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The article presents a study which described the behaviour of sheep infected by bovine spongiform encephalopathy (BSE). It compared two groups of 11 ARR (used as controls) homozygous and 9 ARQ (highly susceptible) homozygous sheep. Among the things they analyzed were the duration of resting, standing, feeding, walking and scraping activities. According to the researchers, despite their failure to find early behavioural signs of BSE in sheep, the results confirmed the significance of scraping activity in BSE infected sheep. They claim that the results are consistent with another study which found a rapid rise of the percentages of animals showing clinical signs.

Abstract In this study, the potential association of PrP genotypes with health and productive traits was investigated. Data were recorded on animals of the INRA 401 breed from the Bourges-La Sapinière INRA experimental farm. The population consisted of 30 rams and 852 ewes, which produced 1310 lambs. The animals were categorized into three PrP genotype classes: ARR homozygous, ARR heterozygous, and animals without any ARR allele. Two analyses differing in the approach considered were carried out. Firstly, the potential association of the PrP genotype with disease (Salmonella resistance) and production (wool and carcass) traits was studied. The data used included 1042, 1043 and 1013 genotyped animals for the Salmonella resistance, wool and carcass traits, respectively. The different traits were analyzed using an animal model, where the PrP genotype effect was included as a fixed effect. Association analyses do not indicate any evidence of an effect of PrP genotypes on traits studied in this breed. Secondly, a quantitative trait loci (QTL) detection approach using the PRNP gene as a marker was applied on ovine chromosome 13. Interval mapping was used. Evidence for one QTL affecting mean fiber diameter was found at 25 cM from the PRNP gene. However, a linkage between PRNP and this QTL does not imply unfavorable linkage disequilibrium for PRNP selection purposes.

Abstract An experimental population (1216 lambs from 30 sires) of the Inra401 sheep was created in an Inra flock to allow QTL detection for susceptibility to Salmonella infection, wool and carcass traits. The Inra401 is a sheep composite line developed from two breeds: Berrichon du Cher and Romanov. At 113 days of age on average, the lambs were inoculated intravenously with 108 Salmonella abortusovis Rv6 (vaccinal strain). They were slaughtered 10 days after the inoculation. Several traits were measured at inoculation and/or slaughtering to estimate the genetic resistance of the lambs to Salmonella infection: specific IgM and IgG1 antibody titres, body weight loss, spleen and pre-scapular node weights and counts of viable Salmonella persisting in these organs. This paper presents a quantitative analysis of the genetic variability of the traits related to salmonellosis susceptibility. The heritabilities of the traits varied between 0.10 and 0.64 (significantly different from zero). Thus, in sheep as well as in other species, the determinism of resistance to Salmonella infection is under genetic control. Moreover, the correlations between the traits are in agreement with the known immune mechanisms. The genetic variability observed should help QTL detection.

Abstract 373 thirteen-week-old chicks issued from a commercial cross and 312 chickens from the L2 line were intravenously inoculated with 106 Salmonella enteritidis and the numbers of Salmonella in the spleen, liver and genital organs were assessed 3 days later. Heritabilities of the number of Salmonella were estimated at 0.02 ± 0.04 and 0.05 ± 0.05 in the liver; at 0.29 ± 0.07 and 0.10 ± 0.06 in the spleen; and at 0.16 ± 0.05 and 0.11 ± 0.08 in the genital organs, in the first and second experiments, respectively. The difference between the two experiments could result from sampling variations and from differences in the genetic structure of the two populations possibly including both heterosis and additive effects as well as their interaction in the first experiment. Genetic correlations between the number of bacteria in the genital organs and liver (0.56 ± 0.58 and 0.76 ± 0.32 in the first and second experiments, respectively) and spleen (0.37 ± 0.24 and 0.79 ± 0.23) were positive. Moreover a significant within-sire effect of VIL1, a marker gene for NRAMP1, was observed in 117 progeny resulting from 25 informative matings. These results indicate that there are genetic differences in the resistance to visceral infection by S. enteritidis in these commercial egg-laying flocks, and suggest that these differences are at least partly due to genetic polymorphism in the NRAMP1 region.

