Unfavorable genetic correlations between fecal egg count and milk production traits in the French blond-faced Manech dairy sheep breed.

BACKGROUND: Genetic selection has proven to be a successful strategy for the sustainable control of gastrointestinal parasitism in sheep. However, little is known on the relationship between resistance to parasites and production traits in dairy breeds. In this study, we estimated the heritabilities and genetic correlations for resistance to parasites and milk production traits in the blond-faced Manech breed. The resistance to parasites of 951 rams from the selection scheme was measured through fecal egg counts (FEC) at 30 days post-infection under experimental conditions. Six milk production traits [milk yield (MY), fat yield (FY), protein yield (PY), fat content (FC), protein content (PC) and somatic cell score (LSCS)], were used in this study and were collected on 140,127 dairy ewes in first lactation, as part of the official milk recording. These ewes were related to the 951 rams (65% of the ewes were daughters of the rams). RESULTS: Fecal egg counts at the end of the first and second infections were moderately heritable (0.19 and 0.37, respectively) and highly correlated (0.93). Heritabilities were moderate for milk yields (ranging from 0.24 to 0.29 for MY, FY and PY) and high for FC (0.35) and PC (0.48). MY was negatively correlated with FC and PC (- 0.39 and - 0.45, respectively). FEC at the end of the second infection were positively correlated with MY, FY and PY (0.28, 0.29 and 0.24, respectively with standard errors of ~ 0.10). These slightly unfavorable correlations indicate that the animals with a high production potential are genetically more susceptible to gastrointestinal parasite infections. A low negative correlation (- 0.17) was also found between FEC after the second infection and LSCS, which suggests that there is a small genetic antagonism between resistance to gastrointestinal parasites and resistance to mastitis, which is another important health trait in dairy sheep. CONCLUSIONS: Our results indicate an unfavorable but low genetic relationship between resistance to gastrointestinal parasites and milk production traits in the blond-faced Manech breed. These results will help the breeders' association make decisions about how to include resistance to parasites in the selection objective.

Towards delimitation of the Echinococcus multilocularis parasite's southernmost range in France.

Alveolar echinococcosis is a severe, potentially fatal, parasitic disease caused by ingestion of microscopic eggs of Echinococcus multilocularis. The lifecycle of the parasite is essentially sylvatic, and based on a prey-predator relationship between red foxes and small rodents. A westward expansion from the eastern historical focus has been reported in France, though the parasite has also been detected in the southern Alps. While the focus in the Auvergne region (central France) was described in the 1980s, the southern delimitation of the actual endemic area, especially in the south, was unknown in the absence of dedicated surveys. Red fox samples were collected from 2013 to 2020 in the framework of other transversal epidemiological studies in five sampling areas from southwestern and southeastern France. One hundred and seven intestines were analysed by SSCT, and 221 faecal samples from intestines were analysed by copro-qPCR. None of the 328 foxes exhibited E. multilocularis worms or DNA. Although the presence of E. multilocularis cannot be totally excluded in the departments from the study areas, the sample size tested argues for an absence of the parasite in these studied areas, which is in accordance with the currently known endemic situation in France. These new data are helpful in determining the southernmost limit of E. multilocularis distribution in France. The warm, dry Mediterranean climate in the southeastern areas is less favourable to the transmission of E. multilocularis and especially to the survival of eggs in the environment than the climate in the French Alps or Liguria (Italy) climate where the parasite is present. The intermediate area between the southwestern study areas and the historical focus of Auvergne, which is separated by around 150 km, will be investigated in the coming years. Moreover, an ongoing national surveillance programme on E. multilocularis in foxes is targeting French departements along the edge of the known endemic area both in the southeast and southwest. The data produced will supplement the results of this study, thus greatly helping to define the current distribution of E. multilocularis in France and to target prevention measures to reduce human exposure.

Risk of Anticoagulant Rodenticide Exposure for Mammals and Birds in Parc National des Pyrénées, France.

The extensive use of anticoagulant rodenticides (ARs) to control rodent populations poses intoxication risks for wildlife: persistence of ARs in rodents can cause secondary exposure and poisoning of predators or scavengers. We investigated risk factors for wildlife exposure to ARs in the Parc National des Pyrénées (PNP), France, using a multivariable logistic regression analysis. A total of 157 liver samples were collected from carcasses of 10 mammal and three bird species found in the PNP between 2010 and 2018 and screened for presence of AR residues. First- and second-generation ARs were detected in more than 60% of red fox (Vulpes vulpes) and stone marten (Martes foina) samples and in around 40% of wild cat (Felis silvestris), European pine marten (Martes martes), American mink (Neovison vison), and Eurasian Buzzard (Buteo buteo) samples. Wildlife exposure to ARs was significantly associated with species having a regular consumption of small mammals (odds ratio [OR]: 2.5, 95% confidence interval [CI]: 1.1-5.8) being collected in the Ossau valley (OR: 2.5, 95% CI: 1.1-6.1) and between 2013 and 2015 (OR: 4.8, 95% CI: 2.0-11.7). We identified wild species that could be targeted for risk-based surveillance program for AR secondary exposure and determined high risk areas in which alternative measures should be applied for rodent control.

