Equine herpesvirus 1 (EHV-1) infection is the cause of high impact disease syndromes, affecting the global horse industry. The effect of vaccination on transmission dynamics of EHV-1 in naturally occurring outbreaks is not quantified. Our aims were to estimate R-0 for EHV-1 in equine populations from outbreak data, and evaluate the effect of vaccination status of the herd on R through a systematic review, model-based estimations and meta-analysis. A literature search for outbreak reports was carried out. Depending on available data, the early epidemic growth rate (GR) or final attack rate (AR) approach was used to estimate the basic reproduction number for that outbreak. Herd vaccination status, as well as virus genotype and use of antivirals were recorded. Only outbreaks in herds where either none or all of the horses had been vaccinated were included. An overall estimate for R-0 (non-vaccinated herds) and R-v (vaccinated herds) was computed by meta-analysis and the two groups were compared using a random effects model. Twelve outbreaks, in herds of 16-135 horses, met the inclusion criteria, of which six occurred in non-vaccinated herds and six in vaccinated herds. One R-0 calculation from a report describing empirical determination of a herd immunity threshold was also included. We found no evidence for a significant difference between estimates of R-0 and R-V in outbreaks: R<^>(0)=3.3(2.6-4.0) and R-V=2.7(2.1-3.2), p = 0.15. Our main limitations were our inability to investigate the influence of genotype or antivirals on results. Sensitivity analyses gave volatile p-values. In conclusion, we found no robust evidence for a significant reduction on transmission of EHV-1 in herds where all horses were vaccinated vs non-vaccinated herds. R in herds where all horses were vaccinated was substantially > 1 and vaccination as a sole mitigating measure may have limited effect on transmission of EHV-1

Strangles, a disease caused by infection with Streptococccus equi subspecies equi (S. equi), is endemic worldwide and one of the most frequently diagnosed infectious diseases of horses. Recent work has improved our knowledge of key parameters of transmission dynamics, but important knowledge gaps remain. Our aim was to apply mathematical modelling of S. equi transmission dynamics to prioritise future research areas, and add precision to estimates of transmission parameters thereby improving understanding of S. equi epidemiology and quantifying the control effort required. A compartmental deterministic model was constructed. Parameter values were estimated from current literature wherever possible. We assessed the sensitivity of estimates for the basic reproduction number on the population scale to varying assumptions for the unknown or uncertain parameters of: (mean) duration of carriership (1/gamma(C)), relative infectiousness of carriers (f), proportion of infections that result in carriership (p), and (mean) duration of immunity after natural infection (1/gamma(R)). Available incidence and (sero-)prevalence data were compared to model outputs to improve point estimates and ranges for these currently unknown or uncertain transmission-related parameters. The required vaccination coverage of an ideal vaccine to prevent major outbreaks under a range of control scenarios was estimated, and compared available data on existing vaccines. The relative infectiousness of carriers (as compared to acutely ill horses) and the duration of carriership were identified as key knowledge gaps. Deterministic compartmental simulations, combined with seroprevalence data, suggest that 0.05<f<0.5 and that the duration of protective immunity after infection is likely 4-6 years. The presence of carriers alone may suffice to keep S. equi endemic in a population, implying that carriers cannot be ignored in control efforts. Weekly screening of herds for signs of strangles could be sufficient to ensure R < 1, provided all horses are screened for carriership post-infection. In some of worst-case scenarios, vaccination alone would not suffice to prevent major outbreaks from occurring. A stochastic agent-based model was also constructed and validated, and used to simulate a remount depot, to evaluate whether historical incidence data of recurrence of strangles within individuals could be explained without the assumption that one in four horses fail to mount a lasting immune response. These simulations demonstrated that the observed data could have occurred without that assumption.

