Dr. Stafford Tick Management Handbook - Newtown, CT

StaffordSmall Mammals and BirdsThe Connecticut Agricultural Experimentation StationRodents and birds can infect ticks with B. burgdorferi and transport these ectoparasites ontoyour property. The importance of these animals in the dynamics of Lyme disease depends on theabundance of the animal host, number of ticks feeding on the host, and the host’s ability to infectfeeding ticks with the Lyme disease spirochete (i.e., the reservoir potential). In other words, whatanimals are contributing infected ticks to your property? Some animals may have a lot of ticks, butthese hosts may not be able to infect their ticks with spirochetes.RodentsWhile different rodent and bird species may predominatein certain years and locations, white-footed mouse,Peromyscus leucopus, is generally the most abundant andef. cient animal reservoir for the Lyme disease bacteria.They contribute more infected ticks than eastern chipmunksor meadow voles do. White-footed mice also are reservoirsfor the causal agents of anaplasmosis and babesisois.Over 90% of white-footed mice will be infected with B.burgdorferi in many areas and up to half have been foundto carry all three pathogens in some areas. In one study,a single mouse was estimated to infect as many ticks as12 chipmunks or 221 voles. Meadow voles, Microtuspennsylvanicus, which are most abundant in . elds, pastures,orchards, harbor few I. scapularis. Although they harborfewer ticks, short-tailed shrews, Blarina brevicauda,with their high reservoir potential, may contribute to themaintenance of both B. burgdorferi and B. microti in someareas, especially when mouse numbers are low. By contrast,squirrels have a lower Lyme disease reservoir potential.One study indicated that squirrels might reduce or dilutethe number of infected ticks in the landscape. Although notquanti. ed, this author has noticed mouse populations dropdramatically (based on trapping success) with resultantdeclines in the tick population at a sample site where afox family or snakes have taken up residence in or nearthe stone walls. Mice have relatively small home ranges.Dense vegetation and ground cover plants like pachysandraadjacent to homes provide cover for rodents as they foragefor food. Shaded stonewalls overgrown with grass andbrush can harbor many mice and chipmunks.White-footed MousePeromyscus leucopus (Rafinesque)White-footed mice (top, middle) and EasternThe white-footed mouse is the principal animal chipmunk (bottom). Note the engorged larvalticks(arrow) feeding on the ears and around thecarrying the pathogens that cause Lyme disease, humaneyes of the white-footed mouse in the middleanaplasmosis (i.e., ehrlichiosis) and human babesisois. picture. Larval ticks become infected with B.White-footed mice are found throughout most of eastern burgdorferi and other pathogens while feeding onand Midwestern United States, except in Florida and an infected mouse or chipmunk.58Bulletin No. 10109899100