INTESTINAL ROUND WORMS. 



Sheep in this country harbor at least six species of round worms, 

 parasitic in the small and large intestines, which their ancestors brought 

 with them from Europe. They are : StrongidusJilicollis,Jind.; Strongij- 

 his ventricosus, Rnd., both found in the duodenum ; Dochmius cernuus, 

 Creplin, found in the small intestine; Ascaris Iwnbricoides, Linn., also 

 found in the small intestine; Trichocephalus affinis, llud., found in the 

 ctecum ; Sclerostoma liypostomunij Diesing, found in the large intestine. 

 A seventh species, (Esophagostoma Coiumbianum, Curtice, is found in 

 the large intestine and is probably indigenous to this country. Of all 

 these the last species i)roduces by far the most injury. Dochmius cer- 

 nuus is uext in importance. The injury inflicted by the others may, at 

 times, and in conjunction with other parasites, be considerable ; but 

 disease which may be ascribed to either species alone has not yet been 

 reported. From personal observations it is believetl that the number 

 of individuals in each sheep are usually too few to ever cause extensive 

 loss, and that their greatest harm is from the little discomforts which 

 thej^ may add to those produced by the more destructive parasites. 



At certain seasons of the year some of the above species are abun- 

 daut, while at other times but few individuals may be found. Strongy- 

 lus Jilicotlis and S. ventricosus are usually found associated together, but 

 are so small that they can easily be overlooked, or if found may be re- 

 garded as the young of other species. Dochmius cernuus is about an 

 inch long, and being large is readily detected. Ascaris Imnhricoides is 

 rare, having been met with only a few times by helminthologistsin any 

 country, and in but one lot of sheep by the author. Trichocephalus 

 affinis is usually found in young sheep, but is met with in comparatively 

 small numbers. Sclerostoma hyposto mum seems to be a rare species in 

 the East, the single instance in which it was met with in these investi- 

 gations being in examining an old sheep in Colorado. (Esophagostoma 

 Golumbianum seems to take the place of the last-named species in the 

 East, and is found most abundantly in spring and summer in its adult 

 state, although it is present throughout the year. The most favorable 

 time for collecting most of these species has been in late fall and win- 

 ter. The quantities in which the various species may be found vary 

 with the season and the flock examined, so much so that no accurate 

 statements of percentage of occurrence or of distribution can be made. 



The symptoms which these worms i)roduce are those of general debil- 

 2303S A P 10 145 



