Fever ticks have proven to be deadly and costly to the U.S. beef industry—so deadly, an entire agency was created to eradicate the specie.
According to the Texas Animal Health Commission (TAHC), fever ticks caused enormous economic losses to the industry in the late 1800s and early 1900s. After a large number of outbreaks, in 1893 the Texas Legislature created the Livestock Sanitary Commission to put an end to the tick. The agency has developed into what we know today as the TAHC.
Since the agency’s introduction, the cattle fever tick has been maintained at the Texas-Mexico border with occasional outbreaks. This summer has been one of those rare periods of outbreaks in previously eradicated locations.
The cattle fever tick, scientifically known as Rhipicephalus annulatus and R. microplus, carries a huge risk to the cattle industry. The ticks are capable of carrying microscopic parasites called Babesia bovis that can cause babesiosis—cattle fever.
The parasites attack an animal’s red blood cells, causing anemia, high fever, and spleen and liver enlargement, said TAHC in a fact sheet. This ultimately results in the death of up to 90 percent of cattle.
Potential hosts of the fever ticks are not limited to cattle, but can also include horses, white-tailed deer and exotic ungulates such as the red deer.
The ticks have three life stages: larva; nymph; and adult. Female adults will stay on one host for the entirety of her life, and once engorged with blood, will drop off the host and lay up to 4,000 eggs on the ground. The eggs will hatch into larvae and attach to a new host and thus, the life cycle continues.
The ticks spread babesiosis by first becoming infected from an affected animal they have consumed blood from. Once the tick lays eggs, the disease will be passed on to its offspring, who will then pass it to their hosts.
What happens if found?
If a tick is found on livestock or wildlife, the premise will immediately be designated as an “infected premise,” according to TAHC. The infected area will be put under quarantine and movement will be restricted. Inspections and treatments will also take place according to regulations.
Areas next to the infested premise will be designated as “adjacent, exposed or check premises” and will also be subject to the same restrictions and inspections as the infected premises. Although there is already a permanent tick eradication quarantine area running along the Texas-Mexico border, TAHC may establish “temporary preventative quarantine areas” or “control purpose quarantine areas” to prevent the spread of ticks to other areas across the state.
Infected premises have several options for treatment. The first option is injecting Doramectin every month throughout the six to nine-month quarantine period. The second option is dipping cattle every week to two weeks throughout the quarantine period. Lastly, the final option is dipping the cattle until tick free. Cattle will then be moved to a different, tick-free pasture and the infected pasture is left empty for nine months, starving the ticks of any hosts.
If the last option is taken, any surrounding wildlife must also be inspected and treated to avoid spreading the tick through wildlife.
The permanent quarantine zone serves as a buffer between Texas and Mexico. It is a zone ranging from 200 yards to 10 miles wide along the Rio Grande River to the Gulf of Mexico. The zone is about 500 miles long and runs through eight Texas counties. Cattle fever ticks are found endemically in Mexico so the zone serves as a detection area to prevent the spread across the state. Officials from the USDA’s Animal and Plant Health Inspection Service inspect cattle near the zone, as well as ride horseback along the river, searching for any wildlife or livestock crossing that may be infested.
TAHC officials quarantined a 13,568-acre area in Jim Wells County after the most recent cattle fever tick incidence. A calf was discovered with the ticks during a voluntary inspection at a program dipping vat on July 22.
“The ticks were discovered when the cattle buyer had the animals voluntarily inspected for fever ticks before leaving a South Texas livestock market,” said Dr. Andy Schwartz, TAHC executive director. “We are thankful for the support and willingness of the buyer. Because of their actions, the fever ticks were not inadvertently moved to a free area of the state and a potential outbreak was avoided.”
The ticks were last eradicated from Jim Wells County in November 2017, after two calves were found with the ticks in 2015. The quarantined area was placed under systematic treatment and inspection for two years before being released in 2017.
There are currently 966,784 acres in quarantine outside of the permanent quarantine zone. — Anna Miller, WLJ editor