CDC: Illnesses caused by ticks, mosquitoes, fleas have surged

Illnesses caused by ticks, mosquitoes and fleas have more than tripled nationwide, exceeding 640,000 cases of Lyme disease, West Nile, flea-borne plague and other serious infections from 2004 to 2016, federal officials said Tuesday.

Nine new pathogens carried by vectors — insects that transmit pathogens to humans and animals — have been identified since 2004, and others that are yet-to-be-discovered will likely emerge, health officials at the Centers for Disease Control and Prevention predicted in a new report.

The findings arrive on the heels of a Stony Brook University symposium last month where researchers said this region is in the grip of a Lyme disease epidemic as the tick population continues its explosive growth.

Beyond the Lyme bacterium, ticks on Long Island also harbor the malaria-like parasite known as babesia and the rickettsial bacterium called anaplasma. Mosquitoes — flying hypodermic needles — can carry a range of viruses. Fleas in Western states transmit Yersenia pestis, the bacterium that causes plague.

“Cases of these diseases have more than tripled in the United States and there are several reasons why we are seeing these increases,” Dr. Robert Redfield, the CDC’s director, said at a news briefing Tuesday.

Overall, the CDC data revealed 96,075 infections from ticks, mosquitoes and fleas in 2016 nationwide, compared with 27,388 in 2004. The data were culled from the agency’s National Notifiable Diseases Surveillance System.

The CDC attributes the rising number of infections to warming temperatures nationwide because biting insects thrive in heat. They’re also blaming the surge on “trade and travel,” meaning that insects and their pathogens are arriving in this country via freight and in the blood of travelers themselves. That was the case in 2016 when a majority of U.S. Zika infections were found to be the result of having traveled abroad.

“Many of these diseases are very sensitive to temperature,” said Dr. Lyle Petersen, director of the CDC’s Division of Vector-Borne Diseases, who said ever-increasing temperatures are the reason mosquitoes and ticks are causing more infections.

Outbreaks of mosquito-borne diseases, especially West Nile, tend to occur during heat waves, which also spur the virus to proliferate inside the insect, Petersen said.

Ticks also thrive in warmer temperatures, which also have allowed them to extend their territorial range, he said.

The Lone Star tick, which has been expanding its range throughout Suffolk County, is a native of Southern U.S. states, but shorter winters and longer warm seasons have allowed the tick to firmly establish itself here, Stony Brook experts said last month.

Zika, meanwhile, was the most commonly reported U.S. vector-borne illness in 2016, according to the CDC, with 41,680 cases followed by Lyme disease, with 36,429 cases, almost double the number of Lyme cases in 2004.

While there have been steady reports of about 30,000 to 36,000 Lyme cases reported annually, the actual number is probably about 300,000 Petersen said, noting that Lyme disease is grossly underreported.