Background
Cattle Fever Ticks are one host ticks, meaning that the larvae, nymph, and adult life stages all occur on one animal and unlike many of the other tick species that must leave its host after each stage to molt and then find another host to continue its life cycle. The female will leave the host after its last blood meal to deposit up to 4000 eggs.
The Cattle Fever Tick Eradication Program is a program started in 1906 led by the USDA-APHIS but involving multiple state and federal public animal health officials and the cattle industry to rid the country of the Cattle Fever Ticks (Rhipicephalus (Boophilus) microplus and Rhipicephalus (Boophilus) annulatus). These two ticks transmit a pathogen that causes babesiosis, commonly known as cattle fever, to cattle. The disease causes production losses (weight loss and reduced milk production) and mortality of the animal. No vaccine is currently available to prevent the disease, so prevention by eradication of the pest is the best current practice.
In 1906, it was estimated to cost the cattle industry $3 million in today’s dollars. Through much effort, by 1943 these ticks were eradicated throughout most of the United States except for a small permanent quarantine zone established along the US-Mexico border. As this pest persists in Mexico as does babesiosis, APHIS maintains the permanent quarantine zone and the Texas Animal Health Commission (TAHC) handles temporarily quarantines on properties throughout Texas where these two ticks are found from. If ticks are found on a property, the transfer of animals in and out of the area is forbidden and all cattle are treated with pesticide every two weeks over the course of 6-9 months.
Current Projects
1. Detection of acaricide resistance mechanisms
Ivermectin is a common broad-spectrum anti-parasitic drug used for the treatment of parasites outside the United States, including Mexico. The abundant use of this drug have led to resistance issues related to R. microplus, but the molecular mechanisms have not been elucidated yet. The Kaufman Veterinary Entomology Laboratory, with cooperation from USDA-ARS personnel, are conducting research to identify the molecular mechanism of Ivermectin resistance in R. microplus and will be comparing the expression of metabolic detoxification enzymes in R. microplus resistant and susceptible strains.
2. Identification of immature attachment sites
The Kaufman lab is trying to better understand the ecology and biology of R. microplus. To do so, we are examining the density and distribution of R. microplus larvae and nymphs on cattle in hopes of identifying “hot spots” of these ticks to aid the Cattle Fever Tick Eradication Program animal screening efforts.
