Survey of the incidence of anaplasmosis among Nigerian zebu trade cattle

Summary Sera samples from 573 Nigerian Zebu trade cattle were evaluated by the rapid card agglutination test for antibodies toAnaplasma marginale between May and July 1977. The results showed 34 per cent reactors as against 66 per cent negatives. The above results showed a significant level of exposure to the infection among the Fulani cattle managed under a husbandry system in which there is no provision for tick control. The significance of this level of exposure toAnaplasma marginale in relation to the livestock industry of the country and the need for a nation-wide anaplasmosis survey are discussed.

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Reconocimiento De La Incidencia De Anaplasmosis En El Ganado Cebú Comercial De Nigeria

Resumen Se evaluaron 573 muestras de suero por el método rápido de la aglutinación de tarjeta, para detectar anticuerpos de Anaplasma marginale. El estudio se realizó entre Mayo y Julio de 1977. Los resultados dieron un 34 por ciento de ractores positivos, lo cual si es significativo, en relación con el grado de exposición a la infección entre el ganado Fulani bajo sistemas de manejo en los cuales no existe control de garrapatas. Se discute el significado de este nivel de exposición, a Anaplasma marginale, en relación con la industria ganadera del país, ye de la necesidad de un reconocimiento de la prevalencia de anaplasmosis a nivel nacional.

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Enquête Sur La Fréquence De L'Anaplasmose Sur Le Bétail Zébu Commercialisé, Au Nigeria

Résumé Entre mai et juillet 1977, 573 échantillons de sérum prélevés sur du bétail zébu du commerce ont été examinés par la méthode d'agglutination rapide sur carte en vue de mettre ou non en évidence des anticorps contreAnaplasma marginale, avec comme résultats 34 p. 100 d'animaux positifs contre 66 p. 100 de réactions négatives.Ces chiffres montrent le niveau élevé de cette affection qui existe chez le bétail Fulani, entretenu par ailleurs dans des conditions d'élevage qui ne comportent aucun dispositif de lutte contre les tiques.La signification de ce niveau d'infection parAnaplasma marginale dans ses relations avec l'industrie du bétail de la région ainsi que la nécessité d'une enquête de niveau national sur l'anaplasmose sont discutées.

     

Self-cure in zebu calves experimentally infected with Trypanosoma vivax

The course of an experimental infection of Zebu calves (6-12 months old) with Trypanosoma vivax was studied. Three of eight (38%) infected calves died, two within the first three weeks of infection and the other at 17 weeks. The remaining animals were self-cured. It would appear that self-cure of the infection was related to the ability of the calves to control parasitaemia as well as the severity of anaemia.     

Experimental infection of the Guyanese zebu with Trypanosoma vivax

The Guyanese strain of Trypanosoma vivax is pathogenic for the local Brahman zebu; the experimental infection of 19 one-year old cattle was followed by a moderate and transitory fever, a drop in packed cell volume (PCV) and a quick and marked weight loss of 10 to 17 kg one month after as compared to the 16 non-infected animals. Other symptoms were associated with the parasitaemia: diarrhoea, swollen haematic glands on the neck and the flank, lachrymation, weakness. Despite a trypanocidal treatment injected one month post-infection, one animal died and the weight losses of others were not compensated for three months later. The particular susceptibility of weaning animals is discussed as well as its implications in the control of trypanosomosis.     

Comparative studies on N''Dama and zebu cattle following repeated infections with Trypanosoma congolense

Twenty N'Dama and eight zebu cattle were inoculated intradermally with bloodstream forms of a cloned strain of Trypanosoma congolense originating from East Africa. All inoculated cattle became parasitaemic. Zebus showed consistently higher levels of parasitaemia and lower packed red cell volume (PCV) percentages than did N'Damas. Three of the eight zebus required treatment when high numbers of trypanosomes were present in the blood and PCV values dropped below 15 per cent. None of the N'Dama cattle needed treatment. Statistical analysis was performed on the data to assess the variability of parasitaemia and PCV levels before and during infection of the N'Dama cattle. The variation in PCV values was large between individuals during the early stages of the disease and diminished as infection continued. After trypanocidal drug treatment and a recovery period of 14 months, the same animals were inoculated intradermally with T congolense bloodstream forms isolated and cloned in The Gambia. Differences in susceptibility to the ensuing disease were apparent when comparing N'Dama and zebu cattle. Five zebu cattle needed trypanocidal drug treatment, while none of the N'Damas needed drug intervention. Ranking the 20 infected N'Damas according to average PCV levels revealed that the animals responded similarly to both infections.     

Response of Trypanosoma vivax and Trypanosoma congolense in zebu cattle in North Cameroon to prophylactic treatment with two formulations of isometamidium

We tested the efficacy of two formulations of isometamidium in a tsetse-infested farm in North Cameroon from 20 August 2000 to 5 January 2001. A total of 90 adult cattle were used in three groups of 30 each corresponding to two treated and one untreated control. Drug efficacies were evaluated in terms of reduction of parasite incidence in the host's blood, maintenance of packed-cell volume (PCV) and weight gains. Both drugs reduced the incidence of parasites even though re-infections 2 weeks after treatment were common. PCV values were similar in both treated groups but higher than in the untreated control. Body weight changes followed a similar trend with the control losing weight from a mean of 427+/-119kg at the beginning to 398+/-93kg in 4 months. Weights increased from 375+/-76 and 396+/-110 to 396+/-69 and 418+/-112kg in the Veridium and Trypamidium groups, respectively. Efficacy was similar between the two formulations of isometamidium in the prophylaxis of bovine trypanosomosis. However, the presence of parasites in some animals barely 2 weeks after treatment suggested that either infections were not cleared or residual drug effects were not sufficient to prevent re-infections.     

