Parasitology and environment: « one health » approach

Le parasitisme est un concept lié au comportement qui conditionne le développement des organismes dans leur environnement. Il s’exprime différemment selon leur développement cyclique. Les modifications de l’environnement parasitaire sont nombreuses : probabilité de contact hôte-parasite, climat, éthologie des espèces, anthropisation, habitudes et réceptivité de l’hôte. Les facteurs environnementaux sont encore plus déterminants sur le développement parasitaire si le cycle biologique nécessite un hôte intermédiaire. Deux concepts dominent les relations entre parasites et environnement : la coévolution et l’adaptation. Les parasites représentent un modèle d’étude de l’approche « One health ».Parasitism is a behavior that conditions the development of organisms in their environment. It expresses itself differently according to their cyclical development. Changes in the parasitic environment are numerous: probability of host-parasite contact, climate, ethology of species, anthropization, habits and receptivity of the host. Environmental factors are even more critical for parasite development if the life cycle requires an intermediate host. Two concepts dominate the relations between parasites and the environment: coevolution and adaptation. Parasites are a model for studying the “One Health” approach

Molluscs in the transmission of human and veterinary helminthiasis

Fresh water gasteropods are intermediate hosts in the life cycle of numerous digeneans of medical and veterinary relevance, and of a few Protostrongylidae helminths. These molluscs harbour the larval development of parasites and their transmission to the final host, either directly or via another aquatic host, whether fish or crustacean. The behaviour of these molluscs plays a crucial role in the maintenance of schistosomiasis or distomatosis foci, knowing that the majority of these helminthiases are cosmopolitan zoonoses. Most of these parasitic diseases are cosmopolitan zoonoses. Although the specificity of the parasite towards its molluscan host is often high, incomplete larval development may occur in many molluscan species without transmission to mammals.Les mollusques gastéropodes d'eau douce interviennent comme hôtes intermédiaires indispensables dans le cycle de développement de nombreuses espèces de digènes d'intérêt médical et vétérinaire, et dans celui de quelques protostrongylidés. Ils assurent le développement larvaire de parasites et leur transmission à l'hôte définitif, de manière directe ou via un deuxième hôte aquatique, poisson ou crustacé. Le comportement des mollusques est déterminant dans le maintien des foyers de bilharziose ou de distomatose, sachant que la majorité de ces helminthoses sont des zoonoses cosmopolites. L'adaptation des espèces parasitaires aux mollusques hôtes est souvent assez étroite, même si un développement larvaire partiel des helminthes est possible chez de nombreuses espèces de mollusques, sans permettre la transmission aux mammifères

Fasciola hepatica: Variations in redial development and cercarial production in relation to the geographic origin of the parasite

Two hundred Galba truncatula, originating from a French population, were subjected to single-miracidium infections with an allopatric isolate (origin, Argentina) of Fasciola hepatica. The control group was constituted by 100 snails coming from the same population and exposed to sympatric miracidia of F. hepatica according to the same protocol. Snail samples were collected bimonthly from both groups between day 14 and day 112 p.e. (at 20 C) and snail dissections were performed to count free rediae, intraredial morulae and free cercariae. Third and fourth generation rediae were significantly more numerous in the allopatric group, while the number of first generation rediae was significantly lower. In the sympatric group, the decrease in the number of intraredial morulae in the first, second and third redial generations was significantly faster. Free cercariae within the snail body were significantly more numerous in the sympatric than in the allopatric groups, whatever the date of snail dissection. The changes in redial development and cercarial production noted in the Argentinean group might be due to the evolution of South American flukes in a divergent way after the introduction of foreign infected ruminants in this continent from the 15th century.Facultad de Ciencias Veterinaria

Fasciola hepatica: Variations in redial development and cercarial production in relation to the geographic origin of the parasite

Two hundred Galba truncatula, originating from a French population, were subjected to single-miracidium infections with an allopatric isolate (origin, Argentina) of Fasciola hepatica. The control group was constituted by 100 snails coming from the same population and exposed to sympatric miracidia of F. hepatica according to the same protocol. Snail samples were collected bimonthly from both groups between day 14 and day 112 p.e. (at 20 C) and snail dissections were performed to count free rediae, intraredial morulae and free cercariae. Third and fourth generation rediae were significantly more numerous in the allopatric group, while the number of first generation rediae was significantly lower. In the sympatric group, the decrease in the number of intraredial morulae in the first, second and third redial generations was significantly faster. Free cercariae within the snail body were significantly more numerous in the sympatric than in the allopatric groups, whatever the date of snail dissection. The changes in redial development and cercarial production noted in the Argentinean group might be due to the evolution of South American flukes in a divergent way after the introduction of foreign infected ruminants in this continent from the 15th century.Facultad de Ciencias Veterinaria

