1931 ANNUAL REPORT, 1930 15 



to be noted that in the outbreaks under observation no adults contracted the 

 disease although many were equally exposed to the infection. The second type 

 is that of broncho-pneumonia, and both pups and adults may be equally 

 affected. The fox appears to have little resistance to either type and clinical 

 cases seldom recover. If the infection is unchecked the mortality is extremely 

 heavy, often reaching from 60 to 100 per cent, of the exposed susceptible animals. 



LOBAR PNEUMONIA 



Cause. — A virulent hemolytic streptococcus has been isolated from all cases 

 examined. The infection is found in pure culture in the lungs. Smears of the 

 bloody serum oozing from the cut surface of the lesions when stained will be found 

 to be swarming with gram-positive short-chain streptococci organisms. 



Courseand Characteristics. — In our experience only pup foxes will be attacked. 

 Dr.F.W.Schofield^ also reports this to be true in an outbreak investigated in 1929. 

 Sometimes the entire litter of four- to five-month old pups will be wiped out while 

 the female in the same pen remains healthy. Cases may appear suddenly but can 

 generally be traced to one or two pens from where the infection has spread or 

 been carried to several parts of the ranch. The history is usually that one or 

 two pups of a litter have died but the owner has not been alarmed until the 

 infection appeared in several adjacent pens. It is to be noted that outbreaks 

 studied have always occurred on ranches where there was lung-worm parasitism. 

 Lung worm and weak pups will often be the first cases. 



Symptoms. — Pups may be picked up dead without showing any previous 

 symptoms. Usually, however, pups in excellent health and with previous good 

 appetites will be noticed to miss their feed. In a few hours they will stand about 

 with heaving sides and in apparent distress. The breathing is heavy and 

 laboured and especially will this be noticeable if they are chased about the pen 

 for catching. Bloody froth may appear at the nose. The affected pups become 

 weaker and finally die in a coma. Most cases die in 24 hours but some few may 

 last for a week. 



Autopsy. — The carcass is usually in excellent condition unless the fox has 

 lasted longer than the usual one to two days. If the animal has been sick for a 

 week or more the carcass will be thin and emaciated. Bloody froth drops from 

 the nose if the carcass is elevated by the hind legs. On opening the thoracic 

 cavity bloody wine-red serus fluid is often present. The entire lung tissue will 

 be greatly swollen and congested. The colour is dark red from the engorged 

 blood which makes the lung tissue appear like liver-red hepatization. Bloody 

 serum oozes from the cut surface of the lung. The thoracic lymph glands are 

 enlarged and acutely inflamed. The other body organs are usually normal. 

 The characteristic post-mortem with the engorged lung tissue is diagnostic. 



BRONCHO-PNEUMONIA 



Cause. — A mixed infection is present with a virulent streptococcus as the 

 predominant organism accompanied by staphylococcus and colon. 



Course and Characteristics. — The disease is a typical pneumonia with sickness 

 lasting about three days to one week in adults. When pups are attacked they 

 succumb in a few days. Foxes of all ages will contract the disease if equally 

 exposed to infection. The history is usually that a few adult foxes have been 



lOntario \'eterinary College Report, 1929. 



