Past Critical Issue Projects

Funded in 2022

The Asian longhorned tick (ALT, Haemaphysalis longicornis) from East Asia is a serious pest of livestock. Since its formal discovery in the United States in 2017, this tick has spread from New Jersey to 16 other states, primarily because an adult female can lay more than 2,000 eggs via asexual reproduction, leading to rapidly growing populations and large infestations per host. To date, ALT life-stages have been found on at least 26 species, including humans, livestock, pets, and wildlife, the latter of which could easily spread ALTs to distant areas. In its introduced range in other countries, ALT causes extensive livestock infestations, leading to low production, hide damage, and even death from severe blood loss. ALT also transmits infectious diseases, such as theileriosis, which can be fatal, as demonstrated recently in Virginia, where several cattle deaths were attributed to theileriosis transmitted by ALTs. However, ALT also transmits human diseases, including severe fever with thrombocytopenia syndrome, which can be fatal. There is also substantial concern that ALTs will pick up native pathogens, such as the agents for Lyme disease and Rocky Mountain spotted fever, thereby becoming a new vector for those diseases. Although ALT has yet to be implicated in human disease within the U.S., health officials suspect it is only a matter of time.

ALT has recently been reported in southeastern Ohio and habitat suitability models predict that it will spread further westwards into the North Central region, where we currently have very little information on the ecology of ALT and the epidemiology of associated pathogens. Our goal with this study is to employ Ohio as a model for the North Central region, to inform IPM programs and evaluate infestation risk to livestock through characterizing ALT ecology, including phenology, density, and preferences for wildlife host and habitat type. In addition, we will describe the epidemiology of ALT-associated pathogens to assess risks to livestock health and occupational safety of producers, a workforce that has already been weakened by the current pandemic. We propose to conduct active surveillance at an established high risk site within Ohio through systematic, standardized sampling of the local environment and wildlife hosts from April to October 2022. ALTs will be tested for the pathogens responsible for theileriosis, Lyme disease and Rocky Mountain spotted fever, using molecular tools to evaluate disease risk. Although this will be a short-term project, it will have large-scale benefits for animal health, occupational safety, and the economic security of the regional livestock industry.

Objectives

• Characterize the ecology of the invasive Asian longhorned tick (ALT) through active surveillance of the environment and wildlife hosts to evaluate infestation risk to livestock.

• Describe the epidemiology of ALT-associated pathogens through testing for their presence in ticks from the environment and wildlife to assess disease risks to livestock and producers.