Human Paragonimiasis in Africa

An up-to-date review on human paragonimiasis in Africa was carried out to determine the current geographical distribution of human cases and analyze the animal reservoir, snails and crustaceans which intervene in the local life cycle of Paragonimus species. Two countries, i.e., Cameroon and Nigeria, were mainly affected by this disease, while the distribution of human cases in the other eight states of the intertropical zone was scattered. Infected patients were currently few in number and two Paragonimus species: P. africanus and P. uterobilateralis , were found. The animal reservoir is mainly constituted by crab-eating mammals. The identity of the host snail remains doubtful and was either a prosobranch, or a land snail. Seven crab species belonging to Callinectes, Liberonautes and Sudanonautes genera are able to harbour paragonimid metacercariae. Due to the current low prevalence of human paragonimiasis recorded in Africa and the high cost of wide-scale screenings for this disease, training of technicians in anti-tuberculosis centers would be the most realistic attitude to detect mycobacteria and/or Paragonimus eggs during the same sputum examination.Une revue sur la paragonimose en Afrique a \ue9t\ue9 r\ue9alis\ue9e pour d\ue9terminer la distribution g\ue9ographique actuelle des cas humains et analyser le r\ue9servoir animal, les mollusques et les crustac\ue9s qui interviennent dans le cycle local des esp\ue8ces de Paragonimus . Deux pays, \ue0 savoir le Cameroun et le Nigeria, sont principalement affect\ue9s par cette maladie tandis que la r\ue9partition des cas humains dans les huit autres \ue9tats de la zone intertropicale est dispers\ue9e. Les patients parasit\ue9s sont actuellement peu nombreux et deux esp\ue8ces de Paragonimus: P. africanus et P. uterobilateralis , ont \ue9t\ue9 identifi\ue9es. Le r\ue9servoir animal est principalement constitu\ue9 par des mammif\ue8res mangeurs de crabes. L\u2019identit\ue9 du mollusque h\uf4te reste douteuse et se rapporte \ue0 un prosobranche ou \ue0 un mollusque terrestre. Sept esp\ue8ces de crabes appartenant aux genres Callinectes, Liberonautes et Sudanonautes sont capables d\u2019h\ue9berger des m\ue9tacercaires de Paragonimus. En raison de la faible pr\ue9valence actuelle de la paragonimose humaine en Afrique et du co\ufbt \ue9lev\ue9 du d\ue9pistage \ue0 grande \ue9chelle pour cette maladie, la formation des techniciens dans les centres anti-tuberculeux serait l\u2019attitude la plus r\ue9aliste pour d\ue9tecter simultan\ue9ment les mycobact\ue9ries ou les \u153ufs de Paragonimus, lors de l\u2019examen du m\ueame crachat

Fasciola hepatica: Variations in redial development and cercarial production in relation to the geographic origin of the parasite

Two hundred Galba truncatula, originating from a French population, were subjected to single-miracidium infections with an allopatric isolate (origin, Argentina) of Fasciola hepatica. The control group was constituted by 100 snails coming from the same population and exposed to sympatric miracidia of F. hepatica according to the same protocol. Snail samples were collected bimonthly from both groups between day 14 and day 112 p.e. (at 20 C) and snail dissections were performed to count free rediae, intraredial morulae and free cercariae. Third and fourth generation rediae were significantly more numerous in the allopatric group, while the number of first generation rediae was significantly lower. In the sympatric group, the decrease in the number of intraredial morulae in the first, second and third redial generations was significantly faster. Free cercariae within the snail body were significantly more numerous in the sympatric than in the allopatric groups, whatever the date of snail dissection. The changes in redial development and cercarial production noted in the Argentinean group might be due to the evolution of South American flukes in a divergent way after the introduction of foreign infected ruminants in this continent from the 15th century.Facultad de Ciencias Veterinaria

Hookworm-Related Anaemia among Pregnant Women: A Systematic Review

Anaemia affects large numbers of pregnant women in developing countries and increases their risk of dying during pregnancy and delivering low birth weight babies, who in turn are at increased risk of dying. Human hookworm infection has long been recognized among the major causes of anaemia in poor communities, but understanding of the benefits of the management of hookworm infection in pregnancy has lagged behind the other major causes of maternal anaemia. Low coverage of anthelmintic treatment in maternal health programmes in many countries has been the result. After systematically reviewing the available literature we observed that increasing hookworm infection intensity is associated with lower haemoglobin levels in pregnant women. We also estimate that between a quarter and a third of pregnant women in sub-Saharan Africa are infected with hookworm and at risk of preventable hookworm-related anaemia. However, all identified intervention studies showed a benefit of deworming for maternal or child health and we argue that increased efforts should be made to increase the coverage of anthelmintic treatment among pregnant women

Rôles vecteurs principaux des ixodidae en France (conduite à tenir après une morsure de tique)

LIMOGES-BU Médecine pharmacie (870852108) / SudocLYON1-BU Santé (693882101) / SudocSudocFranceF

La gale sarcoptique humaine

LIMOGES-BU Médecine pharmacie (870852108) / SudocLYON1-BU Santé (693882101) / SudocSudocFranceF