Trypanosomes In Cattle Research Articles

Field studies of drug-resistant cattle trypanosomes in Kénédougou Province, Burkina Faso

Field studies were conducted to assess the occurrence of resistance to isometamidium chloride and diminazene aceturate in trypanosomes infecting cattle in Kénédougou Province of Burkina Faso. Forty-five of the 166 villages in Kénédougou were randomly sampled and visited to assess livestock numbers, trypanosomosis risk, and tsetse challenge. The proportion of cattle infections associated with drug-resistant trypanosomes was assessed in the nine villages with the highest trypanosome infection prevalence and one village with a confirmed history of drug-resistant infections. These studies showed that resistance to both isometamidium and diminazene was widespread. However, there was considerable variation between villages in drug-resistance parameters, with the proportion of treated cattle with trypanosome infections 3 months after isometamidium prophylaxis varying from 6.9 to 63.8% and the proportion of cattle having infections 2 weeks after treatment with diminazene varying from 0 to 36.8%. The demonstration of widespread resistance to both isometamidium and diminazene has important implications, as administration of trypanocides is the most commonly employed method to control trypanosomosis in this area.

Lessons learned from the emergence of a new Trypanosoma brucei rhodesiense sleeping sickness focus in Uganda.

During the latter months of 1998, cases of sleeping sickness caused by Trypanosoma brucei rhodesiense presented in Soroti district, eastern Uganda, a region which had not previously experienced cases of the disease. Cattle are the main reservoir for T b rhodesiense, by contrast with sleeping sickness caused by Trypanosoma brucei gambiense in west Africa where there appears to be no epidemiologically significant animal reservoir. Several factors have been identified that interacted to produce ideal conditions for the establishment of a new disease focus. After a period of civil unrest, Soroti, which is within the tsetse belt, was repopulated by people and later, cattle. Both the cattle restocking and the subsequent trade in these cattle at a local cattle market had a role in the appearance of the disease. Recently, molecular biology techniques have become available for the detection and genotype identification of T b rhodesiense and thus it is now possible to distinguish human infective and non-infective trypanosomes in cattle. In light of these advances in identification and in both field and epidemiological techniques, successful disease control management has become an achievable goal and will require the collaboration and expertise of clinicians, veterinarians, epidemiologists and laboratory scientists.

All metacyclic variable antigen types of Trypanosoma congolense identified using monoclonal antibodies.

Vaccination against the tsetse-borne trypanosomiases has proved impossible because of the trypanosome's ability to generate a seemingly inexhaustible number of variable antigen types in the blood or tissues of the host. Each variable antigen is a glycoprotein which forms a surface coat on the trypanosome and each glycoprotein is the product of a single gene. The full repertoire of such antigens has not been identified for any trypanosome serodeme (genotype) as yet, but the number of genes coding for variable antigen glycoproteins is estimated to be between 100 and 1,000. We have previously postulated that for Trypanosoma brucei the antigen repertoire of the infective metacyclic stage trypanosomes inoculated by the tsetse fly may be considerably smaller than that expressed in the mammalian host. If this is so then protection against infection by the vector becomes an easier proposition, but the actual scale of the metacyclic repertoire is also unknown. We present here evidence that the metacyclic repertoire of a stock of T. congolense, the most important of the pathogenic cattle trypanosomes, is limited to 12 variable antigen types.

The resistance of Trypanosoma congolense, T. vivax and T. evansi to human plasma

Tests were made in mice on the resistance of cattle trypanosomes to human plasma. 12 stocks of Trypanosoma congolense were tested; three were fully resistant, eight were moderately or highly resistant, and one was fully sensitive. Four stocks of T. vivax were tested; two were fully resistant, one was somewhat resistant and one was highly sensitive. Two stocks of T. evansi were tested; both fully sensitive. The possibility is discussed that T. congolense and T. vivax might produce transient infections in man.

Morphology of typanosomes from white-tailed deer and wapiti in Michigan.

