Vogelgriepvirus kwam aanvliegen uit Azië

CVI acht besmetting via trekvogels 'waarschijnlijk.' Het virus komt oorspronkelijk uit China

Onderzoek naar kritische succesfactoren voor een laag antibioticumgebruik bij vleeskuikens: rapport van het project Kritische Succesfactoren Pluimvee (KSF Pluimvee)

Commissioned by AVINED and the Ministry of Agriculture, Nature and Food Quality, research is carried out to identify critical success factors for low antibiotic use in broilers. By analysis of sectoral databases, associations between farm and flock characteristics and antibiotics use are determined. With the results of an additional survey, differences in technical and social factors between structural low and high users of antibiotics are examined

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

Risicofactoren voor introductie van laag-pathogeen aviare influenza virus op legpluimveebedrijven met vrije uitloop in Nederland

Door middel van een case-control studie is onderzoek gedaan naar veronderstelde risicofactoren voor introductie van laag-pathogene aviaire influenza (LPAI) virus op pluimveelegbedrijven met vrije uitloop. Onder een LPAI virus werd in dit onderzoek verstaan: een aviair influenza virus van elk subtype (H1 tm H16), met uitzondering van de hoog pathogene aviaire influenza (HPAI) virussen. Veertig bedrijven met een LPAI virus introductie in het verleden (cases) zijn vergeleken met 81 bedrijven waar geen introductie heeft plaats gevonden (controls) om te onderzoeken of potentiële risicofactoren voor een besmetting met een LPAI virus geïdentificeerd kunnen worden. Vragen over aanwezigheid van potentiële risicofactoren zijn door middel van enquêtes voorgelegd aan de pluimveehouders

Clinical and Pathological Findings in SARS-CoV-2 Disease Outbreaks in Farmed Mink (Neovison vison)

SARS-CoV-2, the causative agent of COVID-19, caused respiratory disease outbreaks with increased mortality in 4 mink farms in the Netherlands. The most striking postmortem finding was an acute interstitial pneumonia, which was found in nearly all examined mink that died at the peak of the outbreaks. Acute alveolar damage was a consistent histopathological finding in mink that died with pneumonia. SARS-CoV-2 infections were confirmed by detection of viral RNA in throat swabs and by immunohistochemical detection of viral antigen in nasal conchae, trachea, and lung. Clinically, the outbreaks lasted for about 4 weeks but some animals were still polymerase chain reaction–positive for SARS-CoV-2 in throat swabs after clinical signs had disappeared. This is the first report of the clinical and pathological characteristics of SARS-CoV-2 outbreaks in mink farms

Lack of evidence for zoonotic transmission of Schmallenberg virus

The emergence of Schmallenberg virus (SBV), a novel orthobunyavirus, in ruminants in Europe triggered a joint veterinary and public health response to address the possible consequences to human health. Use of a risk profiling algorithm enabled the conclusion that the risk for zoonotic transmission of SBV could not be excluded completely. Self-reported health problems were monitored, and a serologic study was initiated among persons living and/or working on SBV-affected farms. In the study set-up, we addressed the vector and direct transmission routes for putative zoonotic transfer. In total, 69 sheep farms, 4 goat farms, and 50 cattle farms were included. No evidence for SBV-neutralizing antibodies was found in serum of 301 participants. The lack of evidence for zoonotic transmission from either syndromic illness monitoring or serologic testing of presumably highly exposed persons suggests that the public health risk for SBV, given the current situation, is absent or extremely low

Transmission of SARS-CoV-2 on mink farms between humans and mink and back to humans

Animal experiments have shown that nonhuman primates, cats, ferrets, hamsters, rabbits, and bats can be infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In addition, SARS-CoV-2 RNA has been detected in felids, mink, and dogs in the field. Here, we describe an in-depth investigation using whole-genome sequencing of outbreaks on 16 mink farms and the humans living or working on these farms. We conclude that the virus was initially introduced by humans and has since evolved, most likely reflecting widespread circulation among mink in the beginning of the infection period, several weeks before detection. Despite enhanced biosecurity, early warning surveillance, and immediate culling of animals in affected farms, transmission occurred between mink farms in three large transmission clusters with unknown modes of transmission. Of the tested mink farm residents, employees, and/or individuals with whom they had been in contact, 68% had evidence of SARS-CoV-2 infection. Individuals for which whole genomes were available were shown to have been infected with strains with an animal sequence signature, providing evidence of animal-to-human transmission of SARS-CoV-2 within mink farms

SARS-CoV-2 infection in farmed minks, the Netherlands, April and May 2020

Respiratory disease and increased mortality occurred in minks on two farms in the Netherlands, with interstitial pneumonia and SARS-CoV-2 RNA in organ and swab samples. On both farms, at least one worker had coronavirus disease-associated symptoms before the outbreak. Variations in mink-derived viral genomes showed between-mink transmission and no infection link between the farms. Inhalable dust contained viral RNA, indicating possible exposure of workers. One worker is assumed to have attracted the virus from mink

Mastitis and oxidative stress in vitamin E supplemented dairy cows

The research described in this thesis evaluated the effect of vitamin E supplementation under field conditions on the udder health of Dutch dairy cows. Additionally, it investigated the mechanism by which vitamin E influenced oxidative stress, especially during the dry period. Moreover, it investigated whether fat metabolism during the dry period influenced oxidative stress. The main finding presented in this thesis is the adverse effect of vitamin E supplementation on udder health in early lactation; both subclinical and clinical mastitis incidences were significantly higher in dairy cows that received a daily supplement of 3,000 IU/cow/day during the dry period compared to cows that received 135 IU. This appears to be the first time that an adverse effect of vitamin E was found in dairy cows. It was both a completely unexpected outcome, and one that highlights the importance of awareness of possible adverse effects of vitamin E. The adverse effect of vitamin E might be explained by the fact that high levels of vitamin E can, under some conditions, increase oxidative stress. High levels of oxidative stress are, in turn related to a higher risk of clinical mastitis. Thus, for some of the cows in this study, oxidative stress from high amounts of vitamin E during the dry period resulted in more mastitis. Therefore, vitamin E supplements are, for some dry dairy cows, not needed. Moreover based on all the results gathered on oxidative stress, it can be concluded that gaining insight into the mechanism by which vitamin E influences oxidative stress is quite difficult. Even in well-controlled experiments, no general effect of vitamin E supplementation was observed. In addition, while it seems that blood levels of vitamin E and the ratio of vitamin E to cholesterol are very reliable, it still remains difficult to define an oxidative status of the cow only based on blood levels of different oxidative stress related parameters. Because the clinical trial showed an adverse effect of vitamin E, it remains complicated to evaluate whether the assumed link between vitamin E supplementation and (udder) health improvement is through reduced oxidative stress is correc