INTERSTADIAL AND INFESTATION LEVEL-DEPENDENT VARIATION IN THE TRANSMISSION EFFICIENCY OF BORRELIA-BURGDORFERI FROM MICE TO IXODES-RICINUS TICKS

The efficiency with which the spirochaete Borrelia burgdorferi sensu s tricto was transmitted from laboratory mice to larval and nymphal Ixod es ricinus ticks was assessed, using the polymerase chain reaction. Th e transmission efficiency to nymphs was significantly greater than to larvae when both fed together on the same host. Increased tick infesta tion levels of mice were correlated with significantly greater engorge ment weights and higher B. burgdorferi transmission coefficients from mice to nymphs. These observations indicate that both the feeding succ ess of ticks and the transmission coefficients from host to tick may b e influenced by the tick infestation level of an infected host. The in festation level and the relative numbers of each life stage of the tic k are factors which should be considered in the design of transmission experiments. (C) Chapman & Hall Ltd.