IntroductionAbscessation of equine head lymph nodes can be caused by various bacteria, but Streptococcus equi subsp. equi is mainly involved. At our laboratory, samples of three unrelated horses with submandibular abscesses were found negative for S. equi, and further testing proved the presence of another genus. This raised the question for the exact identity of this pathogen and whether these isolates were epidemiologically related and it warranted further characterization with regards of virulence and resistance factors. MethodsCulture followed by identification using MALDI-TOF MS, MIC testing and whole genome sequencing (WGS) was performed to characterize the bacteria. ResultsBacterial culture and subsequent identification with MALDI-TOF MS resulted in the reliable identification of A. denticolens in two of the three cases. Final confirmation of A. denticolens for all three isolates was achieved by analysis of the WGS data, supported by multilocus sequence typing (MLST). The three isolates showed 95% nucleotide sequence identity. The number of single nucleotide polymorphisms (10,170 to 36,058) indicated that the isolates were not clonal, suggesting that these cases were epidemiologically unrelated. Only four known virulence related genes were detected. The absence of known antibiotic resistance genes was in line with the high susceptibility, as indicated by the susceptibility patterns obtained for two of the three isolates. ConclusionWe conclude that A. denticolens should be included in the differential diagnosis of (submandibular) lymph node abscessation in horses, especially if strangles cannot be confirmed with laboratory diagnostics. Furthermore, we report the first draft genome of A. denticolens isolated from horses.

Porcine circovirus type 2 (PCV2) systemic disease is currently considered one of the most relevant infectious diseases in swine industry worldwide from an economical point of view. Although piglets generally become diseased between 8 and 16 weeks of age, they can be infected much earlier, even already in utero. However, data on the prevalence of PCV2 infection in newborn piglets are very variable (lower than 40 up to 82%) and most of the studies have been performed in US. In European pig farms, using group-housing systems for gestating sows, a different herd PCV2 infection and immunological status may be expected and was recently reported in Germany. If that is the current scenario in most European farms, strategies to prevent horizontal transmission become essential for the control of the infection. The aim of our study was to determine the PCV2 prevalence in newborn piglets on 4 endemically infected farms in the Netherlands under European conditions. Eleven sows and 8 piglets per litter from 4 farms selected by their assumed PCV2 endemic infection status were sampled. Plasma from piglets was analysed with a PCV2 qPCR and serum from the sows was analysed with a commercial circovirus IgG ELSIA, circovirus IgM ELISA and PCV2 qPCR. In none of the samples from the piglets PCV2 was detected by the qPCR. None of the samples from the sows tested positive in the qPCR and circovirus IgM ELISA. The true- and apparent prevalence of IgG at herd and sow level were 0.75 and 0.81 and, 0.30 and 0.32, respectively, and no statistically significant association with sow parity was observed. These results reveal a very low prevalence of PCV2 in newborn piglets on endemically infected farms in The Netherlands, opening the opportunity of re-evaluation of the control measures applied in these farms.

The genus Flavivirus in the family Flaviviridae includes some of the most important examples of emerging zoonotic arboviruses that are rapidly spreading across the globe. Japanese encephalitis virus (JEV), West Nile virus (WNV), St. Louis encephalitis virus (SLEV) and Usutu virus (USUV) are mosquito-borne members of the JEV serological group. Although most infections in humans are asymptomatic or present with mild flu-like symptoms, clinical manifestations of JEV, WNV, SLEV, USUV and tick-borne encephalitis virus (TBEV) can include severe neurological disease and death. In horses, infection with WNV and JEV can lead to severe neurological disease and death, while USUV, SLEV and TBEV infections are mainly asymptomatic, however, and induce antibody responses. Horses often serve as sentinels to monitor active virus circulation in serological surveillance programmes specifically for WNV, USUV and JEV. Here, we developed and validated a NS1-antigen protein microarray for the serological differential diagnosis of flavivirus infections in horses using sera of experimentally and naturally infected symptomatic as well as asymptomatic horses. Using samples from experimentally infected horses, an IgG and IgM specificity of 100% and a sensitivity of 95% for WNV and 100% for JEV was achieved with a cut-off titre of 1 : 20 based on ROC calculation. In field settings, the microarray identified 93-100% of IgG-positive horses with recent WNV infections and 87% of TBEV IgG-positive horses. WNV IgM sensitivity was 80%. Differentiation between closely related flaviviruses by the NS1-antigen protein microarray is possible, even though we identified some instances of cross-reactivity among antibodies. However, the assay is not able to differentiate between naturally infected horses and animals vaccinated with an inactivated WNV whole-virus vaccine. We showed that the NS1-microarray can potentially be used for diagnosing and distinguishing flavivirus infections in horses and for public health purposes within a surveillance setting. This allows for fast, cheap, syndrome-based laboratory testing for multiple viruses simultaneously for veterinary and public health purposes.

