Variant surface glycoproteins from Venezuelan trypanosome isolates are recognized by sera from animals infected with either Trypanosoma evansi or Trypanosoma vivax

Salivarian trypanosomes sequentially express only one variant surface glycoprotein (VSG) on their cell surface from a large repertoire of VSG genes. Seven cryopreserved animal trypanosome isolates known as TeAp-ElFrio01, TEVA1 (or TeAp-N/D1), TeGu-N/D1, TeAp-Mantecal01, TeGu-TerecayTrino, TeGu-Terecay03 and TeGu-Terecay323, which had been isolated from different hosts identified in several geographical areas of Venezuela were expanded using adult albino rats. Soluble forms of predominant VSGs expressed during the early infection stages were purified and corresponded to concanavalin A-binding proteins with molecular masses of 48–67 kDa by sodium dodecyl sulfate-polyacrylamide gel electropohoresis, and pI values between 6.1 and 7.5. The biochemical characterization of all purified soluble VSGs revealed that they were dimers in their native form and represented different gene products. Sequencing of some of these proteins yielded peptides homologous to VSGs from Trypanosoma (Trypanozoon) brucei and Trypanosoma (Trypanozoon) evansi and established that they most likely are mosaics generated by homologous recombination. Western blot analysis showed that all purified VSGs were cross-reacting antigens that were recognized by sera from animals infected with either T. evansi or Trypanosoma (Dutonella) vivax. The VSG glycosyl-phosphatidylinositol cross-reacting determinant epitope was only partially responsible for the cross-reactivity of the purified proteins, and antibodies appeared to recognize cross-reacting conformational epitopes from the various soluble VSGs. ELISA experiments were performed using infected bovine sera collected from cattle in a Venezuelan trypanosome-endemic area. In particular, soluble VSGs from two trypanosome isolates, TeGu-N/D1 and TeGu-TeracayTrino, were recognized by 93.38% and 73.55% of naturally T. vivax-infected bovine sera, respectively. However, approximately 70% of the sera samples did not recognize all seven purified proteins. Hence, the use of a combination of various VSGs for the diagnosis of animal trypanosomosis is recommended.     

Pathology of Experimental Trypanosomiasis in the Albino Rat, Rabbit, Goat and Sheep — A Preliminary Report

In rats, rabbits, sheep, and goats experimentally infected with several strains of Trypanosoma brucei, the trypanosomes were observed to localise extravascularly in connective tissues. Focal inflammatory reactions were associated with the localisation of the parasites. Trypanosoma congolense in the same species of animals and T. vivax in sheep and goats, were not observed to localise outside blood vessels. On the basis of these observations it appears that the pathogenesis of the disease caused by T. brucei differs from that caused by T. congolense and T. vivax.     

The isolation ofTrypanosoma brucei fromHippopotamus amphibius in the luangwa valley,Zambia

Summary Trypanosoma brucei was isolated from four out of75 hippopotami by means of intraperitoneal mouse inoculations. This appears to be the first isolation of trypanosomes fromHippopotamus amphibius and a new host record forT. brucei. The four strains of polymorphic trypanosomes isolated were identified asT. brucei by the blood incubation infectivity test. In500 wet and390 dry blood films (total890) of370 hippopotami examined no trypanosome was found. The value of blood film examination for the diagnosis of trypanosome infections in hippopotami is shown to be limited.

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Sumario ElTrypanosoma brucei fue aislado en cuatro de 75 hipopotamos por medio de la inoculación intraperitoneal en ratones. Este parece ser el primer aislamiento de trypanosomas deHippopotamus amphibius y un nuevo hospedero para el record delT. brucei. Las cuatro cepas de trypanosomas polimórficos aisladas fuereon identificadas comoT. brucei por la prueba de infectividad de incubación de sangre (PIIS). En 500 frotices mojados de sangre y en 390 frotices secos (890 en total) de 370 hipopotamos examinados no se encontraron trypanosomas. El valor del examen del frotiz de sangre para el diagnóstico de las infecciones por trypanosomas en hipopotamos es demostrado ser limitado.

