Varkensgriep en Mexicaanse griep

In april 2009 werden in Californië (VS) twee kinderen ziek met wat later een nieuw type griepvirus (influenza) zou blijken te zijn. Influenzaachtige verschijnselen waren in de maand daarvoor al opvallend veel waargenomen in Mexico. Deze bleken te zijn veroorzaakt door hetzelfde type griepvirus. Al snel werd deze influenzavariant bekend onder de naam Mexicaanse grie

Effect of strain and inoculation dose of classical swine fever virus on within-pen transmission.

To improve the understanding of the dynamics and options for control of classical swine fever (CSF), more quantitative knowledge is needed on virus transmission. In this study, virus excretion and within-pen transmission of a strain of low, moderate and high virulence were quantified. Furthermore, the effect of inoculation dose on excretion and transmission were studied. The transmission was quantified using a stochastic susceptible-exposed-infectious-recovered (SEIR) model. Five transmission trials were conducted with ten pigs each. In each trial, three pigs were inoculated with the low virulent strain Zoelen, a low (102 TCID50), middle (103 TCID50), or high dose (105 TCID50) of the moderately virulent strain Paderborn, or the highly virulent strain Brescia. The other seven pigs in each trial served as contact pigs. None of the pigs inoculated with the low dose of the Paderbom strain were infected. When it was assumed that the infectiousness of the pigs coincided with virus isolation positive oropharyngeal fluid and/or faeces, no significant differences in transmission rate ß and basic reproduction ratio R0 between the high inoculation dose of the Paderbom strain (ß = 1.62/day, R0 = 35.9) and the Brescia strain (ß = 2.07/day, Ro = 17.5) were observed. When the middle dose of the Paderbom strain was used for inoculation, the ß (5.38/day) was not significantly higher than the Brescia strain or the high inoculation dose of the Paderborn strain, but the Ro (148) was significantly higher. Infection with the Zoelen strain resulted in a significantly lower ß and Ro (ß = 0/day, Ro = 0) than the other strain

A socio-psychological investigation into limitations and incentives concerning reporting a clinically suspect situation aimed at improving early detection of classical swine fever outbreaks

The aim of this study was to identify limitations and incentives in reporting clinically suspect situations, possibly caused by classical swine fever (CSF), to veterinary authorities with the ultimate aim to facilitate early detection of CSF outbreaks. Focus group sessions were held with policy makers from the veterinary authorities, and representatives of veterinary practitioners and pig farmer unions. Personal interviews with a small group of pig farmers and practitioners were held to check limitations raised and solutions proposed during the focus group sessions. An electronic questionnaire was mailed to pig farmers and practitioners to investigate perceptions and attitudes with respect to clinically suspect situations possibly caused by CSF. After triangulating the responses of veterinary authorities, veterinary practitioners and farmers, six themes emerged across all groups: (1) lack of knowledge on the early signs of CSF; (2) guilt, shame and prejudice; (3) negative opinion on control measures; (4) dissatisfaction with post-reporting procedures; (5) lack of trust in government bodies; (6) uncertainty and lack of transparency of reporting procedures. The following solutions to facilitate early detection of CSF were put forward: (a) development of a clinical decision-support system for vets and farmers, in order to get faster diagnosis and detection of CSF; (b) possibility to submit blood samples directly to the reference laboratory to exclude CSF in a clinical situation with non-specific clinical signs, without isolation of the farm and free of charge for the individual farmer; (c) decrease social and economic consequences of reporting CSF, for example by improving the public opinion on first reports; (d) better schooling of veterinary officers to deal with emotions and insecurity of farmers in the process after reporting; (e) better communication of rules and regulations, where to report, what will happen next; (f) up-to-date website with information and visual material of the clinical signs of CS

C-strain vaccination against Classical Swine Fever: effects on epidemic and final screening

In this project it is evaluated how the use of C-strain vaccine instead of E2-subunit vaccine will affect the effectiveness of controlling Classical Swine Fever (CSF). To this end a CSF transmission model was developed that describes virus transmission on three different levels: between animals, between pens and between herds. The results of transmission and vaccination experiments as well as the data from the 1997/1998 CSF epidemic in The Netherlands serve to parameterize the model. With the model hypothetical epidemics are simulated under different scenarios

Влияние электромагнитного состояния турбоагрегата на работоспособность его узлов. Диагностика, демагнитезация

