The aim of the study was to assess the suitability of multiplex PCR and culture for the detection of virulent R.equi in tracheobronchial aspirate (TBA) and feces of foals from enzootic farms. Fecal and TBA samples were taken randomly from a representative group of foals aged between 1 and 6 months. The solid selective medium NANAT was used for culture examination. Multiplex PCR reaction was performed with the use of two sets of primers complementary to the conservative gene fragment encoding the 16S subunit of ribosomal RNA of R.equi and the plasmid gene encoding virulence associated protein A (VapA), which determines bacterial virulence. During clinical observations three experimental groups (A, B, C), differing in the intensity of respiratory signs, were selected for further studies. In foals from group A, showing no clinical signs from the respiratory tract, the results of the examinations of TBA and fecal samples were negative irrespective of the method used. In group B, showing moderate respiratory signs, 15 TBA and fecal samples were examined. PCR results were positive for 7 TBA samples and 2 fecal samples, whereas culture examinations were positive for only 3 TBA samples from this group. In group C, consisting of 6 foals with severe respiratory signs, positive PCR and culture results were obtained for all TBA samples and for 3 fecal samples.
The aim of the study was to compare the effectiveness of selected DNA extraction methods for the detection of Rhodococcus equi in foal faeces using PCR. Four different nucleic acid extraction methods were compared, which were based mainly on the use of proteolitic enzymes. Moreover, the commercial kit for DNA isolation from faeces was used. In two of the methods additional components, including CTAB detergent and powdered glass, were introduced. The PCR results showed that traditional DNA extraction methods involving proteolitic enzymes and the commercial kit were ineffective in terms of preparing the DNA matrix amplified by PCR. The only method useful for preparing the pure DNA matrix free from inhibitors of the enzymatic reaction was that with the use of powdered glass.
This article describes a case of an abortion storm caused by an EHV1 infection which took place in a stud of thoroughbred horses. The clinical course of the infection in the stud was investigated. On the basis of anamnesis, the analysis of clinical signs and gross pathological changes a suspicion of the aetiology of the abortion storm was put forward. The final diagnosis was made with the use of the PCR method. During the breeding season under investigation, 30 out of 44 pregnant mares from the barn of the stud A delivered healthy foals, 12 mares aborted, one delivered in term a dead foal and one delivered in term a live and weak foal, which succumbed within 24 hours after parturition. The analysis of this case of an abortion storm caused by an EHV1 infection may lead to a conclusion that an indirect cause of the outbreak could have been an insufficient level of protective immunity, connected with the lack of vaccinations of pregnant mares against a herpesvirus infection. Mares newly introduced into the barn, which had not been quarantined, were presumably the main source of the infection.
The final result of a comprehensive microbiological risk assessment should be the estimation of a probability and severity of adverse health effects that could occur in the population. Risk assessment requires the use of high quality data so that the assessment results could enable risk managers to take appropriate action at the appropriate moment. In the previous publication the first two stages of microbiological risk assessment were shown, i.e. hazard identification and hazard characterization. The purpose of this publication is to present the other two steps of risk assessment, i.e. exposure assessment and risk characterization. Exposure assessment describes the likelihood of exposure to biological, chemical and physical hazards with the potential to cause adverse health effects in humans and animals. In the case of microbiological risk assessment, exposure assessment should establish the concentration of a pathogenic agent in food for specific groups of consumers, as well as all possible pathways of exposure. On the other hand, risk characterization should establish qualitatively and/or quantitatively, with associated uncertainties, the likelihood and severity of known or potential adverse effects in a given population. Risk characterization is based on the integration of data collected during the previous stages of risk assessment in order to provide a comprehensive risk estimate.