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Résumé Trypanosoma brucei a été isolé de quatre hippopotames sur 75, par inoculation à la souris par voie intrapéritonéale. Il semble que ce soit la première fois que des trypanosomes ont été isolés d’Hippopotamus amphibius et qu’ils s’agisse d’un nouvel h?te pourT. brucei. Les quatre souches de trypanosomes polymorphes isolés ont été identifiées commeT. brucei par le test d’infectiosité du sang incubé (BIIT). Aucun trypanosome n’a été trouvé dans 890 préparations de sang (500 de sang frais et 390 frottis) de 370 hippopotames. Il a été démontré que la valeur de l’examen de frottis de sang pour le diagnostic d’infections à trypanosomes chez l’hippopotame est limitée.

     

Tsetse flies as vectors of trypanosomes

Glossina spp. can be naturally infected with trypanosomes belonging to the subgenera Duttonella, Nannomonas and Trypanozoon; rates of infection vary but are, in general, highest with those trypanosomes which have the simplest cycle of development in the insect and lowest in those with the most complicated cycle of development. Differences in rates of infection have mainly been accounted for in terms of such factors as the maintenance temperature of puparia and adults, the age of the fly at the time of the infective feed and, perhaps most important, the type of host animals on which the flies feed. Differences in infectibility occur between species of Glossina and may occur between different individuals of a single species. The nature of the mechanism involved is unknown; there is no evidence that trypanosomes have any pathogenic effect on Glossina. Cyclical transmission of a strain of Trypanosoma brucei through Glossina seems to have little effect on the antigenic characters of the strain, the tsetse fly acting only as a carrier of the strain which either remains unaltered throughout the period required for cyclical development and for the rest of the life of the fly or reverts to a so-called basic antigenic type.     

Detection of anti‐TNFα activity in canine hyperimmune serum using a TNFα inhibition assay

Background: Increased serum tumor necrosis factor‐α (TNFα) activity has been associated with onset of serious inflammatory diseases in dogs. Development of treatment with TNFα‐antagonists has been limited by the unavailability of suitable reagents and potency assays for TNFα. Objectives: The objectives of this study were to optimize a cell‐based assay to measure anti‐TNFα activity in serum and plasma from hyperimmune (vaccinated with an Escherichia coli J5 bacterin) and unvaccinated canine donors; to use the assay to determine whether hyperimmune serum inhibits TNFα activity in vivo; and to determine whether soluble TNF receptor‐1 (sTNFR1, a naturally occurring TNFα antagonist) contributes to anti‐TNFα activity. Methods: Commercial plasma and serum from hyperimmune‐frozen plasma (HFP) donors and unvaccinated fresh‐frozen plasma (FFP) donors were used in the study. An L929‐cell TNFα‐inhibition assay (LTIA) was optimized to measure anti‐TNFα activity. Using a rat subcutaneous pouch model of inflammation, the effects of HFP, FFP, a synthetic TNFα antagonist (Etanercept), and carprofen on TNFα activity were compared in vivo. Immunofluorescence was used to measure soluble sTNFR1 concentration. Results: Using the optimized LTIA, HFP serum but not FFP serum decreased canine TNFα activity (P<.01). HFP plasma and Etanercept (but not FFP plasma or carprofen) significantly decreased TNFα activity in pouch exudates (P<.05). A significantly higher concentration of sTNFR1 was found in HFP than FFP serum. Conclusions: Using the LTIA, anti‐TNFα activity is readily measured in canine serum and inflammatory exudates. sTNFR1 appears to contribute to anti‐TNFα activity in HFP serum. These results suggest HFP should be investigated further as a potential immunotherapeutic agent for controlling canine diseases in which TNFα is implicated.     

