Immunological aspects of bovine trypanosomiasis

Summary Patterns of antibody production in relation to the presence or absence of trypanosomes and to drug treatment, were studied in 38 cattle. The animals were infected with one or more of the three groups of African pathogenic trypanosome. An indirect fluorescent antibody test was used. A stronger homologous antibody was noted. High levels of antibody were associated with the presence of circulating trypanosomes. Falling levels of antibody were associated with self-cure or chemotherapeutic treatment. Titre of homologous antibody was considered to be a valuable aid in ascertaining the stage of the disease, and may be useful in assessing the efficiency of chemotherapy in a herd.

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Sumario Los patrones en la producción de anticuerpos en relación a la presencia ó ausencia de tripanosomas y tratamiento con drogas, fueron estudiados en 38 cabezas de ganado. Los animales fueron infectados con uno ó mas de los tres grupos de tripanosomas africanos patogénicos. Se usó una prueba indirecta de anticuerpos fluorescentes (IFT). Se notó un anticuerpo homólogo mas fuerte. Niveles altos de anticuerpos fueron asociados con la presencia de trípanosomas circulantes. Niveles decrecientes de anticuerpos fueron asociados con la ‘autocura’ ó tratamiento quemoterapéutico. El título de anticuerpos homólogos fue considerado como una gran ayuda en la evaluación del estadió de la enfermedad y puede ser útil en la evaluación de la eficiencia de la quimioterapia en un hato.

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Résumé La production d'anticorps en relation avec la présence ou l'absence de trypanosomes et avec la chimiothérapie, a été étudiée chez 38 bovins. Les animaux étaient infectés avec un ou plus des trois groupes de trypanosomes africains pathogènes. Une réaction d'immuno-fluorescence indirecte a été employée. Les anticorps homologues donnaient une plus forte réaction. Des taux élevés d'anticorps étaient associées à la guérison spontanée ou au traitement chimiothérapeutique. Le titre d'anticorps homologués était considéré comme constituant une aide précieuse pour la détermination du stade de la maladie, et comme pouvant être utile pour évaluer l'efficacité de la chimiothérapie dans un troupeau.

     

The epidemiology of bovine trypanosomiasis in Colombia

Summary A review is given of the present knowledge of the epidemiology of bovine trypanosomiasis in Colombia. Search of the literature, discussions with veterinarians, and original observations have given information on the distribution and prevalence of the pathogenicTrypanosoma vivax and non-pathogenicT. theileri-like organisms.T. evansi infections of cattle may exist but were not detected. Improved methods of diagnosis forT. vivax are required to elucidate problems of: differentiating clinically similar diseases; the susceptibility of cattle relative to age; transmission; wild animal reservoirs, and economic importance. The indirect fluorescent antibody test is an important technique to this end.

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Sumario Se hace una revisión del conocimiento actual de la epidemiología de la tripa nosomiasis bovina en la república de Colombia. La revisión de literatura, de talladas discusiones con médicos Veterinariosy observaciones personales han proporcionado información sobre la distribución y prevalencia delT. vivax (uno de los tripanosomas patógenos) y de los tripanosomas semejantes alT. theileri (un tripanosoma no patógeno). ElT. evansi es posible que exista en los vacunos pero no fué detectado. Se requieren mejores métodos de diagnóstico paraT. vivax con el objeto de aclarar problemas tales como: diferenciación clínica de enfermedades simila res; la susceptibilidad de los bovinos según su edad; métodos de transmisión; el papel de los animales salvajes como reservorios y la importacia económica de las tripanosomiasis. Para conseguir estos objectivos se requiere el uso de la técnica de la fluorescencia indirecta de anticuerpos.

