FAIJMKKS l.NSn irTKS. 



sol 



wuiiiis. .Mrii who trt'.-ii li<i;;s fof boa rlKilcr.i .111(1 swiiu- |>l:i;;ur. .iml who 

 fretnu'Utly exjunino liojis that (lie of this discast', an- (iiiitc laiiiiliar with 

 this parasito and roitoit it as iK'iiiix very coiumoii. 



Ik'sci-iptlou.— The ascaris suiUa diijanliii is a hirixc nmiid wuini. tapci- 

 iiijj at both ends, milky white or yellowish white in color, ami liaviu;; a 

 tirni ehistic body and a distinet difjestivi' traet. The female is abont 

 eisht inches in length and one-fifth of an inch thick. The male about six 

 inches lonu' and one-eij^hth of an inch thick. The head is small and 

 armed with three lips, the npi)er one having a pai)illae ai each of its 

 inferior angles, the other two at the middle of their base. The female 

 organs consist of a pair of convoluted tubes, each of Avhich dilates into 

 a uterus, and Itoth uniting to form a single tulie, the vagina. The vulva 

 is situated toward the anterior third, in the middle of ;iii auular con- 

 striction. The male organs are simple, consisting of a single tube, con- 

 volute<l. <lilated below to form a sendnal vesicle and terminating in an 

 I'jaculating duct, which oiiens into the cloaca. The posterior extremity of 

 the male is furnished with a large Tuiiiibci- of pai)illae. some of which are 

 back of the anus. The ova are about one roui-huiubedths of an inch 

 long. 



Source of Infection. Tin- eggs of the .iscaiide arc passed out with the 

 excreta and drop on tlie giound. Moisture aiid waiinlli .ire m-cessary for 

 their hatching. They .ire veiy resisting to .adverse conditions and may 

 resist ilying for some time. When the conditions are favorable, the eggs 

 hatch outside of the body, and the pig beconu'S infected by taking the 

 inunatuie form of tlie worm into the digestive tract along with the food;- 

 or the endiryo when well formed in the egg is taken into the digestive 

 canal, the shell dissolved by the digestive .juices and the endiryo liberated. 



The hog becomes infected through its food sujiply. The embry<»nic 

 worms may be swalhtwed in tiie drinking water or with its food. Karth 

 eating i)igs are pretty sure to become atTected. Feeding hogs on dirt.v 

 floors or on the ground and drinking from jionds .md dirty watering 

 troughs are all .sources of infection. 



Sj-mptujus.— T'nless a number of ascarides .ire present in the intestine 

 no noticeable symi>toms r)f iiarasitism (tccur. Not infrequently the pigs 

 become unthrifty and woiins may be jmssed in the stools. Win-never the 

 general conditions an' such as to bring about a stunted condition, the pig 

 m;iy berome seriously infested. The iriit.itioii to tin- intestine greatl.v 

 aggravates such a condition. They act as an obstruction to digestion, 

 and the maintenance of the colony of woimiis taxes the animal severely. 

 It is in jiigs weighing from twenty-live to one hundred iioumls that the 

 most loss from tJiis p.ir.isite occius. In old Ihrift.v liogs round worms 

 are umible to nuUti]ily. and we seldom liml them present in large enough 

 numbers to cause harm. In coiMic<t ion with other conditions, tliey m.i.v 

 cau.se cliromC indigestion. 



TrcaUneiit. — This is botii |)re\enli\r ,iiid incdiciiial. The preveiiiive 



51-A(rri. 



