infection from ticks, tick feces, and debris in 
tin* wool of sheep and they must occasionally 
-hear animals that are actually sick. This 
exposure has resulted in at least 189 cases of 
tularemia of which we have record. At least 
7 cases were fatal. Human infection from 
contact with sheep or from tick bite is apt to 
be severe. The majority of those who had had 
tularemia attributed infection to “contact with 
sheep" or to tick bites. The ulceroglandular 
type of infection predominated and the greatest 
incidence was during the spring months. The 
cases were largely restricted to Colorado, 
Idaho, Montana, Utah, and Wyoming. 
In North America, sheep are the only large 
mammals among which tularemia is known to 
occur in truly epizootic proportions and which 
serve as important sources of human infection. 
The geographic distribution and seasonal 
incidence of tularemia in sheep industry 
employees and the epizootic nature of the 
disease in sheep characterize an epidemio- 
logical entity distinct but yet closely related 
to the tickborne tularemia. The economic 
loss and the number and severity of human 
cases warrant the consideration of this epi- 
demiological type of disease as a veterinary 
medical and public health problem. 
References 
1) McCoy, G. W., and Chapin, C. W.: Further ob- 
servations on a plague-like disease of rodents 
with a preliminary note on the causative agent, 
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January 1912. 
(2) Francis, E.: The occurrence of tularemia in na- 
ture as a disease of man. Pub. Health Rep. 
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■I 1 Khatenever, L. M. (editor): Tularemia infec- 
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(10) Bow, M. R., and Brown, J. H.: Tularemia in the 
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pathology of tularemia. X. The pathology of 
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H. J.: Tularemia, pulmonic form; report of 
four recoveries. J. A. M. A. 109: 258-262, 
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(16) Parker, R. R., Steinhaus, E. A., Kohls, G. M., 
and Jellison, V. L.: Contamination of natural 
waters and mud with Pasteurella tulan nsis 
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Public Health Monograph Xo. 28, 1955 
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