Chronic pithomycotoxicosis associated with obstructive rhinopathy in sheep.

Pithomycotoxicosis (facial eczema) is a seasonal hepatogenous photosensitization of sheep caused by the ingestion of sporidesmin contained in the spores of the fungus Pithomyces chartarum. We describe 4 cases of obstructive rhinopathy associated with chronic pithomycotoxicosis naturally occurring in the north of Spain. Sheep were 5 to 7 years old and Latxa breed. A detailed clinical study was conducted together with computerized tomography examination and completed by necropsy and histopathology. All sheep developed a permanent narrowing of the nasal lumen close to the nostrils causing inspiratory dyspnea and snoring. Computerized tomography demonstrated a significant increase of soft tissue in the rostral nasal cavity. Elevated gamma-glutamyl transferase, alanine aminotransferase, and lipase were noted on serum biochemistry. At necropsy, liver atrophy and fibrosis associated with chronic pithomycotoxicosis was identified in 3 of the sheep. All sheep had whitish elevations and rough surfaces on the alar folds and areas adjacent to the nasal surfaces. Histopathologic assessments, which included histochemical and immunohistochemical techniques, of the nasal lesions identified moderate to severe arteriosclerosis in 21.5% to 61.9% of the small arteries evaluated with surrounding fibrosis and edema. No changes associated with hypersensitivity reactions were found. These lesions were similar to the ones described in blood vessels of the liver in chronic pithomycotoxicosis and in our cases. The results of this study suggest a direct action of the sporidesmin on the rostral nasal cavity. Further studies are needed to analyze the impact of the sporidesmin on the sheep nasal mucosa.

Jaagsiekte sheep retrovirus found in milk macrophages but not in milk lymphocytes or mammary gland epithelia of naturally infected sheep.

Jaagsiekte sheep retrovirus (JSRV) causes ovine pulmonary adenocarcinoma. JSRV can be transmitted via infected colostrum or milk, which contain somatic cells (SCs) harboring JSRV provirus. Nevertheless, the cell types involved in this form of transmission and the involvement of the mammary gland remain unknown. We separated adherent cells (macrophages and monocytes) by plastic adherence, and lymphocytes (CD4+ and CD8+ T cells, and B cells) by flow cytometry, from SCs in milk samples from 12 naturally infected, PCR blood test JSRV-positive, subclinical ewes. These cell populations were tested by PCR to detect JSRV provirus. The ewes were euthanized, and mammary gland samples were analyzed immunohistochemically to detect JSRV surface protein. We did not detect JSRV provirus in any milk lymphocyte population, but milk adherent cells were positive in 3 of 12 sheep, suggesting a potential major role of this population in the lactogenic transmission of JSRV. Immunohistochemistry did not reveal positive results in mammary epithelial cells, pointing to a lack of participation of the mammary gland in the biological cycle of JSRV and reducing the probability of excretion of free viral particles in colostrum or milk.

Detection of aluminium hydroxide-induced granulomas in sheep by computed tomography: A feasible approach for small ruminant lentiviruses diagnosis and research.

Aluminium (Al) hydroxide use as adjuvant induces local formation of long-lasting subcutaneous granulomas in sheep. Macrophages within these granulomas have been identified as a new small ruminant lentivirus (SRLV) replication site in naturally infected animals. Diagnosis of Al hydroxide-induced granulomas in sheep is mostly based on postmortem observations but little information is available on in vivo detection. Computed tomography (CT) is used for studying these reactions in other animal species. To determine if CT could be a tool for in vivo diagnosis and research of subcutaneous Al hydroxide-induced granulomas in sheep. A retrospective survey on thoracic CT scans was performed on 46 adult sheep. Analysis included absence or presence, number and location of subcutaneous nodules. Thoracic CT scans and pathological studies were prescribed to two further sheep. Single or multiple subcutaneous nodules were detected in 26 (56.52%) sheep. One or two nodules per animal were most often observed (36.95%). Size ranged between 1.5 and 4.5 cm. Pre-contrast two-dimensional (2D) CT images showed focal or multifocal increases in subcutaneous tissue thickness. Post-contrast 2D CT images revealed hypointense areas in the centre. Histopathology indicated the presence of granulomas composed by a large number of activated macrophages, surrounding a central core of necrosis. Large intracytoplasmic Al-positive aggregates were demonstrated by lumogallion staining. CT is a useful tool to detect subcutaneous Al hydroxide-induced granulomas in vivo in sheep. CT provides a diagnostic and research tool that can be very useful in future works in Al hydroxide-induced pathology, SRLV infection, or both.

