RESUMO
The current knowledge of the pathogenicity, clinical signs and mortality of artificial infections by syringe inoculation of Cowdria ruminantium in laboratory and wild strains of mice is reviewed. It is concluded that a wide spectrum of pathogenicity for mice exists in stocks of the organism.
Assuntos
Hidropericárdio , Animais , Modelos Animais de Doenças , CamundongosRESUMO
A study was made of the infectivity of two mouse-adapted strains of Cowdria ruminantium in mice. The Kwanyanga strain was most virulent in Balb/C mice which died nine days after infection with homogenate of liver from infected mice. CD-1 mice were least susceptible of six strains tested. The du Plessis strain of C. ruminantium was equally virulent in all six mouse strains. The du Plessis strain in CD-1 mice was used as the basis of a drug screen to detect activity against heartwater (C. ruminantium infection) and was highly predictive when active compounds were tested in sheep infected with the Ball 3 strain of C. ruminantium.
Assuntos
Hidropericárdio/microbiologia , Rickettsiaceae/patogenicidade , Animais , Hidropericárdio/tratamento farmacológico , Imidocarbo/uso terapêutico , Masculino , Camundongos , Camundongos Endogâmicos , Oxitetraciclina/uso terapêutico , Ovinos , Doenças dos Ovinos/tratamento farmacológico , Doenças dos Ovinos/microbiologia , Tiossemicarbazonas/uso terapêuticoRESUMO
The phagocytosis of erythrocytes and leucocytes in sheep infected with Trypanosoma congolense is shown to be due to the coating of the blood cells with trypanosomal antigen. The occurrence of the phagocytic activity is dependent on fluctuations of the parasitaemia and is significant in maintaining the anaemic state of the subject.
Assuntos
Eritrócitos/imunologia , Leucócitos/imunologia , Fagocitose , Doenças dos Ovinos/imunologia , Tripanossomíase Africana/veterinária , Animais , Sangue/parasitologia , Imunofluorescência , Ovinos , Doenças dos Ovinos/sangue , Tripanossomíase Africana/sangue , Tripanossomíase Africana/imunologiaRESUMO
Fourteen cases of lymphosarcoma occurred in a small experimental flock of sheep in Rhodesia. There appeared to be horizontal spread and the ages of the affected animals varied from one to more than 10 years. Thirteen of the cases so far diagnosed were leucaemic with a high lymphocyte count. Eleven of the sheep demonstrated multicentric lesions and two alimentary mesenteric; the remaining animal is still alive. Transmission attempts in four neonates resulted in one showing a high white cell count after 25 months. Electron microscope studies failed to demonstrate C-type virus-like particles. This appears to be the first recorded example of an outbreak of lymphosarcoma in a flock of sheep in Southern Africa and the descriptive term "enzootic leucosis" has been adopted.
