investigations concerning the FMD-outbreak in Europe in 2001

Deckblatt-Impressum persönlicher Dank Inhaltsverzeichnis Einleitung Literaturübersicht Problemstellung und Ziele Material und Methoden Ergebnisse Diskussion Zusammenfassung Summary Literaturverzeichnis Abkürzungsverzeichnis Danksagung SelbständigkeitserklärungDie Maul- und Klauenseuche (MKS) ist eine akut verlaufende, fieberhafte Infektionskrankheit, die zyklisch mit der Entwicklung typischer Aphthen und Erosionen an den mit Plattenepithel ausgekleideten Teilen der Schleimhaut des Verdauungskanals und an den unbehaarten Stellen der Haut verläuft. Das Wirtsspektrum des Maul- und Klauenseuchevirus (MKSV) umfasst neben der Ordnung Artiodactyla Familien der Ordnungen Insectivora, Rodentia, Proboscidea, Perissodactyla und Carnivora. Beschreibungen von natürlichen MKSV-Infektionen bei Rehen (Capreolus capreolus) in Europa stammen vor allem aus den Jahren 1930 bis 1940 und beruhen auf der Beobachtung klinischer Symptome. Der Nachweis von Antikörpern gegen das MKSV beim Reh erfolgte im Rahmen experimenteller Infektionsversuche in den Jahren 1974/75 mit dem Virusneutralisationstest (VNT). Dabei wurde die Übertragung des MKSV vom Nutztier (Rind und Schaf) auf das Reh und eine Infektionsübertragung der Rehe untereinander nachgewiesen. Während des MKS-Seuchenzuges im Jahr 2001 in den Niederlanden (März und April) bis dicht an die deutsche Grenze bestand die Möglichkeit der Übertragung des MKSV auf Rehe in einem grenznahen Gebiet zu den Niederlanden in den Bundesländern Nordrhein-Westfalen und Niedersachsen. Ziel dieser Studie war es, den Anteil der seropositiven Reagenten (Exposition) gegen MKSV bei Rehen in den Untersuchungsgebieten zu bestimmen und darüber hinaus die Bedeutung dieser Tiere im Rahmen eines MKS-Seuchenzuges zu diskutieren. Als Standardnachweisverfahren zum Nachweis von spezifischen Antikörpern gegen das MKSV sind der Liquid-phase-blocking ELISA (LPBE) und der VNT vorgeschrieben. Für den Antikörpernachweis bei Wildtieren sind diese Testverfahren in der Weise zu verwenden wie sie für Nutztiere beschrieben und zugelassen wurden. In dieser Studie wurde für den Nachweis von Antikörpern gegen MKSV Serotyp OMANISA neben dem LPBE und dem VNT zusätzlich ein Solid- phase-competition ELISA (SPCE) durchgeführt. Im Zeitraum Oktober 2001 bis Oktober 2002 wurden Blutproben von erlegten Rehen aus ausgewählten, grenznahen Revieren in den Bundesländern Nordrhein-Westfalen (n=108) und Niedersachsen (n=43) gesammelt. Dieses Areal wurde aufgrund seiner geographischen Lage (Nähe zu den Ausbruchsgebieten des MKS-Seuchenzuges 2001 in den Niederlanden) ausgesucht. Weiterhin wurden Proben aus einem Negativ-Kontrollgebiet innerhalb Schleswig-Holsteins untersucht (n=72). Von den insgesamt 223 untersuchten Rehseren zeigten 12 Seren (5,4%) im LPBE eine positive Reaktion. Diese Seren stammten sowohl aus dem Untersuchungsgebiet in Nordrhein-Westfalen (n=6) und in Niedersachsen (n=2) als auch aus dem Kontrollgebiet in Schleswig-Holstein (n=4). Im SPCE reagierten 26 Seren (11,7%) positiv (Nordrhein-Westfalen, n=7; Niedersachsen, n=7; Schleswig-Holstein, n=12). Es handelt sich hierbei um falsch-positive Ergebnisse, da keine Bestätigung durch den VNT bzw. LPBE erfolgte. Der statistische Vergleich von LPBE und SPCE als geeignetes Testverfahren zum Nachweis von Antikörpern gegen MKSV bei Rehen zeigt einen signifikanten Unterschied zwischen den beiden Testverfahren. Zudem unterscheiden sich beide Testmethoden signifikant vom Referenztest VNT. Der SPCE in der hier durchgeführten Form scheint daher nicht geeignet für den Nachweis von Antikörpern gegen MKSV beim Reh zu sein. Die Ergebnisse des SPCE geben zudem einen Hinweis darauf, dass die Durchführung der Nachweismethoden für Nutztiere auf Proben für Wildtiere nicht in jedem Fall übertragbar ist. In dieser Studie wurden keine seropositiven Reagenten gegen MKSV bei Rehen in den Untersuchungsgebieten in Nordrhein-Westfalen und Niedersachsen nachgewiesen. Diese Ergebnisse bekräftigen die Ergebnisse der Recherche über serologische Untersuchungen im Vereinigten Königreich und in den Niederlanden im Rahmen des Seuchenzuges im Jahr 2001 und liefern somit keinen Hinweis darauf, dass eine Exposition der untersuchten Rehpopulationen während des Seuchenzuges in den Niederlanden im Jahr 2001 stattgefunden