City crews are placing Altosid briquets in nearly 5,000 catch basins. Altosid is an insect growth regulator that is used to reduce the mosquito population. This is the fifth year the City has used Altosid in catch basins.

Catch basins are breeding grounds for mosquitoes, in particular the Culex pipiens, the main mosquitoes involved in the transmission cycle for West Nile Virus.

The use of Altosid was a recommendation from Mayor Graham Richard'€™s West Nile B.E.S.T. Team that looked at ways to prevent the spread of the West Nile Virus.