Respiratory Pathogen "M. ovi" Documented in Additional Species in Alaska is Also Implicated in Alaska Caribou Death
- ADF&G Press Release
Sam Cotten, Commissioner
P.O. Box 115526
Juneau, Alaska 99811-5526
Press Release: June 15, 2018
CONTACT: Bruce Dale, Division Director, (907) 861-2101, bruce.dale@alaska.gov
Respiratory Pathogen "M. ovi" Documented in Additional Species in Alaska is Also Implicated in Alaska Caribou Death
Mycoplasma ovipneumoniae ("M. ovi") is a respiratory bacterium that can cause disease in susceptible hosts. Previously thought to be host-restricted to sheep and goat species, scientists have identified M. ovi for the first time in healthy moose and caribou in Alaska; a bison in Montana; mule deer in New Mexico, and diseased white-tailed deer from the upper Midwest. These results are in review for publication and one of the papers' co-authors, Dr. Margaret Highland, will be presenting the findings in the afternoon of June 15th at the Idaho Veterinary Medical Association Summer Meeting in Lewiston, Idaho.
ADF&G veterinarian Dr Kimberlee Beckmen, one co-author, said "these are novel findings of this organism, not only in species that are not related to sheep or goats, but also that it was found in apparently disease-free moose and caribou."
In addition to these findings showing the presence of M. ovi in moose and caribou, ADF&G now also reports another first for Alaska: a necropsy determined that a bronchopneumonia was the ultimate cause of death in an emaciated caribou found dead on May 16 during routine radiotracking of the Fortymile caribou herd. Lung samples from the caribou sent to the Washington Animal Disease Diagnostic Laboratory in Pullman, Washington tested positive for M. ovi. This is the same bacteria recently detected for the first time in healthy Alaska Dall's sheep and mountain goats.
"This is the first case where M. ovi has been implicated in respiratory disease in Alaska," said Bruce Dale, director of the Division of Wildlife Conservation.
M. ovi is considered a pathogen because it impairs hosts' respiratory cilia from clearing bacteria that enter the lungs normally at each breath; it has been linked to sporadic pneumonia outbreaks in Lower 48 bighorn sheep. The pathogen does not pose a health risk to humans.
"Finding M. ovi in Alaska's wild sheep and goats, and now also in caribou and moose is groundbreaking," said Dale, "We obviously have much to learn about the extent and implications of this pathogen in Alaska."
Dale cautions that respiratory disease is not uncommon in caribou but is not a driving factor in caribou population dynamics. Also, the presence of M. ovi in an animal does not mean it is or will become sick. More than 100 known Mycoplasma species exist, including M. ovi, and evidence suggests that virulence — the ability to infect and cause disease — varies between M. ovi strains. The ability of M. ovi to cause pneumonia is impacted by the presence of other pathogens as well as multiple stressors including poor nutritional condition (as was the case with this caribou) and/or environmental factors such as extreme weather.
Findings in Alaska Dall sheep and mountain goats so far have confirmed M. ovi detection in 13 of 136 Dall sheep tested in Game Management Units 12, 13A, 20A, 25C, 26B, and 26C; and in five of 39 mountain goats, all in Unit 15B. None of those 13 sheep or 5 goats showed signs of respiratory illness. Of the 230 moose and 243 caribou sampled for this recent study, 5 moose and 6 caribou tested positive for M. ovi.
The department will continue to investigate respiratory pathogens including M. ovi through surveillance efforts in Dall sheep, mountain goats, and other Alaska wildlife in collaboration with the USDA Animal Disease Research Unit and the Washington Animal Disease Diagnostic Laboratory. The department's veterinarian, Dr. Kimberlee Beckmen noted that "Our staff's vigilance in investigating mortalities and collecting and transporting samples for thorough diagnostic work up made the caribou discovery possible."