Serum protein profiles as potential biomarkers for infectious disease status in pigs

<p>Abstract</p> <p>Background</p> <p>In veterinary medicine and animal husbandry, there is a need for tools allowing the early warning of diseases. Preferably, tests should be available that warn farmers and veterinarians during the incubation periods of disease and before the onset of clinical signs. The objective of this study was to explore the potential of serum protein profiles as an early biomarker for infectious disease status. Serum samples were obtained from an experimental pig model for porcine circovirus-associated disease (PCVAD), consisting of Porcine Circovirus type 2 (PCV2) infection in combination with either Porcine Parvovirus (PPV) or Porcine Reproductive and Respiratory Syndrome virus (PRRSV). Sera were collected before and after onset of clinical signs at day 0, 5 and 19 post infection. Serum protein profiles were evaluated against sera from non-infected control animals.</p> <p>Results</p> <p>Protein profiles were generated by SELDI-TOF mass spectrometry in combination with the Proteominer™ technology to enrich for low-abundance proteins. Based on these protein profiles, the experimentally infected pigs could be classified according to their infectious disease status. Before the onset of clinical signs 88% of the infected animals could be classified correctly, after the onset of clinical sigs 93%. The sensitivity of the classification appeared to be high. The protein profiles could distinguish between separate infection models, although specificity was moderate to low. Classification of PCV2/PRRSV infected animals was superior compared to PCV2/PPV infected animals. Limiting the number of proteins in the profiles (ranging from 568 to 10) had only minor effects on the classification performance.</p> <p>Conclusions</p> <p>This study shows that serum protein profiles have potential for detection and identification of viral infections in pigs before clinical signs of the disease become visible.</p

In silico and in vitro evaluation of PCR-based assays for the detection of Bacillus anthracis chromosomal signature sequences

Bacillus anthracis, the causative agent of anthrax, is a zoonotic pathogen that is relatively common throughout the world and may cause life threatening diseases in animals and humans. There are many PCR-based assays in use for the detection of B. anthracis. While most of the developed assays rely on unique markers present on virulence plasmids pXO1 and pXO2, relatively few assays incorporate chromosomal DNA markers due to the close relatedness of B. anthracis to the B. cereus group strains. For the detection of chromosomal DNA, different genes have been used, such as BA813, rpoB, gyrA, plcR, S-layer, and prophage-lambda. Following a review of the literature, an in silico analysis of all signature sequences reported for identification of B. anthracis was conducted. Published primer and probe sequences were compared for specificity against 134 available Bacillus spp. genomes. Although many of the chromosomal targets evaluated are claimed to be specific to B. anthracis, cross-reactions with closely related B. cereus and B. thuringiensis strains were often observed. Of the 35 investigated PCR assays, only 4 were 100% specific for the B. anthracis chromosome. An interlaboratory ring trial among five European laboratories was then performed to evaluate six assays, including the WHO recommended procedures, using a collection of 90 Bacillus strains. Three assays performed adequately, yielding no false positive or negative results. All three assays target chromosomal markers located within the lambdaBa03 prophage region (PL3, BA5345, and BA5357). Detection limit was further assessed for one of these highly specific assays

A conditional limit theorem for independent random variables

In this paper, we prove a conditional limit theorem for independent not necessarily identically distributed random variables. Namely, we obtain the asymptotic distribution of a large number of them given the sum

Monitoring Wind-Borne Particle Matter Entering Poultry Farms via the Air-Inlet: Highly Pathogenic Avian Influenza Virus and Other Pathogens Risk

Wind-supported transport of particle matter (PM) contaminated with excreta from highly pathogenic avian influenza virus (HPAIv)-infected wild birds may be a HPAIv-introduction pathway, which may explain infections in indoor-housed poultry. The primary objective of our study was therefore to measure the nature and quantity of PM entering poultry houses via air-inlets. The air-inlets of two recently HPAIv-infected poultry farms (a broiler farm and a layer farm) were equipped with mosquito-net collection bags. PM was harvested every 5 days for 25 days. Video-camera monitoring registered wild bird visits. PM was tested for avian influenza viruses (AIV), Campylobacter and Salmonella with PCR. Insects, predominantly mosquitoes, were tested for AIV, West Nile, Usutu and Schmallenberg virus. A considerable number of mosquitoes and small PM amounts entered the air-inlets, mostly cobweb and plant material, but no wild bird feathers. Substantial variation in PM entering between air-inlets existed. In stormy periods, significantly larger PM amounts may enter wind-directed air-inlets. PM samples were AIV and Salmonella negative and insect samples were negative for all viruses and bacteria, but several broiler and layer farm PM samples tested Campylobacter positive. Regular wild (water) bird visits were observed near to the poultry houses. Air-borne PM and insects-potentially contaminated with HPAIv or other pathogens-can enter poultry air-inlets. Implementation of measures limiting this potential introduction route are recommended

Phylogeographic Distribution of Human and Hare Francisella Tularensis Subsp. Holarctica Strains in the Netherlands and Its Pathology in European Brown Hares (Lepus Europaeus)

