Neonatal diarrhea (ND) is still a frequently observed problem in modern industrial pig production. ND is predominantly caused by bacterial and viral pathogens. The objective of this study was to give an overview of different pathogens involved in ND in Germany. In 2017, a total number of 555 litters from 205 German pig farms with clinical ND were sampled with pooled fecal samples. All samples were analyzed regarding bacterial pathogens by culture and viral pathogens by polymerase chain reaction (PCR). Isolated strains of Clostridium (C.) perfringens, Escherichia (E.) coli, and C. difficile were further characterized by molecular techniques (e.g., PCR). There were 200 litters (36%), out of 555 sampled litters of 205 farms, which were positive for at least one, while most of them were positive for two or more pathogens. Toxin-producing C. perfringens type A could be detected in 122 farms (59.2%), C. difficile in 116 (56.1%), pathogenic E. coli in 79 (38.6%), and Rotavirus type A in 72 (35%). Among E. coli isolates, enterotoxigenic (8.8%) (F4 fimbriae positive (60.0%)) and necrotoxigenic E. coli (5.3%) were the most frequently detected pathotypes. In conclusion, in most of the farms with porcine ND it turned out to be a disease mainly caused by multiple pathogens, predominantly C. perfringens type A, pathogenic E. coli, and Rotavirus type A. Nevertheless, C. difficile and necrotoxigenic E. coli might be emerging pathogens in ND.

Background Salmonella Typhimurium is an important zoonotic pathogen in pigs, that can cause clinical disease. Many sow herds and finishing herds are infected with Salmonella, and therefore pose a threat for the contamination of pork and pork products and ultimately consumers. Case presentation This case study describes a farrow-to-finish pig herd, producing its own replacement gilts, which had experienced clinical outbreaks of salmonellosis since 2002. Outbreaks were characterised by profuse diarrhoea, dead pigs and high antimicrobial use (colistin sulphate). The aim of this study was to see whether using vaccination of sows and piglets with Salmoporc®, a live attenuated Salmonella Typhimurium vaccine, in combination with standard hygienic precautions, it was possible to reduce Salmonella Typhimurium to below the bacteriological detection limit. Monitoring of the presence of Salmonella was done using a total of 20 pooled faecal, sock and dust samples per herd visit in the period from September 2016 to October 2020. Within the first 10 months after the start of vaccination in August 2016, there was a rapid reduction in clinical symptoms, antimicrobial usage and the number of Salmonella-positive samples. During the winters of 2017/2018 and 2018/2019 the number of positive samples increased again, however with minimal need to use antimicrobials to treat the affected animals. In July 2019, only two samples from a corridor were positive. In September and November 2019 and in October 2020 all three samplings were completely negative for S. Typhimurium. Conclusions This case, together with other longitudinal studies, can be seen as a proof of the principle that long term vaccination with a live attenuated S. Typhimurium vaccine can reduce the level of S. Typhimurium in the herd environment to very low levels within a farrow-to-finish herd initially suffering from clinical salmonellosis. Also, clinical symptoms indicating salmonellosis were no longer observed and antimicrobials to treat clinically diseased pigs were no longer needed.

To date, no comprehensive diagnostics for the study of polymicrobial infections that are associated with porcine respiratory disease have been offered. This precludes the proper understanding of the entire disease landscape, thereby hampering effective preventive and therapeutic actions.

Swine influenza A virus (swIAV), which plays a major role in the porcine respiratory disease complex (PRDC), is eliminated from the respiratory tract within 7–9 days after infection. Therefore, diagnosis is complicated in endemically infected swine herds presenting no obvious clinical signs. This study aimed to investigate the right time point for sampling to detect swIAV. A cross-sectional study was performed in 131 farms from 12 European countries. The sampling protocol included suckling piglets, weaners, and nursery pigs. In each age group, 10 nasal swabs were collected and further examined in pools of 5 for swIAV by Matrix rRT-PCR, followed by a multiplex RT-PCR to determine the influenza subtype. SwIAV was detected in 284 (37.9%) of the samples and on 103 (78.6%) farms. Despite the highest number of animals with clinical signs being found in the nursery, the weaners were significantly more often virus-positive compared to nursery pigs (p = 0.048). Overall, the swIAV detection rate did not significantly differ between diseased or non-diseased suckling and nursery piglets, respectively; however, diseased weaners had significantly more positive pools than the non-diseased animals. Interestingly, in 9 farms, different subtypes were detected in different age groups. Our findings indicate that to detect all circulating swIAV subtypes on a farm, different age groups should be sampled. Additionally, the sampling strategy should also aim to include non-diseased animals, especially in the suckling period.

ZusammenfassungIn einem Jungsauenerzeugerbetrieb in Niederösterreich traten über mehrere Jahre hinweg gehäuft Atemwegserkrankungen bei Jungsauen aus Eigenremontierung nach Einstallung in die Altsauenherde auf. Im Herbst 2019 wurden zudem Fruchtbarkeitsstörungen in Form von Spätaborten und Umrauschen beobachtet. Bei der Untersuchung von Nasentupfern mittels PCR auf Influenza-A-Virus (IAV) konnte bei 3 Jungsauen mit respiratorischer Symptomatik und Fieber der IAV-Subtyp H1avN1 nachgewiesen werden. Die Untersuchung der Serumproben dieser Tiere an 2 Zeitpunkten im Abstand von 3 Wochen ergab jedoch keinen Nachweis von Antikörpern im Hämagglutinationshemmtest (HAH), der standardmäßig im Labor verwendet wurde. Auch bei der Untersuchung von Sauen weiterer Altersgruppen waren keine eindeutigen Antikörpertiter gegenüber H1avN1 detektierbar. Nach Erweiterung des diagnostischen Panels des HAH um 7 H1avN1-Testantigene konnte eine Serokonversion um bis zu 3 Titerstufen bei den PCR-positiven Sauen gegenüber 2 verschiedenen H1avN1-Isolaten gemessen werden. Darüber hinaus ließen sich auch bei der Mehrzahl der restlichen untersuchten Altersgruppen hohe Antikörpertiter gegen diese beiden H1avN1-Teststämme nachweisen. Nach Anwendung des europaweit zugelassenen trivalenten Influenzaimpfstoffs konnte das klinische Erscheinungsbild in der Herde deutlich verbessert werden. Der Fallbericht verdeutlicht, dass für eine zielgerichtete Influenzadiagnostik der direkte und der indirekte Erregernachweis kombiniert verwendet werden sollten. Zudem wurde gezeigt, dass die kontinuierliche Anpassung von Testantigenen an die im Feld zirkulierenden Isolate überaus entscheidend für die Aussagekraft des HAH wäre.