Assessment of targeted selective treatment criteria to control subclinical gastrointestinal nematode infections on sheep farms.

Control of sheep gastrointestinal nematode (GIN) infections mostly relies on the use of anthelmintics. Refugia-based control strategies as targeted selective treatments (TST) can delay anthelmintic resistance development, but the optimal decision criteria for selecting individuals to be treated in subclinical infection scenarios remain unclear. The present study aimed to evaluate the suitability of body condition score (BCS) and faecal egg counts (FEC) as treatment indicators and to determine their optimized threshold values for treatment in TST by determining the relationships of BCS, FEC and anthelmintic treatment with several productive parameters in pre-mating and pre-partum periods at an individual level. Deworming in pre-mating period increased BCS gain, but its magnitude was directly associated with strongyle FEC before treatment. Deworming also increased fertility in ewes with BCS < 2.75 and the proportion of lambing ewes that got pregnant during the first ovulation cycle. Nevertheless, treatment did not yield productive benefits in ewes with higher BCS values. On the other hand, deworming in the pre-partum lowered lamb peri-partum mortality and increased lamb weight at birth and the growth of lambs during lactation, especially in lambs born from ewes with strongyle FEC > 400 epg before treatment. These results showed that FEC and especially BCS can be potential decision criteria for the implementation of TST in these types of scenarios. The TST scheme derived from the present results on the control of GIN infections should include anthelmintic treatment of ewes with BCS lower than ≈ 3 approximately five weeks before mating and lambing. In the pre-lambing period, treatment may be unnecessary if flock mean strongyle FEC is lower than ≈ 200 epg, as the proportion of ewes with individual FEC > 400 epg would be very low. The results suggest that implementation of this TST scheme would provide benefits, such as the improvement of productivity, a rational management of parasites in refugia, and preservation of future efficacy of anthelmintics, in comparison to traditional deworming schemes.

Effect of obstacle position in the flow of sheep through a narrow door.

In a recent work [Phys. Rev. E 91, 022808 (2015)PLEEE81539-375510.1103/PhysRevE.91.022808] it was reported that placing an obstacle in front of a gate has a beneficial effect in the flow of sheep through it. Here, we extend such results by implementing three different obstacle positions. We have observed that the flow is improved in two cases, while it worsens in the other one; the last instance happens when the obstacle is too close to the door. In this situation, the outcomes suggest that clogging develops between the doorjamb and the obstacle, contrary to the cases when the obstacle is farther, in which case clogging always occurs at the very door. The effectiveness of the obstacle (a strategy put forward to alleviate clogging in emergency exits) is therefore quite sensitive to its location. In addition, the study of the temporal evolution of the flow rate as the test develops makes evident a steady behavior during the entire duration of the entrance. This result is at odds with recent findings in human evacuation tests where the flow rate varies over time, therefore challenging the fairness of straightforward comparisons between pedestrian behavior and animal experimental observations.

In silico identification and three-dimensional modelling of the missense mutation in ADAMTS2 in a sheep flock with dermatosparaxis.

BACKGROUND: Dermatosparaxis (Ehlers-Danlos syndrome in humans) is characterized by extreme fragility of the skin. It is due to the lack of mature collagen caused by a failure in the enzymatic processing of procollagen I. We investigated the condition in a commercial sheep flock. HYPOTHESIS/OBJECTIVES: Mutations in the ADAM metallopeptidase with thrombospondin type 1 motif, 2 (ADAMTS2) locus, are involved in the development of dermatosparaxis in humans, cattle and the dorper sheep breed; consequently, this locus was investigated in the flock. ANIMALS: A single affected lamb, its dam, the dam of a second affected lamb and the rams in the flock were studied. METHODS: DNA was purified from blood, PCR primers were used to detect parts of the ADAMS2 gene and nucleotide sequencing was performed using Sanger's procedure. Skin samples were examined using standard histology procedures. RESULTS: A missense mutation was identified in the catalytic domain of ADAMTS2. The mutation is predicted to cause the substitution in the mature ADAMTS2 of a valine molecule by a methionine molecule (V15M) affecting the catalytic domain of the enzyme. Both the 'sorting intolerant from tolerant' (SIFT) and the PolyPhen-2 methodologies predicted a damaging effect for the mutation. Three-dimensional modelling suggested that this mutation may alter the stability of the protein folding or distort the structure, causing the protein to malfunction. CONCLUSIONS AND CLINICAL IMPORTANCE: Detection of the mutation responsible for the pathology allowed us to remove the heterozygote ram, thus preventing additional cases in the flock.

