Lethal Effect ofRickettsia rickettsiion Its Tick Vector (Dermacentor andersoni)

• DOI: 10.1128/aem.65.2.773-778.1999
• Publication Date: 2019-12-19T19:47:12Z
• Authors: Mark L. Niebylski; Mort G. Peacock; Tom G. Schwan
• Keywords: DNA, Bacterial; Nymph; Virulence; Guinea Pigs; Rickettsia rickettsii; Feeding Behavior; Polymerase Chain Reaction; 3. Good health; 03 medical and health sciences; 0302 clinical medicine; Larva; Animals; Arachnid Vectors; Female; Fluorescent Antibody Technique, Indirect; Rocky Mountain Spotted Fever; Dermacentor

ABSTRACTRickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, was lethal for the majority of experimentally and transovarially infected Rocky Mountain wood ticks (Dermacentor andersoni). Overall, 94.1% of nymphs infected as larvae by feeding on rickettsemic guinea pigs died during the molt into adults and 88.3% of adult female ticks infected as nymphs died prior to feeding. In contrast, only 2.8% of uninfected larvae failed to develop into adults over two generations. Infected female ticks incubated at 4°C had a lower mortality (80.9%) than did those held at 21°C (96.8%). Rickettsiae were vertically transmitted to 39.0% of offspring, and significantly fewer larvae developed from infected ticks. The lethal effect ofR. rickettsiimay explain the low prevalence of infected ticks in nature and affect its enzootic maintenance.