June/July 2026 NEBRASKA CATTLEMAN 19 • Ticks do not have to be refrigerated or frozen. • The more ticks submitted, the better since prevalence is not known. • Vials should be sent using ambient temperature packing with absorbent material and in a plastic bag to avoid spillage through the packaging and placed in a rigid box. • Samples can be submitted using our ruminant submission form found by scanning the green QR code, with a test request for Parasite ID. • Mailing labels can be ordered and printed directly from our website. Scan the yellow QR code to learn more. • Samples may be required to be forwarded to the U.S. Department of Agriculture for identification confirmation. Bovine Theileriosis The ALHT is a carrier of Theileria orientalis, a protozoal pathogen that causes the syndrome bovine infectious anemia. There are no approved treatments for these infections, so tick control and biosecurity are essential to disease prevention. NVDC offers multiplex PCR testing for Theileria orientalis and Anaplasma marginale, two common causes of infectious anemia. PCR testing can be conducted on whole-blood samples submitted in EDTA tubes (purple top) or fresh spleen, with pooling available for up to five samples. Theileria orientalis infection promotes the destruction of red blood cells resulting in anemia, which causes decreased oxygen delivery to tissues. As such, the clinical signs associated with bovine theileriosis are nonspecific and variable. Icterus (i.e., jaundice) is one of the more common clinical signs observed in severely affected animals, but most animals show no or very minimal clinical signs. However, increased morbidity and mortality events are commonly reported, particularly in calves and at times of stress such as weaning. Infected animals become lifelong carriers, serving as a reservoir for other ALHT and making iatrogenic transmission to naïve animals possible via needles or other mechanisms that can transfer blood from one animal to another. Bovine theileriosis is a notifiable disease in Nebraska and requires prompt reporting to the Nebraska Department of Agriculture. To date, Theileria orientalis has been detected in specimens from imported feedlot animals at several locations in Nebraska. In each case, the animals originated in states from the southeast United States where the ALHT is well established and bovine theileriosis is very common. The effect of theileriosis on feeder calf health is poorly understood, but the risk of anemia during times of high stress in positive animals may contribute to increased morbidity and/or mortality in the feedyard. According to a recent newsletter, Kansas State Veterinary Diagnostic Laboratory has seen a dramatic increase in percentage of PCR positive detections for Theileria orientalis. The most severe cases also had high respiratory morbidity and mortality in calves. Since the ALHT is not currently established in Nebraska, the risk of disease in native cow-calf herds is likely exceedingly low. However, if the ALHT were to become established in parts of Nebraska in the future, the risk of theileriosis in native animals would increase. Current and Planned Bovine Theileriosis Efforts in Nebraska • University of Nebraska-Lincoln School of Veterinary Medicine and Biomedical Sciences (UNL SVMBS), Extension and other groups are working with stakeholders to communicate and research topics around bovine theileriosis in Nebraska, including management, diagnostic testing and prevention strategies. • SVMBS faculty continue to work to understand current disease status and future risk in Nebraska, including surveillance for vector-borne diseases such as theileriosis in Nebraska in cow-calf and feedlot sectors. If you suspect bovine theileriosis in your animals, contact your herd veterinarian. If you suspect ALHT within Nebraska, contact the Nebraska Department of Agriculture at (402) 4712351. ~NC~ ADDITIONAL RESOURCES Nebraska Department of Agriculture (402) 471-235 Scan the QR code to view NDA’s website Nebraska Veterinary Diagnostic Center (402) 472-1434 • Dustin Loy, DVM, NVDC Director and Veterinary Microbiologist • Matt Hille, DVM, NVDC Pathologist and Extension Specialist • Duan Loy, Ph.D., NVDC Veterinary Microbiologist UNL School of Veterinary Medicine and Biomedical Sciences (402) 472-2952 • Roberto Cortiñas, DVM, Veterinary Parasitologist Nebraska Extension (402) 762-4500 • Brian Vander Ley, DVM, Veterinary Epidemiologist and Extension Specialist • Becky Funk, DVM, Extension Specialist • Lindsay Waechter-Mead, DVM, Extension Educator and Nebraska BQA Director USDA APHIS Scan the QR code to view USDA Aphis website
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