New York City Rats Carry Fleas Known to Transmit Plague

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MONDAY, March 2, 2015 (HealthDay News) -- Rats in New York City are brimming with fleas and other parasites that can carry a number of diseases, including the plague, a new study reports.

Researchers analyzed 6,500 specimens of five well-known species of fleas, lice and mites found on over 130 rats from around the city.

The samples included Oriental rat fleas, a type of flea that can transmit bubonic plague, also called the Black Death. However, it's important to note that while the researchers found fleas capable of transmitting plague, they didn't find the bacteria that causes the plague in the fleas or rats.

"If these rats carry fleas that could transmit the plague to people, then the pathogen itself is the only piece missing from the transmission cycle," study author Matthew Frye, an urban entomologist at Cornell University in Ithaca, N.Y., said in a university news release.

In the United States, the plague is found among ground squirrels, prairie dogs and the fleas they carry. About 10 people are infected each year, according to the researchers. However, they said plague is more common in some other parts of the world.

The researchers did find that Oriental rat fleas in New York City carry several species of Bartonella bacteria. This bacteria can cause a wide range of health problems, some of them severe, according to study co-author Cadhla Firth, a research scientist at Columbia University's Center for Infection and Immunity in New York City.

The study is the first of its kind since the 1920s, according to the researchers. Findings from the study were published March 2 in the Journal of Medical Entomology.

The research suggests that public health officials need to closely monitor city rats and the fleas they carry, Frye said. He also urged everyone to take steps to control rat populations.

"Removing food and water and preventing access to shelter are key to knocking back rodent infestations," he said. Good sanitation is another important method of control.

More information

The U.S. Centers for Disease Control and Prevention has more about plague.