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Mosquito Control
Mosquitoes spend their early life stages as larvae and pupae in nutrient rich, stagnant water, such as
- floodwater puddles,
- ditches,
- ornamental ponds,
- rain-fill tires, and
- horse troughs.
Once they emerge as adults, the female mosquitoes search for a blood meal to provide enough protein to produce eggs. In biting different host animals, they may transmit diseases and parasites to which humans, dogs, birds and horses are susceptible.
Nuisance Mosquito Control Program
Surrey's Nuisance Mosquito Control Program has been in place for many years. The program is managed by Metro Vancouver on behalf of 5 member municipalities
- The City of Surrey
- Township of Langley
- Maple Ridge
- Coquitlam
- and Pitt Meadows.
The target of this program is the control of floodwater mosquitoes that can emerge in very large numbers in the spring and early summer, causing extreme nuisance to residents. The program’s goal is to regulate mosquito populations using environmentally friendly integrated pest management techniques to reduce nuisance mosquito effects.
Mosquito habitat may be identified through targeted routine monitoring and responding to citizen concerns. Monitoring occurs during the mosquito season which is generally May through September, and involves strategic sampling of wetted areas suspected to be occupied by mosquito larvae. Strategic dip-net sampling of the identified areas is performed by contractor mosquito technicians. After predetermined threshold numbers of larvae are identified, population management may be conducted using bacterial larvicides.
The larvicide used is VectoBac and Vectolex.
- VectoBac is a larvicide that kills mosquitoes during the aquatic larvae stage of their development. It contains a naturally occurring bacterium, Bacillus thuringiensis israelensis (Bti), which is common in soils in Canada, North America and throughout the world. Bti has been used since the 1950s for insect control.
- Vectolex contains Bacillus sphaericus, and performs similarly to Bti. Due to the products specificity, it has little effect on plants, fish, or other organisms that live in the water. The toxins in Bacillus are target specific, and will not affect pets, humans, birds, fish and other non-target organisms and provide long term residual control of mosquito larvae. Larvicides are regulated in Canada and the products are used according to provisions of the product label.
The mosquito control contractor for the Nuisance Mosquito Control Program is Culex Environmental Ltd. (Website. New window.) They're responsible for executing the program on behalf of Metro Vancouver and the 5 member municipalities.
Culex Environmental Ltd. takes calls from residents within the 5 member municipalities on their Mosquito Hotline at 604-872-1912. Call the Mosquito Hotline to report areas of potential concern regarding mosquitoes and to get more specific information about the Nuisance Mosquito Control Program.
How to Prevent Mosquito Breeding
- Destroy or dispose of tin cans, old tires, buckets, plastic sheeting, or other containers that collect and hold water;
- Clean bird baths regularly;
- Repair leaky plumbing and outside faucets;
- Clean out leaves and other debris blocking and holding water in roof gutters;
- Empty your pets' water dishes daily;
- Water lawns and gardens carefully to prevent water from standing for several days;
- Empty or cover swimming and wading pools when not in use.
West Nile Virus
West Nile virus (WNv) is a mosquito-borne disease that cycles between mosquitoes and birds and can infect people and other animals through mosquito bites.
The majority of people infected with WNv will not experience symptoms. About 20 percent of those infected will develop mild flu-like symptoms lasting a week or less. Symptoms typically include
- fever
- head and body aches
- rash
- and sometimes swollen lymph glands.
In less than 1 percent of cases, the virus can cause meningitis (inflammation of the lining of the brain and spinal cord) or encephalitis (inflammation of the brain), which can be fatal.
People over 50 years of age are most at risk for severe illness. In areas where mosquitoes do carry the virus, very few mosquitoes, much less than 1 percent, are infected. If bitten by an infected mosquito, less than 1 percent of people who become infected will get severely ill. As a cumulative result, the risk of becoming seriously ill from the virus is very low, but precautions should be taken to avoid mosquito bites and reduce mosquito breeding areas. Being aware of the threat of WNv and the need to protect yourself from mosquito bites goes a long way to reducing the chances of becoming infected.
West Nile prevention efforts
From 2004 to 2011, The Fraser Health Authority through the Union of BC Municipalities (UBCM) provided funds to eligible municipalities to manage for WNv risk reduction through pre-emptive larviciding. In line with the BC Centre for Disease Control (BCCDC) recommendations adopted by the Provincial Centre for Disease Policy Committee in 2012, the following changes to Fraser Health’s WNv risk reduction strategy (Website. New window.) are in effect for the 2012 season:
- Fraser Health does not recommend pre-emptive larviciding to local government catch basins for the control of WNv vector mosquitoes;
- Fraser Health does not recommend catch basin monitoring;
- Fraser Health does not recommend the systematic monitoring and larviciding of high risk surface waters for the control of WNv vector mosquitoes;
- Access to Fraser Health’s Pest Management Plan (PMP # 843-0001 09/14) will not be available to local governments for mosquito control in 2012.
