Quantifying the spatial risk of Avian Influenza introduction into British poultry by wild birds.

The transmission of pathogens across the interface between wildlife and livestock presents a challenge to the development of effective surveillance and control measures. Wild birds, especially waterbirds such as the Anseriformes and Charadriiformes are considered to be the natural hosts of Avian Influenza (AI), and are presumed to pose one of the most likely vectors for incursion of AI into European poultry flocks. We have developed a generic quantitative risk map, derived from the classical epidemiological risk equation, to describe the relative, spatial risk of disease incursion into poultry flocks via wild birds. We then assessed the risk for AI incursion into British flocks. The risk map suggests that the majority of AI incursion risk is highly clustered within certain areas of Britain, including in the east, the south west and the coastal north-west of England. The clustering of high risk areas concentrates total risk in a relatively small land area; the top 33% of cells contribute over 80% of total incursion risk. This suggests that targeted risk-based sampling in a relatively small geographical area could be a much more effective and cost-efficient approach than representative sampling. The generic nature of the risk map method, allows rapid updating and application to other diseases transmissible between wild birds and poultry.

Spindle Cell Tumor in a Brown Long-eared Bat (Plecotus auritus).

Most reports of neoplasia in bats are in captive Egyptian fruit bats (Rousettus aegyptiacus), a megachiropteran species. Only three reports of neoplasia in microchiropteran species have been reported. We report the detection of a tumor in a wild brown long-eared bat (Plecotus auritus), a microchiropteran species, in England. Histolopathology indicated the mass was a spindle cell tumor, likely of smooth muscle origin, which was confirmed by immunohistochemistry.

Syndromic surveillance by veterinary practitioners: a pilot study in the pig sector.

Traditional indicator-based livestock surveillance has been focused on case definitions, definitive diagnoses and laboratory confirmation. The use of syndromic disease surveillance would increase the population base from which animal health data are captured and facilitate earlier detection of new and re-emerging threats to animal health. Veterinary practitioners could potentially play a vital role in such activities. In a pilot study, specialist private veterinary practitioners (PVP) working in the English pig industry were asked to collect and transfer background data and disease incident reports for pig farms visited during the study period. Baseline data from 110 pig farms were received, along with 68 disease incident reports. Reports took an average of approximately 25 minutes to complete. Feedback from the PVPs indicated that they saw value in syndromic surveillance. Maintenance of anonymity in the outputs would be essential, as would timely access for the PVPs to relevant information on syndromic trends. Further guidance and standardisation would also be required. Syndromic surveillance by PVPs is possible for the pig industry. It has potential to fill current gaps in the collection of animal health data, as long as the engagement and participation of data providers can be obtained and maintained.

Surveillance and investigative diagnosis of a poultry flock in Great Britain co-infected with an influenza A virus and an avirulent avian avulavirus type 1.

A detailed veterinary and laboratory investigation revealed an unusual case of concurrent avian avulavirus type 1 (AAvV-1, formerly called avian paramyxovirus type 1) and low pathogenicity avian influenza (LPAI) virus infections of chickens during March 2010 in a mixed poultry and livestock farm in Great Britain. Respiratory signs and daily mortality of 5-6 birds in a broiler flock 8-weeks of age prompted submission of two carcasses to an Animal and Plant Health Agency (APHA) regional laboratory. Infectious bronchitis virus infection was suspected initially and virus isolation in SPF embryonated fowls' eggs was attempted at APHA-Weybridge. Avirulent AAvV-1 was detected in the first sampling. Both in vitro nucleotide sequencing of the fusion gene and in vivo pathotyping by intracerebral pathogenicity index revealed an avirulent AAvV-1 not definitively ascribed to licensed vaccine. Upon initial detection of the AAvV-1 virus, statutory restrictions were placed on the farm, an official veterinary visit was performed and further samples were submitted to APHA-Weybridge for official statutory disease investigation. An H2N3 LPAI virus was subsequently isolated from tissue samples and swabs submitted from the follow-up statutory investigation. The subtype was confirmed by haemagglutination inhibition test (HAIT) and neuraminidase inhibition (NI) tests on egg-amplified virus. As neither virus was notifiable according to the internationally recognized EU and OIE standards, and/or definitions of disease, statutory farm restrictions were lifted. Veterinary investigations identified the broiler flock to be free-range, next to a river and duck pen, reinforcing the suspicion of wild bird origin for both viruses which may have been co-circulating in ducks. It could not, however, be established as to whether there were separate introductions of the two viruses or whether there had been a single co-introduction of the viruses. The described case highlights the value of integrated surveillance and laboratory approaches, including veterinary field investigations, international standards and definitions of notifiable avian disease, validated RRT-PCR assays, and virus isolation in achieving rapid and accurate diagnostic results.

