According to reports, Health Department of New York City made more than 95,000 rat inspections. The department keeps record of rats as they spread most feared diseases. Rat fleas transmit plague is among the disease that no one wants to catch.

In the United States, the last urban outbreak had happened in Los Angeles in 1925. At that time, the last United States survey of parasites on rats was published. For the first time in last nine decades, public health scientists and entomologists studied how many parasites and lice were on the city’s rats.

They had set several traps in different locations around the city to measure what parasites were hitching a ride on the city’s rats. After setting the traps, the public health scientists waited for a long time.

Matt Frye, lead author on the study, said, “The environment doesn’t change much in crawl spaces. There’s a pile of dirt that’s been a pile of dirt for recorded rat history. It’s very difficult to trap rats because they’re cautious of a new trap”. And if a rat is caught in a trap and manages to escape, it will never come near to that trap, Frye added.

According to the researchers, to measure the parasites of New York City rats, they work on Sunday mornings and wriggle about grime-slicked crawl spaces. After retrieving the rats from traps, the researchers carefully examined them and study what type of fleas, lice and mites were present in the rats.

After working for about 10 months, the researchers managed to catch about 133 rats. On those rats, the researchers found 6,500 fleas, lice and mites. According to the researchers, that’s not good as rat fleas are the ones that transmit plague and murine typhus.