RESUMO
Alpacas are the major camelid species in Europe held for hobbies, animal-aided therapy, and commercial reasons. As a result, health-related issues associated with alpacas are of growing significance. This especially holds true for one of the most serious infectious diseases, caseous lymphadenitis, which is caused by the bacterial pathogen Corynebacterium (C.) pseudotuberculosis. Our study focuses on post-mortem examinations, the laboratory diagnostic tool ELISA, and the immunoblot technique for the detection of specific antibodies against C. pseudotuberculosis and detection of the causative pathogen in alpaca herds. We examined a total of 232 alpacas living in three herds. Four of these alpacas were submitted for post-mortem examination, revealing abscesses, apostematous and fibrinous inflammation in inner organs, pleura, and peritoneum. Serological investigation using a commercial ELISA based on phospholipase D (PLD) as antigen and an in-lab ELISA based on whole cell antigens (WCA) revealed an overall seroprevalence of 56% and 61.2%, respectively. A total of 247 alpaca sera originating from 232 animals were tested comparatively using the in-lab and the commercial ELISA and showed a substantial degree of agreement, of 89.5% (Cohen's kappa coefficient of 0.784), for both tests. Further comparative serological studies using the two ELISAs and the immunoblot technique were carried out on selected sera originating from 12 breeding stallions and six breeding mares for which epidemiological data and partial C. pseudotuberculosis isolates were available. The results showed the immunoblot to have a sensitivity that was superior to both ELISAs. In this context, it should be emphasized that evaluation of these investigations and the epidemiological data suggest an incubation period of one to two months. Antibiotic susceptibility testing of 13 C. pseudotuberculosis isolates based on the determination of minimal inhibitory concentrations using the broth microdilution method revealed uniform susceptibility to aminopenicillins, cephalosporines, macrolides, enrofloxacin, florfenicol, tetracycline, sulfonamid/trimethoprime, tiamulin, gentamicin, neomycin, spectinomycin, and vancomycin, but resistance to colistin, nitrofurantoin, and oxacillin.
RESUMO
Early in 2012 fattening pigs in a pig holding in northern Baden-Württemberg developed serious respiratory disease. After detecting Influenza A specific RNA by Real time-RT-PCR in the lung of an euthanized pig, virus isolation was achieved in embryonated chicken eggs. The haemagglutination-inhibition (HI) test performed on this isolate showed a reaction with H1N1 specific serum, so the strain was initially characterised as subtype H1N1. However, serum samples from convalescent pigs of the same stock four and six weeks later did not show any antibodies to H1N1 in HI test. However, using an ELISA, selected serum samples showed positive reactions against the highly conserved nucleocapsid protein. Performing an HI test using the isolated virus as antigen, significantly positive titers between 1:80 and 1:160 were obtained. The virus isolate was finally identified by molecular methods as a subtype H1pdmN2, a reassortant between the human pandemic (pdm) subtype H1N1/2009 virus and a swine influenza virus of the subtype HxN2.