Corrigendum: Genome Reduction for Niche Association in Campylobacter Hepaticus, A Cause of Spotty Liver Disease in Poultry.

[This corrects the article on p. 354 in vol. 7, PMID: 28848714.].

Genome Reduction for Niche Association in Campylobacter Hepaticus, A Cause of Spotty Liver Disease in Poultry.

The term "spotty liver disease" (SLD) has been used since the late 1990s for a condition seen in the UK and Australia that primarily affects free range laying hens around peak lay, causing acute mortality and a fall in egg production. A novel thermophilic SLD-associated Campylobacter was reported in the United Kingdom (UK) in 2015. Subsequently, similar isolates occurring in Australia were formally described as a new species, Campylobacter hepaticus. We describe the comparative genomics of 10 C. hepaticus isolates recovered from 5 geographically distinct poultry holdings in the UK between 2010 and 2012. Hierarchical gene-by-gene analyses of the study isolates and representatives of 24 known Campylobacter species indicated that C. hepaticus is most closely related to the major pathogens Campylobacter jejuni and Campylobacter coli. We observed low levels of within-farm variation, even between isolates collected over almost 3 years. With respect to C. hepaticus genome features, we noted that the study isolates had a ~140 Kb reduction in genome size, ~144 fewer genes, and a lower GC content compared to C. jejuni. The most notable reduction was in the subsystem containing genes for iron acquisition and metabolism, supported by reduced growth of C. hepaticus in an iron depletion assay. Genome reduction is common among many pathogens and in C. hepaticus has likely been driven at least in part by specialization following the occupation of a new niche, the chicken liver.

The Detection of a Low Pathogenicity Avian Influenza Virus Subtype H9 Infection in a Turkey Breeder Flock in the United Kingdom.

In April 2013, an H9N2 low pathogenicity avian influenza (LPAI) virus was isolated in a turkey breeder farm in Eastern England comprising 4966 birds. Point-of-lay turkey breeding birds had been moved from a rearing site and within 5 days had shown rapid onset of clinical signs of dullness, coughing, and anorexia. Three houses were involved, two contained a total of 4727 turkey hens, and the third housed 239 male turkeys. Around 50% of the hens were affected, whereas the male turkeys demonstrated milder clinical signs. Bird morbidity rose from 10% to 90%, with an increase in mortality in both houses of turkey hens to 17 dead birds in one house and 27 birds in the second house by day 6. The birds were treated with an antibiotic but were not responsive. Postmortem investigation revealed air sacculitis but no infraorbital sinus swellings or sinusitis. Standard samples were collected, and influenza A was detected. H9 virus infection was confirmed in all three houses by detection and subtyping of hemagglutinating agents in embryonated specific-pathogen-free fowls' eggs, which were shown to be viruses of H9N2 subtype using neuraminidase inhibition tests and a suite of real-time reverse transcription PCR assays. LPAI virus pathotype was suggested by cleavage site sequencing, and an intravenous pathogenicity index of 0.00 confirmed that the virus was of low pathogenicity. Therefore, no official disease control measures were required, and despite the high morbidity, birds recovered and were kept in production. Neuraminidase sequence analysis revealed a deletion of 78 nucleotides in the stalk region, suggesting an adaptation of the virus to poultry. Hemagglutinin gene sequences of two of the isolates clustered with a group of H9 viruses containing other contemporary European H9 strains in the Y439/Korean-like group. The closest matches to the two isolates were A/turkey/Netherlands/11015452/11 (H9N2; 97.9-98% nucleotide identity) and A/mallard/Finland/Li13384/10 (H9N2; 97% nucleotide identity). Both PB2 partial sequences were a 100% nucleotide identity with A/mallard/France/090360/09, indicating a European origin of the causative virus. Furthermore, partial sequencing analysis of the remaining genes revealed the virus to be genotypically of European avian origin and therefore of lower risk to public health compared with contemporary viruses in Central and Eastern Asia. Occupational health risks were assessed, and preventative measures were taken.

Drowning is an apparent and unexpected recurrent cause of mass mortality of Common starlings (Sturnus vulgaris).

