Cattle Fever Tick Eradication Efforts


Refuge Leads the Fight Against the Tick

Laguna Atascosa National Wildlife Refuge is at the forefront of cattle fever tick eradication in Texas. Working in close cooperation with many federal and state partners including U.S. Department of Agriculture and Texas Animal Health Commission, as well as private ranches and local communities, the Refuge has implemented an aggressive campaign to rid refuge lands of fever ticks. Check back often for updates on this effort and to learn what new tools and techniques are being applied.

In the late 1800’s, the cattle fever tick spread bovine babesiosis (also known as cattle fever) from Mexico to Virginia, ultimately resulting in enormous economic losses in the United States due to cattle mortality. Ticks are known to be on Mexican cattle and other hoofed animals that cross the Mexico-U.S. border. Currently, Mexico does not treat or control cattle fever ticks. In the 1940’s, the U.S. Department of Agriculture eradicated cattle fever tick in the U.S. and established a permanent quarantine zone on the Texas-Mexico border to detect and eliminate ticks quickly, in an effort to limit the spread of fever ticks.

 CattleFeverTick_200-embedThe Ticks Are Spreading
Despite having a quarantine zone, the ticks continue to spread. Lack of control in Mexico, changes in land use, expansion of native and exotic game species (white-tailed deer and exotic nilgai), resistance to pesticides, interstate movement of cattle, and wet-dry climatic cycles all provide favorable conditions for the tick to spread. In 2014, U.S. Department of Agriculture and Texas Animal Health Commission placed 223,000 acres in Cameron County, Texas under blanket quarantine due to detection of ticks. This temporary quarantine zone extends north of the permanent quarantine line and contains the majority of Laguna Atascosa National Wildlife Refuge as well as portions of Lower Rio Grande Valley National Wildlife Refuge. It is important to note that although ticks are present in these locations, the disease that causes “cattle fever” is currently not present in the U.S. Efforts are underway to eradicate the ticks (known carriers or vectors) before the disease does become present.

The U.S. Fish and Wildlife Service Joins the Fight
The U.S. Fish and Wildlife Service is taking aggressive actions to eradicate cattle fever ticks on Refuge lands. Working side by side with the U.S. Department of Agriculture and Texas Animal Health Commission, the Refuge has implemented numerous tools and techniques including those recommended by the Cattle Fever Tick Eradication Program to combat the ticks.

Current Eradication Efforts on Refuge Lands

  • Changes to Refuge Hunt Program: Updated hunter check-station procedures to include fever tick evaluation of all harvested animals. In 2016, Refuge significantly increased white-tailed deer bag limit from two deer to five deer solely to help eradicate ticks. This bag limit continued for the 2017-18 hunt season.
  • Successes: The Refuge has been highly successful in lowering deer numbers on refuge lands. The U.S. Department of Agriculture recommends optimal density of one deer per 30 acres for effective control of fever ticks. Deer density on the Refuge is now approximately one deer per 110 acres, well below the recommended mark.
  • Exotic Nilgai Reduction: Nilgai are an exotic antelope from Asia that were introduced to Texas on private lands and are a known carrier of the tick. Over the years, animals escaped private ranches and it is now estimated that over 30,000 freely roam South Texas. The Refuge has always used public hunts to control nilgai densities, but in 2014 began reducing numbers through aerial harvests in cooperation with the U.S. Department of Agriculture. In 2016 the refuge implemented Exotic Only hunts for both archery and firearm hunters. These continued in the 2017-18 hunting season. In 2018 two Emergency Hunts for exotic species were held in April. 
  • Successes: No other nilgai reduction or control is taking place in Texas. To date, over 565 animals have been harvested on the Refuge in addition to animals taken during the hunting seasons.  
  • Prescribed Fire: Both the U.S. Department of Agriculture and Texas Animal Health Commission recommend burning the landscape to reduce ticks. Ticks reside in vegetation waiting for an animal such as a cow, deer, or nilgai to brush by so they can attach to that animal. A fever tick’s spatial habitat is only 1-½ to 2 feet. Burning the habitat not only directly kills ticks it also removes the vegetation where ticks live reducing the likelihood of them attaching to animals in burned areas. Prairie burning is part of managing that habitat to keep it healthy. 
  • Successes: In 2017, through an expedited planning process, the Refuge burned a record 18,186 acres. Refuge burns typically take place in the winter season, but more burning is planned, including growing season burns. 

Potential New Tools & Techniques
  • Ivermectin-medicated Corn Feeders: The U.S. Fish and Wildlife Service developed an expedited timeline for completing all legal documentation to evaluate placement of ivermectin-laced corn on Refuge lands. In support of U.S Department of Agriculture and Texas Animal Health Commission’s efforts to eradicate ticks, treatment of white-tailed deer is an important tool recommended by the Cattle Fever Tick Eradication Program on all quarantined areas (private and public lands). Feeders are being placed on the Refuge beginning in March, 2018.
  • Experimental Cattle Grazing: Cattle grazing may offer another tool to fight ticks. Cattle are “treated” using an injected medication. The treated animals are then placed in a pasture infested with ticks. The ticks attach to the treated animal, dying, but leaving the cattle unharmed. Although the Refuge does not currently allow grazing, it is completing all required environmental compliance documentation to permit experimental grazing, to assist the Cattle Fever Tick Eradication Program. This technique is part of an integrated approach to eradicate ticks and is consistent with the Cattle Fever Tick Eradication Program goals and strategies within a quarantine area.  

Additional Available Tools

Invermectin-medicated Corn Feeders on Private Lands: In January of 2017, the U.S. Fish and Wildlife Service expedited and approved the use of ivermectin-laced corn in deer feeders on private property. Feeders are available to private landowners through the U.S. Department of Agriculture or Texas Animal Health Commission. Please contact them directly to receive your feeders to treat white-tailed deer.

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