanis said the rate could be closer to one percent — small, but "not insignificant."
"There is so much unknown still about Zika and its effects on pregnancy," said Dr. Galanis. "The concern is warranted until we can get further clarity."
The outcome of the three B.C. pregnancies, including whether the fetuses had Zika-related anomalies, and whether the women had abortions, is not known.
Across Canada, at least 439 people have been diagnosed with Zika after travelling, including 23 pregnant women, according to the Public Health Agency of Canada.
Two of the developing babies had Zika-related anomalies.
Who should get tested
Anyone returning from a country with mosquito-borne Zika virus who displays symptoms including fever, headache, pink eye, skin rash and joint and muscle pain is advised to get tested.
As well, any woman who is pregnant — or wants to get pregnant — and is returning from a country with Zika transmission should get tested, whether or not she is sick, said Dr. Galanis.
Health officials strongly recommend women infected with Zika wait at least two months before becoming pregnant, for the virus to clear their system.
Men are strongly recommended to wait at least six months before trying to conceive or having sex without a condom — a longer duration, as the virus can linger in semen for an extended period.
Men are also told to avoid unprotected sex with a pregnant partner for the duration of the pregnancy.