hat. Die Betrachtung der Ergebnisse der in Europa durchgeführten Studien an Cerviden im Zusammenhang mit MKS- Seuchenzügen lässt keine epidemiologische Bedeutung dieser Tiere als Infektionsquelle für Nutztiere erkennen. So führen die negativen Ergebnisse dieser Studie hinsichtlich des Nachweises von Antikörpern gegen MKSV bei Rehen und die Ergebnisse der serologischen Untersuchungen im Vereinigten Königreich und in den Niederlanden zu der Schlußfolgerung, dass Rehe während des Seuchenzuges 2001 in Europa keine Rolle für die Verbreitung des MKSV gespielt haben.Foot-and-mouth disease (FMD) is an acute febrile infectious disease characterized by the formation of vesicles and erosions on mucous membranes (squamous epithelium) of the alimentary tract and on hairless skin. In addition to the order Artiodactyla families of the order Insectivora, Rodentia, Proboscidea, Perissodactyla and Carnivora are susceptible to a foot- and-mouth disease virus (FMDV) infection. Most descriptions of FMD in naturally infected roe deer (Capreolus capreolus) in Europe are dated from 1930 to 1940. In these cases the diagnosis was based on clinical signs. Antibodies against FMDV were detected in experimentally infected roe deer in 1974/75 by virus neutralization test (VNT). It was shown that transmission of virus among deer was possible as well as mutual transmission between deer and livestock (cattle and sheep). During the FMD outbreak in the Netherlands in 2001 (March and April) in a region close to Germany, FMDV-infection might have been transmitted to free-ranging roe deer in German regions near to the border of the Netherlands in the federal states of North-Rhine Westphalia and Lower Saxony. Therefore, our objective was to determine whether seropositive reactors against FMDV occurred in free-ranging roe deer in the investigation areas. In addition, the possible role of these animals during an FMD-epidemic has been discussed. Liquid-phase-blocking ELISA (LPBE) and VNT are the prescribed tests for the detection of FMDV-specific antibodies in livestock. Procedures similar to these have to be applied for the detection of antibodies in wildlife. In this study, LPBE and VNT were used for the detection of antibodies against FMDV serotype OMANISA. In addition, a solid-phase- competition ELISA was performed. Between October 2001 and October 2002 blood samples of hunted roe deer were collected in selected hunting grounds near to the border of the Netherlands in North-Rhine Westphalia (n=108) and Lower Saxony (n=43). This region was selected because of its location close to the area of the FMD-outbreak in the Netherlands in 2001. Control samples were taken from Schleswig-Holstein (n=72). In LPBE, 12 (5.4%) of 223 sera were tested positive against FMDV OMANISA. These samples originated from North- Rhine Westphalia (n=6), Lower Saxony (n=2) and Schleswig-Holstein (control areas; n=4). In SPCE, 22 (11.7%) of 223 sera were tested positive (North-Rhine Westphalia, n=7; Lower Saxony, n=7; Schleswig-Holstein n=12). These results were considered false-positive because they could not be confirmed by LPBE and VNT, respectively. Significant differences were recorded comparing (1) LPBE and SPCE, (2) LPBE and VNT and (3) SPCE and VNT. It became evident that SPCE in its current form does not seem to be an appropriate method for detecting antibodies against FMDV in hunted roe deer. Moreover, these results indicate that test procedures similar to those described for livestock can not generally be applied for wildlife. In our study, seropositive reactors in roe deer were not detected. These results support serological investigations from the United Kingdom (UK) and the Netherlands in 2001 and suggest that FMDV may not have been transmitted to free-ranging roe deer in the investigation areas during the outbreak in 2001 in the Netherlands. Investigations concerning FMD among cervids in Europe within the last century revealed that these animals do not seem to play an important role for the transmission of FMDV during an epidemic in livestock. The negative results of this study regarding the detection of antibodies against FMDV, as well as the serological investigations in the UK and the Netherlands lead to the conclusion that roe deer did not seem to play a role for the distribution of FMDV during the outbreak in 2001 in Europe