Equine herpes virus type 1 (EHV-1) is een belangrijke pathogeen bij paarden. EHV-1 kan in een gevoelige paardenpopulatie respiratoire klachten en abortus veroorzaken, maar kan ook verantwoordelijk zijn voor het ontstaan van neurologische klachten (equine herpes myeloencephalopathie: EHM). Wereldwijd bestaat de indruk dat EHM de laatste jaren vaker voorkomt, waardoor de aandacht voor epidemiologische aspecten en preventie van overdracht van EHV-1 is toegenomen. Dit heeft er onder meer toe geleid dat de adviestermijn (zowel in de Amerikaanse EHV-1 consensus statement als in de in 2015 verschenen Nederlandse 'Richtlijn rhinopneumonie bij het paard') voor het sluiten van een bedrijf waar EHM is geconstateerd, is verlengd van 21 naar 28 dagen. Dit omdat met name bij de neurologische vorm van EHV-1 is gebleken dat de uitscheiding van het virus langere tijd optreedt dan voorheen wel werd gedacht. Ook in de hier beschreven patient komt dit naar voren. Er wordt een korte update gegeven van de huidige kennis ten aanzien van EHV-1 waarbij de nadruk ligt op belangrijke aspecten van EHM, transmissie van het virus en management van het bedrijf en preventie van verspreiding in het geval van een uitbraak.

During August-September 2012, an outbreak of Foot-and-mouth Disease (FMD) due to serotype Southern African Territories-2 (SAT2) occurred on a large, extensively grazed dairy farm in Nakuru County, Kenya. Over 29 days, 400/644 (62.1%) cattle were recorded as displaying clinical signs consistent with FMD. Out of the 18 management groups present, 17 had clinical cases (weighted mean incidence rate 3.5 per 100 cattle-days, 95% CI 2.4, 5.1; range 0.064-10.9). Transmission may have been encouraged when an infected group was moved to a designated isolation paddock. A four to five day minimum incubation period was apparent in five groups for which a point source exposure was evident. Further transmission was associated with the movement of individual animals incubating infection, use of a common dip and milking parlour, and grazing of susceptible groups in paddocks neighbouring to infectious cases. Animals over 18 months old appeared to be at highest risk of disease possibly due to milder clinical signs seen among younger animals resulting in reduced transmission or cases not being recorded. Cows with a breeding pedigree containing a greater proportion of zebu appeared to be at lower risk of disease. The outbreak occurred despite regular vaccination (three times per year) last performed approximately three months before the index case. Incidence risk by the lifetime number of doses received indicated limited or no vaccine effectiveness against clinical disease. Reasons for poor vaccine effectiveness are discussed with antigenic diversity of the SAT2 serotype and poor match between the field and vaccine strain as a likely explanation. Detailed field-derived epidemiological data based on individual animals are rarely presented in the literature for FMD, particularly in East-Africa and with the SAT2 serotype. This study provides a detailed account and therefore provides a greater understanding of FMD outbreaks in this setting. Additionally, this is the first study to provide field-derived evidence of poor vaccine effectiveness using a SAT2 vaccine. Further field-based measures of vaccine effectiveness in line with evaluation of human vaccines are needed to inform FMD control policy which has previously relied heavily upon experimental data and anecdotal experience.

