C. Chauve

Colonization and organ invasion in chicks experimentally infected with Dermanyssus gallinae contaminated by Salmonella Enteritidis

The poultry red mite (Dermanyssus gallinae) is the most important and common ectoparasite of laying hens in Europe. This haematophagous mite has been experimentally demonstrated to be a vector of Salmonella Enteritidis by acquiring bacteria through the blood meal or cuticular contact. We have evaluated another route of infection by orally inoculating chicks with mites previously infected by S. Enteritidis. Two methods of infecting the mites were tested: mites contaminated by cuticular contact or during the blood meal. After the washing of mites with paraformaldehyde, groups of 10 Salmonella-contaminated mites were inoculated individually into 1-day-old chicks. The titre of the inoculum suspension was evaluated by crushing mites and followed by bacteriological counting. It was 3×104 colony-forming units/chick and 2.7×106 colony-forming units/chick, respectively, for cuticular contact and orally mediated contamination of mites. Each bird was found to be positive 12 days post-inoculation. Salmonella colonized the intestinal tracts and invaded the livers and spleens. The caecal content concentration reached a mean level of S. Enteritidis of 8.5×104 most probable number (MPN) Salmonella/g. This experiment demonstrated the ability of mites to orally infect 1-day-old chicks with subsequent colonization and multiplication of Salmonella. Consequently, mites infected by S. Enteritidis constitute potential reservoir hosts of this bacterium, allowing it to persist in the poultry house as a source of infection for newly introduced animals. If contaminated mites are found in poultry facilities, effective red mite control should be performed before new batches are introduced into the facility.

Detection of Salmonella sp. in Dermanyssus gallinae using an FTA® filter-based polymerase chain reaction

Abstract Salmonella spp. bacteria are responsible for some of the most important zoonoses worldwide. Because Dermanyssus gallinae (DeGeer) (Acari: Dermanyssidae) has been recently reported to be an experimental vector of Salmonella Enteritidis, it would be of benefit to evaluate the presence of this bacterium in mites. A molecular detection tool associating a simple filter‐based DNA preparation with a specific 16S rDNA Salmonella sp. polymerase chain reaction (PCR) amplification was described. The limit of detection with this method was 2 × 104 bacteria per mite. To adapt this technique for large‐scale studies, two sizes of mite pools were tested and a preliminary investigation was carried out on mites from 16 currently or previously contaminated farms. Mites sampled from one farm of each type were positive for Salmonella, suggesting that Dermanyssus could act as a reservoir between flocks. In further investigations, it will be necessary to carry out a large‐scale study to assess the role of D. gallinae in the epidemiology of avian salmonellosis.

Comparison of the VIDAS® system FTA® filter-based PCR and culture on SM ID for detecting Salmonella in Dermanyssus gallinae

Aims:  To compare different analytical methods for detecting Salmonella in Dermanyssus gallinae.

Administration of toltrazuril during experimental Eimeria mulardi coccidiosis in mule ducks: comparison of the efficacy of a single administration at two different endogenous stages

An experimental Eimeria mulardi coccidiosis was reproduced in mule ducks. A single dose of toltrazuril (7 mg per kg) was administered at two different endogenous stages: Day 2 (first meronts) or Day 5 (last meronts and gamonts). The efficacy of the drug was assessed on four criteria (body weight, oocyst counts, macroscopic lesions, and presence of the meronts and gamonts). To have a curative effect, a single dose of toltrazuril should be administered early on. However, a single treatment on Day 5 had a prophylactic effect.

Contribution a l'etude des coccidies de l'oie dans la region du sud‐ouest de la france. Proposition d'une cle de diagnose des differentes especes, basee sur la morphologie de l'ookyste sporule

Eight coccidian species found in the domestic goose (Anser anser domesticus) in the south-west of France are described. An identification key based on the morphological features of sporulated oocysts is proposed. Of the eight species, two had not, previously, been reported in domestic geese; one of them might be a new species.