Рассмотрены условия возникновения электроэрозионных повреждений узлов турбоагрегатов, а так же их характерные признаки. Даны рекомендации по диагностике и устранению электроэрозии на турбоагрегатах находящихся в эксплуатации. При цитуванні документа, використовуйте посилання http://essuir.sumdu.edu.ua/handle/123456789/21587There considered conditions resulting in occurring electroerozion damage sites in turbine unit, as well as their characteristic features. There given recommendations concerning diagnosis and elimination of electroerozion on turbine units being in operation. При цитировании документа, используйте ссылку http://essuir.sumdu.edu.ua/handle/123456789/2158

Development of a virus neutralisation test to detect antibodies against Schmallenberg virus and serological results in suspect and infected herds

Background: At the end of 2011, a new orthobunyavirus, tentatively named Schmallenberg virus (SBV), was discovered in Germany. This virus has since been associated with clinical signs of decreased milk production, watery diarrhoea and fever in dairy cows, and subsequently also with congenital malformations in calves, lambs and goat kids. In affected countries, initial surveillance for the infection was based on examination of malformed progeny. These suspicions were followed up by real-time reverse transcription polymerase chain reaction (RT-PCR) on brain tissue. For epidemiological purposes, a serological assay was, however, needed. Results: A virus neutralisation test (VNT) was developed and optimized, and subsequently evaluated. This VNT has a specificity of >99% and the sensitivity is likely also very close to 100%. The assay is highly repeatable and reproducible. The final assay was used to test for antibodies in cows, ewes and does from herds known to be infected or suspected to be so. Targets for sampling in these herds were the mothers of malformed offspring. In herds with an RT-PCR confirmed SBV infection, more than 94% (190 out of 201) of the ewes and 99% (145 out of 146) of the cows were seropositive. In herds with suspicion of SBV infection based on birth of malformed offspring only (no or negative RT-PCR), more than 90% (231 out of 255) of the ewes and 95% (795 out of 834) of the cows were seropositive. In goats, on the other hand, only a low number of seropositives was found: overall 36.4%, being 16 out of 44 goats tested. Conclusions: Given the characteristics of this VNT, it can be used at a relative high throughput for testing of animals for export, surveillance, screening and research purposes, but can also be used as a confirmation test for commercially available enzyme-linked immunosorbent assays (ELISA's) and for (relative) quantification of antibodies. Suspicions of SBV infections that were confirmed by RT-PCR were almost always confirmed by serology in cows. Due to individual registration and identification of cows and calves, affected offspring could almost always be traced back to the mother. Ewes on the other hand were not always the mothers of affected lambs, but were in many cases herd mates with unaffected lambs. This indicated a high within-herd seroprevalence of antibodies against SBV

Replication, Pathogenesis and Transmission of Pandemic (H1N1) 2009 Virus in Non-Immune Pigs

The declaration of the human influenza A pandemic (H1N1) 2009 (H1N1/09) raised important questions, including origin and host range [1,2]. Two of the three pandemics in the last century resulted in the spread of virus to pigs (H1N1, 1918; H3N2, 1968) with subsequent independent establishment and evolution within swine worldwide [3]. A key public and veterinary health consideration in the context of the evolving pandemic is whether the H1N1/09 virus could become established in pig populations [4]. We performed an infection and transmission study in pigs with A/California/07/09. In combination, clinical, pathological, modified influenza A matrix gene real time RT-PCR and viral genomic analyses have shown that infection results in the induction of clinical signs, viral pathogenesis restricted to the respiratory tract, infection dynamics consistent with endemic strains of influenza A in pigs, virus transmissibility between pigs and virus-host adaptation events. Our results demonstrate that extant H1N1/09 is fully capable of becoming established in global pig populations. We also show the roles of viral receptor specificity in both transmission and tissue tropism. Remarkably, following direct inoculation of pigs with virus quasispecies differing by amino acid substitutions in the haemagglutinin receptor-binding site, only virus with aspartic acid at position 225 (225D) was detected in nasal secretions of contact infected pigs. In contrast, in lower respiratory tract samples from directly inoculated pigs, with clearly demonstrable pulmonary pathology, there was apparent selection of a virus variant with glycine (225G). These findings provide potential clues to the existence and biological significance of viral receptor-binding variants with 225D and 225G during the 1918 pandemic [5]