DEVELOPMENT OF EHRLICHIA-CANIS, CAUSATIVE AGENT OF CANINE EHRLICHIOSIS, IN TICK RHIPICEPHALUS-SANGUINEUS AND ITS DIFFERENTIATION FROM A SYMBIOTIC RICKETTSIA

  • 1 January 1976
    • journal article
    • research article
    • Vol. 37  (2) , 119-126
Abstract
Certain aspects of the development of E. canis, causative agent of canine ehrlichiosis (tropical canine pancytopenia), in R. sanguineus ticks were studied. Partial feeding of nymphs infected as larvae with E. canis was a desirable, if not necessary, preliminary treatment for successful infection of dogs with ground-up ticks. It remains unclear whether feeding increased the number or altered the virulence of ehrlichiae within tick tissues. E. canis organisms were detected by immunofluorescent microscopy in the midgut and hemocytes and by electron microscopy in the midgut and salivary glands of partially engorged adult ticks infected as larvae and nymphs. Organisms were not observed in the ovary. Intracytoplasmic inclusions contained 1-80 elementary bodies, each provided with 2 distinct membranes. Infection of the midgut and salivary gland was confirmed by injecting homogenates of these tissues into susceptible dogs. Staining of gut smears of partially engorged adult ticks by fluorescein-conjugated anti-E. canis antibody was a reliable indicator of the infection.