16 DEPARTMENT OF GAME AND FISHERIES No. 10 



Since the diet for both groups of foxes was similar and all intestinal 

 parasites were removed, the possibilities of anaemia arising from either 

 nutritional or parasitic sources was eliminated. 



THREE-EAY INTERVALS 



The investigation included counts at three-day intervals of the red and 

 white corpuscles and the hemoglobin. The standard for the normal blood 

 of foxes used throughout the work was that established by Kennedy (1933). 



Hemoglobin is the term used to express the oxygen carrying capacity 

 of the blood corpuscles and a balance is maintained in the normal fox 

 between the red corpuscles and hemoglobin at constant levels. 



An increase or decrease in the red corpuscles and hemoglobin may take 

 place in disease and in cases where there is an actual loss of blood, for 

 example in flea infestations, anaemia results. 



By using the red blood and hemoglobin count, the severity and grade 

 of anaemia produced can be estimated by numerical methods. 



In the course of the work a sudden and severe anaemia occurred in the 

 ten foxes under observation, which coincided with the appearance of fleas. 

 Until this date the red blood count and hemoglobin were within the normal 

 range for four to five month old foxes. 



The group averaged from six to seven million red blood corpuscles 

 per cubic millimetre and between sixty and seventy per cent, hemoglobin. 



DIMINISHING A\'ERAGE 



With the appearance of fleas the red corpuscles dropped from an aver- 

 age of nearly seven million to an average of four million, while the hemo- 

 globin dropped from an average of 65.3 per cent, to 38.3 per cent. 



In some cases the anaemia was more pronounced than in others. In 

 one fox the red blood corpuscles dropped from six to two and a half million 

 and the hemoglobin from 63 to 21 per cent. 



By referring to the tables the exact numerical data can be obtained. 



These figures clearly indicate that the common fox flea (Ctenocephalus 

 canis) can be a dangerous pest if present in any number. 



PRONOUNCED REDUCTION 



The pronounced reduction in red corpuscles and hemoglobin would 

 leave the fox with little or no resistance to such adverse conditions as 

 internal parasites, infectious diseases or tainted food. 



Unquestionably the growth and development of pups would be seriously 

 affected and if the cause of the trouble were not removed it might lead 

 directly or indirectly to the death of the animal. 



Following a suitable treatment which rid the foxes completely of all 

 fleas, the red blood corpuscles and hemoglobin immediately commenced to 

 rise. 



It is interesting to note that the counts reached higher levels than is 

 normal for foxes of this age. Apparently, once the source of the anaemia 

 was removed, the blood system responded very actively in replacing the 

 loss of blood which had occurred. 



