A comparative study was made of tick-borne fever in sheep in
Scotland, and bovine petechial fever in sheep and cattle in Kenya.
The results obtained demonstrated the similarity of the two diseases.
Both are caused by rickettsia-like organisms observable principally
in the neutrophils, and tentatively classified in the genus Cytoecetea.
These were considered to be morphologically identical.
Clinical signs and necropsy lesions of experimental animals were
noted. The parameters of normal infections with both diseases were
defined, with reference to haernatological, febrile, and parasitaemic
responses. The distribution of the causative organisms in infected
host at different stages of reaction was investigated by infectivity
studies; spleen and lung were found to contain the highest titros.
A latent infection was a more common sequel to tick-borne fever
than to bovine petechial fever.
A complement fixation test was de^loped for tick-borne fever,
antigen being prepared from infected leucocytes. Similar methods
proved only partially successful for bovine petechial fever.
A hitherto unsuspected breed difference in susceptibility to
bovine petechial fever was observed, and thereafter Sahiwal cross
cattle were used routinely
Investigations were made into the potential role of wild ruminants
in the epidemiology of bovine petechial fever, by experimental inocul¬
ation of captive wild animals. Several species were found to allow
multiplication; as a corollary to this, isolates of the causative
organism were made from wild bushbuck in an enzootic area.
Three antibiotics were compared in the treatment of patent
bovine petechial fever reactions in sheep, and the most efficacious
of these (dithiosemicarbazone) was used successfully to treat the
disease in cattle.