Publications

The Pirbright Institute publication directory contains details of selected publications written by our researchers.

There were a total of 1710 results for your search.
Rehman Z U, Qiu X, Sun Y, Liao Y, Tan L, Song C, Yu S, Ding Z, Munir M, Nair V, Meng C, Ding C (2018)

Vitamin E supplementation ameliorates Newcastle disease virus-induced oxidative stress and alleviates tissue damage in the brains of chickens.

Viruses 10 (4), 173

Abstract

Newcastle disease (ND), characterized by visceral, respiratory, and neurological pathologies, causes heavy economic loss in the poultry industry around the globe. While significant advances have been made in effective diagnosis and vaccine development, molecular mechanisms of ND virus (NDV)-induced neuropathologies remain elusive. In this study, we report the magnitude of oxidative stress and histopathological changes induced by the virulent NDV (ZJ1 strain) and assess the impact of vitamin E in alleviating these pathologies. Comparative profiling of plasma and brains from mock and NDV-infected chicken demonstrated alterations in several oxidative stress makers such as nitric oxide, glutathione, malondialdehyde, total antioxidant capacity, glutathione S-transferase, superoxide dismutase, and catalases. While decreased levels of glutathione and total antioxidant capacity and increased concentrations of malondialdehyde and nitric oxide were observed in NDV-challenged birds at all time points, these alterations were eminent at latter time points (5 days post infection). Additionally, significant decreases in the activities of glutathione S-transferase, superoxide dismutase, and catalase were observed in the plasma and brains collected from NDV-infected chickens. Intriguingly, we observed that supplementation of vitamin E can significantly reduce the alteration of oxidative stress parameters. Under NDV infection, extensive histopathological alterations were observed in chicken brain including neural inflammation, capillary hyperemia, necrosis, and loss of prominent axons, which were reduced with the treatment of vitamin E. Taken together, our findings highlight that neurotropic NDV induces extensive tissue damage in the brain and alters plasma oxidative stress profiles. These findings also demonstrate that supplementing vitamin E ameliorates these pathologies in chickens and proposes its supplementation for NDV-induced stresses.

Waters R, Ludi A B, Fowler V L, Wilsden G, Browning C, Gubbins S, Statham B, Bin-Tarif A, Mioulet V, King D J, Colenutt C, Brown E, Hudelet P, King D P (2018)

Efficacy of a high-potency multivalent foot-and-mouth disease virus vaccine in cattle against heterologous challenge with a field virus from the emerging A/ASIA/G-VII lineage

Vaccine 36 (14), 1901-1907

Abstract

In 2015, outbreaks of foot-and-mouth disease (FMD) in the Middle East were discovered to be caused by a viral lineage (A/ASIA/G-VII), which has recently emerged from the Indian sub-continent. In vitro vaccine matching data generated by the World Reference Laboratory (WRLFMD) indicated that A/ASIA/G-VII field viruses were poorly matched with vaccines (A-SAU-95, A22 IRQ and A-IRN-05) that are already used in the region. In order to assess the likely performance of one of these commercially available FMD vaccines, sixteen cattle were vaccinated with a polyvalent vaccine which contained two serotype A components (A-SAU-95 and A-IRN-05) with a homologous potency of at least 6PD50, and two cattle were left unvaccinated as controls. Twenty-one days later, all 18 cattle were challenged by tongue inoculation with an FMDV field isolate A/IRN/22/2015 from the A/ASIA/G-VII lineage, in line with the European Pharmacopeia PPG test conditions. The two control animals developed generalised FMD, and 7/16 vaccinated animals developed at least one foot lesion, thus only 56.3% were defined as protected. For the vaccine components, there was a significant increase in the probability of protection with increasing serological titres for A-SAU-95 (p = 0.03), but not for A-IRN-05 (p = 0.42). Analysis of FMDV in blood and nasal swabs suggested that vaccination reduced shedding and potential onward spread of FMD virus even if the animal developed foot lesions. In summary, the results from this study suggest that whilst this vaccine would not be appropriate for use in an emergency situation (in previously FMD-free countries), it may be partially effective in the field in endemic countries where repeat prophylactic vaccination is practiced. For emergency reactive vaccination, the findings from this study support the idea that a new vaccine strain should be developed that is tailored to the A/ASIA/G-VII lineage.

