Veterinary Laboratories Agency Research Articles

Updated risk of H5N1 HPAI incursion to poultry in Great Britain via wild birds

Avian influenza (AI) is a highly contagious viral infection, which can affect all species of birds. Highly pathogenic avian influenza (HPAI) viruses can spread rapidly, causing serious disease with high...

Intestinal spirochaetes (Brachyspira species) in pheasants in Great Britain

AVIAN intestinal spirochaetosis (AIS) is characterised by colonisation of the caecum of birds with spirochaetes of the genus Brachyspira (formerly Serpulina ). In chickens the effects of colonisation vary from...

Liver copper concentrations in cull cattle in the UK: are cattle being copper loaded?

With the release of the Department for the Environment, Food and Rural Affairs/Advisory Committee on Animal Feed Guidance Note for Supplementing Copper to Bovines it was noted that the current...

First confirmation of Pseudogymnoascus destructans in British bats and hibernacula

White-nose syndrome (WNS) is a fatal fungal infection of bats in North America caused by Pseudogymnoascus destructans. P. destructans has been confirmed in Continental Europe but not associated with mass...

Monoclonal and polyclonal antibodies for ante- and post-mortem detection of PrPSc in sheep

Scrapie is a disease that affects sheep and goats and is characterized by the accumulation of an abnormal isoform (PrPSc) of the cellular prion protein, PrPC, in the central nervous system (CNS) and in lymphoid tissues. Detection of PrPSc in these tissues can be attempted by a variety of techniques, including immunohistochemistry (IHC) and western blotting (WB), for which a wide range of monoclonal and polyclonal antibodies are commercially available. The objective of this study was to test and compare the efficacy of monoclonal antibodiesF89/160.1.5, F99/97.6.1, and P4 and polyclonal antibodies M52 and R486 in the detection of PrPSc in lymphoid and CNS tissue samples by using IHC. Positive and negative control samples of sheep brain and tonsils were provided by the Animal Health and Veterinary Laboratories Agency (AHVLA, UK). The IHC examination of CNS samples with both monoclonal and polyclonal antibodies confirmed the granular deposition of PrPSc in the neurons of the positive control tissues. However, while the monoclonal antibodies did not produce positive reactions in the negative controls, the polyclonal antibodies showed some non-specific staining. The testing of positive control tonsil samples with polyclonal and monoclonal antibodies identified positive control-specific reactions, whereas the negative control tissues were IHC-negative with all antibodies, although P4 and the polyclonal antibodies produced some background staining. In summary, although the polyclonal antibodies may be more accessible, their use is not advisable because of possible false positive reactions. The polyclonal antibody M52 was able to identify PrPC in brain and spleen samples by WB but other lymphoid tissues were negative.

Seropositivity to Toxoplasma infection in sheep samples submitted to Animal and Plant Health Agency laboratories between 2005 and 2012

Ovine serum samples submitted to Animal and Plant Health Agency (APHA) (formerly the Animal Health and Veterinary Laboratories Agency) – Weybridge regional laboratories in England and Wales for diagnostic and...

Analysis of whole genome sequencing for the Escherichia coli O157:H7 typing phages.

BackgroundShiga toxin producing Escherichia coli O157 can cause severe bloody diarrhea and haemolytic uraemic syndrome. Phage typing of E. coli O157 facilitates public health surveillance and outbreak investigations, certain phage types are more likely to occupy specific niches and are associated with specific age groups and disease severity. The aim of this study was to analyse the genome sequences of 16 (fourteen T4 and two T7) E. coli O157 typing phages and to determine the genes responsible for the subtle differences in phage type profiles.ResultsThe typing phages were sequenced using paired-end Illumina sequencing at The Genome Analysis Centre and the Animal Health and Veterinary Laboratories Agency and bioinformatics programs including Velvet, Brig and Easyfig were used to analyse them. A two-way Euclidian cluster analysis highlighted the associations between groups of phage types and typing phages. The analysis showed that the T7 typing phages (9 and 10) differed by only three genes and that the T4 typing phages formed three distinct groups of similar genomic sequences: Group 1 (1, 8, 11, 12 and 15, 16), Group 2 (3, 6, 7 and 13) and Group 3 (2, 4, 5 and 14). The E. coli O157 phage typing scheme exhibited a significantly modular network linked to the genetic similarity of each group showing that these groups are specialised to infect a subset of phage types.ConclusionSequencing the typing phage has enabled us to identify the variable genes within each group and to determine how this corresponds to changes in phage type.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1470-z) contains supplementary material, which is available to authorized users.

