1932 ANNUAL REPORT. 1931 15 



The lung tissue shows marked engorgement of all blood vessels. The lobules 

 are separated from one another due to the engorgement of the capillaries. The 

 intense filling of the capillaries causes a stretching of the capillary wall which 

 often ends in its rupture. Extravasation of red blood cells into the surrounding 

 tissue from the ruptured capillary wall takes place. Often a rupture in the walls 

 of the alveoli or air sacs has occurred, and extravasation of red blood cells occurs 

 into the air sac, in some instances completely filling it. 



Distemper in Mixk 



An infectious disease of m.ink in many respects closely resembling distemper 

 as seen in the ferret and fitch was reported during the year from several points. 



One particular outbreak undoubtedly resulted from the introduction of 

 infected fitch into the mink ranch. The ranch is a model one and the animals 

 are given the best of care and attention. No disease had ever been experienced 

 until the fitch were brcught in. Two or three days after the fitch arrived one 

 was noticed to be sick with distemper symptoms. The destruction of the fitch, 

 and "torch" and disinfection of the nest boxes and mink house was advised. 

 This was done, but frcm eight to ten days later several mink were taken sick 

 and died. A number of these were nursing females with litters of young. 



The symptomiS were very varied as is always the case with epidemics among 

 fur-bearing animals. In some cases there is a distinct swelling around the eyes 

 which may become mucopurulent. In others there is a localization of pus 

 above the eye but it does not affect the eye proper. The vulva in a number of 

 females becomes swollen and red and the feet have a tendency to swell. This 

 swelling is of an emphysematous nature. The guard and underfur in most cases 

 shed off from the base of the neck to the shoulder. This symptom is characteristic 

 of other diseases affecting mink and is often found in malnutrition cases. With 

 some, the appetite is affected but little, and they will eat up to a few hours 

 before death. Diarrhoea is noticeable. The duration of the disease is very 

 irregular. One animal may appear to be quite normal and suddenly give forth 

 a piercing screech, go into convulsions and die in an hour or two. Others may 

 drag on for as long as five weeks. These cases invariably develop severe chorea 

 and die in convulsions. In some cases an emphysematous swelling is seen around 

 the nostrils and in others there is a profuse purulent discharge from the eyes 

 and nostrils. The incubation period appears to be within ten to fourteen days, 

 but this is difficult to estimate under field conditions. The mortality is high, 

 at least thirty per cent., even where strictest precautions regarding isolation 

 and disinfection are taken. A few mink recover after showing symptoms, but 

 the percentage is very small. 



Post-mortem examinations on fur-bearing animals dying from distemper 

 are very unsatisfactory and the lesions remarkable by their absence. The fact 

 that definite lesions are absent can almost be accepted as diagnostic. The 

 carcass may be thin and emaciated or on the other hand in a good state of 

 nutrition. The brain in some cases appears to be inflamed and the blood 

 vessels engorged, but sections made from these cases showed no microscopic 

 lesions. \A here diarrhoea is present the intestines are inflamed as would be 

 expected. The liver may be yellow and ver\' friable, but this is a common 

 condition in many ailments of the mink. 



Four ferrets were infected with a brain and spleen emulsion from the 

 infected mink. These animals died showing all symptoms of true distemper 

 as it affects ferrets. 



