Rocky Mountain spotted fever
Rocky Mountain spotted fever can be very difficult to diagnose in dogs in its early stages, even among experienced veterinarians who are familiar with the disease. In humans, the classic triad of findings for this disease is fever, rash, and a history of tick bite. In dogs, rash occurs in only 1 out of 5 cases, or even less. But the clinical signs together with the serology, the geographic location and the time of the year will assist in diagnosis. Co-infection with other tick-transmitted pathogens may occur.
Most infected dogs are less than 3 years old and have a recent history of exposure to a tick habitat. First clinical signs may occur about one week after tick attachment and include fever (>39°C), anorexia, depression, lethargy, reluctance to move and stiffness, oedema, lymphadenopathy and neurological signs.
Petechiae and ecchymotic haemorrhages associated with destruction of platelets in response to vasculitis are often seen on exposed mucosal surfaces in the dog. Due to the vasculitis, oedema in the body appendages may also occur. These are including the scrotum, prepuce, and ears of affected dogs. While the disease is generally thought to be self-limiting with duration of approximately 2 weeks in dogs, it may also be fatal.