FIVE YEARS OF PARTULA SNAIL PRE-EXPORT HEALTH SCREENING.

Between 2015 and 2019, a health screening was carried out annually on captive-bred Partula snails prior to export for reintroduction as part of an international effort to repopulate areas of French Polynesia, where the snails were extinct or critically endangered. In total, 129 separate tank populations of 12 different species were screened at ZSL London Zoo. Wet mounts and smears stained with modified Ziehl-Neelsen (MZN) of 535 fecal samples were examined, and 45% contained flagellated protozoa, and 35.5% had MZN-positive oocysts, measuring 3-5 µm in diameter. Smaller (2 µm) presumptive spores, MZN-positive bacilli, ciliated protozoa and nematodes were recorded less frequently. Fecal bacterial culture yielded mixed species, with a clear predominance of Myroides species (88.9% of samples). The MZN-positive oocysts (3-5 µm) were present in 6.5% of impression smears from the apices of 432 snails examined postmortem, plus acid-fast bacilli in a few cases, but no 2 µm spores. Mixed bacteria were cultured from coelomic swabs, with Myroides species again the most common (63.5%). Histologic examination was carried out on 292 snails. Autolysis affected almost 90% of those found dead but only 3.4% of euthanized snails. Histology commonly identified microsporidial sporocysts in the digestive gland and midgut epithelium of all but two species. Intracellular, extracytoplasmic Cryptosporidium-like organisms were also common in the midgut but were only observed when snails were fixed in 10% formalin (2017-2019), not ethanol. There were no clear pathologic changes associated with either organism. Pigmented hemocytic nodules were commonly observed, most frequently in the foot process; these were either age related or evidence of prior chronic inflammatory reaction and of low clinical significance. With no evidence of poor health and no significant organisms found, a total of 4,978 individuals representing 12 species were exported for reintroduction.

The first report of meningitis in a Greenland shark (Somniosus microcephalus).

The Greenland shark (Somniosus microcephalus) is a large species of shark found in the North Atlantic and Arctic Oceans and is believed to be the longest living vertebrate. Relatively little is known about its biology, abundance, health or diseases. In March 2022, only the third reported UK stranding of this species occurred and it was the first to undergo post-mortem examination. The animal was a sexually immature female, measuring 3.96 m in length and 285 kg in weight, and was in poor nutritional state. Gross findings included haemorrhages in the skin and soft tissues, particularly of the head, and silt in the stomach suggestive of live stranding, bilateral corneal opacity, slightly turbid cerebrospinal fluid (CSF) and patchy congestion of the brain. Histopathological findings included keratitis and anterior uveitis, fibrinonecrotic and lymphohistiocytic meningitis of the brain and proximal spinal cord and fibrinonecrotizing choroid plexitis. A near pure growth of a Vibrio organism was isolated from CSF. This is believed to be the first report of meningitis in this species.

The genomic epidemiology of Escherichia albertii infecting humans and birds in Great Britain.

Escherichia albertii is a recently identified gastrointestinal bacterial pathogen of humans and animals which is typically misidentified as pathotypes of diarrhoeagenic Escherichia coli or Shigella species and is generally only detected during genomic surveillance of other Enterobacteriaceae. The incidence of E. albertii is likely underestimated, and its epidemiology and clinical relevance are poorly characterised. Here, we whole genome sequenced E. albertii isolates from humans (n = 83) and birds (n = 79) isolated in Great Britain between 2000 and 2021 and analysed these alongside a broader public dataset (n = 475) to address these gaps. We found human and avian isolates typically (90%; 148/164) belonged to host-associated monophyletic groups with distinct virulence and antimicrobial resistance profiles. Overlaid patient epidemiological data suggested that human infection was likely related to travel and possibly foodborne transmission. The Shiga toxin encoding stx2f gene was associated with clinical disease (OR = 10.27, 95% CI = 2.98-35.45 p = 0.0002) in finches. Our results suggest that improved future surveillance will further elucidate disease ecology and public and animal health risks associated with E. albertii.

Combining host and vector data informs emergence and potential impact of an Usutu virus outbreak in UK wild birds.

