932 DISEASES CAUSED BY FILTRABLE VIRUS 



tigators failed to confirm Graham's work regarding the presence 

 of protozoa-like organisms in the blood. They produced the disease 

 in volunteers with unfiltered blood of Dengue cases. They then 

 injected two volunteers intravenously with diluted defibrinated 

 blood of Dengue patients, filtered through filter candles which held 

 back Micrococcus melitensis and the cholera spirillum. Both of 

 these volunteers developed typical attacks in about three days. They 

 subsequently confirmed Graham's assertion concerning the trans- 

 mission of the disease by Culex fatigans. They also showed that 

 the disease is not contagious in the ordinary sense. Craig suggests 

 the possibility of the disease being caused by a spirochaete, basing 

 his opinion on certain analogies with yellow fever as brought out 

 by Nbguchi's researches. However, 'there is still considerable uncer- 

 tainty concerning this. 



FOOT-AND-MOUTH DISEASE 



This malady occurs chiefly in cattle, sheep, and goats, more rarely 

 in other domestic animals. It is characterized by the appearance 

 of a vesicular eruption localized upon the mucosa of the mouth and 

 upon the delicate skin between the hoofs. In the females similar 

 eruptions may appear upon the udders. With the onset of the 

 eruption there may be increased temperature ; refusal of food, and 

 general depression. Usually the disease is mild ; the vesicles become 

 small ulcers and pustules. Occasionally the disease is complicated 

 by catarrhal gastroenteritis or an inflammation of the respiratory 

 tract, and death may ensue. 



The disease is transmitted from animal to animal by means of 

 virus contained in the vesicular contents. Infection may also take 

 place through the agency of milk. 



Rarely the disease may be transmitted to man. Such infection, 

 when it does take place, occurs usually among the milkers and 

 attendants in dairies, and is transmitted by direct contact. The 

 disease in man is usually very mild. Mohler states that the disease 

 may be transmitted to man by the milk of infected animals. He 26 

 adds that in the United States the disease has been practically 

 eradicated. 



M Mohler, Bull. No. 41, U. S. Pub. Health and Mar. Hosp. Serv., Wash., 1908. 



