Haemaphysalis longicornis, the Asian longhorned tick, longhorned tick, bush tick, Asian tick, or cattle tick, is a parasiticarachnid belonging to the tick family Ixodidae. The Asian longhorned tick is a known livestock pest, especially in New Zealand, and can transmit a disease called theileriosis to cattle but not to humans. However, the tick has been associated with several other tickborne diseases in humans. An unfed female is typically 2.0–2.6 mm long and 1.5–1.8 mm wide, and grows to 9.8 mm long and 8.2 mm wide with engorgement. Distinguishing a specimen from other members of the genus Haemaphysalis requires microscopic examination of minor physical characteristics.
Geographic distribution
The Asian longhorned tick is native to temperate areas of East and Central Asia, including China, Korea, and Japan, as well as Pacific islands including Australia, New Zealand, Fiji, and Hawaii, to name a few. The species was not known to be present on the mainland United States until 9 November 2017, when it was first discovered on a sheep farm in Hunterdon County, New Jersey, although it had been intercepted at U.S. ports on import animals and materials at least a dozen times. The Asian longhorned tick has been found in nine states, including New Jersey, Virginia, West Virginia, North Carolina, Pennsylvania, New York, Arkansas, Maryland, and most recently, Connecticut. Attempts to eradicate the species from New Jersey failed; the tick successfully overwintered and has since become established in the state as an invasive species. The tick may have been present in the eastern US for several years, but only recently detected.
Biology
The seasonal feeding and reproductive cycle resembles that of other ticks. The tick can reproduce sexually or by an asexual process called parthenogenesis. The latter exist in northern Japan and Russia, whereas the former exist in southern Japan, southern Korea and southern parts of the former Soviet Union. An aneuploid race capable of both sexual and asexual reproduction capability exists in China. Unfed ticks can survive for close to a year, nymphs and adult females the longest, depending on temperature and humidity.
Host
The Asian longhorned tick parasitizesmammals and birds. It spreads quickly in farm animals such as cattle, horses, sheep, pigs, and chickens. Natural infestations have been found on wild animals like bear, deer, foxes and hares, small mammals like ferrets and rats, and birds. It has also been found on cats, dogs, and humans. It is believed to migrate by parasitizing birds, which carry it to new areas.