Drowning is infrequently reported as a cause of death of wild birds and such incidents typically involve individual, rather than multiple, birds. Over a 21-year period (1993 to 2013 inclusive), we investigated 12 incidents of mortality of multiple (2 - 80+) Common starlings (Sturnus vulgaris) in Great Britain that appeared to be due to drowning. More than ten birds were affected in ten of these reported incidents. These incidents always occurred during the spring and early summer months and usually involved juvenile birds. In all cases, circumstantial evidence and post-mortem examinations indicated drowning to be the most likely cause of death with no underlying disease found. A behavioural explanation seems likely, possibly related to the gregarious nature of this species combined with juvenile inexperience in identifying water hazards. A review of data from the ringed bird recovery scheme across Great Britain (1909-2013 inclusive) of both starlings and Common blackbirds (Turdus merula), also a common garden visitor, identified additional suspected drowning incidents, which were significantly more common in the former species, supporting a species predisposition to drowning. For each species there was a marked seasonal peak from April to August. Drowning should be included as a differential diagnosis when investigating incidents of multiple starling mortality, especially of juveniles.

Isolation of a novel thermophilic Campylobacter from cases of spotty liver disease in laying hens and experimental reproduction of infection and microscopic pathology.

The condition known as spotty liver disease or spotty liver syndrome can cause significant mortality in free range laying hen flocks. It has been described in Europe and Australia but the aetiology has not been established. There are similarities between spotty liver disease and avian vibrionic hepatitis, a condition which was reported in the 1950s. A Vibrio-like organism was suspected to be the cause of avian vibrionic hepatitis, although this organism was never fully characterised. We report the isolation of a novel Campylobacter from five separate outbreaks of spotty liver disease. The conditions required for culture, the growth characteristics, electron microscopical morphology and results of the phenotypic tests used in the identification of this novel Campylobacter sp. are described. The novel Campylobacter is slow growing and fastidious and does not grow on media routinely used for isolating Campylobacter sp. The morphology is typical for a Campylobacter sp. and phenotypic tests and a duplex real time PCR test differentiate the novel Campylobacter from other members of the genus. 16S rRNA analysis of 19 isolates showed an identical sequence which appears to represent a hitherto unknown sub lineage within the genus Campylobacter. Experimental intraperitoneal infection of four week old SPF chickens produced microscopic liver pathology indistinguishable from natural disease and the novel Campylobacter was recovered from the experimentally infected chicks. The isolates described appear to be a possible causal organism for spotty liver disease.

Mortality associated with avian reovirus infection in a free-living magpie (Pica pica) in Great Britain.

BACKGROUND: Avian reoviruses (ARVs) cause a range of disease presentations in domestic, captive and free-living bird species. ARVs have been reported as a cause of significant disease and mortality in free-living corvid species in North America and continental Europe. Until this report, there have been no confirmed cases of ARV-associated disease in British wild birds. CASE PRESENTATION: Sporadic individual magpie (Pica pica) mortality was detected at a single site in Buckinghamshire, England, April-September 2013. An adult female magpie was found moribund and subsequently died. Post-mortem examination identified hepatomegaly and splenomegaly as the most severe macroscopic abnormalities. Histopathological examination revealed extensive hepatic and splenic necrosis. Transmission electron microscopy (TEM) identified virions of a size (circa 78 nm diameter) and morphology consistent with ARV in both the liver and the small intestinal (SI) contents. Nucleic acid extracted from pooled liver and spleen was positive on both a pan-reovirus nested PCR targeting the RNA-dependent RNA polymerase gene and a PCR using primers specific to the ARV sigma C protein gene. Virus isolated from the liver and the SI contents was characterised by a syncytial-type cytopathic effect, a reovirus-like appearance on TEM and sequence identical to that from PCR of tissues. In situ hybridisation confirmed co-localisation of ARV with lesions in the liver and spleen, implicating ARV as the causative agent. Splenic lymphoid atrophy and necrotic stomatitis associated with Aspergillus fumigatus infection were consistent with generalised immunosuppression and resultant opportunistic infection. CONCLUSIONS: The pathology and comprehensive virus investigations in this case indicate ARV as the primary pathogen in this magpie, with concurrent secondary infection subsequent to immunosuppression, as has been observed with reoviral infections in other bird species. ARV should be considered as a differential diagnosis for magpie, and potentially other corvid, disease and mortality incidents. This is the first demonstration of ARV-associated mortality in a wild bird in Britain. The prevalence and significance of ARV infection in British wild birds, and its implications for poultry and captive bird health, are currently unknown.