Strong R, Graham S P, La Rocca S A, Raue R, Vangeel I, Steinbach F (2018)

Establishment of a bovine viral diarrhea virus type 2 intranasal challenge model for assessing vaccine efficacy

Frontiers in Veterinary Science 5, 24

Abstract

The objective of this study was to develop a bovine viral diarrhea virus type 2 (BVDV-2) challenge model suitable for evaluation of efficacy of BVDV vaccines; a model that mimics natural infection and induces clear leukopenia and viremia. Clinical, hematological and virological parameters were evaluated after infection of two age groups of calves (3 and 9 months) with two BVDV-2 strains (1362727 and 502643). Calves became pyrexic between 8 and 9 days post inoculation and exhibited symptoms, such as nasal discharge, mild depression, cough, and inappetence. Leukopenia with associated lymphopenia and neutropenia was evident in all groups with lowest leukocyte and lymphocyte counts reached 8 dpi and granulocyte counts between 11 and 16 dpi, dependent on the strain and age of the calves. A more severe thrombocytopenia was seen in those animals inoculated with strain 1362727. Leukocyte and nasal swab samples were positive by virus isolation, as early as 3 dpi and 2 dpi respectively, independent of the inocula used. All calves seroconverted with high levels of BVDV-2 neutralizing antibodies. BVDV RNA was evident as late as 90 dpi and provides the first evidence of the presence of replicating virus long after recovery from BVDV-2 experimental infection. In summary, moderate disease can be induced after experimental infection of calves with a low titer of virulent BVDV-2, with leukopenia, thrombocytopenia, viremia, and virus shedding. These strains represent an attractive model to assess the protective efficacy of existing and new vaccines against BVDV-2.

Brugman V A, Hernandez-Triana L M, Medlock J M, Fooks A R, Carpenter S, Johnson N (2018)

The role of Culex pipiens L. (Diptera: Culicidae) in virus transmission in Europe

International Journal of Environmental Research and Public Health 15 (2), 389

Abstract

Over the past three decades, a range of mosquito-borne viruses that threaten public and veterinary health have emerged or re-emerged in Europe. Mosquito surveillance activities have highlighted the Culex pipiens species complex as being critical for the maintenance of a number of these viruses. This species complex contains morphologically similar forms that exhibit variation in phenotypes that can influence the probability of virus transmission. Critical amongst these is the choice of host on which to feed, with different forms showing different feeding preferences. This influences the ability of the mosquito to vector viruses and facilitate transmission of viruses to humans and domestic animals. Biases towards blood-feeding on avian or mammalian hosts have been demonstrated for different Cx. pipiens ecoforms and emerging evidence of hybrid populations across Europe adds another level of complexity to virus transmission. A range of molecular methods based on DNA have been developed to enable discrimination between morphologically indistinguishable forms, although this remains an active area of research. This review provides a comprehensive overview of developments in the understanding of the ecology, behaviour and genetics of Cx. pipiens in Europe, and how this influences arbovirus transmission.

Barber J, Harrup L E, Silk R, Veronesi E, Gubbins S, Bachanek-Bankowska K, Carpenter S (2018)

Blood-feeding, susceptibility to infection with Schmallenberg virus and phylogenetics of Culicoides (Diptera: Ceratopogonidae) from the United Kingdom

