Publications by authors named "Christophe Chartier"

Article Synopsis
  • Gastrointestinal nematodes (GINs) significantly affect sheep health and production in Norway, yet only a few studies have addressed their prevalence.
  • The study collected fecal samples from 134 sheep flocks across various regions in Norway (northern, eastern, western, central, and southern) during 2021/2022 to identify the occurrence of key nematode species.
  • Findings revealed that T. circumcincta was the most common (94% prevalence), followed by H. contortus (60%) and Trichostrongylus (55%), indicating widespread mixed infections among flocks.
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Objective: MEMOSHOP is a virtual reality (VR)-based supermarket application for assessing episodic memory in aging. The aim of this study was to examine its construct validity against the gold standard paper-and-pencil neuropsychological test for clinical memory assessment in mild cognitive impairment (MCI) in older adults.

Methods: Patients with isolated subjective cognitive complaints (SCCs) or MCI were recruited in the Bordeaux Memory Clinic (MEMENTO cohort).

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The aim of this study was to investigate the occurrence of benzimidazole-resistant Haemonchus contortus in Norwegian sheep flocks. Screening was based on detection of one of the resistance-conferring mutations in the β tubulin isotype 1 gene (F200Y, TAC) in larvae (L3) cultivated from H. contortus eggs from naturally infected sheep.

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Clostridial infections in goats have been associated frequently with enteric diseases or gas gangrene but very rarely with the reproductive system. We describe here 12 cases of fatal postpartum gangrenous metritis in does associated with infection by several clostridial species. Clinically, these cases were characterized by rapid onset of hyperthermia followed by death after kidding.

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A questionnaire was distributed to 5487 farmers throughout Norway in order to obtain information about management practices regarding helminth infections in sheep. In addition, the farmers' perceptions of helminths and anthelmintic efficacy were investigated. Most farmers (80%) treated prophylactically against nematodes, and 24% also used prophylactic treatment against Fasciola hepatica.

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In young cattle, bovine respiratory disease (BRD) is a major cause of death and is a frequent pathogen. Knowledge of fatal BRD in adult cattle is more limited. We assessed the importance of infectious BRD as a cause of death in adult cattle and determined the associated pathogens.

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Helminth infections are ubiquitous in grazing ruminant production systems, and are responsible for significant costs and production losses. Anthelmintic Resistance (AR) in parasites is now widespread throughout Europe, although there are still gaps in our knowledge in some regions and countries. AR is a major threat to the sustainability of modern ruminant livestock production, resulting in reduced productivity, compromised animal health and welfare, and increased greenhouse gas emissions through increased parasitism and farm inputs.

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Helminth infections, mainly by gastrointestinal nematodes (GIN), are one of the main concerns for animal health, welfare and productivity in grazing ruminant livestock worldwide. The use of a sensitive, precise, accurate, low-cost, and easy-to-perform copromicroscopic technique is of pivotal importance to perform reliable fecal egg count (FEC) and fecal egg count reduction test (FECRT), in order to determine the need of anthelmintic treatment, but also anthelmintic efficacy or resistance. This approach is fundamental to a correct and efficient control of GIN.

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Eprinomectin (EPM) has been recently granted a marketing authorisation in the European Union for use in goats, with a zero-day milk withdrawal period. Considering the high prevalence of benzimidazole resistance worldwide and the economic implications of managing milk residues, EPM may today be considered the main (or even the only) affordable treatment option, at least in dairy goats in the EU. However, the chosen dose (1 mg/kg) seems to be suboptimal, especially for lactating goats, and the chosen route of administration (Pour-on) highly subject to inter-individual variability.

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Background: Faecal egg counts (FEC) and the FEC reduction test (FECRT) for assessing gastrointestinal nematode (GIN) infection and efficacy of anthelmintics are rarely carried out on ruminant farms because of the cost of individual analyses. The use of pooled faecal samples is a promising method to reduce time and costs, but few studies are available for cattle, especially on the evaluation of different pool sizes and FECRT application.

Methods: A study was conducted to assess FEC strategies based on pooled faecal samples using different pool sizes and to evaluate the pen-side use of a portable FEC-kit for the assessment of FEC on cattle farms.

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Background: Anaplasma ovis is a major cause of small ruminant anaplasmosis, a tick-borne disease mainly affecting small ruminants in tropical and subtropical regions of the world. Due to health and production problems in dairy goat flocks in Corsica, France, and the demonstration of A. ovis infection in some animals, an extensive survey was conducted in the island in spring 2016.