In dairy goats and ewes the use of equine Chorionic Gonadotropin (eCG) as a convenient hormone for the induction of ovulation is necessary for out-of-season breeding and artificial insemination (AI). Treatment for induction and synchronization of ovulation consists of a progestagen delivered by vaginal sponge, followed by an eCG injection. In some females, the first injection of eCG induces a humoral response with high concentrations of anti-eCG antibodies in contrast to other females displaying a very low concentration of anti-eCG antibodies. Females eliciting a low response were also poor responders after the following treatments. Conversely, high responders at the first treatment systematically yielded high immune responses upon the following treatment. By a molecular genetic approach using microsatellites we showed that the anti-eCG immune response phenotypes were associated with MHC class II polymorphism. Females with high residual antibody concentrations at the time of eCG injection exhibited a much lower kidding rate than other females did. Lower fertility of these females, inseminated at a fixed time after eCG treatment (43H for goats and 55H for ewes), might be due to the delay in estrus occurrence and the pre ovulatory LH surge. Consequently, under field conditions old females selected for AI are only those with low residual anti-eCG antibody concentrations and old females with high residual antibody concentration are culled from AI breeding because of their low fertility during the previous year. So we have undertaken comparative studies to establish if the anti-eCG immune response is correlated with the global immunity in animals. [Copyright &y& Elsevier]

The infectious process of bacteria of the genus Salmonella requires the finely regulated use of various virulence factors. Among them, the type 3 secretion system-1 (T3SS-1) and the Rck and PagN invasins are involved in the internalization of the pathogen within eukaryotic cells, but their precise role in the host and in the pathogenic process is still poorly understood. In this study, we aimed to determine the kinetics of expression of these entry factors in a typhoid fever-like and a gastroenteritis model in mice by in vivo imaging using bioluminescent Salmonella Typhimurium reporter strains carrying chromosomal transcriptional fusions. Only pagN and T3SS-1 transcription has been clearly identified. Independently of the pathological model, the caecum was identified as the main transcription site of both pagN and the T3SS-1-encoding gene both at early and late stages of the infection. An intense transcription of pagN was also observed in deep organs in the typhoid fever-like model, while that of T3SS-1 remained quite sporadic in these organs, and mainly focused on the intestine all along the infection. This work will help to understand the respective role of these entry factors at the cellular level in the pathogenesis of Salmonella in vivo .

Close to half of the world's pregnancies are still unplanned, reflecting a clear unmet need in contraception. Ideally, a contraceptive would provide the high efficacy of hormonal treatments, without systemic side effects. Here, we studied topical reinforcement of the cervical mucus by chitosan mucoadhesive polymers as a form of female contraceptive. Chitosans larger than 7 kDa effectively cross-linked human ovulatory cervical mucus to prevent sperm penetration in vitro. We then demonstrated in vivo using the ewe as a model that vaginal gels containing chitosan could stop ram sperm at the entrance of the cervical canal and prevent them from reaching the uterus, whereas the same gels without chitosan did not substantially limit sperm migration. Chitosan did not affect sperm motility in vitro or in vivo, suggesting reinforcement of the mucus physical barrier as the primary mechanism of action. The chitosan formulations did not damage or irritate the ewe vaginal epithelium, in contrast to nonoxynol-9 spermicide. The demonstration that cervical mucus can be reinforced topically to create an effective barrier to sperm may therefore form the technological basis for muco-cervical barrier contraceptives with the potential to become an alternative to hormonal contraceptives.

In vivo bioluminescence imaging facilitates the non-invasive visualization of biological processes in living animals. This system has been used to track virus infections mostly in mice and ferrets; however, until now this approach has not been applied to pathogens in avian species. To visualize the infection of an important avian pathogen, we generated Marek's disease virus (MDV) recombinants expressing firefly luciferase during lytic replication. Upon characterization of the recombinant viruses in vitro, chickens were infected and the infection visualized in live animals over the course of 14 days. The luminescence signal was consistent with the known spatiotemporal kinetics of infection and the life cycle of MDV, and correlated well with the viral load measured by qPCR. Intriguingly, this in vivo bioimaging approach revealed two novel sites of MDV replication, the beak and the skin of the feet covered in scales. Feet skin infection was confirmed using a complementary fluorescence bioimaging approach with MDV recombinants expressing mRFP or GFP. Infection was detected in the intermediate epidermal layers of the feet skin that was also shown to produce infectious virus, regardless of the animals' age at and the route of infection. Taken together, this study highlights the value of in vivo whole body bioimaging in avian species by identifying previously overlooked sites of replication and shedding of MDV in the chicken host., Competing Interests: The authors have declared that no competing interests exist.

