ABILITY OF EXPERIMENTALLY INFECTED CHICKENS TO INFECT TICKS WITH THE LYME-DISEASE SPIROCHETE, BORRELIA-BURGDORFERI

Chickens were used as a laboratory model to determine the conditions a ffecting the ability of birds to infect ticks with Lyme disease spiroc hetes. Chicks (Gallus gallus) were exposed to 12 nymphal Ixodes scapul aris at one week or three weeks of age. Xenodiagnostic larval ticks fe d on these birds at weekly intervals thereafter. Chicks exposed to inf ected nymphs at one week of age infected 87% of larvae at three weeks of age, but only infected 3% of larvae at four weeks and 0% of larvae at five weeks. Chicks exposed to nymphs at three weeks of age infected only 12% of larvae at four weeks, and 0% thereafter. Thus, experiment ally infected chicks can infect larval ticks, but only for a brief int erval after exposure. Young chicks are more infectious than older chic kens. The immune response of infected chicks was rapid and directed ag ainst diverse antigens.