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Article Synopsis
  • * The pathogen's genome is notably small (3.12 Mb) with 1,759 protein-coding genes and 1,081 pseudogenes, indicating significant gene loss and an adaptation for living inside host cells.
  • * Understanding the genomic similarities between this pathogen and leprosy bacilli can aid in identifying important virulence factors and developing quick detection methods.
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A carbohydrate larval surface antigen (CarLA) present on infective larvae of all trichostrongylid nematodes is a target antigen for host immunoglobulins (Ig). Levels of anti-CarLA salivary IgA antibody (CarLA-IgA) have been shown to be correlated to the level of protective immunity to GIN in sheep and deer but no information is available in cattle. The first objective of this study was to assess the pattern of CarLA-IgA response in 7 groups (G1-G7) of first grazing season cattle (FGSC) naturally infected with gastrointestinal nematodes.

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Targeted-selective treatments against gastrointestinal nematode (GIN) in adult dairy cows require the identification of "cows to treat", i.e. cows whose milk production (MP) would increase after treatment.

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A two-year study was carried out to assess the feasibility of a targeted selective treatment to control gastrointestinal nematodes (GIN) in 24 groups of first grazing season (FGS) cattle. A two-step procedure aiming at defining exposure risk at group level and at identifying the most infected individuals within groups through measurement of the average daily weight gain (ADWG) at housing was used. The first step was to define retrospectively, by grazing management practices (GMP) indicators, two levels of groups' exposure to GIN determined by anti O.

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The objective of our study was to explain the variability of average daily weight gain (ADWG) due to gastrointestinal nematode (GIN) infection for 291 non treated first grazing season (FGS) heifers, from 12 independent groups in the western part of France, by combining parasitological and clinical indicators at individual level and grazing management indicators at group level. Parasitological indicators were faecal egg count (FEC), anti Ostertagia ostertagi antibody level (Ostertagia ODR), and pepsinogen level. Clinical indicators were diarrhea score (DISCO) and breech soiling score (BSS).

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An unusual outbreak of teat/udder skin lesions occurred in a dairy goat flock in France. Lesions first appeared as circular, indurated, erythematous areas of skin and progressed to form dark raised haemorrhagic crusts and ulcerative plaques. Histopathological examination revealed marked granulomatous dermatitis with multifocal ulceration.

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Article Synopsis
  • Gastrointestinal nematodes (GIN) infections negatively impact milk production in dairy cows, and a study was conducted in western France to evaluate if spring targeted-selective anthelmintic treatment could improve milk production.
  • The study involved 578 cows across 13 farms, comparing treated cows (given fenbendazole) with control cows (untreated) while tracking milk production and measuring various health indicators over a 15-week period.
  • Contrary to expectations, the spring treatment resulted in a significant decrease in milk production (average -0.92 kg/cow/day), particularly in high-producing cows and those with specific health markers, suggesting that the treatment may trigger immuno-inflammatory responses rather than improve productivity.
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Anthelmintic resistance has been increasingly reported in cattle worldwide over the last decade, although reports from Europe are more limited. The objective of the present study was to evaluate the efficacy of injectable formulations of ivermectin and moxidectin at 0.2 mg per kg bodyweight against naturally acquired gastro-intestinal nematodes in cattle.

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Cohorts of pre-weaned calves were studied for Cryptosporidium infection over three successive years (2010-2012) in one beef cattle herd in western France. Each year 25-34 calves were sampled weekly from 3 days to one month of age in order to characterize oocyst output, Cryptosporidium species and clinical features associated with infection. Faecal samples were screened for the presence of oocysts using immunofluorescence analysis.

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Preliminary results obtained in calves, lambs and goat kids infected by Cryptosporidium sp. have indicated a partial prophylactic efficacy of halofuginone lactate when administered at 100 μg/kg body weight (BW). In this study, the efficacy of halofuginone lactate was evaluated in goat neonates experimentally inoculated with Cryptosporidium parvum oocysts per oral route.

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Eighteen pre-weaned female calves from a single beef cattle herd in western France were sampled weekly from birth to 21/2 months of age in order to characterize Cryptosporidium oocyst output. 182 fecal samples were screened for the presence of oocysts after concentration using immunofluorescence analysis. DNA was extracted from positive samples and a PCR-RFLP protocol, with the restriction enzyme SspI and MboII, to amplify the partial SSU rRNA gene was performed.

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Small ruminant post-mortem testing programs were initially designed for monitoring the prevalence of prion disease. They are now considered as a potential alternative to genetic selection for eradicating/controlling classical scrapie at population level. If such policy should be implemented, its success would be crucially dependent on the efficiency of the surveillance system used to identify infected flocks.

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The present study describes the occurrence of various gastrointestinal helminths, lungworms and liver flukes in Norwegian sheep and goats as assessed from faecal samples and post mortem examinations performed between 2007 and 2010. Faecal samples for gastrointestinal nematode egg counts were collected from 77 sheep flocks and 30 dairy goat flocks from three geographical regions in Norway. Additionally, thirty-two lambs and 16 adult goats were euthanized for necropsy examination and for identification of adult gastrointestinal nematodes and tapeworms, lungworms and liver flukes.

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