424 PARASITISM AND DISEASE IN RUFFED GROUSE 



The heaviest infection observed during this Investifration was 45 worms, the presence of which 

 caused only minor lesions in the gizzard. T^Tiether these parasites would have caused severe 

 damage in time can only be conjectured. 



Incidence and Importance. Gizzard worms were found in birds from practically all areas 

 of the State. The incidence of infection gradually rose from none in grouse chicks less than 

 a month of age to II. 1 per cent infection in the spring and summer adults. The incidence of 

 parasitism with this worm in grouse of three months or over was 7.8 per cent. This figure 

 covers the total number of birds examined in this survey. 



There was no significant difference in the incidence of this parasitism from vear to year. 

 Though the pathogenicity of this worm for birds has been demonstrated in certain instances, 

 in the light of observations during the Investigation, gizzard worm infection is considered to 

 be of little consequence in controlling grouse abundance. 



Large Roundworm (Ascaridia honasae) 



Distribution. This parasite has been found in ruffed grouse in Maine. Michigan. Minne- 

 sota, Wisconsin, Pennsylvania. Massachusetts, and has been found to be widely distributed 

 throughout the three regions in New York. Its distribution in other birds is uncertain. Until 

 recently, A. honasae was not distinguished from another form. .4. lineala. which is common in 

 poultry and has been reported in various species of game birds. 



Description. Ascaridia honasae is a fairly large, whitish, roundworm commonly found in 

 the small intestine of wild grouse. The males measure up to 1% inches long and the females 

 up to 2 inches. A complete description is given by Wehr'"'. Quite often these worms are 

 found within the body cavity of grouse that have been shot, for perforation of the intestine 

 permits the parasites to escape. 



Life Cycle and Dissemination. AckertV description of the life cycle of A. lineata of the 

 chicken is summarized below. It is probable that the life cycle of A. honasae is quite similar. 



In the intestine of the bird, the female worms lay eggs which are eliminated with the feces. 

 Under suitable conditions of temperature and moisture, enibrvonalion takes place in from 12 

 to 16 days. After the birds take in these embrvonated eggs with the feed and water, the young 

 larvae are liberated in the forepart of the small intestine. During the first nine days the larvae 

 live in the intestinal interior. During the following week, development and growth proceed 

 within the tissues of the gut. At the end of this time the worms emerge from the intestinal 

 wall and remain in the interior until maturity is reached. This occupies about .SO davs. 



Ackert and Herrick" and Levine'^ have noted that in chickens there is a definite age imniiiMity 

 to A. Hneata. Furthermore it has also been established that not all of the young worms that 

 emerge into the inside of the intestine succeed in establishing tbcmsclvcs. The viabilitv of the 

 eggs of A. lineata has also been investigated by Ackert and Cautlien". and Lcvinc'^. In gen- 

 eral, drying and exposure to the sun has a marked lethal effect on the ova. while weathering 

 in the shade tends to greatly prolong the period of survival. 



I,evine"° showed that the length of time the eggs remain viable when exposed to the cold de- 

 ])cnds on whether or not thev are embrvonated. Kinbr\onatfd ova were destroyed after two 

 weeks of freezing while non-embryonated ova survived a severe New York winter and devel- 

 oped the following spring. It is safe to sav that pmbablv all of these factors plnv a part in 

 infections of wild grouse. 



Pathogenicity. The harmful effect of A. lineata infection in young chickens has been des- 



