Soft tick study adds new wrinkle to ASF preparedness in Texas

A Texas A&M-led study is sharpening one of the more difficult questions in African swine fever preparedness: what happens if the virus reaches a place where native soft ticks could help it persist. The researchers mapped the likely range of Ornithodoros turicata, a soft tick native to Texas and the southwestern United States, and found suitable habitat across most of Texas. Their conclusion is less about immediate outbreak risk than about response complexity: if ASF were introduced, a local tick reservoir could make elimination harder. (pmc.ncbi.nlm.nih.gov)

That matters because ASF remains one of the most consequential foreign animal disease threats for U.S. swine. USDA APHIS says the virus has never been found in the United States, but it remains a major preparedness focus, particularly after its reappearance in the Americas in the Dominican Republic in July 2021 and later in Haiti. APHIS describes ASF as a contagious, deadly disease of domestic and feral swine with no treatment or approved vaccine for use in the United States, meaning outbreak control would rely heavily on prevention, rapid detection, movement restrictions, and depopulation. (aphis.usda.gov)

The Texas study builds on that preparedness framework by focusing on a native vector that may be easy to overlook. According to the Texas A&M announcement and the underlying paper, the team combined historical occurrence records with new field collections and ecological niche modeling to identify where O. turicata is most likely to survive. They collected 1,649 ticks from 15 Texas counties, and the model pointed to broad areas of suitable habitat in the state. The researchers' concern is that soft ticks can live for long periods in burrows, dens, caves, and crevices, creating the possibility that ASF could persist in the environment even after infected pigs are removed. (pmc.ncbi.nlm.nih.gov)

That concern is consistent with existing federal planning. In APHIS' ASF Response Plan, the agency notes that while the major Old World tick species historically tied to ASF persistence are not present in the United States, three U.S.-endemic Ornithodoros species — including O. turicata — have experimentally been shown to become infected with ASFV and transmit it to swine. The same plan says APHIS and state officials would need to determine whether vectors are present in a control area and whether vector control measures are necessary or cost-effective. In other words, the Texas mapping study doesn't rewrite response policy, but it gives that policy a more concrete geographic frame. (aphis.usda.gov)

The broader scientific literature points the same way. Prior U.S. risk assessments have identified parts of Texas and other southern states as potential hotspots where competent Ornithodoros ticks, feral swine, and domestic swine could overlap. Researchers have also reported that O. turicata occupies microhabitats such as burrows, crevices, and caves, and that contact with invasive wild pigs is biologically plausible, even if not routine. WOAH likewise notes that ASF epidemiology changes depending on whether competent soft tick vectors and wild pigs are present. (pmc.ncbi.nlm.nih.gov)

Texas A&M framed the work as preparedness research, not a warning that ASF is imminent. Meriam Saleh, one of the researchers, said in the university release that introduction may not be probable, but is possible and serious enough to justify attention. The university also emphasized the economic stakes, noting the scale of the U.S. pork sector and the trade consequences that follow any ASF detection. I wasn't able to verify independent expert reaction beyond the university's own commentary, but the federal and international guidance aligns with the paper's core message that vectors could complicate surveillance and eradication if the virus were introduced. (today.tamu.edu)

Why it matters: For veterinary professionals, the practical takeaway is that ASF preparedness in Texas may need to account for more than pig-to-pig transmission. In areas with outdoor swine, feral swine pressure, or habitat favorable to O. turicata, response planning may need to include vector awareness, environmental assessment, and closer coordination with state and federal animal health officials. This is especially relevant because APHIS surveillance already prioritizes outdoor pigs with potential feral swine exposure, and because a nidicolous, long-lived tick reservoir could complicate decisions about when a premises or region is truly clear. (aphis.usda.gov)

What to watch: Expect follow-on work around targeted surveillance, host association studies, and operational planning for how tick habitat data might be incorporated into ASF control zones, feral swine response, and post-depopulation decision-making if the United States ever faces a detection. (pmc.ncbi.nlm.nih.gov)