[Studies in the field of tick-borne blood parasites].

A review of 'piroplasmosis' (a collective name tick-borne protozoan forms of disease of the blood (babesiasis, theileriasis) as well as rickettsial forms (anaplasmosis), written by De Blieck and published in 1916, is compared with the present state of our knowledge. Considerable progress has been made in classifying the causative agents. Moreover, the situation in the Netherlands has become much clearer. However, as regards the situation in the tropics, progress in control is rather limited and these forms of disease continue to be of major economic importance. The use of ascaricides is becoming increasingly confronted with problems and, in particular conditions, the use of cattle characterised by a considerable genetically acquired ability to produce an immune response to ticks is growing. In addition, it is hoped that it will be possible to immunise animals both against ticks and against tick-borne disease using characterised antigens produced by modern biotechnological methods in the future. Finally, a warning note is sounded that the active role of the faculty of veterinary science in the field of tropical veterinary medicine could well be reduced in the near future as a result of economies and changes of structure.