350 PARASITES OF THE DOMESTIC ANIIVIALS 



not exceeding 105° F. The anaemic condition is indicated by the paleness 

 of the visible mucosae, and the extended course brings about great 

 emaciation. In these cases hemoglobin is not usually passed with the 

 urine, hence hemoglobinurea or ''red water," typical of the acute form, 

 is absent. 



Death rarely occurs in this type of the disease, though, due to its 

 prolonged course and the excessive loss of flesh, much loss is sustained 

 in the productive valuation of the animal. 



Prevention and Treatment. — Prevention is by measures dealing 

 with the cattle tick Margaropus annulatus, which is the specific carrier 

 and transmitter of the protozoan causing the disease. As study of the 

 life histoiy of this tick has shown that it will not mature except upon a 

 bovine or equine host, it follows that it can be exterminated from in- 

 fested pi-emises by keeping cattle and horses off of such premises until 

 the larval ticks, unable to find a host, have perished. With this purpose 

 in view, systems of pasture rotation have been devised additional to 

 methods directed toward the destruction of ticks on the cattle (Ref. 

 Margaropiis annulatus, p. 145). 



Medical treatment of animals sick with Texas fever has not proved 

 satisfactory. In the milder type of cases the constipation may be re- 

 lieved somewhat by Epsom salts. Repeated doses of digitalis during 

 the excessive anaemia and the administration of tonics, such as gentian 

 and nux vomica, during the stage of convalescence, have been recom- 

 mended as beneficial. The recovering animal should have free access 

 to pure water and a generous supply of nutritious food. 



Order III. Sarcosportdia 



Sporozoa (p. 336). — The Sarcosporidia are parasites in striated 

 muscle cells of vertebrates. Sporulation takes place during the develop- 

 ment of the trophozoite which becomes surrounded by a protective 

 envelope. 



These muscle parasites are found in man, in domestic and wild birds, 

 and are common in domestic mammals. The muscles more commonly 

 invaded are those of the upper part of the esophagus, larynx, the body 

 wall, the diaphragm, and the psoas muscles. 



Development. — Within the muscle fiber the parasite first appears as 

 a minute body in which stage it is known as Miescher's tube. As the 

 young ti'ophozoite develops it becomes multinuclear and surrounded by 

 a membrane, while groups of spores form in the center of the proto- 

 plasmic body. With the continuation of the spore formation the cyst 

 enlarges, causing such distension of the muscle fiber as to result in its 

 rupture, releasing the cyst which ultimately bursts, the spores thus 

 becoming scattered to infest new muscle cells. By repetitions of this 



