Computer-based model could mitigate cattle fever tick outbreaks

Since the early 1900s, eradicating cattle fever ticks has challenged surveillance and quarantine programs designed to protect the U.S. and Texas cattle industry.

Over the decades, scientists and specialists in state and federal regulatory programs overseeing the U.S. Cattle Fever Tick Eradication Program have developed datasets that track a detailed history of detecting and eliminating cattle fever ticks.

Now, a team of Texas A&M AgriLife researchers is assimilating this information into an interactive, computer-based tool to identify ever-changing risks to prevent or mitigate cattle fever tick infestations.

The three-year project, Agricultural Biosecurity: Harnessing Data Fusion to Meet Emerging Challenges to Cattle Fever Tick Eradication in a Changing World, has received a $600,000 grant from the U.S. Department of Agriculture National Institute of Food and Agriculture, Agricultural Biosecurity Program and is funded by the Agriculture and Food Research Initiative, the nation’s leading competitive grants program for agricultural sciences.

The cattle fever tick team

Texas A&M AgriLife Research project investigators are Pete Teel, Ph.D., Regents Professor, and Taylor Donaldson, Ph.D., assistant research scientist, both in the  Department of Entomology; and Rose Wang, Ph.D., senior research scientist, and William Grant, Ph.D., professor, both in the  Department of Ecology and Conservation Biology.

“The cattle fever tick issue is a constant challenge for Texas,” Teel said.  “It has a considerable history related to the development, security and sustainability of the cattle industry, and not just in the U.S. because of our international boundary with Mexico.”

Other researchers on the team from Texas A&M are Doug Tolleson, Ph.D., professor, Department of Rangeland, Wildlife and Fisheries and director of the Sonora Research Station; David Anderson, Ph.D., Texas A&M AgriLife Extension Service economist and professor, Department of Agricultural Economics. Research collaborators from the USDA Agricultural Research Service, ARS, are Kimberly Lohmeyer, Ph.D., director, Knipling-Bushland U.S. Livestock Insects Research Laboratory, Kerrville; Donald Thomas, Ph.D., research scientist, Cattle Fever Tick Research Laboratory, Edinburg; and Kennan Oyen, Ph.D., research scientist, Animal Disease Research Unit, Pullman, Washington.

The advisory group includes representatives from the USDA Animal and Plant Health Inspection Service, APHIS, Veterinary Services, the Texas Animal Health Commission and the regulatory agencies in charge of the U.S. Cattle Fever Tick Eradication Program.

Cattle tick fever: a long history of challenges

Only two species of cattle fever ticks, Rhipicephalus annulatus and Rhipicephalus microplus, can transmit the pathogens that cause the highly fatal cattle disease, bovine babesiosis, or Texas cattle fever, Teel said.

“There are no drugs or vaccines to protect cattle from this disease, so we rely upon eliminating the vectors to prevent this problem,” Teel said. “The best disease control is to prevent the tick vectors from reestablishing in the U.S. from Mexico, where both the ticks and disease pathogens remain endemic. At risk are U.S. cattle that are immunologically susceptible to infection through the bite of cattle fever ticks.”

Teel said these ticks and the pathogens they transmit were once distributed throughout 13 southern states and southern California. In 1906, the U.S. Cattle Fever Tick Eradication Program was developed to eradicate them. By 1943, the USDA declared the ticks were eradicated in the U.S., except for a zone on the Texas-Mexico border. A permanent quarantine zone inside Texas along the Rio Grande was established to intercept infested animals and ticks that might come across from Mexico.

In Texas, USDA-APHIS operates the eradication program within the permanent quarantine zone, collaborating with the Texas Animal Health Commission and other state and federal agencies outside the permanent zone for inspection, quarantine and other eradication efforts. USDA-APHIS estimates the annual economic benefit of the eradication program to the U.S. cattle industry is more than $1 billion.

Harnessing data fusion to assess risk projections

Both tick species and pathogens are still endemic in Mexico. Teel said the problem remains and has become more complicated in Texas because of several challenges. There have been land use and population changes, and increased resistance to acaricides, the pesticides used to control ticks. Also, wildlife hosts such as white-tailed deer and nilgai antelope can spread ticks to a more extensive range because they are not confined within fence lines like cattle.

The research project uses these challenges as scenarios for risk analysis with data fusion, which integrates multiple data sources to produce information relevant to cattle fever tick eradication.

Teel said the research project’s goal is to combine disparate datasets from the U.S. Cattle Fever Tick Eradication Program to create a computer-based platform that better analyzes and identifies factors conducive for the spread of cattle fever ticks.

Some of these factors are changes in climate and weather patterns, vegetation, land use and fragmentation, and the risk of evolving strains of cattle fever ticks resistant to acaricides.

Some datasets have analytical models going back 65 years; others include real-time weather data, GPS mapping and outbreak investigations.

Another project goal is to develop an interactive tool that regulatory agencies’ staff can use in the field on devices such as a tablet, phone or computer to access the new computer platform.

“Texas has developed different technologies and databases that track the history of these infestations and the interactions of how incidents occurred,” Teel said. “There’s a lot to be learned from the relationship of these datasets if they can be evaluated in conjunction with each other. Then we can develop risk assessments to be proactive about stopping tick incursions as quickly as possible.”