The article describes the major findings concerning the occurrence of previously unrecognized infection with a virus provisionally named “Schmallenberg virus” (SBV) in Germany, the Netherlands, Belgium and Great Britain. The virus belongs to the family Bunyaviridae, genus Orthobunyavirus, serogroup Simbu. Full-length genome sequencing has shown its highest genetic similarity to Shamonda and Akabane viruses. The viruses of this group are transmitted mainly by mosquitoes (Culicidae) and midges (Culicoides) with very limited direct transmission from animal to animal (mostly transplacental transmission from a dam to the foetus during pregnancy). The clinical manifestation of the Schmallenberg virus infection has been associated with non-specific clinical signs in adult cattle (fever, reduced milk yield, diarrhoea), whereas congenital malformations (hydrocephalus with brain hypoplasia, arthrogryposis) have been observed in newborn lambs. For diagnostic purposes, RT-PCR, virus neutralisation and indirect immuno-fluorescence tests have been developed. The latter two assays cannot be applied for large-scale testing, but an assay for serological screening is currently unavailable. The major conclusion of the preliminary risk assessment performed by the European Centre for Disease Prevention and Control (ECDC) is that the threat to human health is very unlikely but cannot be excluded at this stage. None of the infections caused by the viruses of the Simbu serogroup are included in the list of diseases subjected to international notification, but affected countries have notified OIE of the occurrence of SBV infections according to regulations applicable to new and emerging diseases.
Risk assessment is a complex process that requires adequate knowledge of various fields. It consists of four steps: hazard identification, hazard characterization, exposure assessment and risk characterization. It can be conducted in a qualitative, semi-quantitative or a quantitative manner, and its selection depends on the quantity and quality of collected data. The aim of the paper has been to introduce to the historical background, terminology and the first two steps of risk assessment in improving animal health and food safety: hazard identification and hazard characterization. Hazard identification is usually defined as “the identification of biological, chemical, and physical agents capable of causing adverse health effects and which may be present in a particular food or group of foods.” The data concerning a particular hazard can be derived from scientific literature, databases, governmental agencies, international organizations, expert opinions, clinical tests, animal experiments, epidemiological observations, examinations of properties and interactions between microorganisms. Hazard characterization is the qualitative and/or quantitative assessment of the nature of the adverse health effects associated with the hazard. There are several factors considered in hazard characterization, related to both the microorganism and the human host. The most desirable part of this process is establishing a dose-response relationship, describing the relationship between the amount or level of exposure to a substance and the occurrence and intensity of an adverse effect.
In this study, we used RT-PCR to detect and characterize canine distemper virus isolated from 9 naturally infected foxes, 3 minks and 3 dogs in Poland by amplifying and sequencing a portion of the NP gene. A 293-bp fragment of the CDV NP gene was amplified by RT-PCR. Sequencing of the PCR products from the isolates led to the identification of 3 sequence variants. The mostly representative polymorphic variant No. 1 showed high homology with Chinese isolate of CDV with a accession number EF 375619. The sequences of all isolates from this polymorphic variants compared with the sequences of other polymorphic variants obtained in the study and with European and American isolates sequences from GenBank showed the conservative nucleotides changes in positions 57, 132, 143, 159 and 237. These mutations can indicate that in this part of Europe there are new variants of CDV.
The aim of this study was to perform molecular analysis of canine adenovirus 2 (CAV-2) E1B 19K gene fragment isolated from 20 dogs of various breeds (12 males and 8 females aged 1-9 years), with clinical symptoms of upper respiratory tract infections, from the Lubelszczyzna region. Nasal swabs were taken from dogs. DNA of CAV-2 was detected using the PCR method in 16 swabs. All PCR products were sequenced, and the obtained sequences were compared with each other and with the sequence of the E1B 19K gene of the CAV-2 strain from an online database of NCBI GenBank: AC 000003. Based on analysis of the obtained sequences, three polymorphic variants of CAV-2 (No.1-3) with homology of 78 - 100% were distinguished. The nucleotide and amino acid sequences of the most frequently represented polymorphic variant, No. 1, differed from the sequences of polymorphic variant No. 2 with one substitution. The nucleotide and amino acid sequence of the E1B 19K gene of CAV-2 AC 000003 differed from the analogous sequences of representatives of variant No. 1 with 44 nucleotide and 19 amino acid substitutions. The small number of nucleotide differences in the E1B 19K CAV-2 gene among the examined own isolates, compared with AC 000003, suggest that the infections in dogs were caused by a relatively genetically stable virus which occurs in eastern Poland.
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