Absence of host proteins from the surface of Trypanosoma vivax of cattle

Trypanosoma vivax (EATRO 1721) organisms were isolated by DEAE-cellulose chromatography from blood of an experimentally infected calf. Attempts to agglutinate the purified trypanosomes with a rabbit antiserum against whole bovine serum or antisera monospecific for bovine IgG1, IgG2, IgM, complement component C3 or albumin were unsuccessful. The trypanosomes, however, were agglutinated by immune sera of four different calves chronically infected with T. vivax (EATRO 1721). It was concluded that T. vivax organisms purified by DEAE-cellulose chromatography from blood of cattle do not have bovine serum proteins on their surface.     

The effect of double infections with trypanosomes and gastrointestinal nematodes on the productivity of sheep and goats in south Mozambique

The effect of simultaneous infections with trypanosomes (Trypanosoma vivax and Trypanosoma congolense) and gastrointestinal nematodes on the productivity of sheep and goats was studied in 20 animals (6 male goats and 14 male sheep) at a farm near Maputo. The animals were divided into 4 groups which received either treatment against gastrointestinal nematodes, or against trypanosomes, or treatment against both, or no treatment at all.In two-weekly and later in weekly intervals body weight, packed cell volume, body temperature, worm egg burdens and occurence of trypanosomes in the peripheral blood were recorded. Body temperature and packed cell volume did not show the expected close relation to an infection with either trypanosomes or gastrointestinal nematodes, but the differences in the increase of body weight among the 4 groups were very considerable.Animals receiving both treatments gained an average of 13.5 kg in body weight in 40 weeks compared with 5.1 kg (surviving animals with treatment against worm parasites), 6.5 kg (surviving animals with treatment against trypanosomes) and 3.4 kg (surviving animals without any treatment). Of the last 3 groups 1 sheep (21 kg), 2 sheep (50 kg) and 1 sheep (21 kg), respectively, died.One goat, treated against gastrointestinal nematodes, but suffering from an infection with Trypanosoma vivax and Trypanosoma congolense was killed at the end of the experiment. A striking finding during the post-mortem examination was the complete hyperplasia of the red-marrow of the right and left femur.     

Leishmania infantum secreted iron superoxide dismutase purification and its application to the diagnosis of canine Leishmaniasis

Leishmania spp. are digenetic parasites whose infection occurs inside the mononuclear phagocitary system. The iron superoxide dismutase secreted (Fe-SODe) by promastigotes of Leishmania spp. seems to plays an important role in the defense to environmental detoxification and neutralization of oxidative stress damage caused by reactive oxygen species (ROS) produced by macrophages during the infection. Parasites Fe-SODe is involved in establishing the infection and manifestation of Leishmaniasis. Its high immunogenicity makes it a useful molecular marker in diagnosing trypanosomatids infections. The aim of this study is demonstrate that purified Fe-SODe from Leishmania infantum is much more sensitive than un-purified Fe-SODe for diagnosis canine Leishmaniasis. We have purified a Fe-SODe of L. infantum using an ion exchange and a molecular sieve chromatographies and its application in diagnosis of canine Leishmaniasis was tested. One hundred and forty-five dogs’ sera from Andalusia Autonomous Community, Spain were tested by ELISA and Western blot and the antigen Fe-SODe purified is compared with two different antigens: the total parasites soluble lysate and the unpurified Fe-SODe. To validate the results obtained using the Fe-SODe purified we tasted 10 L. infantum infected dogs’ sera from Lombardy, Italy as positive control.     

Failure of hyperimmune plasma to prevent pneumonia caused by Rhodococcus equi in foals

SUMMARY A trial was conducted on a Thoroughbred stud to determine whether or not the administration of anti-Rhodococcus equi hyperimmune plasma would reduce the prevalence of R equi pneumonia (rattles) in foals born in the 1992 horse breeding season. Hyperimmune plasma was administered to 34 foals; another 57 foals were untreated. There was no significant difference in the number of transfused foals developing R equi pneumonia compared with the untreated foals. The time required for recovery from pneumonia between the 2 groups was not significantly different.     

