Particularities and limits of the vaccines in veterinary parasitology

Chez l’homme et les animaux domestiques, les maladies parasitaires dues à des champignons, des protozoaires, des helminthes et des arthropodes constituent un défi majeur car elles sont à l’origine d’une mortalité parfois élevée (paludisme), de pertes économiques considérables et parfois sources de parasitoses zoonotiques. Malheureusement, la thérapeutique actuelle est parfois inadaptée ou inefficace à cause de l’émergence de la chimiorésistance. De nombreuses publications mettent en avant des vaccins efficaces contre la leishmaniose et une babésiose canine, une teigne bovine, la toxoplasmose ovine, les coccidioses aviaires et des tiques de bovins ; malheureusement en dépit de ces nombreuses publications, peu de vaccins parviennent à la commercialisation. La médecine humaine et vétérinaire a besoin aujourd’hui d’une stratégie de recherche efficace pour la mise au point de vaccins dirigés contre des parasitoses majeures et/ou zoonotiques.In human beings and domestic animals, parasitic diseases — due to either fungi, protozoa, helminths or arthropods — are a very important challenge because they are associated with a very high mortality (malaria), or production loss and sometimes are a source of illness for humans. Unfortunately, the presently available chemotherapeutic arsenal is inadequate or ineffective because of the frequent emergence of chemoresistance. Several publications and reviews demonstrate the efficiency of vaccines against canine leishmaniosis and babesiosis, bovine ringworms, ovine toxoplasmosis and poultry coccidiosis of poultry and some tick infections of cattle; but, despite many research publications, few vaccines have reached the commercial market. Medicine quickly need efficious strategies for the discovery of efficacious vaccines against major eventually zoonotic parasitic diseases

Canine leishmaniosis epidemiological update and applications

Canine leishmaniosis is a vector-borne disease caused by Leishmania infantum mainly transmitted by the bites of phlebotomine sandflies. The epidemiological role of domestic dogs (safe, asymptomatic, sick or vaccinated) is very important because it is the main source of parasites for the vector. But the proved or potential epidemiological role of wild animals (rabbit, hare,…) require more investigations for a best efficacy. The displacement or importation of infected dogs combined with the climatic modifications contribute to a significative incidence of canine and human clinical cases. Vaccination associated with topical insecticides should be recommanded for dogs living or travelling in endemic areas.La leishmaniose canine est une maladie vectorielle due à Leishmania infantum principalement transmis par la piqûre de phlébotomes. Le rôle épidémiologique du chien qu’il soit sain, malade, infecté asymptomatique ou vacciné est très important puiqu’il représente la source principale de parasites pour le vecteur. Mais le rôle épidémiologique d’espèces animales sauvages (lapin, lièvre,…) nécessite des investigations complémentaires pour une meilleure efficacité contre cette maladie. Le déplacement ou l’importation de chiens infectés associé aux modifications climatiques contribue à une incidence significative des cas cliniques humains et canins. La vaccination associée à l’utilisation de topiques insecticides doit être recommandée pour tout chien vivant ou se déplaçant en zones d’endémie

The biosecurity in an academic veterinary hospital

La « biosécurité » se définit comme l’ensemble des mesures de prévention et de protection à l’encontre des agents infectieux : lutte contre l’introduction d’un pathogène dans un laboratoire, un établissement de soins vétérinaires,… (notion de bio-exclusion), contre le risque de transmission à l’extérieur et de propagation (notion de bioconfinement). La biosécurité concerne également les risques de nature physique (radiations) et chimique (médicaments, toxines,…). Ces mesures sont permanentes et s’appliquent sur l’ensemble du campus, d’abord pour la protection de l’homme (détenteur de l’animal, personnels et étudiants), ensuite de l’animal (animaux de compagnie, équidés et bétail), enfin du milieu extérieur. L’établissement doit également assurer un haut niveau de formation des étudiants, en particulier en matière de protection et de biosécurité conformément aux recommandations des associations internationales (EAEVE, AVMA).Biosecurity refers to (1) both prevention and protection from infectious agents, including the risk of introduction of pathogens in laboratories, units of production, universities (bioexclusion) and the risk of external trasmission and future propagation (bioconfinement), (2) physical risks : radioactivity and (3) chemical risks : drugs, pesticides, toxins. These measures are permanent and apply to the whole university site for the protection of humans — owners of animal, employees of the veterinary campus, students —, animals — pets, horses, cattle,…— and the environment. A veterinary campus has to secure a high level of training of students and topics related for the biosecurity. International associations (EAEVE and AVMA) define several « day-one competencies » for the students, in particular for the zoonotic diseases and for the safety in the veterinary setting

