Susceptibility of mice (Mus musculus) to repeated infestation with Amblyomma americanum (Acari: Ixodidae) ticks.

Laboratory mice, Mus musculus (L.), BALB/c strain, were assessed for their ability to develop resistance to repeated infestation by Amblyomma americanum (L.) ticks.

Reinfection with Anaplasma phagocytophilum in BALB/c mice and cross-protection between two sympatric isolates.

Infection with Anaplasma phagocytophilum in white-footed mice results in partial protection against reinfection with the same agent. However, humans and domestic animals may be sequentially exposed to different isolates of the agent circulating in the same or adjacent foci. We investigated whether immune response to a tick-borne infection with A.

Effects of Anaplasma phagocytophilum infection on the molting success of Ixodes scapularis (Acari: Ixodidae) larvae.

We assessed the effects of sympatric (occupying the same or overlapping geographic areas) and allopatric (occurring in separate geographic areas) isolates of Anaplasma phagocytophilum on the survival of Ixodes scapularis Say larvae that were derived from ticks collected in Bridgeport, CT. Seven isolates of A. phagocytophilum, originating from different geographic regions of the United States, were tested: four isolates from the northeast (Bridgeport, Dawson, Gaillard, and NY-8), two from the Midwest (Webster and Sp-Is), and one from California (MRK).

Acquisition of different isolates of Anaplasma phagocytophilum by Ixodes scapularis from a model animal.

The prevalence of etiologic agents in ticks reflects the intensity of their transmission in natural cycles and is an important measure of their potential to cause human disease. The distribution of Anaplasma phagocytophilum within the range of its primary vectors is patchy. Even nearby sites differ dramatically in the prevalence of Anaplasma in questing ticks.