Comparing the Relative Potential of Rodents as Reservoirs of the Lyme Disease Spirochete (Borreliaburgdorferi)

Abstract

The authors compared the contribution of white-footed mice (Peromyscus leucopus), chipmunks (Tamias striatus), and meadow voles (Microtus pennsylvanicus) to infection of vector ticks with the Lyme disease spirochete, Borrelia burgddorferi. At one Massachusetts location where Lyme disease is endemic, all three species of rodents were found to be infected. Prevalence of infection, however, varied from 90% for mice, and 75% for chipmunks to just 5.5% for meadow voles. Infectivity of these hosts for larval Ixodes dammini also varied, but mice were found to be the most infective, followed by chipmunks and meadow voles. Density estimates of these three hosts, collected between 1981 and 1986 in three coastal Massachusetts locations, revealed that mice were more abundant than the other two rodents in areas in which ticks were abundant. In addition, mice were infested more abundantly with larval I. dammini than the other two host species. Integrating these results, we determined each species' "reservoir potential," a novel term which describes the relative contribution made by a host species to the horizontal infection of a vector population. The authors' findings demonstrate that, at least in coastal Massachusetts, P. leucopus is the most important small mammal reservoir for B. burgdorferi.

How effective is dog culling in controlling zoonotic visceral leishmaniasis? a critical evaluation of the science, politics and ethics behind this public health policy

“…For example, some observations and mathematical models show that the importance of a reservoir is regulated not only by its competence in infecting vectors, but also by the parameters that measure a) the degree of exposure of vertebrate hosts to vectors and b) the vector daily mortality. Both parameters have a nonlinear (quadratic and exponential) effect on the transmission of the disease 69,70 . This means that small efforts aimed at controlling vectors can have strong results concerning the transmission of the disease.…”

Spatial Dynamics of Lyme Disease: A Review

“…Lyme disease in North America is caused by the spirochete bacterium, Borrelia burgdorferi, which is vectored between hosts by Ixodes scapularis in eastern and central regions and Ixodes pacificus in the west. There are many potential reservoir hosts, mostly small mammals and birds, but the dominant hosts are rodents (e.g., white-footed mice, Peromyscus leucopus; eastern chipmunks, Tamias striatus; western gray squirrels, Sciurus griseus; and dusky-footed woodrats, Neotoma fuscipes) and shrews (e.g., Blarina brevicauda and Sorex cinereus) (Mather et al, 1989;Lane and Brown, 1991;Lane, 1992, 1996;LoGiudice et al, 2003;Lane et al, 2005;Brisson et al, 2008). Humans become infected when bitten by a tick that was previously infected while feeding on an infected host.…”

The wild life of tick-borne pathogens

“…The original framework 77 was created to quantify the relative importance of different host species in infecting I. scapularis larvae with B. burgdorferi in three study sites in North America. We modified the equations to quantify the relative importance of host species in the feeding of I. ricinus as well as the relative importance in infecting larvae with B. burgdorferi.…”

“…RI bbi is the relative importance of species i in infecting larvae with any genospecies of B. burgdorferi and is equivalent to the relative reservoir capacity used by Kahl et al 78 or the reservoir potential of Mather et al 77 . This parameter could also be seen as the relative contribution of a host species to the pool of infected nymphs.…”