Idiopathic necrotising enteritis cases continue

Cases of idiopathic necrotising enteritis in calves continuePolioencephalitis of unknown cause in lambsRare types of deformities seen in pigletsColibacillosis in postweaned pigsRotavirus in gamebirdsThese are among matters discussed in the...

Changes in antimicrobial susceptibility of Mycoplasma bovis isolates from Great Britain

The UK has approximately 10 million cattle (Veterinary Medicines Directorate 2011), and each year approximately 1.9 million of these cattle are affected by respiratory disease. A disease that is often...

Unusual cases of blackleg in cattle

Lesions in the heart seen in unusual cases of blackleg in cattleLead poisoning diagnosed in housed suckler cowsMycotic abortion in pigsOedema disease outbreak in weaners with meningitis-like signsSeabird die-off thought...

Bovine abortions caused by Helcococcus ovis

■ Helcococcus ovis as a potential novel cause of bovine abortion■ Mannheimia haemolytica pneumonia in lambs■ Glässer's disease in growing pigs■ Fibroma in an alpaca■ Pullorum disease in backyard flocksThese...

Unusual presentation of S Dublin infection in a calf

Spinal osteomyelitis caused by Salmonella Dublin infection in a calfNecrotising pleuropneumonia due to Mycoplasma bovis in adult cowsCopper toxicosis in sheepPorcine sapelovirus causing nervous diseaseAvian tuberculosis in a backyard flockThese...

Acorn poisoning in cattle and sheep

Multiple cases of acorn poisoning in cattle and sheep following bumper cropSalmonella Dublin infection causes abortions in cattleRespiratory disease affecting different age groups of pigs on a nursery finisher unitPorcine...

Review of laboratory submissions from New World camelids in England and Wales (2000–2011)

Sample submissions to the Animal Health and Veterinary Laboratories Agency’s (AHVLA’s) diagnostic laboratory network in England and Wales were reviewed for diseases affecting New World camelids (NWCs). In the years 2000–2011, 6757 submissions were analysed, including 5154/6757 (76.3%) for diagnosing a disease problem and 1603/6757 (23.7%) for monitoring (no clinical disease). Wasting (weight loss, ill-thrift) was the most commonly reported clinical sign across all age groups. A diagnosis was reached for 1765/5154 (34.2%) diagnostic submissions. The proportion of submissions with diagnoses was higher for carcasses than non-carcass samples and multiple diagnoses were more likely to be reached from carcasses. Parasitic diseases were collectively the most common problem, including parasitic gastroenteritis (319/1765, 18.2%), coccidiosis (187/1765, 10.6%), fascioliasis (151/1765, 8.6%), ectoparasitic infestations (86/1765, 4.9%) and cryptosporidiosis (24/1765, 1.4%). The most frequently diagnosed non-parasitic problems included nutritional diseases (182/1765, 10.3%), septicaemia (104/1765, 5.9%, including 45 cases of colisepticaemia), gastric ulceration (79/1765, 4.5%), tumours/neoplastic diseases (65/1765, 3.7%), tuberculosis (57/1765, 3.2%), clostridial diseases (44/1765, 2.5%), congenital anomalies (41/1765, 2.3%), peritonitis (39/1765, 2.2%) and Johne’s disease (20/1765, 1.1%).

Widespread reporting of parasitic gastroenteritis in sheep

Parasitic gastroenteritis in sheepSalmonella Dublin in cattleSwine influenza outbreaks in pigsSuspected ionophore toxicity in turkeysCorvid respiratory death in more than 30 birdsThese are among matters discussed in the Animal Health...

Thyroxine concentrations in ruminant health monitoring and diagnostic blood samples

Levels of T4 and tri-iodothyronine (T3), the activated hormone, correspond to thyroid function, but are also affected by changes in environment and physiological status (Suttle 2010). This paper reports serum...

