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Porcine reproductive and respiratory syndrome virus (PRRSV) can persist in different organs of infected pigs, which suggests a failure in the immune response. Antigen-presenting cells (APCs) play a pivotal role in the induction of effective T- and B-cell responses. In this study, we investigated the changes in the different APC subpopulations and T- and B-cell counts in the tonsil, retropharyngeal and mediastinal lymph nodes of pigs experimentally infected with a European PRRSV field isolate. Our results demonstrated that the expression of S100, SWC3, HLA-DR molecule and CD3 was diminished in the studied organs throughout the study, observing a significant negative correlation between viral antigen and HLA-DR expression in both retropharyngeal and mediastinal lymph nodes. In contrast, λ-light chains showed an increase during the study. Taking all into account, after PRRSV infection, no enhancement in the number of APCs and T cells was observed, suggesting an impairment of the immune function which may allow the persistence of PRRSV into the organism. [ABSTRACT FROM AUTHOR]

The influence of lactation period and weaning on the distribution, number, and structure of somatotropic cells (GH cells) in ewes was studied using immunocytochemical procedures for light and electron microscopy, as well as morphometric and stereological techniques. The adenohypophyseal gland of 12 ewes of the Segureña breed in different stages of milk production and weaning was studied, while three ewes in anoestrus served as controls. The size of secretory granules was heterogeneous in all stages, suggesting that this characteristic is not related to functional activity. During lactation and weaning the size of GH cells decreased, while the number of ‘synthesis cells’ increased. The rough endoplasmic reticulum and Golgi complex appeared more developed and small secretory granules showed lower gold particle labelling. These data suggest that GH cells are more active during lactation, particularly during late lactation. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses various reports within the issue on topics including strengthening of building structures for earthquake prone areas, reinforced concrete frames and devices designed to dissipate energy or isolate the structure.

Describes a clinical case of granulomatous hepatitis caused by Salmonella typhimurium in a spur-thighed tortoise. Clinical signs of the tortoise's condition; Histopathological examination of the animals; Detection of fecal excretion of Salmonella species.

The distribution of B cells in the lymphoid organs of the goat was studied using a panel of 13 monoclonal antibodies (mAbs) developed against different markers for bovine B cells. Samples of mesenteric lymph nodes, jejunal and ileal Peyer's patches, duodenum, jejunum, ileum, colon, caecum and rectum were taken from four 7-month-old male Murciano-granadina goats using the avidin-biotin-peroxidase (ABC) method on frozen sections as described by Hsu et al. (1981). The mAbs against immunoglobulins (Ig) recognized a large number of cells, particularly in the light zones of the germinative centres of the lymphoid follicles, regardless of the isotype against which they were directed. However, the greatest numbers of B cells in the germinative centres and outer coronas of the lymphoid follicles of the lymph node, spleen and Peyer's patches were recognized by mAbs against the Lλ chain of Ig and against IgM. This was also the case in other locations where B cells were abundant, such as the medulla of the lymph node and the dome of the Peyer's patches. These mAbs recognized not only B lymphocytes but also plasma cells, showing an intracytoplasmatic reaction (numerous in the spleen red pulp and the intestinal lamina propria when mAbs were used against the Lλ chain of the Ig, scarce in the intestinal lamina propria when used against IgM and scarce in spleen red pulp and numerous in the intestinal lamina propria when mAbs against IgA were used). The mAbs BAQ44 A, GC65 A and GB25 A are of interest because, besides marking cells in the B areas where lymphocytes show surface Ig, they give a positive reaction in areas where there are Ig cells (the dark zone of the germinative centre) and do not immunostain plasma cells. Thus, these mAbs recognize a surface marker which is not an Ig. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the effect of crude glycerin (Gly) added to nursery pig diet on nutrient digestibility, the digestive and metabolic status, intestinal morphology and intestinal cytokine expression. A total of 18 male piglets (weaned at 23 days) were used. There were three dietary treatments that differed in the inclusion level of Gly (0, 9 and 18%). On day 14 of the experiment, the animals were weighed and plasma samples were collected before slaughtering. In addition urine, digesta content and intestinal tissues were sampled post mortem. No differences were observed among the tested diets as regards the coefficients of apparent ileal digestibility of DM and CP. The concentration of lactic acid decreased linearly (P<0.05) in the jejunum and ileum segments as the level of Gly increased, although the concentrations of volatile fatty acids in the cecum and colon were not affected. The plasma concentrations of glucose, fructosamine and IGF-1 were not affected. However, urinary glycerol concentrations increased (P<0.01) with increasing levels of Gly. In general, there were no differences in villus height, crypt depth, villus/crypt ratio or number of lymphocytes in the intestinal segments between the different treatments. Nevertheless, the control treatment produced a higher level of goblet cells in the ileum than either of the Gly treatments (P<0.01), while in the jejunum, the number of IgA-secreting cells in the 9% Gly group was higher (P<0.01) than in the control group. There were no differences among the experimental treatments concerning the gene expression of IL-10, IL-12 p40 and TNF-α. Gene expressions of TGF-β, IL-12 p35, IFN-γ and IFN-α were remained unaffected or increased, depending on the intestinal segment and level of Gly addition. In conclusion, the inclusion of Gly at 9 and 18% to the nursery pig diet did not affect nutrient digestibility or plasma metabolites but increased the levels of urinary glycerol, suggesting that metabolic pathways of glycerol utilization became saturated when high levels of Gly are used. In addition, the intestinal cell structure and intestinal cytokine expression might be affected when Gly is included in the feed. [ABSTRACT FROM AUTHOR]

