Zika Virus

Zika virus infection is caused by a virus which is spread by the bite of infected Aedes aegypti and Aedes albopictus mosquitos. These are the same mosquitos that spread Dengue, Chikungunya and yellow fever viruses.

These mosquitos are not established in Canada and are not well-suited to our climate.

Zika virus has been reported in Africa and parts of Asia since the 1950s and in the southwestern Pacific Ocean in 2007. In 2015, Zika virus emerged in South America. More recently, the virus has caused widespread outbreaks across Central and South America, Mexico, and the Caribbean.

There have been reports of a serious birth defect called microcephaly (a condition in which a baby's head is smaller than expected when compared to babies of the same sex and age) in babies of mothers who were infected with Zika virus while pregnant.

It is recommended that pregnant women and those considering becoming pregnant discuss their travel plans with their health care provider to assess their risk and consider postponing travel to areas where the Zika virus is circulating. If travel cannot be postponed, then strict mosquito bite prevention measures should be followed to protect themselves against bites.

Provincial Reporting

Laboratory-confirmed travel-related cases of Zika virus in Ontario as of Sept 1, 2018

Number of laboratory-confirmed* cases Countries of Travel§
323* Anguilla, Argentina, Aruba, Antigua and Barbuda, The Bahamas, Barbados, Belize, Bonaire, Brazil, British Virgin Islands, Cayman Islands, Cambodia, Cuba, Columbia, Costa Rica, Curaçao, Dominican Republic, Ecuador, El Salvador, French West Indies, Grenada, Guatemala, Guyana, Haiti, Honduras, Indonesia, Jamaica, Martinique, Mexico, Montserrat, Nicaragua, Panama, Peru, Puerto Rico, Saint Barthélemy, Sint Eustatius, Saba, St. Kitts and Nevis, St. Lucia, St. Martin / St. Maarten, St. Vincent & Grenadines, South Caribbean, Thailand, Turks and Caicos Islands, Trinidad and Tobago, United States of America, Virgin Islands of the United States, Venezuela, Vietnam

*Note: Four of the 323 laboratory-confirmed cases of Zika virus in Ontario are non-travel related.

  • §The countries listed are based on the travel history provided by cases, however, this listing does not reflect the risk of acquisition of Zika virus. The World Health Organization and the Pan American Health Organization currently list the above countries as having local transmission of Zika virus. As this list changes regularly, please see the World Health Organizations classification list for the most up-to-date information.
  • Please note, the ministry will be updating this website on a quarterly basis.


While the majority of Zika virus cases will be caused by bites from infected mosquitos, there is evidence that mother-to-child transmission may occur. There have been a few reports identifying the possibility of transmission of the virus via transfusion of infected blood, or possible sexual transmission of Zika virus. Further study is required to evaluate the modes of transmission.

Signs and symptoms

Following the bite of an infected mosquito, symptoms usually appear in 3–12 days. The symptoms are similar to those of Dengue and Chikungunya, and include fever, skin rashes, muscle and joint pain, headache and red eyes. The illness is usually mild with symptoms lasting from several days to a week. Most people infected with Zika virus have few or no symptoms and may be unaware that they are infected with the virus.


Zika virus preliminary diagnosis is based on:

The virus is diagnosed based on laboratory test results. See your health care provider if you develop symptoms of Zika virus after travelling to at-risk areas.

Prevention and control

Currently, there is no vaccine or treatment for Zika virus. Prevention and control of Zika virus relies on reducing the number of mosquitos by removing and modifying their breeding sites and reducing contact between mosquitos and people. This can be done by:

  • Using insect repellent
  • Wearing light-coloured clothes that cover as much of the body as possible
  • Using physical barriers such as screens, closed doors and windows, and sleeping under mosquito nets at night.

Mosquitos carrying Zika virus are known to be mainly day feeders. Special attention and help should be given to those who may not be able to protect themselves adequately, such as young children, the sick or elderly.

Travellers, especially pregnant women, should take the basic precautions described above to protect themselves from mosquito bites and are advised to check with their health care providers before travel.


Zika virus disease is usually mild and requires no specific treatment. People sick with Zika virus should get plenty of rest, drink enough fluids and treat pain and fever with common medicines. If symptoms worsen, they should seek medical care and advice.

Learn more

For More Information

Call ServiceOntario, Infoline at:
1-866-532-3161 (Toll-free in Ontario only)
TTY 1-800-387-5559.
In Toronto, TTY 416-327-4282
Hours of operation: 8:30am - 5:00pm

If you are a member of the media, call Communications and Marketing Branch at 416-314-6197 or visit our News Room section.

  • Connect With Us
Ministry of Health Facebook page Ministry of Health Twitter page