Anaplasmosis – A Health Risk to BC’s Deer Herd?

© By Othmar Vohringer
(Originally published in the Merritt News)

Anaplasmosis is an infectious disease caused by a red blood cell parasite, Anaplasma marginale, which is most often transmitted by tick bites. It affects domestic and wild ruminants (cattle, sheep, goats, deer, elk and moose) but causes symptoms mostly in cattle and sheep. According to the Canadian Food Inspection Agency there is no human health risk associated with this disease. A human disease, human granulocytic ehrlichiosis (HGE) was renamed as human Anaplasmosis in 2003, but this disease is caused by a different microorganism.

Until recently Anaplasmosis has only been found in the United States, but has now spread to Canada and more recently here to the Nicola Valley. In 2008 routine testing of local cattle found that there was Anaplasmosis present in some cattle. Since then about 10,000 cattle have been tested in the valley of which some showed positive for the red blood cell parasite. The testing has shown that the disease is most acute, but rarely fatal, in cattle between the ages of one to two years. Whereas the mortality rate in cattle older than two years is between 29 to 45 percent while calves are rarely infected.

The Ministry of Environment has authorized a deer kill in the Nicola Valley to test for possible wildlife infection of the disease. Helen Schwantje, a wildlife veterinarian with the B.C. Ministry of Environment, said conservation officers are slated to shoot 30 deer on private land March 16-18 to determine if Anaplasmosis is resident in the ungulate wildlife population. Conservation officers of Merritt culled 30 mule and whitetail deer on private ranch land in an effort to determine if Anaplasmosis has spread to wildlife. Two members of the Nicola Valley Fish & Game Club, Fran and Jim George, were present to assist with field dressing and taking test samples of all major organs, skin and blood. As of this writing the test results from the deer culling are not available yet. The meat of the culled deer had been distributed to members of the First Nations.

Anaplasmosis is transmitted through the red blood cells of infected animals. Once an animal is infected, it remains a source of the disease for life even after the animal has fully recovered. Anaplasmosis is most often spread by ticks that bite infected cattle. The disease causing microorganisms also infect and reproduce in the tick. The tick then transmits the parasite to other susceptible animals such as deer, elk and moose. The Ministry of Environment asks hunters and other outdoor users to be vigilant of ticks on pets and humans. If pets or humans have ticks they should be collected and sent for testing to the Ministry of Wildlife or taken to the local Conservation Officer station in Merritt with a description of where the ticks have been contracted.

Ticks are also carriers of several other diseases, some of which affect animal and human health, such as Lyme disease. The best protection against ticks is to avoid walking through thick vegetation and tall grass whenever possible and walk in the middle of overgrown trails and paths where the vegetation is not so high. Wear long sleeved shirts and tape up the pant legs around hiking boots. Spray your shoes and pant legs with an appropriate tick repellent. A trick I learned form an old hunter many years ago and that seems to work very well is to tie a pet tick repellent collar around my ankles, wrists and sometimes even around my neck – especially when I hunt turkeys, which involves sitting for many hours under a tree on the ground- making sure the collar does not touch any part of my skin.

After returning from the outdoors conduct a visual inspection of your clothing, followed by a naked full-body inspection. Have a partner check the backside of your body. Ticks tend to hide in joints, between toes, behind the ears, in the scalp and other body parts. Check your pets very carefully for ticks each time they enter the house, even if they just have been outside for a brief moment. Pets can bring ticks in the house, which then migrate from the pet onto you or other family members, or visitors.

This column has been brought to you by Othmar Vohringer Outdoors