Africa regional award AFR-0000-C-6003 · 1987–1989 · nutrition · University of Florida

The bont tick, Amblyomma hebraeum Koch, is the major vector of heartwater (caused by Cowdria ruminantium) to ruminants in southern Africa. It can become infected in preadult instars and subsequently transmit the organism transstadially and to susceptible hosts. To fully understand the epidemiology of heartwater it is necessary to determine infection rates in field-collected ticks. Also, the production of adequate numbers of organisms from ticks for development of vaccines and diagnostic tests depends upon an understanding of the susceptibility of vector sub-populations to various strains of the organism. Numerous techniques, including animal inoculation, microscopic examinations, and serological and biochemical screening, have been used to demonstrate infectious organisms in vectors. However, some of these procedures are poorly sensitive for heartwater, or are costly, time-consuming, or unavailable in countries affected by the disease. We report distinctive staining of C. ruminantium in paraffin-sections of A. hebraeum midgut. This simple technique may be applicable to sampling of field populations of Cowdria-infected ticks as well as to assays of infectivity in laboratory-re

Source: DEC abstract, PN-ABC-616 (1987). The source's own text.