Asymptomatic Cryptosporidium infections in ewes and lambs are a source of environmental contamination with zoonotic genotypes of Cryptosporidium parvum.

Protozoan parasites of the Cryptosporidium genus cause severe cryptosporidiosis in newborn lambs. However, asymptomatic infections also occur frequently in lambs and ewes. In sheep, the most commonly detected Cryptosporidium species are C. ubiquitum, C. xiaoi and C. parvum. Due to a lack of relevant information about such infections in France, we investigated the situation on five dairy sheep farms in the Pyrénées-Atlantiques Department in south-western France in December 2017. Individual fecal samples were collected from 79 female lambs (5-17 days old) and their mothers (72 ewes). Oocysts were screened using Heine staining before and after Bailenger concentrations. Cryptosporidium species identification and genotyping were performed using real-time PCR and gp60 gene sequencing. No cases of clinical cryptosporidiosis were observed in the 79 lambs. Microscopically, Cryptosporidium spp. oocysts were observed in only one lamb on one farm (prevalence 1.3%) and one ewe on another farm (prevalence 1.4%). By contrast, Cryptosporidium spp. DNA was detected in 17 ewes (prevalence ranging from 10.5% to 50% depending on the farm) and in 36 lambs (prevalence ranging from 0% to 77.8% depending on the farm). Only zoonotic Cryptosporidium parvum IId and IIa genotypes were identified when genotyping was possible. Cryptosporidium ubiquitum and C. xiaoi were detected on one and three farms, respectively. We conclude that healthy young lambs and their mothers during the peripartum period could be a source of environmental contamination with oocysts.

TITLE: Les infections asymptomatiques par Cryptosporidium chez les brebis et les agneaux sont une source de contamination environnementale par les génotypes zoonotiques de Cryptosporidium parvum. ABSTRACT: Les parasites protozoaires du genre Cryptosporidium provoquent une cryptosporidiose sévère chez les agneaux nouveau-nés. Cependant, des infections asymptomatiques surviennent aussi fréquemment chez les agneaux et les brebis. Chez les ovins, les espèces de Cryptosporidium les plus couramment détectées sont C. ubiquitum, C. xiaoi et C. parvum. En raison d'un manque d'informations pertinentes sur ces infections en France, nous avons enquêté sur la situation de cinq élevages ovins laitiers des Pyrénées-Atlantiques en décembre 2017. Des échantillons fécaux individuels ont été collectés sur 79 agnelles (5 à 17 jours) et leurs mères (72 brebis). Les oocystes ont été criblés en utilisant une coloration Heine avant et après concentration par la technique de Bailenger. L'identification et le génotypage des espèces de Cryptosporidium ont été réalisés à l'aide de la PCR en temps réel et du séquençage du gène gp60. Aucun cas de cryptosporidiose clinique n'a été observé chez les 79 agneaux. Au microscope, les oocystes de Cryptosporidium spp. n'ont été observés que chez un agneau dans une ferme (prévalence 1,3 %) et chez une brebis dans une autre ferme (prévalence 1,4 %). En revanche, de l'ADN de Cryptosporidium spp. a été détecté chez 17 brebis (prévalence allant de 10,5 % à 50 % selon les fermes) et chez 36 agneaux (prévalence variant de 0 % à 77,8 % selon les fermes). Seuls les génotypes zoonotiques de Cryptosporidium parvum IId et IIa ont été identifiés lorsque le génotypage était possible. Cryptosporidium ubiquitum et C. xiaoi ont été détectés respectivement dans une et trois fermes. Nous concluons que les jeunes agneaux en bonne santé et leurs mères, autour de l'agnelage, pourraient être une source de contamination environnementale par les oocystes.

Red deer (Cervus elaphus) Did Not Play the Role of Maintenance Host for Bluetongue Virus in France: The Burden of Proof by Long-Term Wildlife Monitoring and Culicoides Snapshots.

Bluetongue virus (BTV) is a Culicoides-borne pathogen infecting both domestic and wild ruminants. In Europe, the Red Deer (Cervus elaphus) (RD) is considered a potential BTV reservoir, but persistent sylvatic cycle has not yet been demonstrated. In this paper, we explored the dynamics of BTV1 and BTV8 serotypes in the RD in France, and the potential role of that species in the re-emergence of BTV8 in livestock by 2015 (i.e., 5 years after the former last domestic cases). We performed 8 years of longitudinal monitoring (2008-2015) among 15 RD populations and 3065 individuals. We compared Culicoides communities and feeding habits within domestic and wild animal environments (51,380 samples). Culicoides diversity (>30 species) varied between them, but bridge-species able to feed on both wild and domestic hosts were abundant in both situations. Despite the presence of competent vectors in natural environments, BTV1 and BTV8 strains never spread in RD along the green corridors out of the domestic outbreak range. Decreasing antibody trends with no PCR results two years after the last domestic outbreak suggests that seropositive young RD were not recently infected but carried maternal antibodies. We conclude that RD did not play a role in spreading or maintaining BTV in France.