The Brown Dog Tick and Epidemic Rocky Mountain spotted fever in Arizona and northwestern Mexico

Abstract

The brown dog tick Rhipicephalus sanguineus, has a worldwide distribution and is found throughout the United States (US) and Mexico. This tick is driving epidemics of Rocky Mountain spotted fever (RMSF) in Arizona and northwest Mexico. As the name suggests, the tick mainly takes blood meals from dogs, but it will also feed on humans and other mammals, and can carry serious disease causing pathogens. In the early 2000’s it was found to transmit Rickettsia rickettsii, (a gram-negative, intracellular, coccobacillus bacterium) that causes RMSF in Arizona. This was the first time this tick species has been associated with the disease in the US (Demma et al. 2005). Similar outbreaks occurred at the same time in Sonora and more recently in Baja California (Alvarez- Hernandez et al. 2017).