Porcine reproductive and respiratory syndrome virus (PRRSV) is the causative agent of the, probably, most economically important disease for the pig industry worldwide. This disease, characterised by producing reproductive failure in sows and respiratory problems in growing pigs, appeared in the late 1980s in the United States and Canada. Since its appearance, strains capable of producing higher mortality rates as well as greater severity in clinical signs and lesions than classical strains have been identified. However, since the first reports of these "virulent" PRRSV outbreaks, no homogeneity and consensus in their description have been established. Moreover, to the authors' knowledge, there is no published information related to the criteria that a PRRSV strain should fulfil to be considered as a "virulent" strain. In this review, we revise the terminology used and gather the information related to the main characteristics and differences in clinical signs, lesions, viral replication and tropism as well as immunological parameters between virulent and classical PRRSV strains and propose a first approximation to the criteria to define a virulent PRRSV strain., (Copyright © 2021 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: Mycoplasma hyopneumoniae causes a chronic respiratory disease that produces important economic losses due to poor productive performance, increased mortality and costs for several control strategies. The prevalence of mycoplasma-like lesions (MLL) at abattoir has been widely studied in different countries, making use of different scoring systems. However, most of them are difficult to apply in abattoirs with high number of pigs sacrificed per hour. For that reason, it is necessary to adapt the scoring system to the reality of the modern abattoir, even if there is a loss of accuracy. Our purpose was to investigate the prevalence and severity of MLL at abattoirs in Spain and Portugal using a 0 to 5 scoring system adapted to abattoirs with high number of sacrificed pigs per hour and to highlight the histopathological diagnosis as confirmatory method to identify patterns of pneumonia correlated to gross lesions., Results: Cranioventral pulmonary consolidation, a typical MLL, was the most frequent lung lesion (30.97 %) detected at the abattoir, followed by dorsocaudal infarcts with pleurisy (12.51 %) and pleurisy alone (6.26 %). The average score for all examined lungs at abattoir was 1.99 out of 5 points. The histopathological study revealed that the 78.17 % of the randomly selected lungs with MLL presented microscopic lesions compatible with M. hyopneumoniae infection. Most bronchointerstitial and interstitial pneumonia lesions had a chronic course while most suppurative and fibrinous bronchopneumonia lesions had an acute course and a higher degree of severity. The combination of microscopic lesions more frequently observed was bronchointerstitial pneumonia + interstitial pneumonia + suppurative bronchopneumonia., Conclusions: The prevalence of MLL at abattoir was 30.97 %, however, after microscopic examination the real prevalence of lungs with lesions compatible with M. hyopneumoniae infection was reduced up to 24.21 %. The six more prevalent combinations of lesions in the microscopic study involved the 66.13 % of examined lungs, and in all of them, microscopic lesions characteristic of M. hyopneumoniae infection were found, what supports the importance of M. hyopneumoniae as a primary pathogen in cases of PRDC.

Porcine reproductive and respiratory syndrome virus (PRRSV) plays a key role in porcine respiratory disease complex modulating the host immune response and favouring secondary bacterial infections. Pulmonary alveolar macrophages (PAMs) are the main cells supporting PRRSV replication, with CD163 as the essential receptor for viral infection. Although interstitial pneumonia is by far the representative lung lesion, suppurative bronchopneumonia is described for PRRSV virulent strains. This research explores the role of several immune markers potentially involved in the regulation of the inflammatory response and sensitisation of lung to secondary bacterial infections by PRRSV-1 strains of different virulence. Conventional pigs were intranasally inoculated with the virulent subtype 3 Lena strain or the low virulent subtype 1 3249 strain and euthanised at 1, 3, 6 and 8 dpi. Lena-infected pigs exhibited more severe clinical signs, macroscopic lung score and viraemia associated with an increase of IL-6 and IFN-γ in sera compared to 3249-infected pigs. Extensive areas of lung consolidation corresponding with suppurative bronchopneumonia were observed in Lena-infected pigs. Lung viral load and PRRSV-N-protein + cells were always higher in Lena-infected animals. PRRSV-N-protein + cells were linked to a marked drop of CD163 + macrophages. The number of CD14 + and iNOS + cells gradually increased along PRRSV-1 infection, being more evident in Lena-infected pigs. The frequency of CD200R1 + and FoxP3 + cells peaked late in both PRRSV-1 strains, with a strong correlation between CD200R1 + cells and lung injury in Lena-infected pigs. These results highlight the role of molecules involved in the earlier and higher extent of lung lesions in piglets infected with the virulent Lena strain, pointing out the activation of routes potentially involved in the restraint of the local inflammatory response., Competing Interests: Declaration of Competing Interest The authors declare that they have no competing interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)