Pathogen and host associations of soft ticks collected in South Texas

Authors: MAYS MAESTAS, SARAH - University Of Texas Rio Grande Valley; Maestas, Lauren; KAUFMAN, PHILLIP - Texas A&M University

Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/24/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Soft ticks are capable of transmitting a suite of diseases, known as relapsing fever in the United States, and are potentially able to transmit African Swine Fever virus, a pathogen that could have a devastating effect on the U.S. swine industry if introduced to the U.S. mainland. Much of the tick-borne disease research in the U.S. focuses on hard ticks, and less is known about the ecology of soft ticks. Some soft tick species found in the southern U.S. have a wide host range and may feed on cattle, swine, native and exotic hoofed animals, small mammals, reptiles, and humans. Because the feeding habits of most soft tick species involves taking short, repeated blood-meals that may include multiple host species, pathogen transmission among hosts is a concern both for human and animal health. Sampling was carried out at four locations in south Texas using dry ice traps placed in or near animal burrows and other sheltering cracks and crevasses that may provide refuge for soft ticks. Collected ticks were identified and subsequently screened for the bacterial groups: Rickettsia and Borrelia and for host identification via bloodmeal analysis using conventional PCR and Sanger sequencing to identify pathogen and host to species. Two hundred fifty-six ticks of two species were screened. Borrelia species were identified in three samples. Bloodmeal detections were made in 22 tick specimens, representing eight vertebrate host species. Results demonstrate that the soft tick species detected herein feed on a range of wildlife hosts in south Texas and are associated with agents of human disease.

Technical Abstract: Soft ticks (Family: Argasidae) are vectors of relapsing fever Borrelia in the United States, and are potential vectors of African Swine Fever virus, a pathogen that could have a devastating effect on the U.S. swine industry if introduced to the U.S. mainland. Much of the tick-borne disease research in the U.S. focuses on hard ticks, and less is known about the ecology of soft ticks. Some soft tick species found in the southern U.S. have a wide host range and may feed on cattle, swine, native and exotic ungulates, small mammals, reptiles, and humans. Because the feeding habits of most soft tick species involves taking short, repeated blood-meals that may include multiple host species, pathogen transmission among hosts is a concern both for human and animal health. Sampling was carried out at four locations in south Texas using dry ice traps placed in or near animal burrows and other sheltering cracks and crevasses that may provide refuge for soft ticks. Collected ticks were identified and subsequently screened for Rickettsia and Borrelia species and for host bloodmeal detection using conventional PCR and Sanger sequencing for pathogen and host species identification. Two hundred fifty-six ticks of two Ornithodoros species were screened. Borrelia species were identified in three samples. Bloodmeal detections were made in 22 tick specimens, representing eight vertebrate host species. Results demonstrate that the soft tick species detected herein feed on a range of wildlife hosts in south Texas and are associated with agents of human disease.