Trypanosomes were isolated from a wapiti (Cervus canadensis) and 72 white-tailed deer (Odocoileus virginianus) from several locations in Michigan. Although significantly fewer fawns were infected, there were no significant differences in rate of infection between sexes or among geographic areas. From appearance of the trypomastigote, the trypanosome from white-tailed deer belongs in the genus Trypanosoma and the subgenus Megatrypanum. It was morphometrically similar to the common trypanosome of cattle, Trypanosoma theileri.

Studies on Trypanosoma Theileri-Like Trypanosomes of Cattle: I. Culture and Storage of Isolations

An account is given of simple procedures by which Trypanosoma theileri -like trypanosomes of cattle may be isolated, cultured and stored. Variations in behaviour of trypanosome populations were seen relating to the longevity of cultures on a blood agar medium at 28°C and to the establishment of populations on bovine leucocyte cultures at 37°C. On rend compte de procédés simples par lesquels on peut isoler, cultiver et garder les trypanosomes du bétail ressemblant au Trypanosoma theileri . On a constaté que les variations dans le comportement des populations de trypanosomes étaient liés à la longévité des cultures dans un milieu de gélose au sang à 28°C et à l’établisement de populations sur des cultures de leucocytes de boeuf à 37°C. Ein Bericht über einfache Methoden, mit deren Hilfe Trypanosoma-Theireri -artige Trypanosomen von Rindern isoliert, kultiviert und aufbewahrt werden können. Variationen im Verhalten der Trypanosomen wurden beobachtet hinsichtlich der Lebensdauer der Blut-agar-kulturen bei 28°C und hinsichtlich ihres Auftretens in Kulturen von Rinderleukozyten bei 37°C. Se presenta una exposición de unos sencillos procedimientos por medio de los cuales se pueden aislar tripanosomas parecidos al Tripanosoma theileri del ganado vacuno, así como su cultivo y su conservación. Se observaron variaciones en el comportamiento de las cepas de tripanosoma en relación a la edad de los cultivos en un medio a base de agar sangre a 28 grados centígrados y al establecimiento de cepas en cultivos de leucocitos de bovinos a 37 grados C.

Survey for Trypanosome Infections in Domestic Cattle and Wild Animals in Areas of East Africa: III. Salivarian Trypanosome Infections in Cattle in Relation to the Glossina Distribution in Busoga District, Uganda