Following the first detection in the United Kingdom of Usutu virus (USUV) in wild birds in 2020, we undertook a multidisciplinary investigation that combined screening host and vector populations with interrogation of national citizen science monitoring datasets to assess the potential for population impacts on avian hosts. Pathological findings from six USUV-positive wild passerines were non-specific, highlighting the need for molecular and immunohistochemical examinations to confirm infection. Mosquito surveillance at the index site identified USUV RNA in Culex pipiens s.l. following the outbreak. Although the Eurasian blackbird (Turdus merula) is most frequently impacted by USUV in Europe, national syndromic surveillance failed to detect any increase in occurrence of clinical signs consistent with USUV infection in this species. Furthermore, there was no increase in recoveries of dead blackbirds marked by the national ringing scheme. However, there was regional clustering of blackbird disease incident reports centred near the index site in 2020 and a contemporaneous marked reduction in the frequency with which blackbirds were recorded in gardens in this area, consistent with a hypothesis of disease-mediated population decline. Combining results from multidisciplinary schemes, as we have done, in real-time offers a model for the detection and impact assessment of future disease emergence events.

Systemic Erysipelothrix rhusiopathiae in seven free-ranging delphinids stranded in England and Wales.

Microbiology records for 1127 cetaceans stranded on English and Welsh beaches and examined at the Institute of Zoology between 1990 and 2019 were reviewed to identify cases of Erysipelothrix rhusiopathiae, an uncommon but potentially fatal zoonotic pathogen. Once cases were identified, prevalence was calculated, corresponding postmortem reports were reviewed, common gross and histopathological findings were identified, and antibiotic susceptibilities were determined. Overall prevalence for E. rhusiopathiae was 0.62% (7/1127; 95% CI: 0.30-1.28%). It was isolated from 3 bottlenose dolphins Tursiops truncatus, 3 harbor porpoises Phocoena phocoena, and 1 short-beaked common dolphin Delphinus delphis, with a prevalence of 21.4% (3/14; 95% CI: 7.6-47.9%), 0.39% (3/779; 95% CI: 0.13-1.13%), and 0.47% (1/212; 95% CI: 0.08-2.62%) for each species, respectively. E. rhusiopathiae resulted in septicemia in all cases from which it was isolated. Gross necropsy findings included pulmonary edema (5/7), hemorrhage (5/7) and/or congestion of various organs (4/7), and serosanguineous effusion (3/7; pericardial: 3/7, pleural: 2/6, abdominal: 2/6). Congestion (5/5), bacterial emboli (4/5), and hemorrhage (4/5) were commonly observed on histopathology, and acute renal tubular injury (2/5) and pulmonary edema (2/5) were occasionally observed. Routine bacterial cultures were vital in identifying E. rhusiopathiae, since gross lesions were often subtle and nonspecific. The liver, kidney, and brain were key organs from which E. rhusiopathiae was consistently isolated. Antibiotic resistance was uncommon and was only observed for amikacin and trimethoprim sulfonamide. Penicillins were consistently effective, along with fluoroquinolones, macrolides, clindamycin, cephalexin, and oxytetracycline.

Atypical Knemidokoptosis in Two Dunnocks (Prunella modularis) in Southern England.

Avian knemidokoptosis, caused by knemidokoptid mites (Knemidokoptinae: Epidermoptidae), has been reported in wild and domestic birds globally. We report two cases of severe knemidokoptosis in Dunnocks (Prunella modularis) from separate sites in Great Britain, where the disease has previously been reported predominantly in finches and, less frequently, in corvids.

Isolation and characterisation of Vibrio cholerae from fish examined postmortem at ZSL London Zoo between 2014 and 2018.

BACKGROUND: When suspect Vibrio cholerae were cultured from fish at ZSL London Zoo, investigations were carried out to determine whether they were possible causes of cholera. METHODS: Bacterial culture was carried out on fish examined postmortem and colonies were identified using standard techniques including the API 20NE biochemical test kits. Suspect isolates were submitted to the Public Health England laboratory for additional testing. Separately, a number of fish were submitted for routine histopathology. RESULTS: On 13 occasions between 2014 and 2018, suspected V cholerae were cultured from individuals of eight different freshwater fish species. Archived cultures for eight of these (from six different fish species) were investigated and seven isolates (from five fish species) were confirmed as V cholerae, but all were non-O1, non-O139 strains. Whole-genome sequencing showed that the five fish species had unique V cholerae multilocus sequence types (three isolates from Aphanius danfordii were identical), all of which were genetically distant from human isolates. CONCLUSIONS: There was no evidence that these isolates could cause cholera. Histopathological changes consistent with vibriosis were seen in several fish, suggesting that V cholerae were causing the disease, but there were also concurrent infections or predisposing stress factors.

YERSINIA PSEUDOTUBERCULOSIS INFECTIONS IN PRIMATES, ARTIODACTYLS, AND BIRDS WITHIN A ZOOLOGICAL FACILITY IN THE UNITED KINGDOM.