Parasites and Vectors 11 (1), 116

Abstract

Culicoides biting midges (Diptera: Ceratopogonidae) are responsible for the biological transmission of internationally important arboviruses of livestock. In 2011, a novel Orthobunyavirus was discovered in northern Europe causing congenital malformations and abortions in ruminants. From field studies, Culicoides were implicated in the transmission of this virus which was subsequently named Schmallenberg virus (SBV), but to date no assessment of susceptibility to infection of field populations under standardised laboratory conditions has been carried out. We assessed the influence of membrane type (chick skin, collagen, Parafilm M®) when offered in conjunction with an artificial blood-feeding system (Hemotek, UK) on field-collected Culicoides blood-feeding rates. Susceptibility to infection with SBV following blood-feeding on an SBV-blood suspension provided via either (i) the Hemotek system or via (ii) a saturated cotton wool pledglet was then compared. Schmallenberg virus susceptibility was defined by RT-qPCR of RNA extractions of head homogenates and related to Culicoides species and haplotype identifications based on the DNA barcode region of the mitochondrial cytochrome c oxidase 1 (cox1) gene. Culicoides blood-feeding rates were low across all membrane types tested (7.5% chick skin, 0.0% for collagen, 4.4% Parafilm M®, with 6029 female Culicoides being offered a blood meal in total). Susceptibility to infection with SBV through membrane blood-feeding (8 of 109 individuals tested) and pledglet blood-feeding (1 of 94 individuals tested) was demonstrated for the Obsoletus complex, with both C. obsoletus (Meigen) and C. scoticus Downes & Kettle susceptible to infection with SBV through oral feeding. Potential evidence of cryptic species within UK populations was found for the Obsoletus complex in phylogenetic analyses of cox1 DNA barcodes of 74 individuals assessed from a single field-site. Methods described in this study provide the means to blood-feed Palaearctic Culicoides for vector competence studies and colonisation attempts. Susceptibility to SBV infection was 7.3% for membrane-fed members of the subgenus Avaritia and 1.1% for pledglet-fed. Both C. obsoletus and C. scoticus were confirmed as being susceptible to infection with SBV, with potential evidence of cryptic species within UK Obsoletus complex specimens, however the implications of cryptic diversity in the Obsoletus complex on arbovirus transmission remains unknown.

Charleston B, Graham S P (2018)

Recent advances in veterinary applications of structural vaccinology

Current Opinion in Virology 29, 33-38

Abstract

The deployment of effective veterinary vaccines has had a major impact on improving food security and consequently human health. Effective vaccines were essential for the global eradication of Rinderpest and the control and eradication of foot-and-mouth disease in some regions of the world. Effective vaccines also underpin the development of modern intensive food production systems such as poultry and aquaculture. However, for some high consequence diseases there are still significant challenges to develop effective vaccines. There is a strong track record in veterinary medicine of early adoption of new technologies to produce vaccines. Here we provide examples of new technologies to interrogate B cell responses and using structural biology to improve antigens.

Flannery J, Rajko-Nenow P, Hicks H, Hill H, Gubbins S, Batten C (2018)

Evaluating the most appropriate pooling ratio for EDTA blood samples to detect bluetongue virus using real-time RT-PCR

Veterinary Microbiology 217, 58-63

Abstract

The control of Bluetongue virus (BTV) presents a significant challenge to European Union (EU) member states as trade restrictions are placed on animals imported from BTV-affected countries. BTV surveillance programs are costly to maintain, thus, pooling of EDTA blood samples is used to reduce costs and increase throughput. We investigated different pooling ratios (1:2, 1:5, 1:10 and 1:20) for EDTA blood samples to detect a single BTV positive animal. A published real-time RT-PCR assay (Hofmann et al., 2008) and a commercial assay (ThermoFisher VetMax™ BTV NS3 kit) were used to analyse BTV RNA extracted from pooled EDTA blood samples. The detection rate was low for the onset of infection sample (0 to 2 days post infection (dpi); CT 36) irrespective of the pooling ratio. Both assays could reliably detect a single BTV-positive animal at early viraemia (3 to 6 dpi; CT 33) when pooled, however, detection rate diminished with increasing pooling ratio. A statistical model indicated that pooling samples up to 1:20, is suitable to detect a single BTV positive animal at peak viraemia (7-12 dpi) or late infection (13-30 dpi) with a probability of detection of >80% and >94% using the Hofmann et al. (2008) and VetMAX assays, respectively. Using the assays highlighted in our study, pooling at ratios of 1:20 would be technically suitable in BTV-endemic countries for surveillance purposes. As peak viraemia occurs between 7 to 12 days post infection, a 1:10 pooling ratio is appropriate for post-import testing when animals are sampled within a similar time frame post-import.

