368 ACUTE GENERAL INFECTIOUS DISEASES 



months are most often affected. The night season is more 

 dangerous than the daytime in this regard. Probably the 

 infection is carried by insects (mosquitoes, anopheles, stego- 

 myia). Keeping a fire smudge near horses on pasture at 

 night or protection with mosquito netting is said to prevent 

 the infection. 



Necropsy. — Gelatinous infiltration of the subcutaneous and 

 intramuscular connective tissue about the eyes and throat is 

 commonly noted. Evidence of gastro-intestinal catarrh or in 

 some cases hemorrhage and ulceration of the intestine is a 

 common finding. The serous membranes show petechise and 

 not infrequently fibrinous exudation. The lungs are edema- 

 tous, the spleen is normal and the liver and kidneys congested 

 or inflamed. The superficial lymph glands are enlarged. 



Symptoms. — The period of incubation is about one week. 

 Four forms of the disease are described from a clinical stand- 

 point: The peracute, acute, subacute, and chronic. The 

 most important are the acute and subacute forms. 



(a) A cute Form. — This form, known in Africa as Dunkop- 

 ziekte, begins with a high fever (104° to 107.6° F.), dyspnea, 

 pulmonary edema, and heart paralysis. Death usually 

 occurs in one to two weeks. 



(b) Subacute Form. — The subacute form, known as Dikkop- 

 ziekte, takes a longer and milder course. Characteristic of 

 this form is a marked swelling of the head, principally about 

 the eyes; swelling and prolapses of the tongue which is 

 markedly cyanotic. From this symptom the name "blaw 

 tong" (blue tongue) is given to the disease. The patient shows 

 marked muscular weakness. In this form the majority of 

 the cases recover. 



The peracute or apoplectic form produces sudden death; 

 the chronic form assumes an atypical course lasting for weeks 

 and resembling infectious anemia. 



Treatment. — ^A medicinal treatment has to date not proved 

 satisfactory. Internally large doses of creolin have been 

 recommended. 



Prevention. — Prevention consists in keeping the horses ofl^ 

 infected or suspected pastures during the night season or 

 driving them to higher altitudes during the dangerous months 



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