Background: New animal and human diseases continue to emerge across the world, influenced by human and animal population densities, climate and globalization in travel and trade. Arboviruses form a specific group within these (re-)emerging threats and, due to their vector-borne and zoonotic nature, require extensive, complex and expensive surveillance and control schemes. They cause clinical diseases in both humans and animals, ranging from life threatening meningoencephalomyelitis and hemorrhagic fever to rash and crippling arthralgia. Diagnosis is based mostly on serology, as viremia is often short-lived. Further complicating diagnostics is the fact that clinical syndromes and geographical distribution overlap, and antibodies cross-react extensively within virus families in common serological tests. Our objective is to be able to detect, diagnose and monitor clinically significant arboviruses simultaneously in multiple species and with an approach easily adaptable to constantly changing demographics and syndromes. Therefore we develop a novel cross-species protein microarray for profiling of antibodies to six flaviviruses (DENV1-4, WNV, JEV, TBEV, USUV, YFV), three alphaviruses (CHIKV, ONNV, SINV) and one phlebovirus (RVFV). Methods & Materials: Target antigens were selected and spotted onto nitrocellulose pads using a non-contact array spotter. Serum samples from humans (180), horses (80), sheep (160), chickens (10) and other bird species (15) with virologically and/or serologically confirmed arboviral infections and control sera of non-exposed individuals were incubated in serial 2-fold dilutions followed by incubation with a species specific IgG, IgM or IgY specific Cy5-labeled conjugate. After quantifying signals using a scanarray scanner, data were analyzed in 'R'. Results: Profiling of antibodies in human patients exposed to flaviviruses and alphaviruses showed highly discriminatory patterns of reactivity with sensitivities and specificities ranging from 87%-100%. Additionally, vaccinated individuals could be distinguished from non-vaccinated individuals. Initial results also showed high sensitivity and specificity of 100% for sheep infected with RVFV and horses infected with JEV, while WNV showed some cross-reactivity with JEV and USUV antigens in horses. Further testing is ongoing to determine the usefulness of this system for multiple bird species. Conclusion: In conclusion, preliminary results show that this method may provide an easily adaptable high throughput alternative for multiplex detection and monitoring of arboviruses in multiple species.

In December 2011, a previously unknown congenital syndrome of arthrogryposis and hydranencephaly in sheep and cattle appeared in the Netherlands as an emerging epizootic due to Schmallenberg virus (SBV). Gross lesions in 102 lambs and 204 calves included porencephaly, hydranencephaly, cerebellar dysplasia and dysplasia of the brainstem and spinal cord, a flattened skull with brachygnathia inferior, arthrogryposis, and vertebral column malformations. Microscopic lesions in the central nervous system showed rarefaction and cavitation in the white matter, as well as degeneration, necrosis, and loss of neurons in the gray matter. Brain and spinal cord lesions were more severe in lambs than in calves. Ovine and bovine cases examined early in the outbreak showed encephalomyelitis. SBV infection was confirmed by real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) in brain samples in 46 of 102 lambs (45%) and in 32 of 204 calves (16%). Immunohistochemistry, performed on tissue samples from 18 RT-qPCR-positive lambs, confirmed the presence of bunyaviral antigen in neurons of the brain in 16 cases. SBV antibodies were detected by enzyme-linked immunosorbent assay in fetal blood in 56 of 61 sampled ovine cases (92%). In a virus neutralization test, all tested dams of affected newborns, 46 ewes and 190 cows, were seropositive. Compared with other teratogenic viral infections, the pathogenesis and lesions of SBV in sheep and cattle fetuses are similar to those of other ruminant orthobunyaviruses. However, the loss of spinal ventral motor neurons and their tracts, resulting in micromyelia, distinguishes SBV infection from other viral central nervous system lesions in newborn ruminants.

To detect Schmallenberg virus (SBV) infections in ruminants and to perform SBV epidemiological studies a cost-effective serological test is required. For these purposes an indirect whole virus Enzyme-linked Immunosorbent Assay (ELISA) for detection of SBV specific antibodies in ruminant blood samples was developed. Schmallenberg virus antigen was produced by propagation on Vero cells, partly purified and coated onto ELISA plates. The indirect ELISA procedure included the subsequent incubation of diluted samples, protein-G-HRP conjugate and TMB substrate solution. Net Optical Densities (OD) values were calculated and expressed as a sample to positive percentage (S/P%) by comparison of the average net OD with the OD of the positive control. Validation of this assay was performed using 633 samples from SBV-free sheep, goats and cattle, and 141 samples from SBV suspect ruminants. The diagnostic specificity was 98.8%. Test results of 86 ruminant serum samples using both the SBV-ELISA and an SBV virus neutralization test (VNT), designated as the gold standard serological test for SBV, showed good correlation: at an S/P cut-off of 15% only one VNT positive sample tested negative in the SBV ELISA. The diagnostic sensitivity of the ELISA, relative to the VNT, was 98.8% (95% CI: 93.3–100.0%). The ELISA showed a high repeatability (cv=6.5%) and reproducibility (100% agreement). It was concluded that this ELISA is a suitable test method for the detection of SBV antibodies in sera from cows, sheep and, possibly, goats.

