Agriculture

Understanding the blacklegged tick can help prevent Lyme disease


When the Manitoba Beekeepers’ Association started to notice its members were contracting Lyme disease, the organization decided it needed to take action.

The first step was to recognize they didn’t know enough about the blacklegged tick, commonly known as the deer tick, which carries the pathogen. What they found out is helping all Manitobans reduce their risk of getting Lyme disease.

“The board of directors noted that the percentage of our members with the disease was, most likely, higher than that of the general population,” said Daryl Wright, secretary of the Manitoba Beekeepers’ Association. Working with Dr. Kateryn Rochon, an Assistant Professor of Veterinary Entomology at the University of Manitoba, the association had learned that the range of the blacklegged tick has expanded considerably over the last 10 years. “Today, the ticks are in many areas where our beekeepers have colonies.” 

“Beekeepers are considered to be at a high risk for getting ticks partly because of where they keep their bees,” said Rhéal Lafrenière, a provincial apiarist with Manitoba Agriculture. “They often house them in areas that are lower in foot traffic, along the bush line, in fields, usually with lots of tall grass and sheltered areas. Beekeepers have notoriously collected hundreds of dog, or wood, ticks a day and thousands throughout the season.”

Covering the basics

With the assistance of the Growing Forward 2 - Growing Innovation program, the Manitoba Beekeepers’ Association worked with Dr. Rochon to study the blacklegged tick. The research took place during 2015 and 2016, covering 200-square-kilometres around Beaudry Provincial Park and Birds Hill Provincial Park, using both sampling and trapping techniques. 

“Prior to the study, we didn’t yet know the basics,” said Rochon. “We knew, for example, that blacklegged ticks have a two-year life cycle to reach adulthood, and we could theorize that as they move north that probably changes, and it takes them longer to grow. We could look at New York and say that in March these ticks are active, but there is a foot of snow outside your window in Manitoba in late March. Also, ticks are generally associated with deciduous forests—leaf litter, shady areas—but we’re in the Prairies without much forest around. We needed customized answers for our Prairie location.”  

The Beekeepers’ Association wanted to examine the seasonality of the blacklegged tick. The better they could understand when it was active throughout the year, the better beekeepers could protect themselves while working outside. The association also wanted to understand more about the preferred habitat of the tick. Do they prefer long grass or trees? With this information, beekeepers can place colonies in places that help them reduce risk. 

Theories confirmed

The study results have brought useful information. 

“We now have a good idea when the blacklegged tick adults are active in Manitoba: as soon as the snow melts and it is over five degrees Celsius. They are the first ticks you’re going to see - even before the wood ticks are active - until sometime in June,” said Rochon. “The other peak time when these ticks look for a host occurs at the end of September and in early October and they will keep looking until there is snow on the ground.” There is a firm relationship between snow fall and melt and when the ticks look for a host.

T
he project also showed that the blacklegged ticks were successfully able to overwinter in Manitoba, predominantly in a habitat at the forest-edge rather than in the forest itself. “Where are the trees in the Prairie landscape? They are often found in a farmer’s field, used as a windbreak,” said Rochon. Ticks need shelter in a humid environment, such as under leaves, when they need water.

This is the same territory where beekeepers tend to set up their colonies. “Beekeepers typically look for a location that offers wind protection, like bush, as well as relatively easy access. We usually find pasture fields that offer some clearing, such as an abandoned farm, so that we can overwinter our bees outside,” said Wright. 

Results bring additional questions

The project also showed a possible relationship between adult blacklegged ticks that were infected with both the Lyme-causing B. burgdorferi bacteria, and one of the other pathogens they can carry, A. phagocytophilium. Researchers now wonder if infection with one pathogen facilitates infection of the other, with further study needed to determine if this is the case.

“Blacklegged ticks can carry a total of four pathogens, including the one that causes Lyme,” said Rochon. “Manitoba is the only province in Canada that counts three of these pathogens as reportable diseases, which makes them easier to track. Now more research is needed in this area of co-infection.” 

Humans can contract Lyme disease from both adult deer ticks and nymphs, which is the life cycle stage of the tick just prior to adulthood. Unexpectedly, the study discovered that nymphs are not commonly found in Manitoba. 

“We know that they’re here because we found adults,” said Rochon. The finding is causing the researchers to wonder if more nymphs than they previously though are being brought into the province on bird migratory routes.

Protecting yourself

“The most important thing that the study has provided is that we now have local knowledge on this tick. To be able to be more specific on where this tick can be found in Manitoba, and when it is most active, is good information for the general public as well as beekeepers to have,” said Lafrenière.

During the active season, the Manitoba Beekeepers’ Association recommends that people check themselves for ticks once or twice every day. The blacklegged tick is much smaller compared to the common wood tick at about the size of a sesame seed for an adult and a poppy seed for a nymph. If walking through longer grass or edges of trees, tuck pants into socks.