Asian Longhorned Tick

The Asian Longhorned tick (ALT), which was first discovered in the United States in 2017 has now be found in 19 states including Virginia. Currently, there are 38 Virginia counties with established ALT populations. As ALT populations have increased, a concern for the health of livestock in affected areas has increased as well. ALT is a vector for the parasite Theileria orientalis Ikeda which can cause theileriosis in livestock, including cattle.

South Carolina public health and livestock officials have recently identified a large population of Asian longhorned ticks infesting a pasture at a cattle farm in York County. This invasive species of tick is not commonly found in the United States, and bites from these ticks have caused illnesses in people, animals and livestock in other countries. As of June 2022, the U.S. Department of Agriculture (USDA) reports Asian longhorned ticks were first identified in the United States in 2010 and have since been found in 17 states. In South Carolina, a small number of these ticks were identified in 2020 on shelter dogs in Lancaster and Pickens counties.

To help state officials learn more about the prevalence of Asian longhorned ticks in South Carolina, residents are asked to carefully submit ticks suspected to be Asian longhorned ticks for confirmatory identification. This surveillance will help determine tick species presence, distribution, seasonality, and potential tick-borne disease risks.

The Centers for Disease Control and Prevention is working with public health, agricultural, and academic experts to understand the possible threat posed by the spread of the Asian longhorned tick (Haemaphysalis longicornis) in several U.S. states since its discovery in 2017, according to today’s Morbidity and Mortality Weekly Report. "The full public health and agricultural impact of this tick discovery and spread is unknown," said Ben Beard, Ph.D., deputy director of CDC's Division of Vector-Borne Diseases. "In other parts of the world, the Asian longhorned tick can transmit many types of pathogens common in the United States. We are concerned that this tick, which can cause massive infestations on animals, on people, and in the environment, is spreading in the United States."

Ticks may not seem dangerous, but they can cause disease and even death in livestock and pets. There are hundreds of tick species in the world, about 10 percent of these species are found in the United States. Now there’s one more to watch out for. In 2017, the U.S. Department of Agriculture (USDA) confirmed the presence of the Asian longhorned tick (Haemaphysalis longicornis). It probably arrived in the United States in or before 2010. Exactly how or when is unknown, but one thing is certain: it may have entered on domestic pets, horses, livestock or people. While we know the impact of this tick in other parts of the world, we are still studying how they may affect U.S. agriculture, and our environment.
See also: APHIS Interactive Maps to explore plant and animal health or wildlife damage management data and an index of APHIS Maps