14 



CIRCULAR 14 8, U. S. DEPARTMENT OF AGRICULTURE 



worms were present in the lungs and in the windpipe and its 

 branches. It is probable that similar symptoms are present in heavy 

 ascarid infestations which are acquired naturally in stables and on 

 pastures. Ordinarily, ascarid infestations in foals result in un- 

 thrifty animals with rough, staring coats, and the removal of the 

 worms frequently leads to marked improvement in condition, hair 

 coat, and gain in weight. 



Thus it is evident that the ascarid, both as an adult and as a 

 wandering larva, has the capacity for causing great damage, and 

 that its presence in horses, especially foals, is a possible source of 



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Figure 



-Life cycle of the horse ascarid, Ascaris equorum. The e£ 

 this illustration are enlarged about 50 times 



cs shown in 



danger. Heavy infestations, in which hundreds of worms may be 

 present, may cause illness and even death as a result of the horse's 

 absorption of toxic products produced by the worms. 



Treatment. — Carbon disulphide is an effective remedy for the re- 

 moval of ascarids from the horse. The drug is given as follows : 

 Fast the animal for 18 hours and give carbon disulphide in a close 

 of 6 fluid drams (24 cubic centimeters) for a 1. 000-pound animal or 

 at a dose rate of 1.5 fluid drams (6 cubic centimeters) for each 250 

 pounds of weight. The worms usually pass for several days follow- 

 ing treatment. Purgatives should not be given with this treat- 



