Volume II 
No. 4 
DECEMBER, 1909 
OBSERVATIONS ON THEILERIA PARVA , THE 
PARASITE OF EAST COAST FEVER OF CATTLE. 
By GEORGE H. F. NUTTALL, F.R.S., H. B. FANTHAM, D.Sc., 
and ANNIE PORTER, B.Sc. 
(Two charts and four diagrams.) 
Although a good deal has been written about East Coast Fever 
in cattle, the literature relating thereto contains very little direct 
information regarding the parasite which stands in causal relation to 
the disease. Robert Koch (1898), who was the first to observe the 
parasite in cases of East Coast Fever occurring in German East Africa, 
regarded it as but a variety of Piroplasma bovis (= bigeminum ) and 
described the disease as Texas Fever. Theiler (1904) was the first to 
distinguish clearly East Coast Fever from Redwater. He stated that 
“the disease has nothing to do with Texas Fever or Redwater; it is a 
new disease due to a parasite different to the one found in Texas Fever.” 
Koch (1903—1904), who gave the disease its distinctive name, reached 
the same conclusions as Theiler. The investigations of Theiler (1904) 
established the following facts: Cattle which are immune to Redwater 
are susceptible to East Coast Fever. East Coast Fever is not com¬ 
municable by blood inoculations (30 experiments, wherein 5 to 2000 c.c. 
of East Coast Fever blood were inoculated). He noted the absence of 
haemoglobinuria in the majority of animals affected with East Coast 
Fever, its presence in the majority of the animals affected with Redwater. 
He found that in most cases of East Coast Fever, there was no appreciable 
decrease in the number of red blood coi-puscles, this being in marked 
contrast to what is observed in Redwater. Theiler noted that cattle 
might harbour both the parasites of Redwater (P. bovis) and those of East 
Coast Fever (bacillary forms = T. parva). The former generally appeared 
Parasitology n 21 
