
It’s widely acknowledged that Lyme disease risk varies from one region to the next, but what’s not as well recognized is that a person’s chances of contracting non-Lyme tick-borne infections can also vary greatly between regions.
Rocky Mountain spotted fever (RMSF) tends to get little press in eastern Canada, largely because it’s extremely rare for a case to occur outside of the three western provinces. But if you happen to live in Saskatchewan, Alberta, or BC (or live anywhere in the rest of Canada and have extremely poor luck), RMSF is worth knowing about.
The illness is caused by infection with a tick-borne bacteria called Rickettsia rickettsii. Most of the time, this bacteria is transmitted to people (and dogs) by the bite of an infected tick that has typically (although not always) been attached for several hours. Unlike most other tick-borne illnesses, it’s also possible to contract RMSF by crushing the tick against your skin. That’s because the disease-causing bacteria is present in the tick’s saliva, blood, bodily fluids and feces. Come in contact with any of those — and crushing an infected tick is an excellent way to do that — and you run the risk of contracting RMSF.
Canada has two resident ticks that are capable of transmitting RMSF. The first is the Rocky Mountain wood tick (Dermacentor andersoni) which, for the most, part makes its home in the Rocky Mountain region of British Columbia and Alberta, but has also been known to turn up as far east as Saskatchewan. Rocky Mountain wood ticks are responsible for the lion’s share of RMSF cases in Canada, which is why those cases tend to be restricted to the western provinces. However, it’s not impossible to contract RMSF from the American dog tick (Dermacentor variabilis), which carries the bacteria at much lower rates than its western cousin. American dog ticks are present in most of southern Canada from southeastern Saskatchewan straight through to the Maritimes.
The symptoms of RMSF kick in anywhere from two days to two weeks following an encounter with an infected tick and typically begin with a moderate-to-high fever followed by a fairly distinctive spotty red rash that gives the disease its name. That rash starts on the wrists or ankles before spreading to other parts of the body. Other symptoms can include headaches, muscle pains, chills, confusion, nausea, vomiting, and/or diarrhea. In severe cases, RMSF can result in an enlarged liver or spleen, bleeding, kidney failure and/or neurological problems.
It’s rare for anyone who has received appropriate antibiotic treatment to die from RMSF. However that can happen if, for some reason, the disease goes untreated. In instances where that happens, the mortality rate for RMSF can spike as high as 30%.