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Vector-borne diseases affecting livestock have serious impacts in Africa. Trypanosomosis is caused by parasites transmitted by tsetse flies and other blood-sucking Diptera. The animal form of the disease is a scourge for African livestock keepers, is already present in Latin America and Asia, and has the potential to spread further. A human form of the disease also exists, known as human African trypanosomosis or sleeping sickness. Controlling and progressively minimizing the burden of animal trypanosomosis (COMBAT) is a four-year research and innovation project funded by the European Commission, whose ultimate goal is to reduce the burden of animal trypanosomosis (AT) in Africa. The project builds on the progressive control pathway (PCP), a risk-based, step-wise approach to disease reduction or elimination. COMBAT will strengthen AT control and prevention by improving basic knowledge of AT, developing innovative control tools, reinforcing surveillance, rationalizing control strategies, building capacity, and raising awareness. Knowledge gaps on disease epidemiology, vector ecology and competence, and biological aspects of trypanotolerant livestock will be addressed. Environmentally friendly vector control technologies and more effective and adapted diagnostic tools will be developed. Surveillance will be enhanced by developing information systems, strengthening reporting, and mapping and modelling disease risk in Africa and beyond. The socio-economic burden of AT will be assessed at a range of geographical scales. Guidelines for the PCP and harmonized national control strategies and roadmaps will be developed. Gender equality and ethics will be pivotal in all project activities. The COMBAT project benefits from the expertise of African and European research institutions, national veterinary authorities, and international organizations. The project consortium comprises 21 participants, including a geographically balanced representation from 13 African countries, and it will engage a larger number of AT-affected countries through regional initiatives.

The animal trypanosomiases of African origin are a rather typical example of a neglected tropical disease. They are caused by blood parasites of the Trypanosoma genus transmitted by haematophagous insects, cyclically by tsetse flies for Trypanosoma congolense, T. vivax and T. brucei brucei, which cause nagana, mechanically by T. evansi, the agent of surra, and finally by T. equiperdum, adapted to sexual transmission, which causes dourine. Nagana affects 38 African countries in the sub-Saharan region with 55 million cattle at risk, not counting small ruminants. These diseases deteriorate the animal’s physical condition, leading to a sharp drop in productivity; in the most severe cases, and in the absence of treatment, the animal dies within a few weeks. The socio-economic impact is estimated at US$ 4.75 billion in annual losses, making these diseases one of the major obstacles to livestock development in Africa. The control of these diseases is hampered by the lack of vaccines, a handful of molecules for treatment against which parasites are increasingly developing resistance, and finally, molecular or serological diagnostics whose robustness needs to be greatly improved. Clinical signs are not specific, parasitological diagnosis is often not very sensitive, and molecular methods are not applicable in the field. Immunodiagnostic methods in the form of rapid diagnostic tests are the only ones suitable for the field, but the few existing tests are poorly available and lack specificity and/or sensitivity. Here we address the advantages and limitations of current diagnostic methods and propose new ways of improving them for better disease control., Les trypanosomiases animales d’origine africaine représentent typiquement une maladie tropicale négligée. Elles sont causées par des parasites sanguicoles du genre Trypanosoma transmis par des insectes hématophages, de manière cyclique par les mouches tsé-tsé pour Trypanosoma congolense, T. vivax et T. brucei brucei, qui causent la nagana, de manière mécanique pour T. evansi, agent de la surra, et enfin par transmission sexuelle pour T. equiperdum, qui cause la dourine. La nagana est présente dans 38 pays d’Afrique subsaharienne où elle peut affecter de nombreuses espèces animales, sauvages et domestiques. Près de 55 millions de bovins vivent sous risque trypanosomien, sans compter les petits ruminants. Ces maladies détériorent la condition physique de l’animal, induisant une forte baisse de productivité. Dans les cas les plus sévères, et en l’absence de traitement, la mort survient en quelques semaines. L’impact socio-économique est estimé à 4,75 milliards de dollars de pertes annuelles, ce qui fait de ces maladies l’un des obstacles majeurs au développement de l’élevage en Afrique. Le contrôle de ces maladies se heurte à l’absence de vaccin, à des traitements dont les molécules sont peu nombreuses et contre lesquelles se développent de plus en plus de résistances de la part des parasites, et enfin à un diagnostic, moléculaire ou sérologique, dont la robustesse demande à être grandement améliorée. Les signes cliniques ne sont pas spécifiques, le diagnostic parasitologique est souvent peu sensible, et les méthodes moléculaires ne sont pas applicables sur le terrain. Les méthodes d’immunodiagnostic sous forme de tests de diagnostic rapide sont les seules adaptées au terrain, mais les rares tests existants sont très peu accessibles (disponibilité, prix), et manquent de spécificité et/ou de sensibilité. Ici, nous traiterons des limites et des avantages comparatifs des méthodes actuelles de diagnostic et proposerons de nouvelles pistes d’amélioration de ces dernières pour un meilleur contrôle de la maladie.

