June 26, 2002
Pet tests positive for Rocky Mountain spotted fever
WEST LAFAYETTE, Ind. The Veterinary Teaching Hospital at Purdue University has diagnosed Rocky Mountain spotted fever (RMSF) in a golden retriever from Reynolds, Ind., in White County.
Kathy Dedaker knew something was wrong when 3-year-old Samson refused his morning dog biscuit. She grew more concerned as the day progressed when he grew weaker and couldn't stand.
"Samson couldn't eat, he couldn't get up, he seemed disoriented and he and was vomiting liquid," Dedaker said. "I knew that something was very wrong, and I called our vet immediately."
Dr. Charles Anderson of Monticello, Ind., (and graduate of the Purdue School of Veterinary Medicine) immediately examined Samson and suspected that his symptoms might be indicative of RMSF and sent blood out for evaluation. Meanwhile, Samson's condition progressively worsened, so Dr. Anderson referred his patient to Purdue for emergency treatment.
"He couldn't even stand up when he was admitted," said Dr. Suliman Al-Ghazlat, the intern who received the case on June 8. "He exhibited signs of mental disorientation, as well. Twenty-four hours after being admitted, Samson was in a coma."
Samson was given emergency treatment, including intravenous administration of the antibiotic doxycycline (a form of tetracycline), and steroids that would help his brain swelling. The Purdue veterinary hospital performed its own lab work and began the process of testing Samson for RMSF, which takes about two weeks to confirm.
"We perform blood work, or serology, which helps us determine the patient's antibody response to the suspected disease," said Dr. Nolie Parnell, small animal internal medicine specialist. "The test is repeated two weeks later, once again measuring the antibody response, before a definitive diagnosis can be made. All indicators confirmed our preliminary diagnosis."
Since Purdue veterinarians treated Samson immediately, as if he was positive for RMSF, he gradually showed signs of improvement after a tense 36 hours. He was released from the hospital on June 13 and is expected to make a full recovery.
Some pets and humans do not receive such a swift diagnosis and treatment for RMSF, since the disease is still relatively uncommon in Indiana. According to the Centers for Disease Control and Prevention in Atlanta, the disease is reputedly the most severe and most commonly reported tick-borne illness in the United States.
The disease is caused by Rickettsia rickettsii, a species of bacteria that is transmitted from Ixodid (or hard ticks) to mammals, with humans occasionally serving as accidental hosts. Human symptoms can include a variety of flu-like symptoms, including fever, loss of appetite, muscle pain and then a rash. Initial diagnosis is difficult, and the disease can be fatal in some cases if not treated with tetracycline antibiotics.
Veterinarians at the Purdue School of Veterinary Medicine emphasize that humans generally do not contract RMSF through direct or indirect contact with an infected pet or mammal meaning a human must be bitten by an infected tick or come in contact with fluid from the tick in order to contract the disease.
"Your pet is not the danger, but rather your exposure to the tick's environment in other words, humans are bitten by ticks just as dogs are bitten by ticks," said Lynn Guptill, small animal internal medicine specialist. "However, pet owners should use caution when removing ticks from dogs, as contact of open wounds with fluid from a crushed tick might transmit the RMSF agent."
The American dog tick is the carrier of RMSF in Indiana. This and other hard tick species carrying the disease agent are common throughout the United States, Canada, Mexico, Central America and some parts of South America. The majority of Rocky Mountain spotted fever cases are reported between April and September.
Writer: Jesica Webb, (765) 494-2079, firstname.lastname@example.org
Sources: Nolie Parnell, (765) 494-1107
Lynn Guptill, (765) 494-1107
Purdue News Service: (765) 494-2096; email@example.com
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A publication-quality photograph is available at ftp://ftp.purdue.edu/pub/uns/guptill.rmsftick.jpeg.