Comparison of Porcine Epidemic Diarrhea Viruses from Germany and the United States, 2014

Since 2013, highly virulent porcine epidemic diarrhea virus has caused considerable economic losses in the United States. To determine the relation of US strains to those recently causing disease in Germany, we compared genomes and found that the strain from Germany is closely related to variants in the United States

Porcine Epidemic Diarrhea in Europe: In-Detail Analyses of Disease Dynamics and Molecular Epidemiology

Porcine epidemic diarrhea (PED) is an acute and highly contagious enteric disease of swine caused by the eponymous virus (PEDV) which belongs to the genus Alphacoronavirus within the Coronaviridae virus family. Following the disastrous outbreaks in Asia and the United States, PEDV has been detected also in Europe. In order to better understand the overall situation, the molecular epidemiology, and factors that might influence the most variable disease impact;40 samples from swine feces were collected from different PED outbreaks in Germany and other European countries and sequenced by shot-gun next-generation sequencing. A total of 38 new PEDV complete coding sequences were generated. When compared on a global scale, all investigated sequences from Central and South-Eastern Europe formed a rather homogeneous PEDV S INDEL cluster, suggesting a recent re-introduction. However, in-detail analyses revealed two new clusters and putative ancestor strains. Based on the available background data, correlations between clusters and location, farm type or clinical presentation could not be established. Additionally, the impact of secondary infections was explored using the metagenomic data sets. While several coinfections were observed, no correlation was found with disease courses. However, in addition to the PEDV genomes, ten complete viral coding sequences from nine different data sets were reconstructed each representing new virus strains. In detail, three pasivirus A strains, two astroviruses, a porcine sapelovirus, a kobuvirus, a porcine torovirus, a posavirus, and an enterobacteria phage were almost fully sequenced

Detection of enteric viruses in turkey flocks using Transmission Electron Microscopy and RT-PCR

