626 INFECTIOUS DISEASES PRODUCED BY PROTOZOA 



its blood, thus directly inoculating the fowl. The spirilla 

 are soon found in the blood. 



Pathology.— The most characteristic lesions on necropsy 

 are enlarged spleen and liver, both organs showing numerous 

 areas of degeneration and necrosis. The heart muscle shows 

 evidence of inflammation. No other lesions of importance are 

 found. 



Symptoms.— The period of incubation is from eight to ten 

 days. Some cases develop in four to six days after the ticks 

 have been placed on the fowl. The early symptoms are those 

 of suppression of appetite, high temperature (108°-111° F.), 

 somnolence, weakness. Later diarrhea sets in; the comb and 

 wattles become bluish-red; marked weakness and paralysis. 

 During the later stages of the disease the temperature 

 becomes normal or subnormal. Death follows in a short 

 time in most cases under symptoms of convulsions and para- 

 lysis. The majority of cases are acute; a few have been 

 observed to assume a chronic type. The course of the disease 

 is usually from four to six days in the acute form and ten to 

 eighteen days in the chronic. 



Diagnosis.— This is made by noting the enzootic character 

 of the disease; the characteristic lesions on autopsy, and the 

 finding of the Spirochsetes in the blood of sick birds. • 



Prognosis.— The prognosis is unfavorable when the disease 

 is well established. Some cases recover. 



Treatment.— Atoxyl (0.1 per oremfortwo consecutive doses) 

 has been recommended, and has proved to be highly efficient 

 in producing immunity from infection in normal fowls. 

 Atoxyl (0.05) as an intramuscular injection is recommended 

 for infected birds. In two to three days the parasites dis- 

 appear from the blood. Atoxylate of mercury has also been 

 used in a similar manner. This treatment when properly 

 administered will produce excellent results. 



Immunization of fowls with the blood of sick chickens, 

 which has been allowed to stand for forty-eight hours, has 

 proved of great value. After this period the blood is no 

 longer infectious and may be injected subcutaneously into 

 healthy fowls. This establishes an immunity against infec- 

 tion. 