A survey for salivarian trypanosomes in cattle, in relation to the known Glossina distribution, was carried out in the southern part of Busoga District, Uganda. The highest incidence of trypanosomiasis existed within the known Glossina infested area but a uniformly lower level was found outside this area. In order to complement this information a survey was made of the flies biting cattle. Evidence is presented which strongly indicates that G. fuscipes fuscipes is present in all suitable habitats throughout Busoga. Two serological tests utilizing blood spots collected on filter paper were given their first field trial in cattle. The results indicate that the indirect fluorescent antibody test may be useful in screening cattle populations for trypanosomiasis. The serum agglutination test also appeared to be of value. Une étude du rapport entre les trypanosomes salivaires du bétail et la répartition connue de la glossine a été menée dans la partie sud du territoire du Busoga, en Ouganda. La plus forte incidence de trypanosomiase se trouvait dans la région connue pour être infectée par la glossine mais le taux en dehors de cette région était toujours inférieure. Afin de compléter cette information on a fait une étude des mouches piquant le bétail. On a pu montrer clairement que G. fuscipes fuscipes existe dans toutes les zones d’habitations adéquates du Busoga. On s’est servi pour la première fois à titre d’essai sur le bétail de deux tests sérologiques utilisant des tâches de sang collecté sur du papier filtre. Les résultats indiquent que la méthode indirecte de l’anticorps fluorescent peut être utile dans la détection de la trypanosomiase dans le bétail. Le test d’agglutination dans le sérum semble avoir aussi son intérêt. Eine Untersuchung über Trypanosomen im Speichel des Viehs im Verhältnis zu der bereits bekannten Verbreitung von Glossina wurde im südlichen Teil des Busoga Gebiets (Uganda) durchgeführt. Am zahlreichsten kam Trypanosomiasis innerhalb des von Glossina befallenen Gebietes vor, während der Durchschnitt ausserhalb dieses Gebietes einhietlich geringer war. Um diese Information zu vervollständigen wurde eine Übersicht über die Fliegen, die das Vieh stechen, gemacht. Die gezeigten Resultate deuten darauf hin, dass G. fuscipes fuscipes sich in allen geeigneten Wohnsitzen durch ganz Busoga findet. Zwei serologische Tests wurden mit auf Filtrierpapier aufgenommenen Blutstropfen gemacht; dies war der erste praktische Versuch an Vieh mit diesen. Die Resultate zeigten, dass der indirekte Antikörper-Fluoreszenz-Test von Nutzen sein kann, um grossangelegte Tests für Trypanosomiasis beim Vieh zu machen. Auch der Serum-Agglutinations-Test schien wertvoll zu sein. Se efectuó una investigación en la parte sur del distrito de Busoga, Uganda, sobre las tripanosomas salivales en el ganado en relación a la distribución conocida de Glossina. La mayor incidencia de tripanosomiasis existe dentro de el área conocida infestada por Glossina pero se encontró un nivel uniformemente más bajo fuera de este área. Para complementar esta información se efectuó una investigación sobre las moscas que pican al ganado. Se presenta evidencia que indica que la G. fuscipes fuscipes se encuentra presente en todos los habitats adecuados de Busoga. Se emplearon por primera vez en el campo y en ganado dos pruebas serológicas que utilizaron manchas de sangre recogidas en papel filtro. Los resultados indican que la prueba indirecta de anticuerpos fluorescentes pudiera ser útil en el examen de ganados para la presencia de tripanosomiasis. La prueba de la aglutinación del suero también pareció ser valiosa.

Diminazine aceturate and homidium chloride. Resistance in tsetse fly-transmitted trypanosomes of cattle in Northern Nigeria.

Diminazine aceturate and homidium chloride. Resistance in tsetse fly-transmitted trypanosomes of cattle in Northern Nigeria.

Prophylaxis of trypanosome infections in cattle.

THE introduction of ‘Ethidium’ (I) in 1952 made available to veterinarians in Africa a drug with very high therapeutic activity against the two most important trypanosomes of cattle, Trypanosoma congolense and T. vivax, and this drug is now widely used. There still seemed to be the need, however, for a drug which would confer a prolonged period of protection to dosed animals, and we have therefore, worked to this end. One particular series of drugs (II) showed, in mice, therapeutic activity of a very high order, and also a prophylactic action greater than that of any other drug available. Two of the most active of this series, ‘R.D. 2787’ and ‘R.D. 2801’, were sent to Africa for trials in cattle. ‘R.D. 2801’, which had appeared the better of the two in tests in mice, has shown considerable promise in tests in Tanganyika and in Nigeria, against both T. congolense and T. vivax. In one trial, for example, a single dose of 2 mgm./kgm. protected cattle for at least six months. Trials are still in progress, and full results of both these trials and of our laboratory findings will be published elsewhere.

A summary of an entomological survey of Kaduna District, Northern Nigeria

Kaduna, the future capital of Nigeria, is situated in the Northern Provinces, on the River Kaduna, at an elevation of roughly 2,200 feet. The present Kaduna is a small station (Kaduna Bridge) south of the river, but the capital now in the process of construction is some two or three miles to the north, near the small native town of Doka.Being instructed to make an Entomological Survey of the district, with especial reference to Glossina and the resulting presence of trypanosomes in cattle, I left Lagos on 30th July 1914, reaching Kaduna Bridge on 1st August.

A trypanosome of cattle in the Southern Sudan

A trypanosome of cattle in the Southern Sudan

The Demonstration of Trypanosomes in Cattle

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