Fractionation of trypanosome antigens for species-specific sero-diagnosis

Crude somatic antigens from isolated and ultrasonically treated trypanosomes were fractionated by column chromatography. A protein-free antigenic fraction was isolated which reacted monospecifically when tested against hyperimmune sera from rabbits. The method has a potential application in the improvement of serodiagnosis of trypanosomiasis.     

Trypanosome genetics: populations, phenotypes and diversity

In the last decade, there has been a wide range of studies using a series of molecular markers to investigate the genotypic diversity of some of the important species of African trypanosomes. Here, we review this work and provide an update of our current understanding of the mechanisms that generate this diversity based on population genetic analysis. In parallel with field based studies, our knowledge of the key features of the system of genetic exchange in Trypanosoma brucei, based on laboratory analysis, has reached the point at which this system can be used as a tool to determine the genetic basis of a phenotype. In this context, we have outlined our current knowledge of the basis for phenotypic variation among strains of trypanosomes, and highlight that this is a relatively under researched area, except for work on drug resistance. There is clear evidence for ‘strain’-specific variation in tsetse transmission, a range of virulence/pathogenesis phenotypes and the ability to cross the blood brain barrier. The potential for using genetic analysis to dissect these phenotypes is illustrated by the recent work defining a locus determining organomegaly for T. brucei. When these results are considered in relation to the body of research on the variability of the host response to infection, it is clear that there is a need to integrate the study of host and parasite diversity in relation to understanding infection outcome.     

Relapse infection after chemotherapy in dogs experimentally infected with Trypanosoma brucei brucei

Studies on relapsing Trypanosoma brucei brucei infections in dogs after Berenil treatment revealed that the first relapse occurred 13 to 64 days after chemotherapy and 36 to 79 days after inoculation. A second relapse infection was observed in two dogs 43 and 60 days after a second Berenil treatment. During the aparasitaemic period following chemotherapy in four dogs, successful transmission (as evidenced by subsequent parasitaemia) following the intraperitoneal inoculation of homogenate of brain from two of the dogs into recipient rats was obtained. Transmission with blood collected just before the animals were sacrificed was, however, negative. Hornogenates of other organs (liver, spleen, eyes, testes, kidneys, heart and lymph node) were also non-infective. One dog inoculated with relapsed trypanosomes and treated with Berenil soon after showing parasitaemia was completely cured of the infection. It was considered that the brain is the source of relapse in T b brucei infection after Berenil therapy and that the relapse was not due to drug resistance.     

Fucoidan directly regulates the chemotaxis of canine peripheral blood polymorphonuclear cells by activating F-actin polymerization

Fucoidan was recently shown to enhance innate immune functions. The objective of this study was to examine the direct stimulatory effect of fucoidan on the chemotactic activity of canine peripheral blood polymorphonuclear cells (PMNs). The chemotactic activity of PMNs was evaluated in a modified Boyden chamber assay and total cellular filamentous (F)-actin levels were measured using a flow cytometer. The chemotactic response of PMNs was increased by exposure to recombinant canine (rc) interleukin (IL)-8. In vitro treatment with fucoidan increased the chemotactic activity of PMNs in response to rcIL-8 compared with that of untreated PMNs, and also stimulated total cellular F-actin polymerization. The increased chemotactic activity of fucoidan-treated PMNs was suppressed by cytochalasin D, an inhibitor of F-actin polymerization. These results suggest that fucoidan directly regulates PMN chemotaxis, and that this effect is associated with an increase in actin polymerization.     