Recent expansion and adaptive evolution of the carcinoembryonic antigen family in bats of the Yangochiroptera subgroup

Background: Expansions of gene families are predictive for ongoing genetic adaptation to environmental cues. We describe such an expansion of the carcinoembryonic antigen (CEA) gene family in certain bat families. Members of the CEA family in humans and mice are exploited as cellular receptors by a number of pathogens, possibly due to their function in immunity and reproduction. The CEA family is composed of CEA-related cell adhesion molecules (CEACAMs) and secreted pregnancy-specific glycoproteins (PSGs). PSGs are almost exclusively expressed by trophoblast cells at the maternal-fetal interface. The reason why PSGs exist only in a minority of mammals is still unknown. Results: Analysis of the CEA gene family in bats revealed that in certain bat families, belonging to the subgroup Yangochiroptera but not the Yinpterochiroptera subgroup an expansion of the CEA gene family took place, resulting in approximately one hundred CEA family genes in some species of the Vespertilionidae. The majority of these genes encode secreted PSG-like proteins (further referred to as PSG). Remarkably, we found strong evidence that the ligand-binding domain (IgV-like domain) of PSG is under diversifying positive selection indicating that bat PSGs may interact with structurally highly variable ligands. Such ligands might represent bacterial or viral pathogen adhesins. We have identified two distinct clusters of PSGs in three Myotis species. The two PSG cluster differ in the amino acids under positive selection. One cluster was only expanded in members of the Vespertilionidae while the other was found to be expanded in addition in members of the Miniopteridae and Mormoopidae. Thus one round of PSG expansion may have occurred in an ancestry of all three families and a second only in Vespertilionidae. Although maternal ligands of PSGs may exist selective challenges by two distinct pathogens seem to be likely responsible for the expansion of PSGs in Vespertilionidae. Conclusions: The rapid expansion of PSGs in certain bat species together with selection for diversification suggest that bat PSGs could be part of a pathogen defense system by serving as decoy receptors and/or regulators of feto-maternal interactions

A freedom from disease study: Schmallenberg virus in the south of England in 2015

In 2011–2012, northern European livestock faced a threat from a newly emerged virus, Schmallenberg virus (SBV), only a few years after a major outbreak of bluetongue serotype 8 (BTV-8). Like BTV-8, SBV is transmitted by Culicoides biting midges to ruminants and spread throughout Europe. SBV, however, spread faster, reaching the UK within three months of initial discovery. Adult ruminants show only mild, if any, clinical signs; however, infection of naive ruminants by SBV during the vulnerable period of gestation leads to abortions, stillbirths and fetal malformations. Although some data exist for the prevalence of SBV on UK sheep farms early in the outbreak, we have no information on its current status. Is SBV still circulating in the UK? To answer this, the authors designed a freedom from disease study across the southernmost counties of the UK. During autumn 2015, 1444 sheep, from 131 farms, were tested for antibodies against SBV by ELISA; 5 samples from 4 farms were twice found positive by ELISA but were later confirmed negative by virus neutralisation test. As the sheep were born between October 2014 and April 2015, the authors conclude that it is unlikely that SBV is still circulating in the south of England

The Risk of Foot and Mouth Disease Transmission Posed by Public Access to the Countryside During an Outbreak

During the 2001 UK FMD outbreak, local authorities restricted rural access to try to prevent further disease spread by people and animals, which had major socio-economic consequences for rural communities. This study describes the results of qualitative veterinary risk assessments to assess the likelihood of different recreational activities causing new outbreaks of foot and mouth disease, as part of contingency planning for future outbreaks. For most activities, the likelihood of causing new outbreaks of foot and mouth disease is considered to vary from very low to medium depending on the control zone (which is based on distance to the nearest infected premises), assuming compliance with specified mitigation strategies. The likelihood of new outbreaks associated with hunting, shooting, stalking, and equestrian activities is considered to be greater. There are areas of significant uncertainty associated with data paucity, particularly regarding the likelihood of transmission via fomites. This study provides scientific evidence to underpin refinement of rural access management plans and inform decision-making in future disease outbreaks

Intracerebral gadolinium deposition following blood–brain barrier disturbance in two different mouse models

Abstract To evaluate the influence of the blood–brain barrier on neuronal gadolinium deposition in a mouse model after multiple intravenous applications of the linear contrast agent gadodiamide. The prospective study held 54 mice divided into three groups: healthy mice (A), mice with iatrogenic induced disturbance of the blood–brain barrier by glioblastoma (B) or cerebral infarction (C). In each group 9 animals received 10 iv-injections of gadodiamide (1.2 mmol/kg) every 48 h followed by plain T1-weighted brain MRI. A final MRI was performed 5 days after the last contrast injection. Remaining mice underwent MRI in the same time intervals without contrast application (control group). Signal intensities of thalamus, pallidum, pons, dentate nucleus, and globus pallidus-to-thalamus and dentate nucleus-to-pons ratios, were determined. Gadodiamide complex and total gadolinium amount were quantified after the last MR examination via LC–MS/MS and ICP-MS. Dentate nucleus-to-pons and globus pallidus-to-thalamus SI ratios showed no significant increase over time within all mice groups receiving gadodiamide, as well as compared to the control groups at last MR examination. Comparing healthy mice with group B and C after repetitive contrast administration, a significant SI increase could only be detected for glioblastoma mice in globus pallidus-to-thalamus ratio (p = 0.033), infarction mice showed no significant SI alteration. Tissue analysis revealed significantly higher gadolinium levels in glioblastoma group compared to healthy (p = 0.013) and infarction mice (p = 0.029). Multiple application of the linear contrast agent gadodiamide leads to cerebral gadolinium deposition without imaging correlate in MRI

Additional file 1: of Recent expansion and adaptive evolution of the carcinoembryonic antigen family in bats of the Yangochiroptera subgroup

Nucleotide sequences from the N domains of Myotis lucifugus CEACAMs. (DOCX 30 kb