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Résumé Il s’agit d’une revue des connaissances actuelles sur l’épidémiologie de la trypanosomose bovine en Colombie. Des recherches bibliographiques, des entretiens avec les vétérinaires et des observations originales ont permis d’acquérir des renseignements sur la distribution et l’importance deT. vivax pathogène et d’un trypanosome non pathogène ressemblant àT. theileri. Les infections du bétail àT. evansi peuvent exister, mais n’ont pas été décelées. Des méthodes améliorées de diagnostic sont nécessaires pourT. vivax afin d’élucider certains problèmes: diagnostic différentiel avec des maladies cliniquement semblables, sensibilité du bétail en fonction de son age, transmission, animaux sauvages ‘réservoirs’, importance économique. On suggère que la méthode d’immunofluorescence indirecte pourrait être très utile à ces fins.

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E. A. Wells 10th April, 1967–12th July, 1967, and 4th Sept., 1969–13th Dec., 1969; W. A. Page, 7th Sept., 1969–13th Dec., 1969.     

Depleted serum haptoglobin in acute bovine trypanosomiasis

Haemoglobin-binding protein (Haptoglobin, Hp) was assayed in the sera of control and zebu calves with acute T. vivax infection. Hp in control Zebu calves ranged between 123.5 and 236.5 mg dl-1 while Hp in the infected calves was too low to measure or absent. It was suggested that absence of Hp in the infected calves may be as a result of gradual intravascular haemolysis and removal of the Hp-Hb complex by the reticuloendothelial system.     

Immunological aspects of coliform mastitis

Antibodies presumably stimulated by absorption of endotoxin arising from the gut flora (and in coliform mastitis) are present in all cattle blood so far examined. These antibodies do not appear in the mammary gland in appreciable concentrations until considerable growth of invading coliforms has occurred. They probably have limited value in a bactericidal sense but may be very important as opsonins in the phagocytic process. In a negative sense, these antibodies also may be involved in hypersensitivity reactions which may be responsible for some of the clinical signs. Complement is needed for bactericidal antibody activity. Both the classical and shunt pathways of C activation are present in mastitic milk. Dilution experiments suggest that C concentration may be the rate-limiting factor in bactericidal antibody activity.Although lysozyme may function to lyse coliforms, it does not appear to function in killing. This, coupled with its relatively low concentration in the normal gland, probably makes it relatively unimportant in protection. Properdin activity is present in mastitic milk but its importance has not been assessed. Lactoferrin is a functional bacteriostat but its limited activity in normal milk is also probably of limited importance in protecting the lactating gland. Lactoferrin undoubtedly has an important protective function in the involuted gland.There is no evidence so far obtained that vaccination is of benefit in protection of cows against coliform mastitis. Much more research on this aspect is needed.     

Effect of pregnancy on clinical manifestation of bovine trypanosomiasis

Four groups of non-pregnant, first second and third trimester pregnant Zebu heifers were used to study and compare the clinical manifestations of Trypanosoma vivax infection. All the infected heifers developed clinical trypanosomiasis manifested by massive parasitaemia, fluctuating pyrexia, anaemia, dull hair coat, emaciation, jugular pulse and enlarged superficial lymph nodes. There were group variations in the severity of signs shown. Infected non-pregnant heifers and heifers in the third trimester of pregnancy developed a more severe form of the disease than pregnant heifers in the first and second trimesters of pregnancy.     

Haematocrit centrifugation technique for the diagnosis of bovine trypanosomiasis

The reliability of the haematocrit centrifugation technique (HCT) was compared to the wet film, the thin and thick stained smears and the lymph node aspirate examination techniques in the diagnosis of bovine trypanosomiasis. Blood samples from cattle naturally as well as experimentally infected with T. vivax were used. In the experimental infection, HCT and thick blood smears were more efficient than the wet blood films, thin blood smears and lymph node aspirations in detecting the infection. In 753 field samples, 16 positive cases were detected by HCT. It was estimated that 62.5–75.0% of positive samples were not detected by using the wet or the thin films alone. Despite the relative unreliability of most of the methods tested, the Woo technique showed significant difference in relationship to the other techniques evaluated. It could be recommended, in combination with thick and thin films, for the diagnosis of trypanosomiasis in cattle.     