Following these directives for 2012, the Fraser Health Authority has not released any funds to municipalities to further support the WNv risk reduction program at the municipal level. As a result, the City of Surrey will not be conducting any specific WNv risk reduction activities. It should be noted that there is no evidence of WNv to date in the local community; however, during the summer of 2009, WNv was detected in a horse in Aldergrove.
The Province (BCCDC) and the Fraser Health Authority will continue to evaluate the risk of WNv. Due to the susceptibility of corvids (crows and jays) to WNv, the Fraser Health Authority will collect the dead corvids found in the area and the BCCDC will continue to test the collected dead corvids to help determine WNv presence. In addition, the Fraser Health Authority and the BCCDC will continue providing public messaging around protective measures to take in reducing the risk of WNv illness.
To report a dead corvid (crow, raven, jay) call 1-888-WNV-LINE (1-888-968-5463).
Reducing the Risk of Mosquito Bites and WNV
The best protection is to avoid mosquito bites and reduce mosquito populations in your home and yard. We recommend:
- using insect repellent containing DEET (10% for children and up to 30% for adults) when outdoors.
- avoiding mosquito-laden areas during dawn and dusk.
- wearing loose, light coloured clothing when outdoors, including long-sleeved shirts and pants.
- applying tight-fitting, well maintained screens to doors and windows.
- keeping your lawn regularly mowed to decrease mosquito rest areas.
- eliminating or regularly changing any sources of stagnant water around your home such as saucers under flower pots, bird baths, wading pools, and other areas where rainwater may collect.
How many mosquitoes are present in BC and which ones are problems to humans?
There are approximately 47 species of mosquito in BC. Mosquitoes may acquire their blood meal from a variety of sources such as amphibians, birds and mammals. About 40 of these species have been known to bite humans; however, humans may not be the primary source of blood for a majority of the mosquitoes.
Of the 40 species known to bite humans, only 7 species have been classified as high risk, 4 species have been classified as moderate risk, 6 species have low risk, and the remainder are nil risk species for being WNv vector species.
Is it more dangerous to live near a Wetland?
The numerous wetlands and parks in Surrey are often perceived as WNv-hazard risk areas when in fact, the ecosystem associated with wetlands help control mosquitoes and maintain biodiversity. The often abundant mosquitoes in these areas serve as a food source for many of the wetland inhabitants and the predator/prey balance of nature proves an effective control in most cases.
Frequently, those mosquito species known to carry WNv do not exist in wetlands and parks, but breed extensively in urban man-made stagnant or polluted water such as rain-filled tires and storm water catch basins. Visitors to local wetlands and parks should still take precautions to protect themselves from mosquito bites by applying insect repellent and wearing protective clothing.
What is the risk of infection from WNv in BC?
WNv is an emerging infectious disease in North America. Since arriving in New York in 1999, WNv has spread steadily across the continent. WNv was first detected in BC in 2009, when 3 humans disease cases were reported (1 travel-related). In addition, 3 horses and 10 mosquito pools tested positive for WNv.
Now that WNv is present in BC, it is expected to spread across the southern half of the province, but it is not yet known how far and how fast WNv will eventually spread. The BCCDC and the Fraser Health Authority will continue to monitor WNv activity and may change their management recommendations upon receiving new information.
What is the treatment for WNv?
Although there is no specific treatment, medication or cure, many of the symptoms and complications of the disease can be treated. Most people who are infected with WNv recover. There is no human vaccine for WNv at this time. There is a vaccine available for horses. Horse owners should contact their veterinarian for more information.
I have a mosquito bite. Should I be worried?
No, the chance of contracting WNv from a mosquito bite is very low. Only a few of the many mosquito species in the province carry WNv. If you suspect you have symptoms associated with WNv, you may want to call the BC Nurse Line at 8-1-1 or 7-1-1 for the hearing impaired.
For more information regarding Surrey's Nuisance Mosquito Control Program, contact
Culex Environmental Ltd. http://www.culex.ca/ , or
Nuisance Mosquito Control Hotline: 604-872-1912
For more information regarding WNv, contact
BC Nurse Line: 8-1-1 or -1 for the hearing impaired,
BC Centre for Disease Control (Website. New window.) at 604-707-2400
Fraser Health Authority (Website. New window.) or call 1-888-WNV-LINE (1-888-968-5463)