Heartwater in Senegal: experimental study of the disease and morphology ofCowdria ruminantium infectious forms.

Five Cowdria ruminantium samples isolated in Senegal have been used for an experimental study of heartwater and the description of the morphology of t he organism. The clinical signs and lesions noticed are those commonly describe in the l iterature, but they are not seen in the same animal. The most characteristic forms of Cowdria ruminantium are represented by the small to medium sized organisms which measure from 0.2 to 0.5 mu m in diam eter for the coccoid forms, 0.2-0.5 mu m in wide to 0.4-0.8 mu m in lengh f or the cocco-bacillary bodies. These different forms present various stanin gs related to their size : the smallest organisms stain a reddish purple an d the medium-sized a dark-blue. The paraffin and semi-fine sections were al so used to bring to the fore other staining affinities of the germ by the M allory technique and the use of toluidine bleu. The electron microscopy sho ws in the same colonies the presence of the less dense electron-pale forms and the intermediary electron-dense bodies.