O parasita Babesia bovis é um dos agentes causadores da babesiose bovina, uma doença tropical associada a altas taxas de mortalidade. Esta doença é transmitida por caraças da espécie Riphicephalus (Boophilus) microplus. A babesiose é responsável por elevados prejuízos económicos, especialmente a redução na produção de carne e leite, além de custos com medidas preventivas e tratamento dos animais. Para o diagnóstico da babesiose são usadas várias técnicas: o diagnóstico parasitológico baseado na observação microscópica, os métodos com base em ADN, os testes serológicos e os testes rápidos de diagnóstico (RDT's) que vem oferecendo um potencial para a ampliação do diagnóstico preciso sendo simples de executar e fáceis de interpretar. O presente trabalho teve como objectivo produzir e avaliar anticorpos policlonais com base em peptídeos sintéticos da proteína LDH de Babesia bovis como poencial para o desenvolvimento de um teste ELISA de captura. A LDH é uma enzima importante para o metabolísmo energético do género babésia onde ela atinge altas concentrações no estágio eritrocítico do parasita. Com ajuda do programa de bioinformática Swiss-Model, a estrutura tridimensional da LDH foi construída; 4 peptídeos sintéticos foram desenhados e produzidos e imunizou-se 8 coelhos e 4 galinhas com os peptídeos. Todos os coelhos e galinhas apresentaram curvas cinéticas de produção de anticorpos crescentes quando testados em ELISA indirecto, com variações dependentes do peptídeo administrado. Contudo, de acordo com o teste ANOVA (p

A tripanossomose africana é uma hemoparasitose transmitida pela mosca tsé-tsé que afeta o homem e os animais, causando grandes perdas económicas. Os principais agentes causadores são o T. congolense, T. vivax e T. brucei spp. A principal medida de controlo é a quimioterapia e quimioprofilaxia, embora limitada pelo número de tripanocidas disponíveis. Assim, o diagnóstico torna-se uma ferramenta importante pois permite o desenho de tratamento adequados, todavia, os métodos existentes não são satisfatórios. Neste contexto abriu-se espaço para o desenvolvimento dum teste ELISA de captura de antigénios circulantes, que detecta infeções ativas, com a vantagem de poder ser adaptado em formato ``dipstick´´. A malato desidrogenase citoplasmática (cMDH) foi escolhida como antigénio candidato devido à sua abundância na corrente sanguínea de hospedeiros após lise do tripanossoma, e a possibilidade de deteção enzimática. A fim de expressar a forma recombinante da cMDH, a sequência codificante da proteína foi clonada no plasmídeo pTZ57R/T, seguido da sub-clonagem no plasmídeo de expressão pET32a na estirpe Escherichia coli BL21(DH3). Após indução por IPTG foi produzido uma proteína solúvel. Com a proteina imunizou-se dois coelhos e duas galinhas para obtenção de anticorpos policlonais, os quais foram usados para desenvolver o teste de ELISA de captura. A cMDH recombinate, é uma proteina com 55 kDa de peso molecular. Os anticorpos produzidos em coelho e em galinha mostraram capacidade de reconhecimento da cMDH nativa de T. congolense presente em soro de bovinos infectados, num sistema ELISA de captura e imunoblot. Este estudo demonstra que os anticorpos policlonais produzidos são capazes de capturar a cMDH nativa em soro de animais infectados por T. congolense com diferentes níveis de parasitémia. Estes resultados sugerem que o sistema de captura do cMDH pode ser desenvolvido e validado como um ELISA de captura para o diagnóstico de campo de infecções Trypanosoma congolense. (Texte intégral)

International audience; Animal trypanosomosis is one of the most severe constraints to agricultural development in sub-Saharan Africa and is also an important disease of livestock in Latin America and Asia. The causative agents are various species of protozoan parasites belonging to the genus Trypanosoma, among which T. congolense and T. evansi are the major pathogenic species. The extracellular position of trypanosomes obliges us to consider both the parasite and its excreted/secreted factors in the course of the physiopathologic process. The advent of proteomics led us to propose a comparative approach of the proteome (i.e., the whole parasite content) and the secretome (i.e., naturally excreted/secreted molecules) of T. congolense and T. evansi with particular attention to common and specific molecules between strains of differing virulence and pathogenicity. The molecular identification of differentially expressed trypanosome molecules correlated with either the virulence process or the pathogenicity will provide new potential molecular targets for improved field diagnosis and chemotherapy of animal trypanosomosis

The causative agents of animal trypanosomosis are various species of protozoan parasites belonging to the genus Trypanosoma, among which T. congolense and T. evansi are the major pathogenic species. The extra cellular position of the trypanosomes implies to consider both the parasite and its excretedsecreted factors in the course of the physiopathological processes. Proteome (i.e. parasite constitutive proteins) and secretome (i.e. naturally excreted-secreted proteins) analysis need to be conducted in parallel to identify key trypanosome¿s proteins potentially involved in both virulence and pathogenicity. We developed and standardised a method to produce purified proteome and secretome of the two sub-genus Trypanozoon and Nannomonas. The protocol is based on the production of trypanosome bloodstream forms by infection of naturally immunosupressed rodents (Nude/SOPF®) and incubated in a defined secretion medium that mimics the blood biochemical environment deprived of cells and macromolecules. Supernatants representing secretome are separated from parasites pellets representing proteome by centrifugation and filtration and both are conditioned for further analysis in two-dimensional gel electrophoresis and mass spectrometry. The defined secretion medium appears to reduced expression of stress proteins. Two-dimensional difference gel electrophoresis (2-D DIGE) analysis of secretomes in particular confirmed both the differences observed in 1-D gels and the high reproducibility between secretome batches of a same trypanosome strain. The molecular identification of differentially expressed trypanosomes molecules correlated with either the virulence process or the pathogenicity will provide new potential molecular targets.