STATEN ISLAND, N.Y. -- Staten Island’s booming deer population is carrying hundreds of the recently discovered Asian longhorned tick -- an invasive species researchers say could be a threat to the borough.

At least 855 Asian longhorned ticks -- including adult, nymph and larvae life stages -- were removed from just 16 white-tailed deer on Staten Island last summer.

The species is considered a threat to Staten Island because it can quickly grow in numbers. A single female tick can produce up to 2,000 eggs at a time without mating, according to the Centers for Disease Control (CDC). As a result, hundreds to thousands of ticks can be found on a single animal, person or in the environment.

Researchers from Columbia University have been surveying Staten Island the last two summers to learn more about the borough’s rise in ticks and Lyme disease. The researchers told the Advance last September that many of the deer they examined carried the Asian longhorned tick.

The researchers released their findings in a study, which was published in the April issue of the Emerging Infectious Diseases journal, detailing concerns of the invasive tick’s rapid emergence because it can reproduce asexually, feed on a wide range of domestic and wildlife hosts and can handle a wide range of environmental temperatures.

The graphic below shows the number of ticks removed from deer on Staten Island in August 2018.

The number of ticks removed from deer on Staten Island during August 2018. (Courtesy of Columbia University researchers)

From Aug. 5 to 21, ticks were removed from deer found in four forest and grassy locations on Staten Island: the College of Staten Island, Willowbrook; Clay Pit Ponds State Park Reserve, Charleston; Mount Loretto State Forest, Pleasant Plains; Freshkills Park, Travis.

The graphic below shows the total amount of Asian longhorned ticks found in each location.

Researchers anesthetized the male white-tailed deer and groomed them for ticks. They checked the deer’s antlers, ears/head, front legs, hind legs and body for ticks.

Each animal was screened for 15 minutes to minimize time spent under anesthesia. Ticks were removed with forceps and stored in 100 percent ethanol for future identification.

Researchers only found ticks on deer, not mice or bird species. The findings indicate that immature stages of these ticks may feed exclusively on white-tailed deer or unsampled medium-sized animals, according to the study.

The graphic below shows the amount of Asian longhorned ticks removed from deer by life stage in each location. A high proportion of larvae was found on deer because samplings were collected during peak larval activity, the study said.

RISE IN TICKS, LYME DISEASE

Columbia University researchers said they believe the population boom of white-tailed deer on Staten Island is a main contributor to the growing number of ticks and Lyme disease cases on the borough.

Centers for Disease Control and Prevention (CDC) data shows that the Island saw a 250 percent rise in Lyme disease cases from 2012 (35 cases) to 2016 (123 cases). That’s the sharpest jump in Lyme disease cases in the five boroughs.

To battle rising Lyme disease numbers, Mayor Bill de Blasio announced last summer that the city would increase spending by $600,000 annually to fight ticks on Staten Island.

Efforts would include stepping up tick surveillance at city parks and doubling the number of surveillance sites on Staten Island from 14 to 28. The main focus would be disinfecting mice, despite experts saying the rise in Lyme disease and ticks is linked to the growing deer population.

To curb the deer population, the city spent $4.1 million on a three-year deer vasectomy program that came to an end in January. In February, the city said it was looking to spent another $2.5 million for five more years of vasectomies.

The Parks Department told the Advance at the time it was looking to award a contract to continue the program.

TICK FIRST SPOTTED ON STATEN ISLAND

The first of the Asian longhorned tick species spotted in New York City was found in the southernmost section of Staten Island, according to the city Department of Health. It is normally found in areas of east Asia, Japan, Australia and New Zealand.

Researchers from TickEncounter Resource Center at the University of Rhode Island also found the invasive species in Tottenville’s Conference House Park last August.

The CDC reported that no harmful germs have been found yet in the ticks collected in the United States. But the agency is still urging caution about the tick’s potential to spread disease. In other countries, bites from these ticks can make people and animals seriously ill.

Staten Islanders should continue to follow procedures to prevent tick bites and tick-borne diseases, and use effective tick-repellent products.

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