516 DISEASES OF CATTLE. 



of the parasite is not known, but infection is apparently derived 

 through the medium of pastures where infested cattle have grazed. 

 In the later stages of the disease the cattle cough, especially at night. 

 Young cattle are more seriously affected than old animals. 



Treatment for lung worms. — Various treatments have been advo- 

 cated for lung worms, including fumigating with different substances 

 and injections of remedies into the trachea by means of a large hypo- 

 dermic syringe, but none has been very successful from a practical 

 standpoint. About all that can be done is to feed affected animals 

 well and protect them from exposure. 



PARASITES OP THE BLOOD. 



A species of fluke {Schistosoma bovis) which lives in the blood ves- 

 sels (the large veins) of cattle in tropical and subtropical countries 

 causes bloody urine, and a condition of the rectum somewhat resem- 

 bling piles. 



The embryos of Filaria labiato-papillosa (p. 515) which occur in the 

 blood may be found by microscopical examination. They apparently 

 cause no trouble. 

 The organism which causes Texas fever is a protozoan parasite 



(Piroplasma bigeminum) of micro- 

 scopic size, which lives in the blood 

 and attacks the red blood corpus- 

 cles. For a discussion of this para- 

 site and the disease which it pro- 

 duces see page 461 of this volume, 



Fig. 27.-Lung worms (Dictyocaulus vivipa- QJ . f Qr mQre comp l ete information 



rus) of cattle. r 



consult Farmers Bulletin No. 258, 

 which can be obtained free on application to the Secretary of Agri- 

 culture, Washington, D. C. 



Other parasites which live in the blood cause serious diseases known 

 as surra and nagana (p. 493), but as yet neither of these diseases has 

 gained a foothold in the United States. 



PARASITES OF THE EYE. 



Roundworms sometimes seen swimming about in the anterioi 

 chamber of the eye ("snakes in the eye") are supposed to be imma- 

 ture stages of Filaria labiato-papillosa (see p. 515). Their location 

 in the eye is possibly due to their going astray from the normal course 

 of their migration. Treatment for these worms is surgical. They 

 often disappear without treatment. 



A species of slender roundworm, one-half an inch to an inch in 

 length, has been described, under the name of Filaria lachrymalis, as 

 a parasite of cattle found in summer and fall beneath the eyelids and 

 on the surface of the eyeball, causing an inflammation of the eyes. 

 The worms may be removed by washing out the eyes with an anti- 

 septic, such as a weak solution of coal-tar stock dip, after which 

 iodoform ointment may be applied if the condition is severe. 



