A serosurvey for ruminant pestivirus exposure conducted using sera from stray Mexico origin cattle captured crossing into Southern Texas

Authors: Falkenberg, Shollie; BAUERMANN, FERNANDO - Oklahoma State University; Scoles, Glen; BONILLA, DENISE - Animal And Plant Health Inspection Service (APHIS); Dassanayake, Rohana

Submitted to: Frontiers in Veterinary Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/20/2022
Publication Date: 3/15/2022
Citation: Falkenberg, S.M., Bauermann, F., Scoles, G.A., Bonilla, D., Dassanayake, R.P. 2022. A serosurvey for ruminant pestivirus exposure conducted using sera from stray Mexico origin cattle captured crossing into Southern Texas. Frontiers in Veterinary Science. 9. Article 821247. https://doi.org/10.3389/fvets.2022.821247.
DOI: https://doi.org/10.3389/fvets.2022.821247

Interpretive Summary: Stray cattle along the TX/Mexico border pose a potential risk for introduction of pathogens. Current methods of control include collecting these stray cattle that are unaccounted for along the border and testing for some pathogens, but all potential pathogens that pose a risk to the cattle industry are not evaluated. One potential screening method for exposure to potential pathogens is evaluation of serological titers and utilizing comparative serology to determine predominating titers. Data from the current study evaluated titers against three bovine pestiviruses; bovine viral diarrhea virus (BVDV) 1 and 2, and HoBi-like virus. Fifty percent of the cattle tested were sero-positive and titers were highest against BVDV-1. No sample had an antibody titer higher for HoBi-like virus, although 50% of the cattle were sero-negative and suggests a large number of susceptibile animals that are unaccounted for along the border which pose a risk for introduction of novel bovine pestiviruses. This cattle population provides a unique opportunity to evaluate and monitor changes in seroprevalence of economically important cattle diseases affecting the cattle industry.

Technical Abstract: U.S. Department of Agriculture (USDA), Animal Plant Health Inspection Service (APHIS), Cattle Fever Tick Eradication Program (CFTEP) monitor a quarantine zone along the Texas border to prevent the introduction of stray livestock carrying cattle fever ticks entering the U.S. from Mexico. Stray cattle collected by CFTEP are checked for ticks and several infectious disease-causing pathogens, but not for bovine viral diarrhea virus (BVDV). BVDV is one of the most economically impactful viruses affecting U.S. cattle producers. BVDV is present in all parts of the world, but it has been demonstrated that another distantly related pestivirus, HoBi-like virus, can also cause BVD. To date HoBi-like virus has not been detected in the United States, but sporadically detected in South America, Europe, and Asia. The objective of the current study was to evaluate the seroprevalence of pestiviruses, with a specific focus on HoBi-like pestiviruses, in stray cattle. Virus neutralization (VN) assay was used to determine seroprevalence (or antibody titers) of BVDV-1, BVDV-2, and HoBi-like viruses. Approximately 50% (67 of 134) samples were seropositive for pestiviruses, 50% for BVDV-1, 50.7% for BVDV-2 and 50.7% for HoBi-like virus. Due to the antigenic cross-reactivity among Pestiviruses, the comparative antibody against each pestivirus was calculated from all VN-positive samples. Titers were clearly higher against BVDV-1, and only one sample had a titer clearly higher against BVDV-2. No sample had an antibody titer higher for HoBi-like virus, and while this does not prove the absence of HoBi-like virus, it does provide evidence that the prevalence of Hobi-like virus is less predominant than BVDV-1. Additionally, data from these samples provide evidence on the susceptibility of animals that may enter into the US, with approximately 50% of the animals seronegative for bovine pestiviruses. This cattle population provides a unique opportunity to evaluate and monitor changes in seroprevalence of economically important cattle diseases affecting the cattle industry.