Female ticks (Ixodes scapularis) infected withBorrelia burgdorferihave increased overwintering survival, with implications for tick population growth

Abstract

The tick,Ixodes scapularis, vectors pathogens such asBorrelia burgdorferi, the bacterium that causes Lyme Disease. Over the last few decadesI. scapularishas expanded its range, introducing a novel health threat into these areas. Warming temperatures appear to be a major cause of this northward expansion. However, other factors are also involved. We show that adult ticks infected withB. burgdorferihave greater overwintering survival than uninfected ticks. Adult ticks were placed in individual microcosms and allowed to overwinter in both forest and dune grass environments. In the spring we collected the ticks and tested both dead and living ticks forB. burgdorferi DNA. Infected ticks had greater overwintering survival compared with uninfected ticks every winter for three consecutive winters in both forest and dune grass environments. The increased winter survival of adult female ticks could have a large impact on tick population growth, as we demonstrate. Our results suggest that, in addition to climate change,B. burgdorferiinfection itself may be promoting the northern range expansion ofI. scapularis. Our study highlights how pathogens could work synergistically with climate change to promote host range expansion.

Acaricidal Biominerals and Mode-of-Action Studies against Adult Blacklegged Ticks, Ixodes scapularis

“…Vaccination of animals, such as dogs or rats, which can act as reservoirs of Lyme disease, and cattle, which can be vaccinated against the cattle tick, Rhipicephalus microplus, is also used to prevent tick infection [2,[6][7][8][9]. With an expanding range for ticks that can possibly vector diseases [10,11] and the possibility that being infected with B. burgdorferi could increase the survivability of overwintering ticks [12], alternative methods of control are greatly needed.…”