Scientists say tick population exploding across Long Island

Scientists predict a record year for ticks on Long Island and the rest of the Northeast, and they are attributing the surge to a confluence of phenomena: climate, acorns and mice.

New York has the highest number of confirmed Lyme disease cases nationwide, according to the national Centers for Disease Control and Prevention, which has cataloged more than 95,000 Lyme infections in the state since 1986. Lyme disease remains the most common tick-borne infection nationwide, and Suffolk County has been a hot zone of the ailment for decades, experts said.

“In the Northeast, and possibly across the northern United States, 2017 is gearing up to be a good season for ticks, which is bad for us,” said Jody Gangloff-Kaufmann, an urban entomologist with the Cornell Cooperative Extension in Babylon.

Distant cousins of spiders and crabs, with powerful pincers and mouthparts, ticks have eight legs as adults and adeptly use the appendages to cling to blades of grass or dig into human skin. A tick’s bite often is painless because of a potent anesthetic it injects. It can stay attached for as long as seven days.

Concern about Lyme disease this year is only one chapter of the unfolding tick story.

The creatures can carry a veritable zoo of microbes in their minuscule bodies, and doctors now are certain that ticks can transmit more than one kind of pathogen in a single attachment and feeding.

Bacterial, viral and protozoal pathogens are known to inhabit individual ticks. Some tick-transmitted pathogens can be deadly: An infant in Connecticut contracted the extremely rare Powassan virus last fall but survived and is recovering. That virus has been found on Long Island.

“We definitely know that people can be co-infected,” said Dr. Saul Hymes, director of the Pediatric Lyme and Tick-Borne Disease Center at Stony Brook Children’s Hospital. After identifying specific tick-transmitted agents, patients are treated for more than one infection, he said.

Scientists pointed to a perfect storm underlying this spring’s tick onslaught: a shorter, milder winter, likely the result of climate change; oak trees that produced a staggering number of acorns last fall; and legions of white-footed mice. The rodents dine voraciously on acorns, and mice are the main hosts of ticks.

With more mice and ticks on the move, the risk for human exposure intensifies, Gangloff-Kaufmann said.

For weeks, she and other scientists who specialize in the study of ticks have been conducting “dragging” exercises, the practice of pulling a white flannel flag across brushy or grassy areas. Ticks adhere to the fabric, enabling entomologists to pluck them off for study.

Gangloff-Kaufmann has conducted draggings at a variety of sites where tick bites have been reported, including school grounds. Ticks can bite even in their early nymph stage, while still the size of a poppy seed.

Mani Lejeune, a veterinary parasitologist at Cornell University’s College of Veterinary Medicine in Ithaca, said scientific analysis of ticks is crucial. It reveals which species are most active in an area, he said, adding, “Accurate identification of ticks is important to determine what microbes to test for.”

About 16 different species have been identified in New York. Not all ticks are carriers of infectious agents, but a resident’s simple inspection of a tick would not reveal whether it is infectious.

“There are several species of ticks that carry human and animal diseases,” Gangloff-Kaufmann said.

Three key species often are responsible for tick-related infections on the Island, she said — Ixodes scapularis, the blacklegged tick, commonly called the deer tick; Amblyomma americanum, or the Lone Star tick; and Dermacentor variabilis, the American dog tick, or wood tick.

The best-known of the trio is the blacklegged tick. It prefers moist woodland areas and is a notorious carrier of the bacterium Borrelia burgdorferi, which causes Lyme disease.

Lyme, first identified 41 years ago in the Connecticut town for which it is named, produces a constellation of symptoms, with a rash usually an initial sign of infection, doctors said.

Although Lyme disease can be successfully treated with antibiotics, it has been known to morph into advanced symptoms in some patients, producing arthritic pain and neurological problems that persist long after initial exposure. Doctors suspect a potent autoimmune response — the body attacking itself — in the aftermath of a powerful assault on Lyme disease bacteria.

Nationally, about 300,000 cases of Lyme disease are diagnosed annually, with a majority of cases clustered in 14 states, including New York. Some doctors believe there probably are more cases than those tallied by public health agencies.

“I think Lyme is vastly underreported,” said Dr. Patricia DeLaMora, a specialist in pediatric infectious diseases at NewYork-Presbyterian/Weill Cornell Medical Center in Manhattan. Some people may have mild cases without knowing it, she said.

Dr. Benjamin Luft, an infectious disease specialist at Stony Brook University School of Medicine, said the lack of a Lyme vaccine is a problem that encumbers medical science. Doctors have no preventive measure to offer residents of tick-endemic regions.

He and his Stony Brook colleagues have developed a vaccine, but it is not yet ready for federal approval.

Lyme isn’t the only pathogen carried by blacklegged ticks.

Hymes, at Stony Brook Children’s Hospital, said the arachnid also carries a host of other infectious agents — babesia, anaplasma and Borrelia miyamotoi, a corkscrew-shaped bacterium identified in recent years as the cause of a relapsing fever.

Babesia are protozoa — or parasitic — infectious agents that zero in on red blood cells, similar to the way that a malaria parasite invades the same cells, he said.

Another infection, called anaplasmosis, is caused by the bacterium Anaplasma phagocytophilium. It can trigger aches, fever, chills and confusion. About 500 cases are reported in New York annually, according to the state Department of Health.

Another pathogen-carrying tick identified on Long Island is the Lone Star, so named because of the white starlike patch on the female’s back, Gangloff-Kaufmann said.

Migrants from southern states, Lone Star ticks have proliferated on the Island and now are well-adapted here, thriving “in hotter, drier places, such as lawns,” she said.

These ticks can carry bacteria that transmit ehrlichiosis, a disease that also is typified by flulike symptoms, body aches and fever. The infection responds to antibiotic treatment.

In addition, Lone Stars can transmit bacteria that cause tularemia, a rare disease that also can be treated with antibiotics. Tularemia, which can be transmitted from animals to humans, can cause skin ulcerations and, in its most serious form, can cause respiratory illness and fatalities.

A third tick seen on Long Island is the American dog tick, or wood tick, which transmits the bacterial infections Rocky Mountain spotted fever and tularemia, Gangloff-Kaufmann said.

Given the lack of a vaccine or an effective method of eliminating ticks, she offered her best scientific prescription for staying clear of tick-transmitted infections.

“Our best advice for avoiding tick-borne illnesses is to avoid ticks,” she said. “I know that may be easier said than done.”