Postweaning multisystemic wasting syndrome (PMWS) is among the most important emerging pig diseases worldwide. Initially, the insidious nature of the disease made it difficult to pinpoint the pathogen. The presence of porcine circovirus type 2 (PCV2) in all PMWS diseased animals led to its acceptance, possibly together with an unknown factor, as the causative agent for PMWS. Also, presence of PCV2 in healthy individuals did not facilitate the understanding of the disease. Phylogenetic classification separates PCV2 viruses into at least two major groups. With the aid of a signature motif, a short amino acid motif encoded within the capsid protein, the viruses are determined as belonging to PCV-2a or PCV-2b. Recently, this classification received more attention, as it seemed to define PCV-2b to be more virulent. This simplification, however, could not be confirmed experimentally. Hence, we investigated whether virus genetic shift was an initiator for the PMWS epizooty in Switzerland. Piglet lymphoid tissues from 1973 to 2005 were investigated by histology, immunohistochemistry (IHC) and PCR. For genotype classification, a sequence amplificate of 137bp was used encompassing the signature motif. The onset of Swiss PMWS epizooty exhibited a marked shift in PMWS diseased and subclinically infected piglets to PCV-2b and specifically to one genotype subgroup. Complementary to these observations, healthy piglets also defined by IHC as negative are positive in the PCR reaction and are void of any PCV-2b virus during epizooty. Consequently, our data support PCV2 genome plasticity as a major contributing factor for PMWS disease manifestation.

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Background: Bats are hosts for a variety of microorganisms, however, little is known about the presence of Chlamydiales and hemotropic mycoplasmas. This study investigated 475 captive and free-living bats from Switzerland, Germany, and Costa Rica for Chlamydiales and hemotropic mycoplasmas by PCR to determine the prevalence and phylogeny of these organisms. Results: Screening for Chlamydiales resulted in a total prevalence of 31.4%. Positive samples originated from captive and free-living bats from all three countries. Sequencing of 15 samples allowed the detection of two phylogenetically distinct groups. These groups share sequence identities to Chlamydiaceae, and to Chlamydia-like organisms including Rhabdochlamydiaceae and unclassified Chlamydiales from environmental samples, respectively. PCR analysis for the presence of hemotropic mycoplasmas resulted in a total prevalence of 0.7%, comprising free-living bats from Germany and Costa Rica. Phylogenetic analysis revealed three sequences related to other unidentified mycoplasmas found in vampire bats and Chilean bats. Conclusions: Bats can harbor Chlamydiales and hemotropic mycoplasmas and the newly described sequences in this study indicate that the diversity of these bacteria in bats is much larger than previously thought. Both, Chlamydiales and hemotropic mycoplasmas are not restricted to certain bat species or countries and captive and free-living bats can be colonized. In conclusion, bats represent another potential host or vector for novel, previously unidentified, Chlamydiales and hemotropic mycoplasmas.

This case report describes the clinical, ultrasonographic and postmortem findings in an alpaca with Mycobacterium kansasii infection. The alpaca was referred because of chronic weight loss and weakness. The results of clinical examination, haematology and serum biochemistry were not diagnostic. Ultrasonography of the liver revealed multiple, hyperechogenic lesions with a diameter of 1 to 3 cm. Histological evaluation of a liver biopsy sample showed acute, multifocal, suppurative, necrotising hepatitis. Despite treatment with antibiotics, the alpaca died. Postmortem examination revealed nodular to coalescing lesions in the liver, lungs, mediastinum, pleura and greater omentum, which could not be differentiated macroscopically or histologically from lesions caused by tuberculosis. Ziehl-Neelsen staining showed massive numbers of rods within epithelioid macrophages, which were identified as Mycobacterium kansasii by polymerase chain reaction analysis.