250 PARASITES OF THE DOMESTIC ANIMALS 



According to Noe, some of the larvae are taken with the infected blood 

 into the bodies of blood-sucking insects. From the intestine they 

 migrate to the Malpighian tubes where they undergo a certain degree of 

 development. In about twelve daj^s from the time they entered the 

 body of the insect they pass through the walls of the Malpighian tubes 

 and enter the mouth parts. If the piercing organ of the insect is broken 

 during the act of sucking blood, the animal becomes infected, and the 

 larvse are carried with the blood or lymph to the heart where they attain 

 sexual maturity. 



Grassi demonstrated by his investigations that nearly all of the larvae 

 of the filaria of man die in the intestines of mosquitoes, and that the dog 

 filaria cannot live in other parasitic insects harbored by dogs. He con- 

 cluded, therefore, that the larvae from affected animals reach the water 

 directly. 



The prevalence of the disease in low marshy localities points to the 

 transmission of hematic filariasis through contaminated water. The 

 larvae from affected animals may reach the water with the excrement, the 

 urine, or, occasionally, with blood from wounds. In such case infection 

 may be direct or after the larvae have undergone a further development 

 in an intermediate small crustacean, as Cyclops, the parasites gaining 

 entrance to the mammalian host by way of the alimentary canal and 

 from here reaching the blood stream to be carried by the venous blood 

 to the right heart. 



Treatment. — Therapeutic measures in this form of filariasis, espe- 

 cially where there is pronounced disturbance of nutrition and circula- 

 tion, is unsatisfactory. Nutritious food and the avoidance of exertion, 

 conjoined with the administration of heart stimulants and prevention, 

 so far as possible, of reinfection, may bring results if the parasites are 

 not too numerous or the disturbances occasioned by them are not too 

 far advanced. 



2. Spiroptera sanguinolenta (Filaria sanguinolenta). Filariidae 

 (p. 244). — The most prominent characteristic of this worm is its blood- 

 red color. The tail of the male is obtuse, spiral, and has two lateral 

 wings. There are two spicules. The tail of the female is obtuse and 

 slightly curved. The vulva is situated 2 to 3 mm. behind the mouth. 



Length of female, 6-8 cm. (2 3/8-3 1/8 inches) ; male, 3-5 cm. (1 1/4- 

 2 inches). 



The eggs are thick-shelled, elliptical, and about 30 microns long by 

 12 microns in width. 



Occurrence and Pathogenesis. — This nematode of the dog is usually 

 found lodged in tumors of the esophagus and stomach, though it is 

 occasionally met with in large blood vessels, the lungs, and in lymph 

 nodes. The tumors vary in size from that of a hazel nut to that of a 

 pigeon's egg, and usually but few are present. They lie beneath the 