EQUINE infectious anaemia (EIA) is a persistent viral infection of equids. The causative agent, equine infectious anaemia virus (EIAV), is a lentivirus in the family Retroviridae , subfamily Orthoretrovirinae. All lentiviruses cause persistent infections, and most lentiviruses cause a slow, progressive disease that frequently results in death. In contrast, EIA results in an acute phase, followed by recurrent but eventually subsiding, clinical disease periods. These horses become persistently infected inapparent carriers. The clinical signs of EIA were first described in horses in France in 1843 (Lignee 1843) and the causative agent was shown to be a filterable agent in 1904 (Vallee and Carre 1904). EIA can be diagnosed on the basis of clinical signs, pathological lesions, serology and molecular methods. Infected horses remain viraemic carriers for life and, with very rare exceptions, yield a positive serological test result. Most horses develop antibodies that can be detected by agar gel immunodiffusion test (AGIDT) on average up to 24 days after infection, but sometimes it can take up to three months for antibodies to be detected. The antibody response …

At the end of 2011, a new Orthobunyavirus was discovered in Germany and named Schmallenberg virus (SBV). In the Netherlands malformations in new-born ruminants were made notifiable from the 20th of December 2011. After a notification, malformed new-borns were necropsied and brain tissue was sampled for reverse transcription-polymerase chain reaction (RT-PCR). In addition, blood samples from mothers of affected new-borns were tested for antibodies in a virus neutralization test (VNT). The aim of this study was to summarize and evaluate the diagnostic data obtained and to gain insight into the possible regional differences. In total 2166 brains were tested: 800 from lambs, 1301 from calves and 65 from goat kids. Furthermore 1394 blood samples were tested: 458 from ewes, 899 from cows and 37 from goats. Results showed that 29% of the lamb brains, 14% of the calf brains, and 9% of the goat kid brains were RT-PCR positive. The number of malformed and RT-PCR positive lambs decreased over time while the number of malformed and RT-PCR positive calves increased. In the VNT 92% of the ewes, 96% of the cows and 43% of the goats tested positive. Combining RT-PCR and VNT results, 18% of all farms tested positive in both the RT-PCR and VNT. The relative sensitivity and specificity of the RT-PCR are 19% and 97% respectively, and of the VNT 99% and 6%. The results show a widespread exposure to SBV and the regional evaluation seems to indicate an introduction of SBV in the central/eastern part.

Coxiella burnetii infections are mostly subclinical in cattle, but can occasionally be associated with abortion. In the present study, 100 aborted fetuses or stillborn calves that were submitted for postmortem examination between September 2007 and March 2008 were examined for infection with C burnetii. Samples of both pooled fetal tissues and placental cotyledon were tested using a real-time PCR assay. In addition, the sections of placental cotyledon were examined using immunohistochemistry (IHC). The IHC of four placentas was positive. The PCR results of the IHC-positive placentas were high positive (HP); the PCR results of the organs of these four fetuses and calves varied from low positive (LP) to HP. The four IHC-positive fetuses had a gestation length of seven to nine months. All four placentas had histological signs of inflammation, but only one of four placentas had gross pathological signs of inflammation possibly due to a concomitant infection with Bacillus licheniformis. Five other IHC-negative placentas had (high) positive PCR results; the PCR results of the organs of these fetuses were LP or negative. The present study indicates that C burnetii infections are detected in a limited percentage of aborted fetuses and stillborn calves by IHC. To assess the importance of placentas with PCR-positive and IHC-negative test results, more research is needed.

