590 ACUTE GENERAL INFECTIOUS DISEASES 



Belgium, Italy and France). There is no doubt but that 

 it has frequently been mistaken for fowl cholera. 



Etiology.— This disease is produced by an ultramicroseopic 

 virus. The exact nature of this virus has never been deter- 

 mined. It is contained in the blood, the droppings, the 

 exudate found in the serous cavities, the bile and in the 

 nasal discharges. The filtrate, when passed through porce- 

 lain filters and injected into healthy chickens will produce 

 the characteristic symptoms rather constantly. 



Pathogenicity.— Practically all fowls are susceptible to the 

 virus which is most commonly found in chickens, turkeys, 

 sparrows and pheasants. Water fowls and pigeons are less 

 susceptible to infection. Mammalia are not susceptible to 

 the virus. 



Natural Infection.— Cohabitation of birds so that they 

 come in contact with the nasal discharges and droppings 

 from the sick is the most likely way in which infection is 

 spread through a flock. Ingestion of food contaminated 

 with the virus, or the eating of infected viscera, or blood, 

 introduces the virus immediately into the digestive tract 

 where it develops and produces the disease. Infection takes 

 place no doubt in some cases from the infection entering 

 the tissues through lesions in the skin or mucous membranes. 

 The transmission of the disease may be brought about by 

 the virus being carried through intermediate objects. 



Pathology. — The lesions found on autopsy are similar in 

 some respects to those found in fowl cholera. In the per- 

 acute cases the lesions may be very slight. The principal 

 lesions are those found in ordinary septicemia, especially 

 hemorrhages in the serous membranes (pleura, peritoneum, 

 epi- and endocardium), and in the mucous membranes of 

 the digestive tract. The finding of a fibrinous exudate on 

 the peritoneum and pleura has been frequently reported. 

 Hyperemia of the spleen, liver and kidneys is usually present. 

 The comb and wattles are dark bluish in color (cyanotic). 

 Catarrhal inflammation of the conjunctiva and buccal mem- 

 brane, with collections of frothy mucus, is often noted. In 

 the digestive tract changes occur on the mucous membrane 

 such as hemorrhages, collections of grayish-white, or yel- 