Experimental proof of faster-is-slower in systems of frictional particles flowing through constrictions.

The "faster-is-slower" (FIS) effect was first predicted by computer simulations of the egress of pedestrians through a narrow exit [D. Helbing, I. J. Farkas, and T. Vicsek, Nature (London) 407, 487 (2000)]. FIS refers to the finding that, under certain conditions, an excess of the individuals' vigor in the attempt to exit causes a decrease in the flow rate. In general, this effect is identified by the appearance of a minimum when plotting the total evacuation time of a crowd as a function of the pedestrian desired velocity. Here, we experimentally show that the FIS effect indeed occurs in three different systems of discrete particles flowing through a constriction: (a) humans evacuating a room, (b) a herd of sheep entering a barn, and (c) grains flowing out a 2D hopper over a vibrated incline. This finding suggests that FIS is a universal phenomenon for active matter passing through a narrowing.

Cells infected with Jaagsiekte sheep retrovirus are detected in the bone marrow of asymptomatic sheep.

Ovine pulmonary adenocarcinoma (OPA) is a transmissible lung cancer caused by Jaggsiekte sheep retrovirus (JSRV). It is difficult to identify animals infected with JSRV but are clinically healthy. The virus does not induce a specific antibody response and, although proviral DNA sequences of JSRV can be found in mononuclear blood cells, the detection is inconsistent. The aim of this study was to investigate the presence of JSRV in the bone marrow of infected sheep and develop a more consistent screening method. Immunohistochemical examination of bone marrow samples from 8 asymptomatic JSRV-infected sheep revealed the presence of positively labelled cells. However, JSRV could not be detected by a highly sensitive polymerase chain reaction (PCR) in bone marrow aspirates periodically collected from these animals. Results suggest that JSRV-infected cells may be present in the bone marrow of symptomless animals, but the number is below the detectable level for PCR. Therefore, this technique does not seem to be helpful for preclinical diagnosis of OPA.

L'adénocarcinome pulmonaire ovin (OPA) est un cancer pulmonaire transmissible causé par le rétrovirus ovin de Jaggsiekte (JSRV). Il est difficile d'identifier les animaux infectés par le JSRV mais qui sont cliniquement en santé. Le virus n'entraine pas la production d'anticorps spécifiques et, bien que des séquences d'ADN provirales de JSRV peuvent être retrouvées dans les mononucléaires du sang, la détection est inconstante. L'objectif de la présente étude était d'examiner la présence de JSRV dans la moelle osseuse de moutons infectés et de développer une méthode de tamisage plus constante. L'examen par immunohistochime d'échantillons de la moelle osseuse de huit moutons asymptomatiques mais infectés par JSRV a révélé la présence de cellules positivement marquées. Toutefois, le JSRV ne put être révélé par une épreuve d'amplification en chaine par la polymérase (PCR) très sensible à partir d'aspirations de la moelle osseuse récolées périodiquement à partir de ces animaux. Les résultats suggèrent que les cellules infectées par JSRV peuvent être présentes dans la moelle osseuse d'animaux asymptomatiques, mais le nombre se situe sous le seuil détectable pas PCR. Ainsi, cette technique ne semble pas utile pour le diagnostic préclinique d'OPA.(Traduit par Docteur Serge Messier).

Horner's syndrome associated with parotid duct obstruction in a sheep.

A 9-year old, Rasa Aragonesa ewe was presented with a left-sided, facial, soft fluctuant swelling. The postmortem examination showed grass awns filling the entire length of the parotid gland duct. The presence of parotid duct obstruction with Horner's syndrome, previously unreported in sheep, is discussed.