Veterinary RecordVolume 171, Issue 12 p. 299-299 Research Schmallenberg virus antibodies in bovine and ovine fetuses C. van Maanen DVM, PhD, Corresponding Author C. van Maanen DVM, PhD [email protected] Animal Health Service (GD-Deventer), P.O. Box 9, Deventer, 7400 AA, The NetherlandsE-mail for correspondence: [email protected]Search for more papers by this authorH. van der Heijden PhD, H. van der Heijden PhD Animal Health Service (GD-Deventer), P.O. Box 9, Deventer, 7400 AA, The NetherlandsSearch for more papers by this authorG. J. Wellenberg BSc, PhD, G. J. Wellenberg BSc, PhD Animal Health Service (GD-Deventer), P.O. Box 9, Deventer, 7400 AA, The NetherlandsSearch for more papers by this authorG. Witteveen, G. Witteveen Animal Health Service (GD-Deventer), P.O. Box 9, Deventer, 7400 AA, The NetherlandsSearch for more papers by this authorS. Luttikholt BSc, MSc, S. Luttikholt BSc, MSc Animal Health Service (GD-Deventer), P.O. Box 9, Deventer, 7400 AA, The NetherlandsSearch for more papers by this authorR. Bouwstra, R. Bouwstra Department of Virology, Central Veterinary Institute (CVI), PO Box 65, Lelystad, 8200 AB, The NetherlandsSearch for more papers by this authorB. Kooi, B. Kooi Department of Virology, Central Veterinary Institute (CVI), PO Box 65, Lelystad, 8200 AB, The NetherlandsSearch for more papers by this authorP. Vellema DVM, PhD, P. Vellema DVM, PhD Animal Health Service (GD-Deventer), P.O. Box 9, Deventer, 7400 AA, The NetherlandsSearch for more papers by this authorK. Peperkamp DVM, K. Peperkamp DVM Animal Health Service (GD-Deventer), P.O. Box 9, Deventer, 7400 AA, The NetherlandsSearch for more papers by this authorJ. Mars DVM, PhD, J. Mars DVM, PhD Animal Health Service (GD-Deventer), P.O. Box 9, Deventer, 7400 AA, The NetherlandsSearch for more papers by this author C. van Maanen DVM, PhD, Corresponding Author C. van Maanen DVM, PhD [email protected] Animal Health Service (GD-Deventer), P.O. Box 9, Deventer, 7400 AA, The NetherlandsE-mail for correspondence: [email protected]Search for more papers by this authorH. van der Heijden PhD, H. van der Heijden PhD Animal Health Service (GD-Deventer), P.O. Box 9, Deventer, 7400 AA, The NetherlandsSearch for more papers by this authorG. J. Wellenberg BSc, PhD, G. J. Wellenberg BSc, PhD Animal Health Service (GD-Deventer), P.O. Box 9, Deventer, 7400 AA, The NetherlandsSearch for more papers by this authorG. Witteveen, G. Witteveen Animal Health Service (GD-Deventer), P.O. Box 9, Deventer, 7400 AA, The NetherlandsSearch for more papers by this authorS. Luttikholt BSc, MSc, S. Luttikholt BSc, MSc Animal Health Service (GD-Deventer), P.O. Box 9, Deventer, 7400 AA, The NetherlandsSearch for more papers by this authorR. Bouwstra, R. Bouwstra Department of Virology, Central Veterinary Institute (CVI), PO Box 65, Lelystad, 8200 AB, The NetherlandsSearch for more papers by this authorB. Kooi, B. Kooi Department of Virology, Central Veterinary Institute (CVI), PO Box 65, Lelystad, 8200 AB, The NetherlandsSearch for more papers by this authorP. Vellema DVM, PhD, P. Vellema DVM, PhD Animal Health Service (GD-Deventer), P.O. Box 9, Deventer, 7400 AA, The NetherlandsSearch for more papers by this authorK. Peperkamp DVM, K. Peperkamp DVM Animal Health Service (GD-Deventer), P.O. Box 9, Deventer, 7400 AA, The NetherlandsSearch for more papers by this authorJ. Mars DVM, PhD, J. Mars DVM, PhD Animal Health Service (GD-Deventer), P.O. Box 9, Deventer, 7400 AA, The NetherlandsSearch for more papers by this author First published: 22 September 2012 https://doi.org/10.1136/vr.101061Citations: 24 Provenance: not commissioned; externally peer