The infection ofGlossina morsitans weid byTrypanosoma brucei in relation to the parasitaemia in the mouse host

Summary G. morsitans were fed upon white mice infected withT. brucei TREU667, within 24 hours of emergence from the puparium. Infection rates in the flies averaged 5.8 per cent mature infections with a maximum of 15.4 per cent in one experiment. Irradiation of mice with 400r X-rays 24 hours before infection was found to slightly enhance the infection rate in flies. Flies are more readily infected when the blood-meal contains 50–20,000 trypanosomes per mm³ and 10–20,000 short stumpy forms per mm³. With the strain ofT. brucei used, suitable conditions in the mouse occur subsequent to 12 days after infection.

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Sumario MoscasG. morsitans fueron alimentadas sobre ratones blancos infectados conT. brucei TREU 667, dentro de las 24 horas de su emergencia del puparium. Las tasas de infección en las moscas promediaron 5.8 por ciento de infecciones maduras con un maximo de 15.4 por ciento en un experimento. La irradiación de ratones con 400r de rayos X por 24 horas antes de la infección acrecentó ligeramente la tasa de infección en las moscas. Las moscas son mas facilmente infectables cuando la sangre de los ratones contiene de 50–20,000 tripanosomas por mm³ y 10–20,000 formas cortas de mu?ón por mm³. Con la cepa deT. brucei usada, las condiciones adecuadas en el ratón occurren subsecuente a los 12 dias despues de la infección.

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Résumé DesG. morsitans écloses depuis moins de 24 heures ont été nourries sur souris blanche infectée avecTrypanosoma brucei. Les taux d'infection chez les mouches ont atteint une moyenne de 5,8 p. 100 de formes infectantes avec un maximum de 15,4 p. 100 dans une expérience. L'irradiation des souris aux rayons X à la dose de 400 r, 24 heures avant l'infection, a augmenté légèrement le taux d'infection chez les mouches. Les mouches sont plus aisément infectées quand le repas de sang contient de 50 à 20,000 trypanosomes par mm³ et 10 à 20,000 formes courtes et trapues par mm³. Avec la souche deT. brucei utilisée, ces taux d'infection favorables apparaissent chez la souris 12 jours après l'infection.

     

Prolonged administration: A new concept for increasing the spectrum and effectiveness of anthelmintics

Cambendazole (CBZ), fenbendazole (FBZ), oxfendazole (OFZ) and thiabendazole (TBZ) all inhibited the fumarate stimulated oxidation of NADH in Haemonchus contortus mitochondria. These observations plus the phenomenon of cross resistance to benzimidazoles suggested that the different benzimidazole anthelmintics affect parasitic helminths in a similar manner.The variation in efficiency and spectrum of activity may therefore be due to differences in their pharmacokinetic behaviour. To test this hypothesis, the magnitude and duration of concentrations of TBZ, FBZ and OFZ in plasma and other body compartments after administration were compared with their effectiveness against parasites. The effects of similar doses against benzimidazole-resistant. Trichostrongylus colubriformis and H. contortus were found to correlate with the period high plasma concentrations were maintained.Further evidence of this relationship was obtained by infusion or multiple drenching of TBZ to cattle harbouring arrested Ostertagia ostertagi larvae, so as to maintain high circulating concentrations for an extended period. This resulted in the removal of 90% of the arrested larvae, whereas TBZ as normally administered is considered quite ineffective against these larvae.These observations suggest that the spectrum and effectiveness of benzimidazoles may be improved by extending the period during which parasites are exposed to toxic concentrations.     

