A species of tick native to Southeast Asia has somehow found its way to the United States and has survived the winter, making it likely a permanent resident. The New Jersey Department of Agriculture first announced the discovery of the East Asian or Longhorned tick at a farm in the state back in the fall, and authorities monitored the ticks through the winter.

The National Veterinary Services Laboratory confirmed the finding that the ticks had survived back on April 17 and were now established in New Jersey. A farmer discovered thousands of the ticks on a sheep as it was being sheared, prompting authorities to get involved.

Authorities are not sure how the tick got here, as the Longhorned tick is native to Southeast Asia and the sheep in question had not traveled out of the country, and rarely even traveled out of the New Jersey county in which it resides. While the Longhorned tick can carry deadly diseases, these particular ticks were not carrying any.

“Following initial identification by the Center for Vector Biology at Rutgers University and the Hunterdon County Department of Health, the National Veterinary Services Laboratory (NVSL) in Ames, Iowa confirmed on November 9, 2017 the finding of an exotic East Asian tick (Haemaphysalis longicornis), also known as the Longhorned tick or bush tick, on a farm in Hunterdon County. Until that time, this tick was not known to exist in the U.S. How it arrived in New Jersey remains a mystery,” reads a statement from the department.