People who have been wondering why so many dead deer have been turning up on Galiano Island received confirmation last week that a new disease is most likely at work in the Gulf Islands.
Provincial wildlife veterinarian Dr. Helen Schwantje is waiting for definitive results of testing, but says an outbreak of Adenovirus Hemorrhagic Disease (AHD) is suspected as the cause of death of over 60 deer. Most of the dead animals have been seen on Galiano. Some suspicious deaths have also occurred in deer on Parker, Mayne and Pender islands.
“It would be very odd for it to be located on just one island,” Schwantje told the Driftwood. “Disease in wildlife can be very subtle and it can be very silent. We could have animals dying in the back country and we would never know about it. This summer is very unusual since we had more people in the bush hiking around, so maybe we are just seeing it more. But it’s very rare that animals die suddenly with no signs of ill health, so that’s what got my spidey-senses up.”
While there is no known human health risk from the virus, and there is no evidence that it can be transmitted to humans, hunters in the area are being advised not to consume meat from animals found dead, obviously ill or acting abnormally prior to death. Research indicates AHD is not transmitted to livestock or pets.
Information from the B.C. wildlife health branch states cervids (mule deer, white-tailed deer, elk, moose and caribou) are all susceptible to the disease, but members of the black-tailed deer family appear to be most severely affected. Fawns are far more susceptible than adults and suffer much higher rates of death. The disease course is usually rapid and fatal as the virus damages small blood vessels in the lungs and intestines.
Schwantje said with the over-population of deer in the Gulf Islands, it’s not surprising that disease would travel quickly and hit hard.
“Any time an infectious disease occurs in a high-density population you will see a far wider spread than if the population density is low. If there were controls such as predators on the islands, we probably wouldn’t see a disease spread like this,” she said.
Detection of a new disease is also not surprising to experts who have been studying the impact of deer on local ecosystems. That work has been led by Salt Spring resident Tara Martin, a professor in the University of British Columbia’s forestry faculty.
“We have been predicting such an outbreak for some time as a result of hyper-abundance. Perhaps now that it’s clearly an animal welfare issue along with it being a key ecological issue driving the loss of rare plants and ecosystems in the islands, we can begin to discuss deer management across the islands,” Martin said.
Parks Canada has contracted Martin and her colleague Peter Arcese to develop such a plan for the Gulf Islands National Park Reserve.
AHD was initially discovered in California and outbreaks are recorded annually in some parts of the western United States. No outbreaks are currently underway in California and Oregon. However, B.C. has never documented the disease and there is no outbreak recorded happening in Washington state or in the nearby San Juan Islands.
Schwantje said it’s therefore unclear how AHD made its way to the Gulf Islands. Since the disease is carried in body fluids, it’s possible that it was transferred from an infected carcass or hunting equipment.
“It may always be a mystery,” she said.
A network of wildlife professionals has assisted provincial wildlife health staff to investigate the possible emergence of AHD since deer were discovered dead on Galiano in September, with participation from the RestQ Animal Sanctuary being a particular help. Schwantje said she suspected the disease was the culprit after seeing photos of the dead deer. She then asked a veterinarian colleague on the islands if he would mind taking samples. Those samples were sent to Canadian and United States laboratories to confirm the disease.
“None of this would have been possible without the diligent work of the rescue organization and that particular veterinarian, and some dedicated people in the background,” Schwantje said. “That’s how a lot of my work gets done — by networks of people bonding together and helping.”
Acute signs of the disease include difficulty breathing, foaming or drooling from the mouth, diarrhea (sometimes bloody) and seizures. More chronic symptoms include ulcers and abscesses in the mouth and throat. Anyone observing deer displaying these signs should report it to the Wildlife Health Laboratory at 250-751-7246.