Project Rodeo: Rounding Up Varmint Brown Dog Ticks, Reducing Human Disease
The words 'good news' & 'ticks' don't usually appear together. But here's an integrated tick management (ITM) success story. Between 2003-2012, with brown dog ticks as vectors and human cases of Rocky Mountain Spotted Fever (RMSF), including 19 deaths, spiraling upwards at >150 times the national average among residents living on the American Indian reservations of eastern Arizona, it was definitely time to take action. Beginning in 2012, the Centers for Disease Control and a host of partners, including Bayer Healthcare and PetSmart Charities, launched a multi-pronged RMSF Rodeo program to corral the dog carriers and tick vectors. Results of the two year pilot intervention were published recently in the open access journal PLOS One.
The hot, dry climate of eastern Arizona is a pretty inhospitable place for most types of ticks and tickborne disease. So, it came as quite an unsuspected finding that an explosion of RMSF among American Indians without any history of travel away from the reservations was caused by brown dog ticks. It was the first time brown dog ticks were shown to transmit the agent of this disease, Rickettsia rickettsii, in the United States.
Dogs serve as primary host for all stages of brown dog ticks, and dogs are susceptible to RMSF infection. To combat the public health nightmare underway, investigators focused on both dog and tick management—spaying & neutering free-roaming dogs, application of long-acting Seresto tick collars, and spray applications of synthetic pyrethroid acaricides both outside and sometimes even inside of homes. Health workers logged some 10,000 hours implementing and monitoring over the massive 2 year effort covering about 600 homes and some 1,000 dogs in the Rodeo pilot community.
Now for the good news--it seems like all of the effort was worth it! At the start of the study in the Rodeo community, some 51% of dogs had visible tick infestations but this number decreased to < 4% by the end of the first year, and by the end of the study about 98% of dogs had no visible tick infestation. In non-Rodeo communities, 64% of dogs had tick infestations. And the bottom-line…disease rates also decreased by some 43% in the intervention community.
While complete tick elimination was not achieved in such a challenging setting, the level of control using long-acting Seresto collars and environmental sprays was remarkable. The study authors hope that this integrated approach can be used in other communities to reduce the risk for human illness. And for people that find brown dog ticks in their own home, it seems this tick success story can give them hope of reclaiming their home from the grips of a truly nasty pest.