Soft ticks could complicate African swine fever response in Texas, study finds

African swine fever virus (ASFV) has never established itself in the United States. But a new Texas A&M University study suggests the country may already have one potential piece of the ecological puzzle: a native soft tick that could potentially complicate efforts to control the virus if it crosses the border.

The study, published in Ecology and Evolution, mapped the geographic range and habitat suitability of Ornithodoros turicata, a soft tick found across much of Texas.¹ Earlier laboratory studies have shown the species can become infected with and transmit ASFV to pigs, though a 2019 review of the evidence found the transmission data limited and called for additional replication.³ The research team behind the new range-modeling study, led by Christopher Butler, PhD, an instructional associate professor of biology at Texas A&M, used climate-based modeling to identify most of Texas—excluding its easternmost counties—as a suitable tick habitat. The model also projected potential northward expansion and identified a highly suitable habitat in southeastern Georgia where the tick has not been documented.¹

"It's on our doorstep. Even though introduction isn't probable, it's possible—and because the consequences are so severe, it warrants serious attention," said Meriam Saleh, PhD, clinical assistant professor in the Department of Veterinary Pathobiology at Texas A&M's College of Veterinary Medicine & Biomedical Sciences and a primary investigator on the study.²

A tick built to outlast an outbreak

ASFV is highly contagious and often fatal in pigs, with no approved vaccine or treatment in the US. The virus does not infect humans, but an outbreak in domestic or feral swine could have major economic consequences. The US pork industry contributes more than $50 billion annually to the country's gross domestic product and supports more than 550,000 jobs.¹

ASFV is currently absent from the US but circulates in parts of Africa, Europe, Asia, and the Caribbean.

What concerns researchers is not only whether ASFV reaches the US, but what could happen after an introduction. Unlike hard ticks, O. turicata feeds briefly, primarily at night, and can survive for years between blood meals.

"These ticks are very sneaky. They feed at night, they can survive for years waiting for another blood meal, and most notably, they can live for 10 years or more," Saleh said.²

That longevity could complicate outbreak control if the ticks were able to acquire and maintain ASFV, potentially allowing the virus to persist after infected pigs were removed. "Even if you depopulate infected pigs, infected ticks could reintroduce the virus when new animals are brought in," Saleh said.²

Dee Ellis, DVM, MS, a veterinarian with Texas A&M AgriLife Research and the Department of Entomology and a co-lead on the study, similarly described the ticks as a potential long-term reservoir for reintroduction of ASFV into feral swine or backyard swine populations.² "The tick would contribute more to persistence than large-scale spread," Saleh said.²

The study also flags a warthog-related concern specific to South Texas. "In parts of South Texas, the presence of free-ranging African warthogs—the natural wildlife reservoir in endemic regions—further elevates concern," according to the release.² Warthogs can carry ASFV without becoming visibly ill. "That's a big concern because warthogs can have the virus and not be sick. That ups the ante," Saleh said.²

Why it matters for surveillance

The study's modeling approach is intended to help direct surveillance toward areas where ticks, potential hosts and suitable environmental conditions overlap.

"A lot of tick surveillance is passive or by chance. By the time you know there's a problem, it's already been happening for months," Saleh said.²

The work was supported by a $1.4 million grant from the US Department of Homeland Security through the Cross-Border Threat Screening and Supply Chain Defense Center of Excellence at Texas A&M.^1,2 For veterinarians working with swine, the study's findings point to the value of understanding where potential vectors and susceptible animal populations overlap before ASFV arrives.

References

1. Butler CJ, Garcia CP, Mendoza AK, et al. Range modeling and surveillance of Ornithodoros turicata ticks: implications for detecting African swine fever virus in the United States. Ecol Evol. Published online December 19, 2025. doi:10.1002/ece3.72738
2. Texas A&M researchers map tick habitat to strengthen African swine fever preparedness. News release. Texas A&M College of Veterinary Medicine & Biomedical Sciences. July 14, 2026. Accessed August 31, 2026. https://vetmed.tamu.edu/news/press-releases/african-swine-fever-soft-tick-texas/
3. Golnar AJ, Martin E, Wormington JD, Kading RC, Teel PD, Hamer SA, Hamer GL. Reviewing the potential vectors and hosts of African swine fever virus transmission in the United States. Vector Borne Zoonotic Dis. 2019;19(7):512-524. doi:10.1089/vbz.2018.2387