Mosquito larvae ŠAMNH   Mid-April: Death to Larvae! New York City begins a program of dispensing larvicide, which kills mosquito larvae, into thousands of drains and catch basins in all five boroughs. Adult mosquitoes can only be killed with synthetic chemicals, but non-toxic, environmentally safe materials can do the job on larvae. Two different kinds of larvicide are used. One is a bacterium that directly attacks larvae; the second is an insect growth regulator that stunts the larval growth, so that adults never emerge. City officials plan to continue initial application through May, with follow-up applications administered through the end of October as needed. Larvicide programs are also begun for various Connecticut communities. Enter the larvae-eating fish The city also expands the use of Gambusia affinis, often called "mosquito fish," at its waste treatment plants. These sturdy fish can survive in almost any kind of water, live through the winter, reproduce every 28 days, and can consume up to 230 mosquito larvae in one hour. Keeping an eye on the birds Connecticut officials had been netting live birds, taking blood samples, and testing for West Nile and Eastern Equine Encephalitis (EEE) viruses throughout the winter (EEE has been a concern in the state since 1997). On April 17th, Connecticut begins a wild bird surveillance program, monitoring bird deaths statewide and formally reporting mortality data on a regular basis. Birds can be valuable as "sentinel species" that provide an early warning of an outbreak (the widespread death of American crows in New York was the first tip-off to the WNV's presence last summer). Early May: Sentinel chickens go into action! In New York City, flocks of chickens--which catch West Nile but show no symptoms--are set out in 17 different locations in all five boroughs, as a form of mosquito bait. Flocks are also placed in all 21 New Jersey counties. The birds will undergo weekly blood tests throughout mosquito season to test for presence of the virus. (In 1990, sentinel chickens in Florida detected St. Louis encephalitis before it infected people, giving public health officials time to spray and to warn the population.) Health officials also begin regularly screening crows and other dead birds submitted for testing for WNV. Monitoring the mosquitoes City officials begin larval surveillance as well: monitoring places like ponds and sewers to see whether mosquitoes are breeding. This surveillance begins in Queens, Brooklyn, and the Bronx, where most prior WNV cases were reported, and will continue in all five boroughs through the summer. Additionally, traps for catching adult mosquitoes are placed in numerous key spots around the city. Trapped mosquitoes will regularly be tested for WNV.      2 of 6