Environmental risk mapping of canine leishmaniasis in France

<p>Abstract</p> <p>Background</p> <p>Canine leishmaniasis (CanL) is a zoonotic disease caused by <it>Leishmania infantum</it>, a Trypanosomatid protozoan transmitted by phlebotomine sandflies. Leishmaniasis is endemic in southern France, but the influences of environmental and climatic factors on its maintenance and emergence remain poorly understood. From a retrospective database, including all the studies reporting prevalence or incidence of CanL in France between 1965 and 2007, we performed a spatial analysis in order to i) map the reported cases in France, and ii) produce an environment-based map of the areas at risk for CanL. We performed a Principal Component Analysis (PCA) followed by a Hierarchical Ascendant Classification (HAC) to assess if the locations of CanL could be grouped according to environmental variables related to climate, forest cover, and human and dog densities. For each group, the potential distribution of CanL in France was mapped using a species niche modelling approach (Maxent model).</p> <p>Results</p> <p>Results revealed the existence of two spatial groups of CanL cases. The first group is located in the Cévennes region (southern Massif Central), at altitudes of 200-1000 m above sea level, characterized by relatively low winter temperatures (1.9°C average), 1042 mm average annual rainfall and much forest cover. The second group is located on the Mediterranean coastal plain, characterized by higher temperatures, lower rainfall and less forest cover. These two groups may correspond to the environments favoured by the two sandfly vectors in France, <it>Phlebotomus ariasi </it>and <it>Phlebotomus perniciosus </it>respectively. Our niche modelling of these two eco-epidemiological patterns was based on environmental variables and led to the first risk map for CanL in France.</p> <p>Conclusion</p> <p>Results show how an ecological approach can help to improve our understanding of the spatial distribution of CanL in France.</p

Results of vaccination against canine visceral leishmaniasis (Leishmania infantum) in enzootic areas

Protection against canine leishmaniasis was evaluated in dogs living in enzootic areas in the south of France, and vaccinated with a candidate vaccine, LiESP with the adjuvant MDP. A double-blind field study was carried out in a large number of dogs (n = 414) over two years. At the end of the study, infection rate was 0% in vaccinated dogs versus 5.14% in the placebo group. The candidate vaccine induced an effective and lasting immunity against canine leishmaniasis.La protection contre la leishmaniose canine est évaluée chez des chiens vivant en zone d'enzootie dans le sud de la France, vaccinés par un candidat LiESP adjuvé par MDP. Une étude de terrain randomisée en double aveugle est conduite dans une large population de chiens (n = 414), durant une période de deux années. À l'issue de l'étude, le taux d'infection est de 0 % chez les chiens vaccinés et de 5,14 % chez les chiens du groupe placebo. Le candidat vaccinal a induit une immunité efficace, durable contre la leishmaniose canine

