Zika virus: What you need to know and how to protect yourself

What you need to know about the Zika virus and how to prevent it from Dr. Mark Loeb, Infectious Disease Physician and Microbiologist at Hamilton Health Sciences and McMaster University.

Hamilton expert explains the virus and how Canadians can protect ourselves when travelling

Aedes mosquito is photographed through a microscope. This is the insect behind the Zika virus. Canadians should exercise precaution when travelling to areas affected by the illness. (Felipe Dana/Associated Press)

The Public Health Agency of Canada is advising women who want to get pregnant to wait at least two months after visiting countries where the Zika virus is circulating — or could begin circulating — before trying to conceive.

While there aren't any cases of the virus being transmitted locally, it does raise concern for many people who are planning to travel or have recently visited areas where the virus exists.

Dr. Mark Loeb, Director of Infectious Diseases in the Department of Medicine at Hamilton Health Sciences warns us to exercise caution when travelling to areas where the Zika virus is being reported. Loeb spoke to CBC Hamilton about the virus and what Canadians need to know to stay safe.

Dr. Mark Loeb, Infectious Disease Physician and Microbiologist at Hamilton Health Sciences and Mcmaster University

Q: What is the history of Zika virus?

The Zika virus was first identified in Uganda in 1947 in a monkey. It was isolated in people in 1952 in Uganda and Tanzania and in 1951 to 1968 in parts of Asia and Africa. More recently, there was an outbreak in 2007 in Yap, a Federated State of Micronesia. In October 2013, 10,000 cases were reported in French Polynesia, 70 were severe cases with people reporting neurological issues or auto-immune complications. In July 2015, Brazil started reporting patients who also presented neurological symptoms associated with the virus. A steep increase was reported in October 2015 in Brazil and within the first week of 2016, more than 3500 cases of mirocephaly was reported.  

It is rapidly spreading.


The virus is in the Caribbean as well as parts of Central and South America. Cuba is not reporting yet but that doesn't mean it's not circulating and it does not mean it won't be circulating very shortly. (Ed. note: this interview was conducted prior to the first reported case of Zika in Cuba.)

How is the virus transmitted?

The major way it is transmitted is by daytime active Aedes Mosquitoes. The virus has been reported to spread through blood transfusion or sexual contact though no one knows how likely you are to contract the virus through sexual contact. The virus can be passed from a pregnant woman to her fetus. A mother who is infected with Zika near the time of delivery could pass along the virus to the fetus during birth, though it is rare. 

How long does it take for symptoms to occur?

It is not entirely clear. The incubation period (the time from exposure to symptoms) could be three to 12 days. It would be like a bad case of the flu. Some people may not present any symptoms.  
Dr. Mark Loeb at McMaster University studies dengue virus. He's following Zika virus developments closely. (Melanie Glanz/CBC)

What are the symptoms?

The symptoms could be: rash, joint pain, fever, headache, nausea, vomiting, retro orbital pain (pain behind the eye), conjunctivitis (red eyes). Exposure to the fetus can cause a condition called 'microcephaly' which is a birth defect. The size of the baby's head is smaller than the body, a sign of the brain not developing normally during pregnancy. There is also the possibility of neurological problems called 'Guillain-Barr' syndrome, a disorder that can present itself like muscle weakness. An infected person would have symptoms like trouble moving their limbs. They would experience numbness, tingling, pain and then weakness. It can also be very serious where they could experience trouble breathing and need to be in the hospital. 

What is the warning to Canadians?

There are potentially risks to pregnant women. Public health is advising expectant mothers to avoid travel where the virus is being transmitted. Talk to your healthcare provider before you intend to travel. 

When travelling to affected areas, how do people protect themselves?

When visiting countries where the Zika virus or other mosquito-born viruses exist, wear long-sleeved shirts and long pants, stay in areas that are air conditioned or that use window and door screens to keep mosquitoes outdoors. Sleep under a mosquito net if you are overseas or outside and not able to protect yourself from being bitten. Wear insect repellents that are safe for pregnant and breast-feeding women. If you are travelling with an infant, do not use insect repellent on babies younger than two months old. Adults can spray repellent on their hands, then apply to their infant. Make sure to cover their crib, stroller or baby carrier with mosquito netting.  

How likely is it for the virus to set up in Canada?

The Aedes mosquito is not breeding in Canada at this time, the climate is not suitable. It may creep into areas of the United States where the mosquito can breed. It is most likely to come to Canada through travellers bringing it here.

What is the greatest misconception about the virus?

There is a lot of information still required about the virus. There is a relative lack and few scientific studies done to really understand the virus itself and the illnesses it causes. A lot of questions, not enough answers.

You had a Q+A on Twitter recently. Was there anything in particular people are worried about around the Zika virus?

The questions asked were expected. Some included how to recognize the signs and symptoms of the virus, what precautions should be taken and is it possible for the virus to migrate to Canada. Many people planning to travel to Cuba were also concerned about the virus there. As mentioned previously, Cuba is currently not reporting the virus yet. It doesn't mean it's not already circulating or that it won't be circulating very shortly.


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