Plague in dogs is caused by the bacteria Yersinis pestis that affects many other animals such as cats, sheep, cattle and pigs. Plague doesn’t spare humans either. Rodents, and the fleas that live on them, are the main perpetrators of this disease that can be fatal in dogs and people too.
The Black Death, the widespread epidemic that caused more than 25 million human casualties in 14th century Europe was nothing but plague. Starting from 1437, in just five years, 1/3 of the population of the European continent was wiped out by this highly contagious disease. It continued to cause epidemics regularly for another two hundred years.
Plague still occurs sporadically even though better sanitation and control of rodent population have reduced the outbreaks. Invention of antibiotics has made it possible to treat the disease. The causative organism is still active in wild animals in Africa, Asia, Europe, and both the American continents. The disease is frequently reported from the western parts of the United States, mainly from Arizona, Colorado, California and New Mexico, but dogs are rarely affected.
The bacteria Yersinia pestis finds a reservoir in rodents such as wood rats and squirrels and the fleas that are parasitic on them. Dogs may get infected when they come in contact with tissues or body fluids of rats, squirrels or rabbits that are infected with the bacteria. Fleas that carry this organism may bite the dogs and transmit the disease to them. Dogs can become potential carriers of these fleas and bring the infection home to their households too.
The natural resistance of dogs to the plague bacteria may protect the dog to some extent. But it may make an infected dog asymptomatic too, unlike cats and other animals that are more susceptible to the disease. Fever, swollen lymph nodes under the lower jaw, cough and lethargy are the usual symptoms. Pus-filled lesions may develop in the dog’s mouth and along its jaws.
The disease progresses rapidly, hence treatment and control measures should be initiated without waiting for confirmation of the disease. Even the slightest suspicion should be taken seriously considering the potential danger the disease poses not only to the affected dog but to humans and other animals too.
Antibiotic therapy is the main treatment for plague. Since the disease is highly contagious, protective measures against its spread should be instituted without any delay. The pet suspected to be having plague should be quarantined while it undergoes the antibiotic treatment so that the disease does not transmit to others. The pet’s owner and family members as well as other pets or people who have come in contact with the affected dog, should be closely monitored for symptoms of the disease.
In areas with high prevalence of plague, the dogs should be protected from exposure by keeping them away from rodents. They should not be allowed to roam freely and hunt wild animals or eat the carcasses of dead animals. The dogs should be kept free of fleas to prevent infection and spread of plague to others. Regular grooming and the use of flea control measures recommended by the veterinarian are important.