Researchers map tick habitat to strengthen African swine fever preparedness

Researchers have mapped the habitat of a tick species found in Texas to better understand its potential role in preventing or spreading African swine fever (ASF) if the virus were to reach the United States. Led by Dr. Meriam Saleh from the Texas A&M College of Veterinary Medicine and Biomedical Sciences, the study, published in the journal Ecology and Evolution, examined the conditions under which Ornithodoros turicata, a soft tick species native to Texas and the southwestern United States, thrives.

Though ASF has not yet been detected in the U.S., it is present in other parts of the world and can cause significant economic damage to the pork industry. The virus is highly contagious among pigs and can be transmitted through contaminated feed, meat, or environments. While the risk of ASF introduction to the U.S. is considered low, even a small chance warrants serious attention due to the virus's severe consequences, including mass pig depopulation, trade restrictions, and billions in economic losses.

The study highlights the unique behavior of O. turicata, which lives inside animal dens and burrows rather than on vegetation and feeds quickly before retreating. These ticks can survive for years without a blood meal and can persist in the environment even after infected animals are removed. This means that if ASF were introduced to pig populations and infected local tick populations, the virus could persist even after the pigs are depopulated.

To assess the risk, the researchers used ecological range modeling to identify suitable habitats for O. turicata in Texas and potentially in southeastern Georgia. They found that most of Texas, except for the eastern portion, is suitable for the tick, and there is potential for northward expansion. The model also highlighted areas in Georgia where the tick has not yet been documented.

The study emphasizes the need for proactive surveillance, particularly along the U.S.-Mexico border and in regions with dense swine populations, to identify where the tick occurs and refine effective sampling methods. Soft ticks are challenging to detect due to their habit of living inside burrows, making traditional surveillance methods less effective.

The findings also stress the importance of considering wild hog populations, as they can serve as amplifying hosts and contribute to the virus's persistence.