Use of antigens of culturedTrypanosoma brucei in tests for bovine trypanosomiasis

Summary MicroELISA tests for the detection of trypanosomal antibodies in cattle infected withTrypanosoma brucei, T. vivax andT. congolense were carried out using antigens prepared from culture forms and bloodstream forms ofT. brucei. Antigens prepared from culture forms gave similar microELISA values to those obtained with bloodstream form antigens and statistical analysis of the results obtained with both antigen preparations and sera from the infected animals showed significant high positive correlation. It would thus be possible to use culture form antigens as an alternative to bloodstream form antigens in diagnostic tests for trypanosomiasis, with the advantage that culture form antigens are more easily prepared free from extraneous protein.

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Uso De Antigenos De Cultivos DeTripanosoma Brucei En Pruebas Para Detectar Tripanosomiasis Bovina

Resumen Se llevaron a cabo estudios de laboratorio con la prueba microELISA para detectar anticuerpos contra tripanosomiasis en ganado infectado conTrypanosoma brucei, T. vivax y T. congolensis. Los antígenos se prepararon con formas cíclicas deT. brucei obtenidas de cultivos y de formas sanguíneas. Los antígenos preparados con formas cíclicas obtenidas de cultivos, dieron valores microELISA similares a los obtenidos con antígenos preparados con formas sanguíneas del tripanosoma. Los análisis estadísticos de los resultados obtenidos con preparaciones de ambos antígenos y sueros de animales infectados tuvieron una alta correlacíon positiva. Se concluye que, sería posible preparar antígenos con formas del triposoma obtenidas de cultivos para el diagnóstico de la tripanosomiasis, como alternativa de antígenos preparados con formas sanguíneas. También se sugiere que los antígenos preparados de cultivos tienen la ventaja de estar libres de proteinas extrañas.

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Utilisation D'Antigenes De Culture DeTrypanosoma Brucei Dans La Diagnose De La Trypanosomose Bovine

Résumé Les tests MicroELISA pour la détection des anticorps trypanosomiens chez le bétail infecté parTrypanosoma brucei, T. vivax etT. congolense ont été effectués en utilisant des antigènes préparés à partir de formes de culture et de formes sanguines deT. brucei. Les antigèns de culture ont donné des titres semblables à ceux obtenus avec les antigènes des formes sanguines et l'analyse statistique a montré une corrélation positive élevée entre les résultats fournis par les deux types d'antigène vis-à-vis des mêmes sérums d'animaux infectés. Il serait donc possible d'utiliser les antigènes de culture comme alternative des antigènes de formes sanguines pour le sérodiagnostic des trypanosomoses, avec l'avantage qu'ils sont plus faciles à préparer à l'état pruifié.

     

Immunosuppression in bovine trypanosomiasis: studies with louping-ill vaccine.

The antibody response to louping-ill virus vaccine was examined in mice infected with Trypanosoma brucei and T congolense, and in Ethiopian cattle experimentally infected with T brucei, T congolense and T vivax. In mice the antibody response was completely suppressed, while in cattle infected with T congolense and T vivax the antibody response to the vaccine was only 10 per cent that of uninfected animals. In contrast, the response of cattle infected with T brucei was not significantly reduced, and this was attributed to their relatively light and transient parasitaemias. Trypanocidal chemotherapy (diminazine aceturate) administered on the same day as vaccination largely restored the competence of the immune response of both mice and cattle infected with T congolense. The use of such drugs should be considered when cattle are vaccinated in trypanosome endemic areas.     

Immunological aspects of human growth hormone and prolactin

We demonstrated that human lymphocytes secrete growth hormone and that the secretion is regulated in a different manner from that in the endocrine system. We could also show that some patients with hyperprolactinemia, especially asymptomatic type, have anti-prolactin autoantibody, which may be a novel case of hyperprolactinemia.