Rocky Mountain Spotted Fever
Rocky Mountain Spotted Fever (RMSF) is a potentially life-threatening disease that dogs can develop from being bitten by ticks. The actual organism that causes Rocky Mountain Spotted Fever is Rickettsia rickettsii. The infective organisms get into dogs (and people and other mammals) when they are bitten by ticks that have them in their bloodstream. The “bugs” go from the saliva of the blood-sucking ticks into the mammals that they are feeding upon, and this is what causes the infection. Rocky Mountain Spotted Fever has been reported in North America, Central America and South America. It is considered to be one of the most significant tick-borne diseases of humans in the United States, although the number of cases in people is dropping. People can become infected incidentally, if they come into contact with the blood of infected ticks, especially when they are pulling ticks off of their dogs.
Most cases of RMSF in this country are seen in children and young adults along the eastern seaboard (especially North and South Carolina), in the Mississippi River valley (in the Southeast), in the Midwest and in the south-central states. RMSF has been confirmed in other areas, as well. Only a small percentage of RMSF cases are now reported in the Rocky Mountains, where the disease was first discovered at the turn of the 20th century.
Rocky Mountain Spotted Fever (RMSF) is caused by a tiny parasite, Rickettsia rickettsii, which infects the cells that line small blood vessels. Most cases of RMSF in our pets show up between late March and the end of September. This is considered to be the height of the tick season. Rodents are the main reservoirs for Rickettsia rickettsii, which means that these organisms live inside rodents, in their blood, but usually do not cause any
Some dogs infected with the organism that causes Rocky Mountain Spotted Fever (RMSF) never become observably ill. Others, however, develop a high fever, body aches, tissue and organ swelling and a great deal of discomfort. Dogs with severe cases of this disease are extremely ill and require immediate veterinary attention. RMSF can be fatal.Dogs infected with Rickettsia rickettsii may have subclinical disease, which means that they show no outward signs of illness even though they
Rocky Mountain Spotted Fever (RMSF) should be high on the differential list for any dog that shows general signs of illness accompanied by a history of tick bites, especially between late March and late September. The veterinarian will take a complete history of the dog’s medical background and will perform a thorough physical examination. This initial data base usually will also include routine blood work (a complete blood count [CBC] and a serum biochemistry profile),
If a dog is suspected of being infected with Rickettsia rickettsii, especially if ticks are found attached to its body, the veterinarian probably will prescribe oral antibiotics based on a presumptive diagnosis of Rocky Mountain Spotted Fever (RMSF). Most authorities feel that clinical suspicion of RMSF justifies treatment. Current antibiotics that are effective against the microorganisms that cause RMSF include tetracycline, oxytetracycline, doxycycline, chloramphenicol and enrofloxacin, among others. Each of these drugs has potential side