Applications of bioluminescence for the in vivo study of pathogenic microorganisms are numerous, ranging from the quantification of virulence gene expression to measuring the effect of antimicrobial molecules on the colonization of tissues and organs by the pathogen. Most studies are performed in mice, but recent works demonstrate that this technique is applicable to larger animals like fish, guinea pigs, ferrets, and chickens. Here, we describe the construction and the utilization of a constitutively luminescent strain of Salmonella Typhimurium to monitor in vivo and ex vivo the colonization of mice in the gastroenteritis, typhoid fever, and asymptomatic carriage models of Salmonella infection., (© 2022. The Author(s).)

Background: Bacterial colonization in cystic fibrosis (CF) lungs has been directly associated to the loss of CFTR function, and/or secondarily linked to repetitive cycles of chronic inflammation/infection. We hypothesized that altered molecular properties of mucins could contribute to this process., Methods: Newborn CFTR +/+ and CFTR -/- were sacrificed before and 6 h after inoculation with luminescent Pseudomonas aeruginosa into the tracheal carina. Tracheal mucosa and the bronchoalveolar lavage (BAL) fluid were collected to determine the level of mucin O-glycosylation, bacteria binding to mucins and the airways transcriptome. Disturbances in mucociliary transport were determined by ex-vivo imaging of luminescent Pseudomonas aeruginosa., Results: We provide evidence of an increased sialylation of CF airway mucins and impaired mucociliary transport that occur before the onset of inflammation. Hypersialylation of mucins was reproduced on tracheal explants from non CF animals treated with GlyH101, an inhibitor of CFTR channel activity, indicating a causal relationship between the absence of CFTR expression and the sialylation of mucins. This increased sialylation was correlated to an increased adherence of P. aeruginosa to mucins. In vivo infection of newborn CF piglets by live luminescent P. aeruginosa demonstrated an impairment of mucociliary transport of this bacterium, with no evidence of pre-existing inflammation., Conclusions: Our results document for the first time in a well-defined CF animal model modifications that affect the O-glycan chains of mucins. These alterations precede infection and inflammation of airway tissues, and provide a favorable context for microbial development in CF lung that hallmarks this disease., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interests., (Copyright © 2020. Published by Elsevier B.V.)

Toxoplasma gondii is a parasitic protozoan of worldwide distribution, able to infect all warm-blooded animals, but particularly sheep. Primary infection in pregnant sheep leads to millions of abortions and significant economic losses for the livestock industry. Moreover, infected animals constitute the main parasitic reservoir for humans. Therefore, the development of a One-health vaccine seems the best prevention strategy. Following earlier work, a vaccine constituted of total extract of Toxoplasma gondii proteins (TE) associated with maltodextrin nanoparticles (DGNP) was developed in rodents. In this study we evaluated the ability of this vaccine candidate to protect against latent and congenital toxoplasmosis in sheep. After two immunizations by either intranasal or intradermal route, DGNP/TE vaccine generated specific Th1-cellular immune response, mediated by APC-secretion of IFN-γ and IL-12. Secretion of IL-10 appeared to regulate this Th1 response for intradermally vaccinated sheep but was absent in intranasally-vaccinated animals. Finally, protection against latent toxoplasmosis and transplacental transmission were explored. Intranasal vaccination led to a marked decrease of brain cysts compared with the non-vaccinated group. This DGNP/TE vaccine administered intranasally conferred a high level of protection against latent toxoplasmosis and its transplacental transmission in sheep, highlighting the potential for development of such a vaccine for studies in other species., (Copyright © 2020 Ducournau, Moiré, Carpentier, Cantin, Herkt, Lantier, Betbeder and Dimier-Poisson.)