Infection with Yersinia pseudotuberculosis can be difficult to diagnose and treat successfully. Twenty-four cases from the Zoological Society of London (ZSL) London Zoo and ZSL Whipsnade Zoo were identified between 2001 and 2019. Husbandry, medical, and postmortem records for six primates, 10 artiodactyls, and eight birds were reviewed to identify common clinical signs and gross lesions. Most cases occurred during the winter; however, an outbreak in four primates occurred during the summer following a period of stress associated with increased ambient noise and activity. Common clinical signs included lethargy (6/6 primates, 4/10 artiodactyls, 4/8 birds) or death without premonitory signs (3/10 artiodactyls, 4/8 birds). Once clinical signs were observed, disease progressed quickly. Poor condition was common in mammals (6/6 primates, 9/10 artiodactyls), but often went undetected until postmortem examination. Neurological signs occurred in three of six primates. Diarrhea and anorexia were uncommon in all animals. Hepatitis was observed in all groups (4/6 primates, 2/10 artiodactyls, 4/8 birds), mesenteric lymphadenomegaly was common in mammals (4/6 primates, 8/10 artiodactyls), and gastroenteritis was common in artiodactyls (7/10). Erythematous, punctate rashes, which have only been reported with yersiniosis in humans, were present in three of six primates. Bacterial cultures from the liver in primates and birds or enlarged mesenteric lymph nodes in artiodactyls were often diagnostic. All isolates were susceptible to marbofloxacin, oxytetracycline, streptomycin, ceftazidime, amoxicillin clavulanic acid, trimethoprim sulfamethoxazole, azithromycin, and doxycycline, and resistant to clindamycin. Histopathology and Perl's Prussian blue stains were performed on available liver samples (n = 18). Intracellular hemosiderin was present in 17 of 18 cases. Additional research is needed to determine if there is a relationship between hemosiderosis and yersiniosis.

THE ISOLATION AND ANTIMICROBIAL SENSITIVITY OF ASPERGILLUS FUMIGATUS FROM FROZEN RESPIRATORY TISSUES OF PENGUINS FROM ZOOLOGICAL COLLECTIONS IN THE UNITED KINGDOM, 2007-2018.

Fifty-eight frozen postmortem lung and air sac samples were collected from penguins housed at 21 zoological collections throughout the United Kingdom, from 2007 to 2018. Aspergillus fumigatus, a significant respiratory pathogen of penguins in captivity, was isolated from 15 of the 22 penguins with gross lesions. Of the penguins with gross lesions of aspergillosis at postmortem examination, the pathogen was cultured from 63.6% (15 of 22) of frozen samples. Aspergillus fumigatus was cultured from 2.7% (1 of 36) of tissues collected from penguins without gross lesions at postmortem. Additionally, of 18 fresh samples that cultured A. fumigatus at the time of postmortem, 15 samples (83%) yielded isolates that were successfully cultured from frozen tissue. Minimum inhibitory concentration (MIC) data demonstrated that all isolates were susceptible to terbinafine and voriconazole, and all were resistant to itraconazole, using published MIC cutoff values. Comparison isolates from fresh tissues had identical antimicrobial susceptibility to isolates from the same tissues after being frozen. This study demonstrates that A. fumigatus can be isolated from frozen respiratory tissues of penguins, even after freezing for more than 10 yr.

Forensic microbiology reveals that Neisseria animaloris infections in harbour porpoises follow traumatic injuries by grey seals.

Neisseria animaloris is considered to be a commensal of the canine and feline oral cavities. It is able to cause systemic infections in animals as well as humans, usually after a biting trauma has occurred. We recovered N. animaloris from chronically inflamed bite wounds on pectoral fins and tailstocks, from lungs and other internal organs of eight harbour porpoises. Gross and histopathological evidence suggest that fatal disseminated N. animaloris infections had occurred due to traumatic injury from grey seals. We therefore conclude that these porpoises survived a grey seal predatory attack, with the bite lesions representing the subsequent portal of entry for bacteria to infect the animals causing abscesses in multiple tissues, and eventually death. We demonstrate that forensic microbiology provides a useful tool for linking a perpetrator to its victim. Moreover, N. animaloris should be added to the list of potential zoonotic bacteria following interactions with seals, as the finding of systemic transfer to the lungs and other tissues of the harbour porpoises may suggest a potential to do likewise in humans.

Novel Salmonella Variant Associated with Mortality in Two Great Spotted Woodpeckers (Dendrocopos major).

