A plague-infected dog spread the dangerous disease to four
Colorado residents, according to a new report from the U.S. Centers for Disease
Control and Prevention.
Health officials told ABC News that this is the first report
of a dog infecting a human with the plague in the U.S.
The dog, a 2-year-old American pit bull terrier, became sick
last summer with a fever and jaw rigidity, among other symptoms. The dog's
health declined so quickly that it was euthanized the following day at a local
vet's office, health officials said.
Four days later, the dog's owner entered the hospital with a
fever and a bloody cough that became worse over the next few hours, but an
initial blood culture was misidentified, according to the CDC report.
As the patient's symptoms grew worse, the test was redone
and he was found to have been infected with pneumonic plague, according to the
CDC report. The remains of the dog were also tested and were found to be
positive for the plague bacteria.
"Frankly one of the biggest surprises of this outbreak
is the source," said John Douglas of Tri-County Health Department in
Colorado, one of the study authors. "Primarily...dogs don’t get sick at
all or they get a minor illness" after being infected with the plague.
Janine Runfola of the Tri-County Health Department in
Colorado, lead author of the report, explained that cats are more likely to
infect humans with the disease than dogs because they exhibit more symptoms.
"For pneumonic plague a more likely scenario would be
you have a cat [play] with prairie dogs and infected fleas get on the
cat," Runfola said. "The cat gets sick and sneezes and coughs on its
owner."
The dog's owner remained hospitalized for 23 days as he
recovered from the potentially deadly disease, the report said. In addition to
the owner, a close contact of the owner and two veterinary employees who
treated the dog or handled its body also became infected with the plague. All
three were successfully treated with medication after exhibiting symptoms.
The plague is caused by the bacteria Yersinia pestis, and
can infect the body in different ways. For example, a flea bite can lead to
infection of the glands, which is called bubonic plague -- notorious for the
epidemics it spawned during the Middle Ages in Europe. Because this plague was
spread from dog to owner through coughing, it developed into pneumonic plague,
according to Douglas.
The plague is known to be endemic to prairie dogs in the
American Southwest, which can then lead to isolated outbreaks of the disease in
domestic animals or humans.
"Pneumonic plague is the worst form," said
Douglas. "It’s the one that you least want to get. You get sick fast and
the chances of getting a rocky or even fatal course" are increased.
The plague is incredibly rare in the U.S., with an estimated
eight infections in the country reported every year. Douglas said pneumonic
plague is even rarer and accounts for just 3 to 5 percent of plague cases.
Douglas said the case shows the importance of considering
all the options when diagnosing a patient, even extremely rare options like the
plague.
FOLLOW US! 
