The U.S. Department of Agriculture’s Agricultural Research Service (ARS) announced that a vaccine used in combination with safer pesticides has eradicated a multi-pesticide resistant population of cattle ticks from a dairy and beef production farm in Yabucoa, Puerto Rico.

In August 2020, multi-pesticide resistant Southern Cattle Ticks (Tropical Cattle Ticks) were detected in Yabucoa, Puerto Rico and immediately considered a threat to the cattle industry. Although Tropical Cattle Ticks are not a public health concern, ARS researchers partnered with the USDA’s Animal and Plant Health Inspection Service (APHIS), and the Puerto Rico Department of Agriculture to establish an ad-hoc research team on the island that would manage and prevent multi-pesticide resistant cattle ticks from spreading to other parts of the island.

Tropical Cattle Ticks are vectors of pathogens that cause bovine babesiosis and anaplasmosis in the Puerto Rico cattle population. Both diseases can cause significant morbidity and mortality in herds, with bovine babesiosis being the most severe. For the Puerto Rican dairy industry, mortality to tick-borne diseases alone was estimated to be $6.7 million per year in 2005, or approximately 3.3% of the total value of all marketed milk.

“During the research team’s first visit to the Yabucoa index farm, we found that 82% of the cattle, or 615 animals, were infested with multi-pesticide resistant ticks,” said Dr. Robert Miller, lead researcher of ARS. “But by the third visit, only 1% of the cattle, or eight animals, were infested with ticks. No ticks have been found on the farm for the past three months.”

The vaccine was used in small research trials on the island before gaining approval for use on cattle in Puerto Rico in 2016.

“This project provides many benefits to the dairy and beef industries in Puerto Rico, as it has developed alternative methods of tick control that are safer for human use and do not produce harmful environmental impacts,” said Dr. Fred Soltero, APHIS area veterinarian in charge for Puerto Rico. “It also reduces the intervention time, so it is more economical for the producers.”

Current trade as well as meat and milk production will not be affected by the vaccine and pesticide treatment. The products used in this research are safe and approved for use in dairy (lactating and nonlactating) and beef cattle.

"All cattle shipments from Puerto Rico to the U.S. mainland must undergo an APHIS Tick Quarantine and be accompanied by Tick Treatment inspection,” said Ramón González Beiró, secretary of the Puerto Rico Department of Agriculture.

The tick eradication and research on farms in Yabucoa follows all COVID-19 precautions and guidelines. Research will continue until July 2021.