Durchfallerkrankungen gehören zu den bedeutsamsten Erkrankungen bei Puten und verursachen weltweit hohe wirtschaftlichen Verluste. Als Krankheitsauslöser werden verschiedene Infektionserreger wie Viren, Bakterien und Parasiten vermutet, welche entweder allein oder in Mischinfektionen vorkommen. Oftmals wird der Krankheitsverlauf auch durch nicht infektiöse Ursachen wie Fütterungs- und Haltungsfehler negativ beeinflüsst. Aufgrund des multikausalen Charakters von Darmerkrankungen sind die primären Durchfallursachen häufig nur schwer zu ermitteln. Unter den viralen Erregern gelten Astro-, Rota- und Coronaviren als darmpathogen. In Deutschland gab es bislang keine Daten zum Vorkommen dieser Viren in Putenbeständen. Ziel dieses Projektes war es, die Prävalenz dieser Erreger in ausgewählten Putenbeständen zu ermitteln und eine verlässliche Diagnostik für Astro-, Rota- und Coronaviren zu etablieren. Der Virusnachweis bzw. der Nachweis von viraler RNA erfolgte mittels konventioneller RT-PCR und Elektronenmikroskopie. Die Primer für die RT-PCRs zum Nachweis der viralen RNA von Astro- und Rotaviren wurden im Rahmen der vorliegenden Arbeit etabliert. Der Coronavirusnachweis erfolgte mittels einer PCR nach Cavanagh et al. (2001). Im Rahmen der differenzialdiagnostischen Untersuchungen wurde auch auf Salmonellen und parasitäre Durchfallerreger untersucht. Für die Untersuchung wurden acht Betriebe aus dem süddeutschen Raum ausgewählt. Weibliche und männliche Tiere wurden getrennt beprobt. In einem Betrieb wurden nur Hennen gehalten. Die Sammelkotproben wurden von der 2. Woche an über die gesamte Mastzeit (Hähne 20 Wochen, Hennen 16 Wochen) im Abstand von zwei Wochen entnommen und am CVUA Stuttgart untersucht. Mit Hilfe der Elektronenmikroskopie wurden Mischinfektionen mit Astro- und Rotaviren in 18% der 107 untersuchten Kotproben nachgewiesen. Die Nachweisrate von Astroviren lag hier zwischen 28% bei männlichen und 36% bei weiblichen Tieren. 35% der Proben von Hähnen und 49% der Proben von Hennen waren Rotavirus- positiv. Mittels RT-PCR konnte in allen Beständen Astro- und Rotavirus-RNA detektiert werden. Doppelinfektionen wurden in 84% (90/107) der untersuchten Proben mittels RT-PCR nachgewiesen. Die Prävalenz der Astrovirusinfektionen lag zwischen 98% und 100% bei Hähnen und Hennen. Rotavirus-RNA wurde in 83% der Proben von männlichen Tieren und in 87% der Proben von weiblichen Tieren festgestellt. Coronaviren konnten weder mit dem Elektronenmikroskop noch mittels RT-PCR nachgewiesen werden. Ein Vergleich der Ergebnisse beider virologischer Methoden zeigt eine deutlich höhere Sensitivität des viralen Genomnachweises mittels PCR gegenüber der Elektronenmikroskopie. Die Untersuchungsergebnisse machen deutlich, dass man mit einer hohen Prävalenz von Astro- und Rotaviren in deutschen Putenbeständen rechnen muss. Im Gegensatz dazu konnten Coronaviren weder mittels Elektronenmikroskopie noch mittels RT-PCR nachgewiesen werden.Enteric disorders are one of the most important groups of diseases affecting turkeys and continue to cause high economic losses in many areas world-wide. Several pathogens (viruses, bacteria and parasites) have ben incriminated as possible causes of enteric disorders either alone, in synergy with other microorganisms or with noninfectious causes such as feed or/and management related factors. Under field conditions, however, it is difficult to determine the true cause of enteric disorders. Viruses from several virus families have been implicated as causative agents in enteric diseases in turkey such as turkey coronavirus, avian rota- and astroviruses. Currently there are no data available on the prevalence of these viruses in German meat turkey flocks. The aim of the present investigation was therefore to establish reliable diagnostic tools and to monitor turkey flocks. All samples were tested using transmission electron microscopy (TEM) as well as RTPCR. For RT-PCRs, we designed specific primers for astro- and rotaviruses. The coronavirus identification was performed by a PCR which was developed by Cavanagh et al. (2001). For differential diagnosis of causes of enteric diseases we tested for Salmonella spp. and parasites. Eight different commercial turkey farms located in Southern Germany were monitored. Faecal samples from hens and toms were collected separately at 2 week intervals from the 2nd to the 16th and 20th week of age (age of slaughter of females and males respectively) and screened for virus infections. One farm reared only hens. Using TEM dual infections with rota- and astroviruses were detected in 18% of 107 samples tested. The incidence of astrovirus detection ranged between 28 and 36% in males and females respectively. For rotaviruses, the detection rate was 35% in males and 49% in females. Using RT-PCR, infection with rota- and astroviruses was detected in all flocks. 84% (90/107) of the faecal samples tested were positive for both viruses at the same time. The incidence of astrovirus infection ranged between 98-100% in toms and hens respectively. For rotaviruses the detection rate in males and females ranged between 83 and 87%. No coronaviruses were detected in any of the flocks or samples using both TEM and RT-PCR. A comparison of the results of both detection methods used exhibited higher sensitivity of the PCR assays compare electron microscopy. The results of this study revealed a high prevalence of astro and rotavirus in turkey flocks in Germany. In contrast, no coronaviruses were detected by either RT-PCR or TEM

Poult Enteritis and Mortality Syndrome in Turkey Poults: Causes, Diagnosis and Preventive Measures

Poult enteritis and mortality syndrome (PEMS) is one of the most significant problem affecting turkeys and continues to cause severe economic losses worldwide. Although the specific causes of PEMS remains unknown, this syndrome might involve an interaction between several causative agents such as enteropathogenic viruses (coronaviruses, rotavirus, astroviruses and adenoviruses) and bacteria and protozoa. Non-infectious causes such as feed and management are also interconnected factors. However, it is difficult to determine the specific cause of enteric disorders under field conditions. Additionally, similarities of clinical signs and lesions hamper the accurate diagnosis. The purpose of the present review is to discuss in detail the main viral possible causative agents of PEMS and challenges in diagnosis and control