Dissection and internal anatomy of the giant tropical bont tick Amblyomma variegatum.

The tropical bont tick, Amblyomma variegatum, is endemic in sub-Saharan and southern Africa, as well as several Caribbean islands. This tick is deleterious for the general health of ruminants and is the primary vector of Ehrlichia ruminantium, the causative agent of heartwater. Understanding the ecology and biology of A. variegatum is thus crucial to describe tick-host-bacteria interactions and thus develop effective control methods. To better understand vector competence, detailed functional characterization and precise isolation of tick organs is needed. All procedures described in this study were performed using a simple, high-quality binocular magnifying glass. Following this approach, we present descriptions and illustrations of the internal anatomy of A. variegatum at male, female (at various stages of engorgement), and nymph stages. This study focused on critical tissues associated with vector competence, including midguts, salivary glands, or ovaries, which were targeted and isolated. We identified morphological differences in the reproductive systems of both A. variegatum male and female ticks when compared with other tick species. We also provide numerous practical and technical aspects for obtaining organs suitable for detailed studies. The method presented here ensures organs of high quality, without degradation or contamination, as required for cellular or molecular studies on host-vector-pathogen interactions.