Alderman: Sterilize Rats So They Don't Become A Post-Thaw Problem

By Chuck Sudo in News on Mar 13, 2014 3:40PM

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Photo credit: Tim Schreier

Last month we wrote about how mice and rats have handled this winter about as well as we, with spikes in calls to exterminators and the city’s 311 call center to handle the pest problem. One alderman is sounding the alarm the rat problem could grow as Chicago trudges toward warmer weather.

Ald. Bob Fioretti (2nd) is concerned enough about a possible explosion in the rat population he’s advocating the sterilization of female rats with “liquid rodent sterilization bait.” (There goes our image of Streets and San workers chasing male rats through alleys armed with bonsai shears and tweezers.)

The bait, called “ContraPest,” contains an industrial chemical called 4-vinylcyclohexene diepoxide (VCD) which accelerates egg loss in female rats and can cause infertility within days of ingestion. New York City’s Metropolitan Transportation Authority launched a pilot program last year with SenesTech, the Arizona-based company that invented ContraPest, to see how to best use the bait and pair it with food the rats would be most likely to eat. An MTA spokesman told New York magazine last December the program was successful; SenesTech said their data showed a 43 percent decline in the rat population in Grand Central Station’s trash room.

Female rats can give birth to up to a dozen pups per litter and have as many as seven litters a year so ContraPest is an attractive pest control option. Fioretti told DNAInfo Chicago he “saw a lot of the scurrying around of our rat population” while touring the current and future 2nd Ward boundaries. Firoetti has met with SenesTech officials and is confident ContraPest could be used to effectively cull the rodent population in Chicago, which was named the fourth-worst in the world in an Animal Planet survey.