Oriental Rat Fleas Found on NYC Rats

Annapolis, MD: March 3, 2015 -- In the first study of its kind since the 1920s, rats in New York City were found to carry Oriental rat fleas (Xenopsylla cheopis), which are capable of transmitting pathogens that cause bubonic plague, also known as the Black Death. The study is published in the Journal of Medical Entomology.

Researchers collected more than 6,500 fleas, lice, and mites from 133 Norway rats (Rattus norvegicus) in NYC and found more than 500 Oriental rat fleas.

“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,” said lead author Matthew Frye, an urban entomologist with Cornell University’s New York State Integrated Pest Management Program.

In the U.S., the plague pathogen is found in the American Southwest among ground squirrels, prairie dogs, and the fleas they harbor, infecting roughly 10 people each year. In other parts of the world, the incidence of plague is higher.

In addition to the plague, the researchers also used molecular screening methods to find several species of Bartonella bacteria, which can also spread various diseases.

“These pathogens can cause a wide range of clinical syndromes, some severe,” said co-author Cadhla Firth, a research scientist at Columbia University’s Center for Infection and Immunity Firth.

The study’s results suggest that public health officials should closely monitor city rats and the fleas that call them home, and that citizens should use sanitary practices to protect themselves.

“Removing food and water and preventing access to shelter are key to knocking back rodent infestations,” Dr. Frye said. “Our identification of Bartonella spp. from fleas, and the detection of multiple human pathogens from Norway rats reported elsewhere, indicates a risk of disease exposure for humans that could be addressed with rodent management efforts.”

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The Journal of Medical Entomology published by the Entomological Society of America, the largest organization in the world serving the professional and scientific needs of entomologists and people in related disciplines. Founded in 1889, ESA today has nearly 7,000 members affiliated with educational institutions, health agencies, private industry, and government. Members are researchers, teachers, extension service personnel, administrators, marketing representatives, research technicians, consultants, students, and hobbyists. For more information, visit http://www.entsoc.org.