Fleas could be carrying diseases to human residents of New York City by hitching rides in the fur of rats, a new study reveals. Some of these tiny insects are even capable of carrying plague pathogens.
Cornell University researchers collected over 6,500 samples of fleas, mites, and lice from 133 rats.
Over 500 Oriental rat fleas were found in the samples. These insects are believed to have been responsible for spreading the bubonic plague through Europe, peaking between 1346 and 1353. Historians traditionally believe rats played host to the fleas, but new research suggests gerbils may have carried the insects.
Rats were examined in the study, because the animals live in such close quarters with human beings, they could represent a path for the illness to spread.
With fleas and rats both present in such large populations in the nation's largest city, the bubonic plague could result in a modern-day Black Death if the pathogen is introduced into the environment. The microorganism is still found in the southwestern United States, where it infects around 10 people each year. There, the fleas that harbor the disease are carried on prairie dogs and ground squirrels. Other areas of the world still see cases of bubonic plague.
Driving rats away from homes is one of the best methods people can use to keep themselves healthy from diseases carried by the rodent-borne fleas. This can often be accomplished by removing food sources and blocking shelter. After ridding a house of rats, it is also vital to eliminate lice, mites, and fleas from the property in order to prevent disease, researchers warn.
"It's not that these parasites can infest our bodies, but they can feed on us while seeking other rats to infest," Matthew Frye, an urban entomologist with the New York State Integrated Pest Management (IPM) Program at Cornell University, said.
Research announced in 2014 on pathogen samples from the same 133 animals showed a wide range of diseases present, some of which could be dangerous to human populations.
The fleas that carry bubonic plague can also pass Bartonella bacteria, which can cause flu-like symptoms in human victims. Although that disease is not fatal, it is already found in New York City, meaning it could spread through the dense urban region more readily than plague, making an outbreak more likely. Both illnesses, however, can be treated with antibiotics, making an epidemic unlikely.
This study was the first investigation of parasites in rats in New York City since the 1920s.
Analysis of the prevalence of disease-carrying fleas on rats in New York City was detailed in the Journal of Medical Entomology.