Pathogénicité d‘Eimeria mulardi Chauve et al., 1994 chez le canard mulard après infection expérimentale. Précision des stades pathogènes

Summary Pathogenicity of Eimeria mulardi Chauve et al., 1994 in experimentally infected mule‐ducks. Precision on pathological stages The pathogenicity of Eimeria mulardi has been studied in mule‐ducklings orally inoculated with sporulated oocysts. With two dose levels (105 or 106 oocysts per bird), a significant loss of body‐weight was observed, whereas no loss of weight was observed with a dose level of 104. With a dose of 106 oocysts per bird, inflammatory and haemorrhagic changes associated with obstruction mainly involving the end of the jejunum, the ileum and the caeca were seen from day 5 post‐inoculation. Pathogenicity of Eimeria mulardi is due to the last generation of meronts and essentially to gamonts.

Les coccidies du canard mulard. Bilan d'une premiere enquete realisee dans trois elevages du sud‐ouest de la France

Coccidia of mule ducks: preliminary survey in three farms of the south-west region of France A coprological survey carried out on mule duck farms, has revealed seven different coccidian species: Cryptosporidium (1), Tyzzeria (2) and Eimeria (4). Tyzzeria was the most frequent. The four Eimeria species have never been previously noted in France and one of them could be a new species.Summary Coccidia of mule ducks: preliminary survey in three farms of the south‐west region of France A coprological survey carried out on mule duck farms, has revealed seven different coccidian species: Cryptosporidium (1), Tyzzeria (2) and Eimeria (4). Tyzzeria was the most frequent. The four Eimeria species have never been previously noted in France and one of them could be a new species.

Experimental studies on the potential role of the poultry red mite, Dermanyssus gallinae, as a vector of Salmonella serotype Enteritidis

Dermanyssus gallinae is the most important and common ectoparasite of laying hens in Europe and it is suspected of being a vector of pathogens. Salmonellosis is a major sanitary problem in poultry farms. We performed an in vitro experiment to evaluate the role of D. gallinae as a vector of Salmonella enterica serotype Enteritidis (SE). Two ways of infection of the mites were tested: through the blood meal by artificially engorging mites on contaminated blood, and after cuticular contact by leaving mites on a bacterial coating. The results showed that the mites could be infected via both infection routes. Bacterial multiplication within the mites has also been demonstrated, as well as the transstadial passage of Salmonella from the protonymph to the deutonymph stage, and the transovarial passage associated with a negative effect of SE on Dermanyssus oviposition. Mites have been shown to retransmit bacteria through a blood meal. In order to check whether the ingestion of previously contaminated mites by chicks led to an infection dose sufficient to contaminate birds, sets of 10 mites were orally administered to 1-day-old chicks. Each bird was found to be positive 12 days post-inoculation. Salmonella colonized the intestinal tracts and invaded liver, spleen, and caeca. Therefore, this study demonstrated experimentally that D. gallinae is a vector of SE. The mite may represent a suitable environment for the development of Salmonella and could be an additional factor for the persistence of Salmonella infection between two flocks. This underscores the importance of effective red mite control during the down time following a batch of poultry infected by Salmonella.

[Coccidia of mule ducks: preliminary survey in three farms of the south-west region of France].

Coccidia of mule ducks: preliminary survey in three farms of the south-west region of France A coprological survey carried out on mule duck farms, has revealed seven different coccidian species: Cryptosporidium (1), Tyzzeria (2) and Eimeria (4). Tyzzeria was the most frequent. The four Eimeria species have never been previously noted in France and one of them could be a new species.Summary Coccidia of mule ducks: preliminary survey in three farms of the south‐west region of France A coprological survey carried out on mule duck farms, has revealed seven different coccidian species: Cryptosporidium (1), Tyzzeria (2) and Eimeria (4). Tyzzeria was the most frequent. The four Eimeria species have never been previously noted in France and one of them could be a new species.

Coccidia of mule ducks. Results of a first survey of three farms in southwestern France.

Coccidia of mule ducks: preliminary survey in three farms of the south-west region of France A coprological survey carried out on mule duck farms, has revealed seven different coccidian species: Cryptosporidium (1), Tyzzeria (2) and Eimeria (4). Tyzzeria was the most frequent. The four Eimeria species have never been previously noted in France and one of them could be a new species.Summary Coccidia of mule ducks: preliminary survey in three farms of the south‐west region of France A coprological survey carried out on mule duck farms, has revealed seven different coccidian species: Cryptosporidium (1), Tyzzeria (2) and Eimeria (4). Tyzzeria was the most frequent. The four Eimeria species have never been previously noted in France and one of them could be a new species.