It’s time to be on the lookout for the Asian longhorned tick (ATL). While this tick is native to East Asia, it is spreading across the United States and has come as far east as Arkansas and as far north as New York. First discovered in the U.S. in 2017, it has been found in Arkansas, Connecticut, Delaware, Kentucky, Maryland, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Virginia, and West Virginia. The United States Department of Agriculture’s Animal and Plant Health Inspection Service currently maintains a map of the tick’s spread.
According to USDA, other countries sometimes refer to Asian longhorned ticks are also called bush ticks, cattle ticks, or scrub ticks. USDA warns they are known to carry pathogens, which can cause disease and may also cause distress to the host from their feeding in large numbers. For example, a dairy cow may have a 25% decrease in milk production after becoming a host.
“Native ticks are known to carry blood borne diseases such as Anaplasmosis,” said Grant Dewell, associate professor and extension beef veterinarian at Iowa State University. “The Asian longhorned tick could potentially transmit these diseases once exposed, as well as other blood borne diseases that are not common in the U.S.”
The ALT targets livestock and must feed from a host animal at least three times to complete its life cycle. Feeding from multiple hosts provides opportunity for spread of disease. In New Zealand, these ticks are known to spread Theileria orientalis Ikeda, and so far, one similar occurrence has been documented in Virginia. Livestock can die from this disease or even from blood loss due to large numbers of ticks attached.
“Additionally, the sheer number of ticks feeding on individual animals can cause negative impacts on health,” said Dewell. “Producers should be on the lookout for the Asian Longhorn tick and unusual symptoms in livestock.”
A single Asian longhorned tick female can essentially start a new tick population on her own; she can lay up to 2,000 eggs without ever finding a mate. Identifying new infestations and preventing spread is essential.
The ALT resembles the brown dog tick, which can make the ALT easy to miss. The brown dog tick has two spots that resemble eyes near the edge of its body, which are missing from the ALT. USDA said the ATL are light brown in color and are very small, often smaller than a sesame seed.
“They are difficult to detect, given their small size and quick movement. In fact, the adult female is only about the size of a pea when it is full of blood.”