Canine leishmaniosis due to Leishmania infantum: immunotherapy trials

As most methods currently available to treat and control canine leishmaniasis have a limited efficacy, researchers are testing immunotherapeutic methods with great interest. Excreted–secreted antigens (ES Ag) of promastigotes of Leishmania infantum cultured in a defined medium were selected. Three Leishmania–infected dogs received two intradermal injections of 25 mg of ES Ag, at 3 weeks interval. This treatment was the first ever in one of the dogs, whereas the other two had previously received a standard treatment with Glucantime® and Zyloric®. Marked clinical improvement was noted as of Day 15 after the first injection, as well as an intense leishmanicide activity in collected monocytes, and a significant decrease of antibody titres. No clinical relapse was recorded over two years later.La plupart des méthodes disponibles aujourd'hui de traitement et de contrôle de la leishmaniose canine sont d'une efficacité limitée, aussi le développement de méthodes immunothérapeutiques est-il d'un grand intérêt. Des antigènes d'excrétion-sécrétion (Ag ES) de promastigotes de Leishmania infantum cultivés en milieu défini sont retenus. Trois chiens leishmaniens en reçoivent 25 μg, 2 fois à 3 semaines d'intervalle, par la voie intra-dermique: un chien est traité pour la première fois selon ce protocole, les 2 autres avaient été traités antérieurement selon un protocole classique à base de glucantime et de zyloric. Une nette amélioration clinique est observée dès J15 après la première injection, ainsi qu'une forte activité leishmanicide des monocytes récoltés et une diminution significative des titres en anticorps. Aucune rechute clinique n'est enregistrée plus de 2 ans plus tard

Survey of digestive parasitism in dogs in a rural area of Gabon

A parasitological study was carried out on 198 dogs living almost completely free in villages in the north-east of Gabon . Faeces samples were collected and analysed. The prevalence of digestive parasitism measured by microscopic coproscopy (flotation method) reached 91% (181/198). The vast majority of parasites thus isolated were ascarids (59% of samples), but they also included Ancylostoma (35%), Trichuris (49%) and Spirocerca (25%). Some embryophores of cestodes were found in 17 samples (9%).Une étude parasitologique a été menée chez 198 chiens vivant en liberté quasi complète dans des villages du Nord-Est du Gabon. Des échantillons de fèces ont été prélevés et analysés. Une prévalence du parasitisme digestif de 91 % (181/198) a été mise en évidence par coproscopie microscopique (méthode d'enrichissement par flottation). La prévalence, par parasite, est de 59 % pour les ascarides, de 49 % pour les trichures, de 35 % pour les ankylostomes, de 25 % pour les spirocerques, de 11 % pour les capillaries et de 10 % pour les coccidies. Des embryophores de cestodes ont été retrouvés dans 17 échantillons (9 %)

recommendations from the CVBD World Forum

The human-animal bond has been a fundamental feature of mankind's history for millennia. The first, and strongest of these, man's relationship with the dog, is believed to pre-date even agriculture, going back as far as 30,000 years. It remains at least as powerful today. Fed by the changing nature of the interactions between people and their dogs worldwide and the increasing tendency towards close domesticity, the health of dogs has never played a more important role in family life. Thanks to developments in scientific understanding and diagnostic techniques, as well as changing priorities of pet owners, veterinarians are now able, and indeed expected, to play a fundamental role in the prevention and treatment of canine disease, including canine vector-borne diseases (CVBDs).The CVBDs represent a varied and complex group of diseases, including anaplasmosis, babesiosis, bartonellosis, borreliosis, dirofilariosis, ehrlichiosis, leishmaniosis, rickettsiosis and thelaziosis, with new syndromes being uncovered every year. Many of these diseases can cause serious, even life-threatening clinical conditions in dogs, with a number having zoonotic potential, affecting the human population.Today, CVBDs pose a growing global threat as they continue their spread far from their traditional geographical and temporal restraints as a result of changes in both climatic conditions and pet dog travel patterns, exposing new populations to previously unknown infectious agents and posing unprecedented challenges to veterinarians.In response to this growing threat, the CVBD World Forum, a multidisciplinary group of experts in CVBDs from around the world which meets on an annual basis, gathered in Nice (France) in 2011 to share the latest research on CVBDs and discuss the best approaches to managing these diseases around the world.As a result of these discussions, we, the members of the CVBD Forum have developed the following recommendations to veterinarians for the management of CVBDs