reviewed Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article. References 1Charles J. A. (1994) Akabane virus. The Veterinary Clinics of North America Food Animal Practice 10, 525 –546 2Dijkman R. Mars J. Wellenberg G. J. (2012) Detection of Schmallen-berg virus in bovine semen by one-step real-time PCR. In Proceedings 2nd EAVLD con-gress 1–4 July 2012. pp S3-P–19 3Elbers A. R. Loeffen W. L. Quak S. De Boer-Luijtze E. Van Der Spek A. N. Bouwstra R. Maas R. Spierenburg M. A. De Klui-Jver E. P. Van Schaik G. Van Der Poel W. H. (2012) Seroprevalence of Schmallenberg Virus Antibodies among Dairy Cattle, the Netherlands, Winter 2011 –2012. Emerging Infectious Diseases 18, 1065 –1071 4Hartley W. J. Desaram W. G. Della-Porta A. J. Snowdon W. A. Shephard N. C. (1977) Pathology of congenital bovine epizootic arthrogry-posis and hydranencephaly and its relationship to Akabane virus. Australian Veteri-nary Journal 53, 319 –325 5Hoffmann B. Scheuch M. Hoper D. Jungblut R. Holsteg M. Schirrmeier H. Eschbaumer M. Goller K. V. Wernike K. Fischer M. Breithaupt A. Mettenleiter T. C. Beer M. (2012) Novel orthobunyavirus in cattle, europe, 2011. Emerging Infectious Siseases 18, 469 –472 6Kurogi H. Inaba Y. Goto Y. Miura Y. Takahashi H. (1975) Se-rologic evidence for etiologic role of Akabane virus in epizootic abortion-arthrogryposis-hydranencephaly in cattle in Japan, 1972 –1974. Archives of Virology 47, 71 –83 7Miura Y. Hayashi S. Ishihara T. Inaba Y. Omori T. (1974) Neu-tralizing antibody against Akabane virus in precolostral sera from calves with congenital arthrogryposis-hydranencephaly syndrome. Archives Gesamte Virusforschung 46, 377 –380 8Parsonson I. M. Della-Porta A. J. O'Halloran M. L. Snow-Don W. A. Fahey K. J. Standfast H. A. (1981) Akabane virus in-fection in the pregnant ewe. 1. Growth of virus in the foetus and the development of the foetal immune response. Veterinary Microbiology 6, 197 –207 9Van Den Brom R. Luttikholt S. J. Lievaart-Peterson K. Peper-Kamp N. H. Mars M. H. Van Der Poel W. H. Vellema P. (2012) Epizootic of ovine congenital malformations associated with Schmallenberg virus infec-tion. 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In 2007, a human Q fever epidemic started, mainly in the south eastern part of The Netherlands with a suspected indirect relation to dairy goats, and, to a lesser degree, to dairy sheep. This article describes the Q fever prevalences in Dutch dairy goat and dairy sheep bulk tank milk (BTM) samples, using a real-time (RT) PCR and ELISA. Results of BTM PCR and ELISA were compared with the serological status of individual animals, and correlations with a history of Q fever abortion were determined. When compared with ELISA results, the optimal cut-off value for the RT-PCR was 100 bacteria/ml. In 2008, there were 392 farms with more than 200 dairy goats, of which 292 submitted a BTM sample. Of these samples, 96 (32.9 per cent) were PCR positive and 87 (29.8 per cent) were ELISA positive. All farms with a history of Q fever abortion (n=17) were ELISA positive, 16 out of 17 were also PCR positive. BTM PCR or ELISA positive farms had significantly higher within-herd seroprevalences than BTM negative farms. In the south eastern provinces, the area where the human Q fever outbreak started in 2007, a significantly larger proportion of the BTM samples was PCR and ELISA positive compared to the rest of The Netherlands. None of the BTM samples from dairy sheep farms (n=16) were PCR positive but three of these farms were ELISA positive. The higher percentage of BTM positive farms in the area where the human Q fever outbreak started, supports the suspected relation between human cases and infected dairy goat farms.

