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Friday, October 28, 2016 | 10 a.m. | Windsor-Essex County

Photo of Aedes aegypti mosquito on human skin

In the United States, the Aedes aegypti mosquito primarily exists in the southern states and along the eastern seaboard, where temperatures are more favourable for its survival. There are records of this mosquito being found in some northern states, including Michigan and New Hampshire; however, these were only temporary summer incursions, as the relatively cold winters prevented establishment. To our knowledge, this is the first time Aedes aegypti has been collected in Canada.

Although it is unknown exactly how the larvae arrived in Ontario, one possibility is that the eggs were transported from the U.S. in shipping containers or other cross-border vehicle traffic. Aedes aegypti eggs could also have been imported in recycled products, such as tires or other containers. Given that this is a tropical mosquito, the extremely hot temperatures this past summer allowed for the species to exist in Windsor.

Conference Media Files

Watch the conference video on Facebook, or listen to the media conference audio on Soundcloud.

“We will continue to ensure that our community stays informed about infectious diseases and the local mosquito surveillance program. It is a key public health service that we provide to Windsor-Essex County residents. The discovery of the yellow fever mosquito larvae through enhanced surveillance of the Aedes albopictus mosquito is an important reminder that we should continue to protect ourselves and our families from mosquito bites,” said Dr. Kirk. 

The Aedes aegypti mosquito is even less cold tolerant than the Aedes albopictus and will not survive the cold winter temperatures. For Zika virus transmission to occur, the Aedes aegypti mosquito would need to feed on an infected person, within the first several days of infection, and then feed upon another susceptible person. The greatest risk to contracting Zika virus continues to be centred on those who have travelled to Zika-risk areas (such as South America, the Caribbean and Florida) or who are or have been in sexual contact with these travellers.

The biting behaviour of the Aedes aegypti is different than those that transmit West Nile Virus in Ontario. It is a sneaky, human, daytime biter; it tends to approach humans from behind and bite them on the elbows and ankles. Like the Aedes albopictus, these mosquitoes do not breed in ponds, puddles or marshes. They typically lay eggs in and near standing water in items such as buckets, bowls, animal dishes, flower pots and vases. It is important to change water regularly, especially in pet dishes and water in bird baths.

Although the mosquito season is closing because of the cooler temperatures, it is still important to protect yourself and your family from mosquito bites, especially when traveling to warmer climates. Individuals can do so in several ways:

  • Use insect repellents that contain DEET, Icaridin or other approved ingredients on clothing as well as exposed skins. Always read and follow label directions.
  • Wear long-sleeved shirts, long pants, and a hat when outdoors. Light-coloured clothing is best as mosquitoes tend to be attracted to dark colours.
  • Make sure that door and window screens fit securely and are free of holes.

We are uncertain if these Aedes mosquito species will return next year. Whether they do or not depends largely on whether the mosquitoes are again transported into Ontario and whether we experience another extremely hot summer. The Windsor-Essex County Health Unit is working closely with the Ministry of Health and Long-Term Care, Public Health Ontario, and the Public Health Agency of Canada to determine enhanced surveillance plans for next year to monitor for the presence of Aedes albopictus and Aedes aegypti.

In summary, based on all we know about this mosquito, the absence of Zika virus in the tested mosquitos and in our community, we conclude that there has not been nor is there current risk of local mosquito Zika virus transmission in Windsor-Essex County.  Furthermore, on the basis of all we know, we would recommend no additional Zika virus testing for Windsor-Essex County residents beyond the current guidelines.

Brock University Media Conference

Brock University will host a press conference Friday, Oct. 28 at 1:15 p.m. with Hunter, Giordano and Alessio Gasparotto, Manager, Entomogen Inc., the company that identifies mosquitoes for the Windsor-Essex County Health Unit’s mosquito surveillance program.

View the full detail of the Brock University Media Advisory.

BACKGROUNDER

  • The Zika virus is transmitted primarily through the bite of an infected Aedes species mosquito (Aedes aegypti  and Aedes albopictus).
  • Aedes aegypti are more likely to spread the Zika virus than the Aedes albopictus.
  • Aedes aegypti probably originated in Africa but has been transported globally through shipping and trade. It has been known to occur in the United States for centuries.
  • As this is a tropical mosquito, its expansion is limited to areas with suitable temperatures that can allow it to survive. The cold winter temperatures of Ontario will prevent the mosquito’s ability to survive over the winter.
  • In the United States, this mosquito primarily exists in the southern states and along the eastern seaboard, where temperatures are more favourable for its survival. There are records of this mosquito being found in some northern states, including Michigan and New Hampshire; however, these were only temporary summer incursions, as the relatively cold winters prevented establishment.
  • The Aedes aegypti that were found in Windsor were discovered at the end of the mosquito season as part of Windsor-Essex’s extended mosquito surveillance program for Aedes albopictus. To our knowledge, this is the first time Aedes aegypti has been collected in Canada.
  • In Ontario, the mosquito that primarily spreads West Nile is Culex pipiens. This species of mosquito is not known to transmit the Zika virus.
  • The biting behaviour of the Aedes aegypti is different than those that transmit West Nile Virus in Ontario. It is a sneaky, human, daytime biter; that tends to approach humans from behind and bite them on the elbows and ankles.