About the authors

The effects of exposure to natural parasitic infestations from birth to 2 years of age on body growth and blood composition were studied in British (Shorthorn × Hereford), Brahman cross and Africander cross female cattle grazing in a tropical environment. Within breeds, one half of the animals were treated regularly for the control of ecto- and endoparasites while the other half were untreated.Treatment against parasites over the trial period increased body weights, 50, 34, and 23 kg respectively within the Africander cross. Brahman cross and British breeds. Without treatment for parasites the Africander cross were 52 and the Brahman cross 27 kg heavier than the British animals at 2 years of age.The blood composition was compared during age periods when faecal egg counts (e.p.g.) were high (11–15 months) and low (19–22 months). Within breeds, treatment increased (P < 0.001) the haematocrits and the plasma concentrations of thyroxine, cholesterol, glucose and albumin when the e.p.g. was high. During 19–22 months of age were no significant differences in haematocrit nor in the concentrations of cholesterol and glucose between untreated and treated animals within breeds, but differences (P < 0.01) in the plasma concentrations of thyroxine and albumin persisted.The total e.p.g., Cooperia and Haemonchus e.p.g. and the numbers off mature ticks, (Boophilus microplus) during 11–15 months of age in untreated animals were negatively correlated within breeds (P < 0.001) with the haematocrit and plasma levels of thyroxine and cholesterol in this period and also with body weight gains from birth to 2 years of age.The results are discussed in relation to the development of blood biochemical tests for monitoring the health and production of cattle in tropical regions taking account of genotype and environment.     

Oxygen uptake by Trypanosoma brucei and there strains of T. vivax

The oxygen uptake of Trypanosoma brucei and three strains of T. vivax was studied in the presence of electron-accepting substrates, α-glycerophosphate or succinate using polarographic electrodes. T. brucei incorporated oxygen only in the presence of α-glycerophosphate. Both a naturally infective (wild strain) and a standard ruminant-passaged strain of T. vivax incorporated oxygen in the presence of α-glycerophosphate and in the presence of succinate. A mouse-adapted strain of T. vivax, however, appeared to be similar to T. brucei in that it incorporated oxygen in the presence of α-glycerophosphate, but did not do so in the presence of succinate.     

Japanese encephalitis virus immunoglobulin M antibodies in porcine sera

A solid-phase enzyme-linked immunosorbent assay (ELISA) was developed for detection of porcine immunoglobulin (Ig)M antibodies to Japanese encephalitis virus (JEV). Antibodies in sera were captured onto the solid phase of Microtiter plates sensitized with mouse monoclonal antibodies to porcine mu heavy chain. Virus antigen binding to the lawn of IgM was quantitated by subsequent binding of peroxidase-labeled human hyperimmune anti-JEV IgG, which in the final step, catalyzed a substrate color change. In sucrose density-gradient fractionated sera from recently infected pigs, the peak of ELISA JEV IgM activity corresponded to the peak of 18-S, 2-mercaptoethanol-sensitive hemagglutination-inhibiting (HAI) antibody activity. Within 2 to 3 days, JEV-infected sentinel pigs developed high JEV IgM activity; this activity decreased within 2 weeks. Among specimens collected from 99 random swine at abattoirs in Thailand during a period of low JEV transmission, none of 25 JEV HAI-negative sera had JEV IgM activity, 7 of 74 JEV HAI-positive sera did have JEV IgM activity, and the remaining 67 sera had readily detectable JEV HAI antibodies, but lacked JEV IgM. The JEV IgM solid-phase ELISA was useful for rapidly diagnosing active or recent JEV infections in swine.     

Evaluation of a commercial ELISA for the specific detection of antibodies against Besnoitia besnoiti

