Following domestication, livestock breeds have experienced intense selection pressures for the development of desirable traits. This has resulted in a large diversity of breeds that display variation in many phenotypic traits, such as coat colour, muscle composition, early maturity, growth rate, body size, reproduction, and behaviour. To better understand the relationship between genomic composition and phenotypic diversity arising from breed development, the genomes of 13 traditional and commercial European pig breeds were scanned for signatures of diversifying selection using the Porcine60K SNP chip, applying a between-population (differentiation) approach. Signatures of diversifying selection between breeds were found in genomic regions associated with traits related to breed standard criteria, such as coat colour and ear morphology. Amino acid differences in the EDNRB gene appear to be associated with one of these signatures, and variation in the KITLG gene may be associated with another. Other selection signals were found in genomic regions including QTLs and genes associated with production traits such as reproduction, growth, and fat deposition. Some selection signatures were associated with regions showing evidence of introgression from Asian breeds. When the European breeds were compared with wild boar, genomic regions with high levels of differentiation harboured genes related to bone formation, growth, and fat deposition.
The aim was to detect and characterize chlamydial infections in guinea-pigs (GP) with ocular disease, study their pathogenicity and zoonotic potential and to test for the presence of Acanthamoebae spp. in GP eyes and to investigate whether they could act as vectors for Chlamydia-like organisms. Overall 126 GP, of which 77 were symptomatic, were screened by clinical examination, cytology, gross pathology, histology, immunohistochemistry, polymerase chain reaction (PCR) and bacteriology. A new Chlamydiaceae-specific intergenic spacer rRNA gene PCR, designed to amplify this segment linking the 16S and 23S regions, was performed. DNA samples were also received from one owner including samples of his cat and rabbit. Guinea-pigs: 48 of 75 symptomatic, but only 11 of 48 asymptomatic GP were positive by PCR for Chlamydophila caviae guinea-pig inclusion conjunctivitis (GPIC) (P < 0.0001). Eighteen of 75 or 15/48, respectively, were positive for DNA from Chlamydia-like organisms. Acanthamoebae-DNA could be found in two GP, of which one was symptomatic. Owner, cat and rabbit: Samples of all three species were positive by PCR for C. caviae GPIC and the owner's one-day disposable contact lenses showed a positive PCR result for the Chlamydia-like organism Parachlamydia acanthamoebae. No Acanthamoebae-DNA could be detected. This study is the first to describe Chlamydia-like organisms in GP and to detect C. caviae GPIC in human, cat and rabbit. Therefore, C. caviae GPIC could pose a zoonotic potential. We believe that the finding of C. caviae GPIC in species other than GP is probably not unique.
Abstract.A retrospective study on reptile tissues presenting with granulomatous inflammation was performed to detect the possible presence of mycobacteria and chlamydiae in these lesions. Ninety cases including 48 snakes, 27 chelonians, and 15 lizards were selected. Mycobacteria were detected by Ziehl-Neelsen (ZN) staining and a broad-range polymerase chain reaction (PCR) followed by DNA sequencing. To detect chlamydiae, immunohistochemistry with monoclonal antibodies against chlamydial lipopolysaccharide (LPS) and a Chlamydiales order-specific PCR and sequencing were applied. Acid-fast bacilli were found in 14 cases (15.6%) by ZN staining and in 23 cases (25.6%) by PCR. Sequence analysis revealed the presence of Mycobacteria other than Mycobacterium tuberculosis complex (MOTT). Chlamydial LPS antigen was observed within granulomas from five samples (5.6%), whereas the PCR screen revealed 58 positive cases (64.4%). Of these, 9 cases (10%) showed 98-99% similarity to Chlamydophila (Cp.) pneumoniae and 49 cases (54.4%) displayed a high similarity (88-97%) to the newly described ''Chlamydia-like'' microorganisms Parachlamydia acanthamoebae and Simkania negevensis. Results from this study confirm, on the one hand, that MOTT are probably the most important infectious etiology for granulomatous inflammation in reptiles. On the other hand, they indicate that chlamydia infects reptiles and that Cp. pneumoniae should be considered an etiological agent of granulomatous lesions of reptiles. Because both MOTT and Cp. pneumoniae are human pathogens, the potential of zoonotic transmission from reptiles to humans has to be considered. In contrast, the significance of Chlamydia-like isolates remains completely open, and further studies are needed to evaluate their role.
Application of a broad-range detection method resulted in identification of a new agent associated with ocular disease in cats. Finding chlamydia-like agents such as N hartmannellae in coinfections with their obligate amebic host, Hartmannella vermiformis, raises questions about the potential role of these microorganisms in causation or exacerbation of ocular disease in cats.
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