Sequence-based typing of Francisella tularensis has led to insights in the evolutionary developments of tularemia. In Europe, two major basal clades of F. tularensis subsp. holarctica exist, with a distinct geographical distribution. Basal clade B.6 is primarily found in Western Europe, while basal clade B.12 occurs predominantly in the central and eastern parts of Europe. There are indications that tularemia is geographically expanding and that strains from the two clades might differ in pathogenicity, with basal clade B.6 strains being potentially more virulent than basal clade B.12. This study provides information on genotypes detected in the Netherlands during 2011–2017. Data are presented for seven autochthonous human cases and for 29 European brown hares (Lepus europaeus) with laboratory confirmed tularemia. Associated disease patterns are described for 25 European brown hares which underwent post-mortem examination. The basal clades B.6 and B.12 are present both in humans and in European brown hares in the Netherlands, with a patchy geographical distribution. For both genotypes the main pathological findings in hares associated with tularemia were severe (sub)acute necrotizing hepatitis and splenitis as well as necrotizing lesions and hemorrhages in several other organs. Pneumonia was significantly more common in the B.6 than in the B.12 cases. In conclusion, the two major basal clades present in different parts in Europe are both present in the Netherlands. In hares found dead, both genotypes were associated with severe acute disease affecting multiple organs. Hepatitis and splenitis were common pathological findings in hares infected with either genotype, but pneumonia occurred significantly more frequently in hares infected with the B.6 genotype compared to hares infected with the B.12 genotype

Signalling and responding to zoonotic threats using a One Health approach: a decade of the Zoonoses Structure in the Netherlands, 2011 to 2021

In the Netherlands, the avian influenza outbreak in poultry in 2003 and the Q fever outbreak in dairy goats between 2007 and 2010 had severe consequences for public health. These outbreaks led to the establishment of an integrated human-veterinary risk analysis system for zoonoses, the Zoonoses Structure. The aim of the Zoonoses Structure is to signal, assess and control emerging zoonoses that may pose a risk to animal and/or human health in an integrated One Health approach. The Signalling Forum Zoonoses (SO-Z), the first step of the Zoonoses Structure, is a multidisciplinary committee composed of experts from the medical, veterinary, entomology and wildlife domains. The SO-Z shares relevant signals with professionals and has monthly meetings. Over the past 10 years (June 2011 to December 2021), 390 different signals of various zoonotic pathogens in animal reservoirs and humans have been assessed. Here, we describe the Zoonoses Structure with examples from signals and responses for four zoonotic events in the Netherlands (tularaemia, Brucella canis, West Nile virus, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)). This may serve as an example for other countries on how to collaborate in a One Health approach to signal and control emerging zoonoses

The Workshop on Animal Botulism in Europe

A workshop on animal botulism was held in Uppsala, Sweden, in June 2012. Its purpose was to explore the current status of the disease in Europe by gathering the European experts in animal botulism and to raise awareness of the disease among veterinarians and others involved in biopreparedness. Animal botulism is underreported and underdiagnosed, but an increasing number of reports, as well as the information gathered from this workshop, show that it is an emerging problem in Europe. The workshop was divided into 4 sessions: animal botulism in Europe, the bacteria behind the disease, detection and diagnostics, and European collaboration and surveillance. An electronic survey was conducted before the workshop to identify the 3 most needed discussion points, which were: prevention, preparedness and outbreak response; detection and diagnostics; and European collaboration and surveillance. The main conclusions drawn from these discussions were that there is an urgent need to replace the mouse bioassay for botulinum toxin detection with an in vitro test and that there is a need for a European network to function as a reference laboratory, which could also organize a European supply of botulinum antitoxin and vaccines. The foundation of such a network was discussed, and the proposals are presented here along with the outcome of discussions and a summary of the workshop itself

Animal Botulism Outcomes in the AniBioThreat Project

Botulism disease in both humans and animals is a worldwide concern. Botulinum neurotoxins produced by Clostridium botulinum and other Clostridium species are the most potent biological substances known and are responsible for flaccid paralysis leading to a high mortality rate. Clostridium botulinum and botulinum neurotoxins are considered potential weapons for bioterrorism and have been included in the Australia Group List of Biological Agents. In 2010 the European Commission (DG Justice, Freedom and Security) funded a 3-year project named AniBioThreat to improve the EU's capacity to counter animal bioterrorism threats. A detection portfolio with screening methods for botulism agents and incidents was needed to improve tracking and tracing of accidental and deliberate contamination of the feed and food chain with botulinum neurotoxins and other Clostridia. The complexity of this threat required acquiring new genetic information to better understand the diversity of these Clostridia and develop detection methods targeting both highly specific genetic markers of these Clostridia and the neurotoxins they are able to produce. Several European institutes participating in the AniBioThreat project collaborated on this program to achieve these objectives. Their scientific developments are discussed here

Management of Animal Botulism Outbreaks: From Clinical Suspicion to Practical Countermeasures to Prevent or Minimize Outbreaks

Botulism is a severe neuroparalytic disease that affects humans, all warm-blooded animals, and some fishes. The disease is caused by exposure to toxins produced by Clostridium botulinum and other botulinum toxin–producing clostridia. Botulism in animals represents a severe environmental and economic concern because of its high mortality rate. Moreover, meat or other products from affected animals entering the food chain may result in a public health problem. To this end, early diagnosis is crucial to define and apply appropriate veterinary public health measures. Clinical diagnosis is based on clinical findings eliminating other causes of neuromuscular disorders and on the absence of internal lesions observed during postmortem examination. Since clinical signs alone are often insufficient to make a definitive diagnosis, laboratory confirmation is required. Botulinum antitoxin administration and supportive therapies are used to treat sick animals. Once the diagnosis has been made, euthanasia is frequently advisable. Vaccine administration is subject to health authorities' permission, and it is restricted to a small number of animal species. Several measures can be adopted to prevent or minimize outbreaks. In this article we outline all phases of management of animal botulism outbreaks occurring in wet wild birds, poultry, cattle, horses, and fur farm animals