Reconsideration of the diagnostic criteria required for PCV2 reproductive disease.

Porcine circovirus type 2 (PCV2) causes a variety of clinical conditions including PCV2-associated reproductive disease (PCV2-RD) characterized by late term abortions and mummifications. The generally accepted diagnostic triad includes the presence of reproductive disorders, the histopathological finding of myocarditis, and detection of moderate to high viral loads within the heart tissue. A new threshold of 109 PCV2 genome equivalents (GE)/g heart tissue is suggested to fulfil the third criterion using the diagnostic settings of quantitative real time PCR and in situ hybridization of 30 fetal heart tissues. The need to identify histopathological lesions in fetal heart tissue appears to be invalid or overestimated in confirming a diagnosis of PCV2-RD, at least at the individual fetus level. The highest viral loads (1012 GE/g tissue) were detected in autolyzed and mummified piglets and were identified as PCV2d, although concurrent detection of PCV2d + a and PCV2d + b also occurred.

[Diagnostic procedure after abortions in sows after simultaneous infection with leptospira and chlamydia]. / Diagnostische Abklärung von Aborten bei Zuchtsauen nach Leptospiren- und Chlamydieninfektion.

INTRODUCTION: In a farrowing farm 2 first parity sows aborted on day 95 and day 110 of gestation due to an infection with leptospira and chlamydia. The double infection was diagnosed by PCR examination of abortion material. Serum samples of both sows and additional 8 sows taken three weeks after abortions were sent to two different labs for serological examination for antibodies against leptospira and chlamydia using a microagglutination test and a complement fixation test, respectively. In both labs the tests for antibodies against chlamydia were negative. Titers against diverse leptospira serovars varied between both labs and were low, so that they were not indicative for the involvement of the two pathogens regarding abortion. This case report indicates the diagnostic difficulties of direct and indirect detection methods for leptospira and chlamydia to assess the impact of these pathogens on observed reproductive failure.

Administration of non-pathogenic isolates of Escherichia coli and Clostridium perfringens type A to piglets in a herd affected with a high incidence of neonatal diarrhoea.

A bacterial cocktail of living strains of Clostridium perfringens type A (CPA) without ß2-toxin gene and non-pathogenic Escherichia coli was administered orally to newborn piglets before first colostrum intake and on 2 consecutive days on a farm with a high incidence of diarrhoea and antibiotic treatment in suckling piglets associated with E. coli and CPA. This clinical field study was driven by the hypothetic principle of competitive exclusion of pathogenic bacteria due to prior colonization of the gut mucosal surface by non-pathogenic strains of the same bacterial species with the aim of preventing disease. Although CPA strains used in this study did not produce toxins in vitro, their lack of pathogenicity cannot be conclusively confirmed. The health status of the herd was impaired by a high incidence of postpartum dysgalactia syndrome in sows (70%) and a high incidence of neonatal diarrhoea caused by enterotoxigenic E. coli and CPA during the study. No obvious adverse effect of the bacterial treatment occurred. On average, more piglets were weaned in litters treated (P=0.009). Visual pathological alterations in the small intestinal wall were more frequent in dead piglets of the control group (P=0.004) and necrotizing enteritis was only found in that group. A higher average daily weight gain of piglets in the control group (P<0.001) may be due to an increased milk uptake due to less competition in the smaller litters. The bacterial cocktail was tested under field conditions for its potential to stabilize gut health status in suckling piglets before disease development due to colibacillosis and clostridial infections; however, the gut flora stabilizing effect of the bacterial cocktail was not clearly discernible in this study. Further basic research is needed to confirm the positive effects of the bacterial treatment used and to identify additional potential bacterial candidates for competitive exclusion.