RESUMO
Studied were morphologically the organs of 10 cattle originating from two provinces of Cuba that suddenly succumbed ( muerte subita ). There were hemorrahagic diathesis, and histologically--general activation of the reticulo-endothelial system, nonsuppurative encephalomyocarditis, interstitial nonsuppurative hepatitis, nephritis, and pneumonia as well as catarrhal hemorrhagic gastroenteritis. In all cases there were among the lymphoid proliferations diffusely disseminated eosinophile leukocytes ( hyperergia ). This finding showed that the disease had run a subacute or chronic course which was made acute by the action of some stress factors (continuous running, intoxications oligoelement disturbances, etc.). The finding was also characteristic of reactive processes taking place under the action of some specific virus that probably took part in the etiology of the disease and required an intermediary host that remained unknown at the time.