426 PARASITISM AND DISEASE IN RUFFED GROUSE 



cribed by Ackert and Herrick'. They found that definite symptoms of parasitism and death 

 resuhed from heavy infections. The greatest injury to the birds took place during the 10th 

 to 17th day of the infection when extensive tissue invasion and destruction was occurring. 



Although A. bonasae in grouse was found more frequently than any other nematode, no in- 

 stances of the pathogenic effects of this worm were observed. The worms were nearly always 

 adult and occurred for the most part in small numbers, five being the average number found. 



Incidence and Importance. Grouse chicks pick up the infection when quite voung. 10.5 

 per cent of them becoming infected by the second month after hatching. The following 

 month shows the infection rate more than doubled and from that time on there is a fluctuation 

 in the incidence of infection. A higher percentage of grouse is infected during the summer 

 months and a lower percentage infected during the fall and winter, table 67. The data avail- 

 able suggests that Ascaridia infection is unimportant from the standpoint of brood mortality. 



This large roundworm is one of the most frequently encountered parasites of ruffed grouse 

 in New York State. In its adult stage it feeds on intestinal contents. On account of its size, 

 it is the parasite most often observed and rated as important by amateurs. The number of 

 worms found in each bird is small. In one instance, however. 78 worms were found in the in- 

 testine of a male bird. Despite this heavv infection, no deleterious effects were observed. No 

 significant vearly variation in incidence took place during the course of the Investigation. 



Insofar as this study is concerned, no evidence was uncovered which would indicate thai in- 

 fection with A. bonasae is a factor in reducing the grouse population in the Northeast. 



Large Tapeworm ( RaiUietina tetragona) 



Distribution. This parasite is found in the small intestine, occasionallv in the cecum, of 

 ruffed grouse, chickens, bobwhite quail, turkeys and guinea fowl. It has been reported from 

 Europe and Asia as well as from North and South America. It occurs in all three regions 

 of New York. 



Description. These tapeworms mav attain a length of 10 inches. Thev appear as creamv 

 white ribbons about ^s of an inch broad, composed of manv segments. Thev possess, as 

 a means of attachment, four suckers as well as a crown of minute hooks. 



Lije Cycle ami Dissemination. The segments farthest from the attached end of the worms 

 contain many eggs. As these segments become detached from the rest of the parasite and 

 pass out with the droppings, the eggs become available to various invertebrate animals which 

 serve as intermediate hosts. 



A number of organisms have been reported as the vectors of this common tapeworm of grouse 

 but the most likely suspect in this area is the ant. Horsfall"* reported ants of the genera 

 Tetramorium and Pheidole to be involved in this life cycle. While these particular insects have 

 not been found in the food analyses bv tlic InvcsliLiation. manv of their close relatives are 

 taken by the young chicks. 



Since infection with this parasite must fullnu the eating of some intermediate host, it is not 

 surprising to find that most of the cases of parasitism with this form occur in the wild grouse 

 chicks, whose early diet contains such high amounts of animal matter. Conversely, in the vege- 

 tarian adult grouse this tapeworm is seldom found and when it does occur it represents the 

 chance ingestion of an infected intermediate host. 



Pathogenicity. Although experimental work with tapeworms (Davainea proploltina) in 

 poultry"" has furnished definite e\idence of the deleterious effects of infections with these par- 



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