Schmallenberg cases continue to be found in cattle

Schmallenberg virus found on many farms and diagnosis by PCR not always acheived Intestinal torsion on an outdoor pig unit Outbreaks of Glässers disease in the early postweaning period Tuberculosis outbreak in sheep Live bat found in a timberyard in a container from USA These are among matters discussed in the Animal Health and Veterinary Laboratories Agency's (AHVLA's) disease surveillance report for April

An observational study involving ewe postmortem examination at a fallen stock collection centre to inform flock health interventions

Effective sheep flock health plans must be underpinned by flock-specific diagnostic information and should make use of wider national flock health information. However, information on disease prevalence at flock level is often incomplete. This is despite the fact that protocols to diagnose common sheep diseases are well established and cost effective. Annual ewe mortality rates in the UK are estimated at 3–8 per cent (Johnston and others 1980, Scott 2007). The profile of diseases which contribute to mortality and involuntary culling in adult ewes in the UK flock is at present probably best estimated using Veterinary Investigation Diagnosis Analysis (VIDA) data (Gibbens and others 2008). This is generated by the Animal Health Veterinary Laboratories Agency (AHVLA) endemic disease scanning surveillance programme, which examines 500–700 ewes annually (VIDA 2012). However, the sample size, especially for carcases, is small, and the programme may have inherent biases (Nevel and Stark 2009) with under-representation of some important endemic diseases. By law, all fallen stock from UK farms must be collected for appropriate disposal by a licensed collector. This study aimed to investigate the diagnostic potential of this material, with an emphasis on adult ewes, and to consider how such information might be applied to improve sheep health, welfare and productivity. Between February 2012 and January 2013, a total of 106 adult ewes, collected from farms throughout the northeast of England, were examined postmortem during 11 sessions at a fallen stock collection centre. All postmortem examinations were performed by two experienced veterinary surgeons including at least one of the authors, whose competence in postmortem examination was gained during six years at …

Influences of farmer and veterinarian behaviour on emerging disease surveillance in England and Wales

Surveillance for new and re-emerging animal diseases in England and Wales is based on post-mortem and syndromic analysis of laboratory data collated in a central database by the Animal Health and Veterinary Laboratories Agency (AHVLA), with the aim of providing early warning of disease events prior to clinical diagnosis. Understanding the drivers for participation in such systems is critical to the success of attempts to improve surveillance sensitivity. The aim of this study was to investigate the decision-making process governing the submission of biological samples on which this surveillance system is based by use of questionnaires. Data extracted were used to structure and parameterize scenario trees modelling the probability of generating an entry in the surveillance database. The mean probability for database entry per case ranged from 0.085 for neurological disorders to 0.25 for enteric disease. These findings illustrate the importance of on-farm decision making to the generation of surveillance data.

Factors associated with bovine tuberculosis confirmation rates in suspect lesions found in cattle at routine slaughter in Great Britain, 2003–2008

Bovine tuberculosis (bTB) is one of the most complex and intractable animal health problems facing the British cattle industry today. The inspection of carcasses from cattle sent to slaughter is part of routine surveillance for bTB in Great Britain (GB). Tissue with suspect lesions from cattle from herds previously considered uninfected with bTB is sent to the Animal Health and Veterinary Laboratories Agency (AHVLA) for culture and histopathological examination for Mycobacterium bovis infection. In this study, risk factors for confirmation of infection in suspect bTB lesions found at routine slaughter of cattle from officially bTB-free (OTF) herds in GB were investigated. The study sample included the first record of a suspect lesion in a bovine from any OTF herd identified during post-mortem inspection between 2003 and 2008. There were 3663 submissions from 151 slaughterhouses of which 2470 (67.4%) were confirmed as culture positive for M. bovis. Logistic regression analysis with a random intercept for slaughterhouse was used to investigate relationships between bTB confirmation and animal and herd-level risk factors. Slaughterhouse of post mortem and the following factors related to bTB prevalence were significant predictors of confirmation probability: region of farm of origin of the animal, the testing interval for routine field surveillance for bTB on the farm, number of reactors in the last bTB incident on the farm within the last 4 years, if applicable, the animal's date of birth and the year of animal's slaughter. The modelled predicted population averaged probabilities for confirmation varied from 0.14 to 0.90 between slaughterhouses. Differences in the detection of cattle with bTB between British slaughterhouses warrant further study.