Evaluation of two different swab transport systems in the detection of avian influenza virus excretion from infected Pekin ducks (Anas platyrhynchos).

The role of wild birds in the epidemiology and ecology of influenza A viruses has long been recognised (Alexander, 2007a). As a result of the emergence of a H5N1 highly pathogenic avian influenza (HPAI) virus and the apparent role of wild birds in its spread across Asia, Europe and Africa, avian influenza (AI) wild bird surveillance has been implemented in many countries including, since February 2006, a mandatory programme in the European Union (CEC, 2006a). In the present study the detection of virus excreted from Pekin ducks (Anas platyrhynchos) infected experimentally with A/mallard/England/2126/07 (H3N6) was investigated over a fourteen day period post-infection using cloacal and oropharyngeal swabs, with (wet) and without (dry) viral transport medium which were collected from each duck in alternating order. For influenza A virus matrix gene RNA detection, wet oropharyngeal swabs were significantly more sensitive than dry oropharyngeal on days 4-5 after infection. For cloacal samples, dry swabs were equivalent or superior to wet swabs throughout the study. Although differences in detection between dry and wet swabs were observed, the qualitative bird-level results were unaffected, meaning that the infection status of individual birds was correctly determined.

An evaluation of wild bird avian influenza surveillance in Great Britain.

This study presents a method for evaluation of surveillance for avian influenza (AI) in wild birds and compares surveillance activities before and after changes in surveillance strategy in Great Britain (GB). In October 2008 the AI Wild Bird Surveillance (AIWBS) system in GB was modified to focus on passive surveillance (birds found dead), including those found during warden patrols of wetlands and wildlife reserves, with less emphasis on public reporting of birds found dead. The number of birds sampled by active surveillance (birds live-trapped or shot) was also reduced. In the present study the impact of these changes was investigated by comparing the 12 mo prior to October 2008 with the subsequent 12 mo. Four factors were considered for each surveillance system component: 1) the number of wild birds tested; 2) whether the tested wild birds were considered "higher risk species" (HRS) for being infected with AI; 3) the location of the birds tested with respect to counties designated as a priority for surveillance; and 4) the probability that the birds tested might yield a positive AI virus result based on surveillance results in wild birds across Europe. The number of birds tested by both surveillance types was greatly reduced after the strategy change. The proportion of birds sampled in priority counties also significantly decreased in the second year for both active and passive surveillance. However, the proportion of HRS sampled by active surveillance significantly increased, while a significant decrease in these species was seen for passive surveillance in the second year. The derived probability scores for detecting AI based on European surveillance results indicated a reduction in sensitivity for H5N1 highly pathogenic AI detection by passive surveillance. The methods developed to evaluate AIWBS in GB may be applicable to other European Union countries. The results also reflect the complex issues associated with evaluation of disease surveillance in wildlife populations in which the disease ecology is only partially understood.

First reported detection of influenza A (H1N1)pdm09 in turkeys in the United Kingdom.

We report the first occurrence of pandemic (H1N1) 2009 virus [A(H1N1)pdm09] infection on two epidemiologically linked turkey breeder premises in the United Kingdom during December 2010 and January 2011. Clinically, the birds showed only mild signs of disease, with the major presenting sign being an acute and marked reduction in egg production, leading to the prompt reporting of suspected avian notifiable disease for official investigation. Presence of A(H1N1)pdm09 infection in the United Kingdom turkey breeder flocks was confirmed by detailed laboratory investigations including virus isolation in embryonated specific pathogen-free fowls' eggs, two validated real-time reverse transcription-PCR tests, and nucleotide sequencing of the hemagglutinin and neuraminidase genes. These investigations revealed high nucleotide identity with currently circulating human A(H1N1)pdm09 strains, suggesting that human-to-poultry transmission (reverse zoonosis) was the most likely route of infection. Peak levels of human influenza-like illness community transmission also coincided with the onset of clinical signs in both affected turkey breeder flocks. This case demonstrated the value of the existing passive surveillance framework and associated veterinary and laboratory infrastructure that enables the detection and management of both exotic and new and emerging disease hazards and risks. The case also presents further evidence of the susceptibility of turkeys to infection with influenza A viruses of nonavian origin.