While examining cattle in Florida, you observe many Rhipicephalus appendiculatus ticks in the ears. What is your primary concern?

• A. This tick is found in the US and may carry Lyme disease
• B. This tick is not found in the US and it might carry East Coast fever (Theileria parva)
• C. This tick is found in the US and might carry bovine anaplasmosis
• D. This tick is not found in the US and might carry African swine fever

Answer: (B)

Rhipicephalus appendiculatus, the brown ear tick, is the main vector of Theileria parva, the parasite that causes East Coast fever in cattle. This tick is not established in the United States. Finding it on cattle in Florida signals a serious exotic-disease risk: if these ticks are infected with T. parva and become established, naive US cattle could suffer severe outbreaks of East Coast fever, which can be devastating for herds. The other diseases mentioned are not carried by this tick (for example, Lyme disease is transmitted by a different tick, and African swine fever involves other vectors and hosts), so the most immediate concern is the potential introduction and spread of East Coast fever via this exotic vector.