An exotic tick species that mysteriously appeared in North America has now been spotted in seven New Jersey counties.

And it turns out the tick's been around here for much longer than experts had originally thought.

The Asian longhorned tick was first discovered last summer on a sheep in Hunterdon County. Before then, it had not been known to exist in the United States. How the species arrived in New Jersey is still unknown.

But while that was the first official detection, the Asian longhorned tick has had a New Jersey presence since 2013, according to Manoel Tamassia, director of the state Department of Agriculture's Division of Animal Health. In that year, he said, it was was found on a dog in Union County — researchers had misclassified the tick as another species.

And New Jersey was not home to the first sighting of this species. Analyses of archived records determined the tick was found on a white-tailed deer in Virginia in 2010. That tick, too, was misclassified.

Presence of the tick species has also been confirmed in Connecticut, Maryland, Pennsylvania, New York, North Carolina, West Virginia and Arkansas.

Most recently in New Jersey, the Asian longhorned tick was found on a dog at a residence in Somerset County. Earlier findings of the tick species have been confirmed in Bergen, Hunterdon, Union, Middlesex, Mercer and Monmouth counties.

"The northwest part of the state — we have not identified a tick. Neither have we identified a tick south of Mercer and Monmouth," Tamassia said.

Tamassia said it's "wishful thinking" to believe the tick is not present elsewhere in the state.

Asian longhorned ticks have been known to spread diseases in other countries, but those collected in New Jersey have tested negative for various human and animal pathogens.

Tamassia said the public has played an important role in helping officials identify where the species of tick may be located, and the Department is encouraging residents to "submit" the ticks they find on themselves, their pets or livestock.

Sign up for the WPG Talk Radio 104.1 Newsletter

Get South Jersey news and information e-mailed to you every week.