Town Plans Larvicide Application To Combat West Nile Virus

By Andrew Gorosko

The town is on the verge of placing larvicide for a second time this year in its 4,000 roadside stormwater catch basins to combat the spread of the mosquito-borne West Nile virus.

Mark Cooper, the town health director, and Fred Hurley, the town public works director, demonstrated on Tuesday morning how they check on whether catch basins contain mosquito larvae. The larvae evolve into mature mosquitoes that carry the virus. Mosquito larvae breed in the stagnant water found in catch basins, among other places.

Mr Cooper said there has been no report of the West Nile virus having been found in Newtown this year. But the virus recently was found in Danbury in Culex pipiens, a bird-biting mosquito, he cautioned.

The presence of the West Nile virus in that mosquito is considered a warning that the virus will soon be found in mosquitoes which are inclined to bite humans, Mr Cooper said.

“With the recent heavy rains, there are bound to be pools and puddles of water which will be ideal habitat for mosquito activity,” he said.

The town health district and the public works department will continue looking for the presence of mosquito larvae in stormwater catch basins, and will place a bacteriological agent in those basins, as needed, to reduce the biting mosquito population, Mr Cooper said.

This year’s mosquito-control program is similar to last year’s project, which was useful in controlling mosquito breeding, he said.

Town workers dropped doughnut-shaped larvicide tablets into the 4,000 catch basins in the two rounds of larvicide application last year and also in the initial round of larvicide application this year in May.

In the planned second round of larvicide application this year, workers will place a small scoopful of granulated larvicide into each of the 4,000 basins.

The doughnut-shaped tablets tended to float on water and required weighting to be effective. The granulated material sinks to the bottom of standing water in the catch basins and is thus more easily applied.

Both the tablets and the granular material are the same bacteriological agent, Bacillus sphaericus Serotype, which is sold in large bags under the trade name VectoLex CG.

The West Nile virus threat remains a potential public health problem until the first frost, Mr Cooper said.

Based on weather conditions, once the decision is made to start applying the larvicide to catch basins, it will take between four and ten work days to do the job, Mr Hurley said. Once the larvicide has been placed in the basins, it is effective for about 30 days. Mr Hurley said he expects the town will apply the larvicide within the next few weeks.

In placing the larvicide in catch basins, two-man crews drive along the town’s snowplow routes. One man drives and the other gets out of the truck and drops a small scoopful of the larvicide into catch basins.

Personal Protection

Mr Cooper offered some tips for residents on protecting themselves from the West Nile virus.

Minimize the time spent outdoors around dusk and dawn when mosquitoes are most active.

Door screens and window screens should fit tightly and be in good repair.

Wear shoes, socks, long pants and long-sleeve shirts when outdoors for long periods, or when mosquitoes are most active. Clothing should be light-colored and made of tightly woven materials.

Mosquito netting should be used when sleeping outdoors or sleeping in an unscreened structure. Babies should be protected by mosquito netting when outdoors.

Consider using mosquito repellent when outdoors.

 

Source Reduction

Residents can prevent the breeding of mosquitoes by taking certain precautions.

Water-holding containers, such as ceramic pots, used tires and tire swings should be disposed of.

Recycling containers should have holes drilled in their bottom surfaces for drainage.

Clogged roof gutters should be cleaned.

Plastic wading pools and wheelbarrows should be turned upside down.

Water should be changed in bird baths weekly.

 Swimming pools which are not in use should be cleaned and chlorinated.

Landscaping can be used to eliminate standing water on properties.