Singleton H, Graham S P, Frossard J-P, Bodman-Smith K B, Steinbach F (2018)

Infection of monocytes with European porcine reproductive and respiratory syndrome virus (PRRSV-1) strain Lena is significantly enhanced by dexamethasone and IL-10

Virology 517, 199-207

Abstract

Monocytes are considered refractory to porcine reproductive and respiratory syndrome virus type 1 (PRRSV-1) infection. However, monocytes are only short-lived in blood, being able to differentiate into macrophages and dendritic cells (DC). It was therefore merited to revisit PRRSV-1 interaction with monocytes, particularly those treated with cytokines influencing monocyte biology. Thus, several factors were screened, particularly those modulating monocyte differentiation and expression of putative PRRSV-1 receptors (CD169 and CD163). M-CSF, known to stimulate macrophage differentiation, did not increase their susceptibility to PRRSV-1. Nor did GM-CSF or IL-4, known drivers for monocyte-derived DC (MoDC) differentiation. In contrast, monocyte treatment with IL-10 or the corticosteroid, dexamethasone, known to be potent suppressors of monocyte differentiation, was correlated with increased susceptibility to PRRSV-1 infection. While this effect was strongly correlated to CD163 and CD169 expression, our data suggest that receptor expression is not the only factor driving successful infection of PPRSV-1 in monocytes.

Pridans C, Sauter K A, Irvine K M, Davis G M, Lefevre L, Raper A, Rojo R, Nirmal A J, Beard P, Cheeseman M, Hume D A (2018)

Macrophage colony stimulating factor increases hepatic macrophage content, liver growth and lipid accumulation in neonatal rats

American Journal of Physiology-Gastrointestinal and Liver Physiology 14 (3), G388-G398

Abstract

Signaling via the colony stimulating factor 1 receptor (CSF1R) controls the survival, differentiation and proliferation of macrophages. Mutations in CSF1, or CSF1R in mice and rats have pleiotropic effects on postnatal somatic growth. We tested the possible application of CSF1-Fc as a therapy for low birth weight (LBW) at term, using a model based upon maternal dexamethasone treatment in rats. Neonatal CSF1-Fc treatment did not alter somatic growth, and did not increase the blood monocyte count. Instead, there was a substantial increase in the size of liver in both control and LBW rats, and the treatment greatly exacerbated the lipid droplet accumulation seen in the dexamethasone LBW model. These effects were reversed upon cessation of treatment. Transcriptional profiling of the livers supported histochemical evidence of a large increase in macrophages with a resident Kupffer cell phenotype, and revealed increased expression of many genes implicated in lipid droplet formation. There was no further increase in hepatocyte proliferation over the already high rates in neonatal liver. Conclusion: Treatment of neonatal rats with CSF1-Fc caused an increase in liver size and hepatic lipid accumulation, due to Kupffer cell expansion and/or activation rather than hepatocyte proliferation. Increased liver macrophage numbers and expression of endocytic receptors could mitigate defective clearance functions in neonates.

Baron M D, Iqbal M, Nair V (2018)

Recent advances in viral vectors in veterinary vaccinology

Current Opinion in Virology 29, 1-7

Abstract

Viral vectored vaccines, particularly using vectors such as adenovirus, herpesvirus and poxviruses, are used widely in veterinary medicine, where this technology has been adopted much more quickly than in human medicine. There are now a large number of programmes to develop viral vector vaccine platforms for humans and very similar or identical vectors are being developed for veterinary medicine. The shared experiences of developing these new vaccine platforms across the two disciplines is accelerating progress, a striking example of the value of a 'One Health' approach. In particular, there is growing use of adenoviruses, either replicating or replicationincompetent, to create new vaccines for use in livestock or companion animals. Live replicating avian herpesvirus vectors are increasingly used as vaccines against poultry diseases.

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