The aim of the study was to determine the situation of equine arteritis virus (EAV) infections in hucul horses. A total of 176 horses (154 mares and 22 stallions) from the biggest hucul horse stud in Poland were tested. Antibodies against EAV were detected in 97 (55.1%) horses. The EAV seroprevalence among mares was 53.2% while in stallions – 68.2%. The percentage of positive mares increased with their age, thus amongst the mares of less than 2 years of age the percentage was 32.5%, while in the group of 3–5 years old increased to 59.4% and in the mares in the age of 6–10 years and older than 10 years 89.5% and 95% were seropositive, respectively. Among 11 seropositive stallions five were supposed to be shedders of EAV with their semen. It is likely that those persistently infected stallions were the reservoirs of the virus in the stud. Genetic studies using of ORF5 gene showed high homology between the viruses detected in the semen of those stallions what suggested lateral transmission between the stallions sharing the same stable. Persistent infection in an immature stallion, which has not yet been used for breeding, was established as a result of infection via respiratory route. Phylogenetic analysis confirmed that all hucul viruses shared the same ancestor and as most of EAV strains dominating in Polish horse population belonged to the European origin EAV subgroup (EU-1).

Commercial poultry is vaccinated routinely to protect the birds against infection or disease caused by several pathogens. The number of vaccines that are used in a particular flock depends on many factors such as disease pressure, pathogenicity of the pathogen, life span of the chicken, type of chicken, efficacy, availability, and costs of the vaccines, labor, regulations, efficacy of maternally derived antibodies, housing system, and relevance of vertical transmission. Vaccines can be applied individually or by mass application. Mass application by spray, feed, or drinking water is relatively cheap, fast, and safe regarding potential breaks of biosecurity as few people can vaccinate many birds in this way. Individual application is used for inactivated vaccines and for live vaccines that cannot, or cannot in a reliable way, be applied by a mucosal route.

Equine herpes virus 1 (EHV-1) strains are associated with respiratory disease, abortion and myeloencephalopathy. Worldwide outbreaks of EHV-1-associated myeloencephalopathy (EHM) occur rarely but cause disproportionately damage to the equine industry. The percentage of horses with neurological disease during natural outbreaks of EHM in horse operations is usually 10–20%. This study aims to elucidate why four minor outbreaks became a massive media hype and raised great concerns in the general public opinion. Two EHM outbreaks occurred in two premises in the same period (February 2012). There appeared to be a connection between both premises (horses stabled in premise A were visiting premise B weekly for indoor riding lessons). A third case of EHM (C) was confirmed in a geographically divergent location, with a history of indirect contact with one of the diseased horses of premises B. Some weeks later a fourth individual case of EHM was confirmed in another premise without an apparent connection to premises A, B or C. In premises A and B most of the horses developed fever, and in the course of the outbreak about 25% of the horses developed neurological signs consistent with EHM. In both premises several horses had to be euthanized. Case C had to be euthanized within a few days but no other horses on this premise became febrile or showed neurology. Premise D was already closed for 3 weeks before the first horse became febrile and here one horse showed ataxia (recovered) and one other aborted. During the onset of the outbreaks nasal swabs and EDTA blood samples were scored EHV-1 positive by real-time PCR. The EHV-1 strain responsible for these outbreaks was characterised by allele-specific PCR as a classical N752 strain. Although the limited number of outbreaks was not significantly different from the normal EHM incidence in the Netherlands, a media hype developed on radio, television, Facebook, twitter, and several website discussion platforms. Even in parliament the question was raised whether EHM should become a notifiable disease. The Dutch National Equestrian Federation advised to transport horses only for emergencies, and regional and national competitions were cancelled. The impact of social media was enormous e.g. the topic ‘herpes virus neurology’ on the largest equine websites of the Netherlands was visited >90,000 times/day. Retrospectively only a limited number of horses on four premises were involved. However, as result of the ‘voluntary’ standstill and the cancellation of horse shows and meetings the additional costs of the outbreak were very high. For future outbreak management the role of social media platforms for knowledge sharing and demystification should be considered as an important component of a communication strategy.