Protective efficacy of isometamidium chloride and diminazene aceturate against natural Trypanosoma brucei, Trypanosoma congolense and Trypanosoma vivax infections in cattle under a suppressed tsetse population in Uganda

The protective efficacy of isometamidium chloride (ISMM) and diminazene aceturate (DIM) against Trypanosoma brucei, Trypanosoma congolense and Trypanosoma vivax infections in cattle under a suppressed tsetse population was assessed in southeast Uganda. A total of 66 and 57 trypanosome-infected cattle were treated with ISMM and DIM, respectively together with 177 trypanosome-free animals not treated were followed for 12 months, checked every 4 weeks. There was no statistical difference in the mean time to infection with any trypanosome species in animals treated with ISMM or DIM. However, the mean time to trypanosome infection was significantly longer for treated animals than controls. The mean time to infection with each of the three trypanosome species differed significantly, with the average time to T. vivax infection the lowest, followed by T. congolense and then T. brucei. The protective efficacy of DIM was as good as that of ISMM; implying curative treatments against trypanosomosis are sufficient for combination with tsetse control. Isometamidium chloride or DIM had the highest impact on T. brucei and T. congolense infections in cattle.     

Haemorrhagic pancarditis in cattle infected with Trypanosoma vivax

Haemorrhagic pancarditis has been studied microscopically and ultrastructurally. Haemorrhages, oedema, mononuclear cell infiltration, degeneration, fragmentation, atrophy and lysis of myofibres, and extravascular localisation of the parasite were observed.     

Relationship between ticks and zebu cattle in southern Uganda

Summary Tick populations were observed on zebu(Bos indicus) cattle over a period of 2 years at Entebbe, Uganda where the climate was thought to be highly favourable for the free-living stages of ticks. Collections of all instars of ticks were made from the body surfaces of the cattle at intervals of between 1 and 5 weeks. The species recorded in order of decreasing abundance wereRhipicephalus appendiculatus, Amblyomma variegatum, Boophilus decoloratus, Rhipicephalus evertsi evertsi, Rhipicephalus simus, Rhipicephalus compositus andHyalomma marginatum rufipes. The rankings of the cattle based on burdens of any particular species of tick were always correlated with their rankings for other species; animals that carried more adult stages of a species also carried more of its immature stages. There were more adult males than females ofR. appendiculatus, A. variegatum andR. e. evertsi even when the cattle had had all ticks removed 1 week previously; several possible mechanisms are suggested to explain the biased sex ratio. It is concluded that there is promise for improvement in control of 3-host ticks by increasing the resistance of herds of zebu cattle by culling or selective breeding.

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Relacion Entre Garrapatas Y Ganado Cebu En El Sur De Uganda

Resumen Se observaron las poblaciones de garrapatas en ganado cebú (Bos indicus) en Entebe, Uganda, donde el clima parecía favorecer a los estados libres de las garrapatas. Las observaciones duraron dos años. Las colecciones de los estadios larvales se realizaron con intervalos de 1 a 5 semanas. Las especies identificadas en orden numérico decreciente fueronRhipicephalus appendiculatus, Amblyommavariegatum, Boophilus decoloratus, Rhipicephalus evertsi evertsi, Rhipicephalus simus, Rhipicephalus compositu andHyalomma marginatum rufipes. Los rangos del ganado basados en la carga de garrapatas de una especie en particular, tuvieron correlación en rangos para otras especies en los animales que tuvieron una carga mayor de etapas maduras de una especie se observaron tambie más ejemplos de las etapas no maduras. Hubo más machos adultos que (hembras deR. appendiculatus, A. variegatum yR. e. evertsi aun cuando todas las garrapatas del ganado habían sido removidas 1 semana previamente; se sugieren varios mecanismos para explicar este fenómeno. Se concluye que existe una posibilidad para controlar garrapatas de 3 huéspedes, incrementando la resistencia de ganado cebú mediante selección y cruzamiento de animales resistentes.

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Relation Entre Les Tiques Et Les Zebus Dans Le Sud-Est De L'Ouganda

Résumé Des populations de tiques ont été observées sur des zébus (Bos indicus) pendant 2 ans à Entebbe, en Ouganda où le climat est connu pour être très favorable aux stades libres des tiques. Des collections de tous les stades de tiques présentes sur le corps des animaux ont été faites à des intervalles allant de 1 à 5 semaines. Les espèces suivantes ont été recueillies dans l'ordre d'abondance décroissante:Rhipicephalus appendiculatus, Amblyomma variegatum, Boophilus decoloratus, Rhipicephalus evertsi evertsi, Rhipicephalus simus, Rhipicephalus compositus etHyalomma marginatum rufipes. Le classement du bétail basé sur la charge en une espèce de tique a toujours été en corrélation avec la charge dans les autres espèces de tiques. Les animaux porteurs du plus grand nombre d'adultes d'une espèce étaient également porteurs du plus grand nombre de stades préimaginaux. Il y avait beaucoup plus de mâles que de femelles deR. appendiculatus, A. variegatum etR. e. evertsi même lorsqu'on avait prélevé toutes les tiques sur le bétail une semaine auparavant. Plusieurs mécanismes possibles sont suggérés pour expliquer le déséquilibre dans le pourcentage des sexes. La conclusion porte sur les promesses d'amélioration de la lutte contre les tiques trixènes par l'accroissement de la résistance des troupeaux de zébus par élevage sélectif.