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Invasive Tick Persists in New Jersey

Haemaphysalis longicornis

In the summer of 2017, specimens of an “unusual-looking” tick were reported to public health officials in New Jersey, and they were later determined to be a species, Haemaphysalis longicornis, from the other side of the world. No established population of the species, native to Asia, has ever been previously documented in the United States. In April 2018, surveillance at the site found that the species had successfully overwintered, as additional specimens were found at the location once again. Pictured above are engorged (left) and partially engorged (middle) adult females and an engorged larva (right). Scale at top is in millimeters. (Photo credit: James L. Occi, Rutgers University)

In February, Entomology Today shared a report from the Journal of Medical Entomology detailing the first-ever appearance of the tick species Haemaphysalis longicornis within North American borders. The tick, native to Asia, was found when an infestation was reported in summer 2017 on a rural property in Hunterdon County, New Jersey.

By November, researchers and public health officials at the Hunterdon County Division of Health, the New Jersey Division of Fish and Wildlife, and the Tick-Borne Disease Laboratory at Rutgers University were able to tamp down the infestation, but they noted they couldn’t be sure if the H. longicornis had been eradicated until the spring, when any remaining overwintering ticks would emerge.

Last Friday, the news came: Haemaphysalis longicornis ticks had indeed overwintered and were found on the property once again in mid-April. The New Jersey Division of Fish and Wildlife (NJDFW) announced that ticks collected from the property this month were confirmed to be Haemaphysalis longicornis by the National Veterinary Services Laboratory.

Importantly, NJDFW notes that “Tests on the exotic tick in November failed to reveal any tick-borne diseases.” Nonetheless, work is already underway to contain and possibly eliminate the H. longicornis population in New Jersey: “Surveillance in wildlife and livestock species will continue throughout the year. State and USDA employees will be working with the public to determine if the tick has spread to new areas and to educate the public about protecting livestock and pets from this pest. Questionnaires will be distributed to property owners within a 3-kilometer radius of the index property to gather pertinent information vital to the investigation.”

A complicating factor in fighting H. longicornis is its capability for parthenogenesis—i.e., reproduction without fertilization, in which females produce offspring that are (roughly) clones of herself. Andrea M. Egizi, Ph.D., research scientist at the Tick-Borne Disease Laboratory at Rutgers University, told Entomology Today in February that “there are only a couple species in the world that are known to exhibit this trait, and H. longicornis is one of them.”

It remains unknown how the invasive tick arrived in New Jersey. NJDFW describes Haemaphysalis longicornis, in places known as the bush tick or longhorned tick, as a “non-descript, brown colored tick with both males and females able to feed.” It asks New Jersey residents to report unusual ticks on livestock or wildlife to the state veterinarian or to NJDFW Bureau of Wildlife Management.

Haemaphysalis longicornis provides yet another example of the challenge of preventing, detecting, and managing invasive insect and arthropod species—one of the three primary concerns identified in the Grand Challenge Agenda for Entomology initiated by the insect science community in 2016. In November 2018, invasive species will be the focus of a Grand Challenges summit hosted by the Entomological Society of America in conjunction with Entomology 2018, the Joint Annual Meeting of the Entomological Societies of America, Canada, and British Columbia, in Vancouver.

Update (April 26, 2018): Per the New Jersey Department of Agriculture, Haemaphysalis longicornis has been confirmed in Union County, New Jersey, as well.

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New Jersey Department of Agriculture

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