Bovine besnoitiosis is an economically important disease in cattle caused by the protozoan parasite Besnoitia besnoiti, which occurs endemically in many countries of Africa and Asia and is spreading in Europe. Serological identification of subclinically infected cattle is important to avoid the introduction of infected animals into naive herds. Here we determine the sensitivity and specificity of the PrioCHECK^® Besnoitia Ab, a serological test recently introduced into the European market. Analytical specificity was examined using sera from animals experimentally infected with parasites related to B. besnoiti (n = 27). Three animals experimentally infected with Neospora caninum or Toxoplasma gondii showed inconclusive reactions in the ELISA (percent positivity relative to the positive control [PP] 10% ≤ 20%) while all other sera reacted negative (PP < 10%). An estimate of the diagnostic specificity was obtained by analysing field sera from bovine herds without besnoitiosis but with abortion problems associated to N. caninum (n = 403). The analysis revealed a specificity of 94.3% or 96.8% depending on the applied cut-off (PP 10% or 20%, respectively). Sensitivity was assessed with sera from 110 animals of a herd in Germany where clinical bovine besnoitiosis was first diagnosed in September 2008. A positive serological reference standard was defined regarding sera from animals as reference positive, if these animals had tested positive in at least two of a panel of three other serological tests (two different B. besnoiti immunoblots and one immunofluorescence antibody test) on both of two sampling dates, November 2008 and April 2009. A diagnostic sensitivity of 91.8% or 75.5% was determined for sera collected in November 2008 and a sensitivity of 82.7% or 50% for sera collected in April 2009 (cut-off PP 10% or PP 20%, respectively). The marked drop in sensitivity from November 2008 to April 2009 was predominantly observed in reference-positive cattle without clinical signs. We conclude that PrioCHECK^® Besnoitia Ab is a valuable diagnostic tool to detect clinically infected animals. Thus it may be used to support control measures, e.g., for the separation of infected animals from the remaining herd to avoid a further transmission of the infection within the herd.     

Porcine trypanosomosis in nigeria: Infections in local and exotic pigs in the Nsukka Area of Anambra State

Summary A twelve-month survey in three Local Government Areas (LGA) in Nsukka zone, Anambra State, Nigeria revealed that out of 150 local and exotic breeds of pig examined, 46 (30·7%) were infected with trypanosomes. Both single and mixed infections ofTrypanosoma brucei andT. congolense were observed. However,T. brucei was the predominant trypanosome encountered. The husbandry system in practice was the most significant factor influencing the prevalence of trypanosomes in the pigs. In addition significantly higher prevalences were recorded during the rainy seasons. Clinical trypanosomosis was encountered in only eight of the 46 positive cases seen, with anaemia, loss of weight and anoestrus being the most important effects associated with these infections. The pathogenic and economic significance of these findings are discussed.

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Resumen Un estudio epidemiológico de 12 meses, sobre tripanosomiasis en cerdos, se llevó a cabo, en tres áreas gubernamentales en Nigeria. El estudio reveló, que de las 150 razas exóticas y locales de cerdos examinados, 46 (30·7 por ciento) se encontraron infectadas con tripanosomas. Se observaron al respecto infecciones únicas y mixtas deTrypanosoma brucei yT. congolense. Sin embargo,T. brucei fue el tripanosoma más observado. Las prácticas de manejo fueron los factores más significativos, sobre la prevalencia de tripanosomiasis en los cerdos estudiados. La prevalencia fue mayor en invierno, encontradose tripanosomiasis clínica en ocho de 46 casos positivos vistos, siendo la anemia, pérdida de peso y anestro, los efectos más importantes asociados con la infección. Se discute la patogénesis e importancia económica de estos hallazgos.

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Résumé Une enquête de 12 mois, dans 3 zones de la région de Nsukka (état d'Anambra au Nigeria) a montré que parmi 150 races ou variétés exotiques ou indigènes de porcs examinées, 46 soit 30, 7 p. 100, étaient infectées de trypanosomes. Des infections uniques ou doubles àTrypanosoma brucei et T. congolense ont été observées, avec prédominance deT. brucei. Le système d'élevage pratiqué s'est révélé le facteur le plus significatif quant à la prévalence des trypanosomes chez cette espèce. De plus, des prévalences significativement plus élevées ont été enregistrées pendant la saison des pluies. Les trypanosomoses cliniques n'ont été constatées que sur 8 des 46 cas positifs. La présence d'anémie, la perte de poids et l'anoestrus ont été les signes les plus importants associés à ces mêmes infections. Les conséquences pathologiques et économiques de ces résultats sont discutées.