Ecology 2003

• Main Authors: British Ecological Society, M. K. Laurenson, R. A. Norman, L. Gilbert, H. W. Reid, P. J. Hudson
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2003
• Subjects: Hudson; Lepus timidus
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.61.6486; http://www.personal.psu.edu/pjh18/downloads/138_Laurenson_et_al_2003_Hares_as%20_reservoirs_J_Anim_Ecol.pdf

this paper we examine the role of a putative new reservoir host in a complex system of a generalist pathogen with a non-specific vector, the louping-ill virus and the sheep tick (Ixodes ricinus L.). This virus can infect a range of domestic and wild vertebrate hosts such as sheep, cattle, pigs, red grouse (Lagopus lagopus scoticus Lath), red deer (Cervus elaphus L.), mountain hares (Lepus timidus L.), roe deer (Capreolus capreolus L.), short tailed voles (Microtus agrestis L.) andhumans. The virus is transmitted through the tick vector and causes encephalomyelitis in susceptible hosts. In upland Britain, only two numerous vertebrate hosts, sheep and red grouse, exhibit a post-infection viraemia sufficient for feeding tick instars to acquire the virus and thus allow vector--host--vector transmission (Beasley, Campbell&Reid 1978; Reid 1978). Red grouse were not thought to be a reservoir host for two reasons (Reid 1975; Reid 1978; Hudson 1992). First, it was argued first that high grouse mortality rates would lead to a decline in red grouse productivity and therefore reduce the population below the critical community size for viral persistence. Second, adult ticks rarely feed on birds and so grouse could not support the vector population. Louping-ill virus persistence has therefore traditionally been considered to be largely dependent on sheep (Reid 1978), which could sustain both tick and virus populations. Thus the removal of sheep, or their effective removal through the use of acaracides and vaccination against louping-ill virus, is predicted to lead ultimately to louping-ill eradication. Despite the vaccination of adult sheep for over 30 years, the disease is poorly controlled in red grouse in certain regions of the Scottish Highlands (Hudson et al. 1995). Several hypo.