ASCARID^ 233 



by the horde of parasites in the alimentary canal, is also a morbid factor. 

 Manifestations of the toxemia are often of a nervous character; there 

 is hyperreflex irritability, and convulsions are a not infrequent accom- 

 paniment. 



In general, it may be said of the ascarids that, while they often in- 

 habit the intestines without perceptible indications of their invasion 

 other than their occasional expulsion with the feces, their presence con- 

 stitutes a condition calUng for treatment. They should be expelled by 

 the administration of a vermifuge, in most cases followed by a purgative, 

 and their bodies collected and burned. Not only should the treatment 

 be carried out for considerations pertaining to the health of the host, 

 but to prevent the spreading about of the worms with their eggs and 

 embryos to infest other animals. 



AscaridjB of the Horse 



One species of ascarid inhabits the intestine of the horse, ass, and mule. 



Ascaris equi (A. megalocephala, A. equorum). Ascaridse (p. 229). — 

 This is the largest species of the family. The body is yellowish white, 

 about the thickness of a lead pencil, and somewhat rigid. The head 

 is distinct and bears three lips. The caudal extremity of the male is 

 bordered laterally by two small membranous wings, and ventrally on 

 each side there are 80-100 papillse. The female is considerably longer 

 and thicker than the male. The vulva is situated toward the anterior 

 quarter of the body. 



Length of female: 15-30 cm. (6-12 inches), or it may be somewhat 

 longer. 



Eggs globular, 90-100 microns in diameter. 



The species is found only in Equidse, and lives in the small intestine, 

 occasionally found in other organs by migration. 



Occurrence and Symptoms. — The large ascarid is very common in 

 the sm all i ntestiD£-of the horse. Unless numerous, they do not, as a 

 rule, perceptibly affect the health of their host, often the only evidence 

 of their presence being the voiding of one or more of the worms with 

 the feces. Young animals do not bear the parasitism so well, and in 

 moderate to heavy infestations are likely to manifest serious disturb- 

 ances of a local and systemic character. 



As a result of the irritation to the mucosa there is a chronic intestinal 

 catarrh, and this may be accompanied by a diarrhea which is persistent, 

 or alternating with a hard dry feces covered with slimy mucous material. 

 Colic is a not infrequent symptom, and there may be intervals of more 

 or less t3Tnpany. The worms, when massed in large numbers, are 

 capable of bringing about an obstruction with all that follows such a 

 condition, possibly involving intussusception and even rupture. 