Two adult Great Spotted Woodpeckers (Dendrocopos major) from separate sites in Great Britain were examined postmortem in 2013 and 2016. A Salmonella sp. was isolated from multiple tissues in both birds. Histopathology and immunohistochemistry confirmed disseminated salmonellosis. Whole-genome sequencing and biochemical analyses putatively identified both isolates as a novel variant of Salmonella enterica subsp. enterica serovar Hessarek (S. Hessarek). Salmonellosis has seldom been reported in Piciformes, and never before in association with S. Hessarek infection. These findings, therefore, add to current knowledge regarding the range of wild bird species susceptible to this Salmonella serovar, and our understanding of the pathogens affecting Great Spotted Woodpeckers, in particular.

LISTERIA MONOCYTOGENES INFECTION OF FREE-LIVING WESTERN EUROPEAN HEDGEHOGS (ERINACEUS EUROPAEUS).

Listeria monocytogenes is a ubiquitous environmental bacterium that causes disease in a wide range of species. Infection with this pathogen is most frequently diagnosed in ruminant livestock, but is also known to infect people and occasionally wildlife. Postmortem examinations of Western European hedgehogs (Erinaceus europaeus) in Great Britain (2011-2017) identified five (5/266, 2%, 95% confidence interval: 0.8-4.3%) animals with L. monocytogenes infection. The L. monocytogenes isolates comprised three serogroup 1/2a and two serogroup 4 from three multilocus sequence types (2, 37, and 121), all of which were different by single-nucleotide polymorphism analysis, indicating they were distinct and epidemiologically unrelated. These findings are consistent with hedgehogs contracting sporadic infection from the environment, perhaps through eating soil-dwelling invertebrates. Examination of data from scanning surveillance programs focused on other British wildlife species indicates that the hedgehog is one of the wildlife species from which L. monocytogenes has been most frequently identified to date in Great Britain. However, further studies of multiple taxa with comparable sampling efforts are required to assess the relative frequency of L. monocytogenes infection in different wildlife species. The bacterium was isolated from extraintestinal sites in multiple hedgehogs, which may indicate septicemia. However, histological examination was limited and could not discriminate subclinical infection from disease (i.e., listeriosis). Although L. monocytogenes is a zoonotic pathogen, disease in people is typically contracted from the ingestion of contaminated foods. The risk to immunocompetent people of contracting listeriosis from hedgehogs is considered very low to negligible.

Fatal phaeohyphomycosis due to Exophiala sp. infection in a free-living common toad Bufo bufo.

A wild adult female common toad Bufo bufo found dead in Scotland in September 2016 was observed to have hepatomegaly, a large soft tissue mass in the coelomic cavity (2.7 g, 3.5 × 2.3 × 1.8 cm) and numerous dark-red papules (1-2 mm diameter) in the skin and subjacent tissue over the back and dorsal aspects of the limbs. Histopathological examination identified marked hepatitis and coelomitis associated with pigmented fungal hyphae, which are results consistent with a diagnosis of phaeohyphomycosis. Sequencing of the internal transcribed spacer region and the D1-D2 region of the large subunit of the ribosomal RNA gene from affected liver tissue identified the presence of Exophiala (Chaetothyriales) sp., a black yeast previously identified as a cause of amphibian phaeohyphomycosis. To our knowledge, this is the first published report of Exophiala sp. in a wild or captive amphibian in Europe and the first description of phaeohyphomycosis affecting a free-living amphibian in Great Britain. Exophiala spp. are saprobes and opportunistic pathogens. It has been postulated that phaeohyphomycosis is a disease of immunocompromised amphibians; however, we found no evidence of significant concurrent infection or generalised debility in this common toad. Phaeohyphomycosis appears to be a sporadic cause of mortality in amphibians, and this report adds to the growing list of pathogens known to affect wild amphibians in Europe.

Salmonella Enteritidis ST183: emerging and endemic biotypes affecting western European hedgehogs (Erinaceus europaeus) and people in Great Britain.

The impacts of hedgehog (Erinaceus europaeus) Salmonella infection on public health and on animal welfare and conservation are unknown. We isolated Salmonella Enteritidis multi-locus sequence-type (ST)183 from 46/170 (27%) hedgehog carcasses (27 S. Enteritidis phage type (PT)11, 18 of a novel PT66 biotype and one with co-infection of these PTs) and from 6/208 (3%) hedgehog faecal samples (4 PT11, 2 PT66) from across Great Britain, 2012-2015. Whole genome phylogenetic analysis of the hedgehog isolates and ST183 from people in England and Wales found that PT11 and PT66 form two divergent clades. Hedgehog and human isolates were interspersed throughout the phylogeny indicating that infections in both species originate from a common population. PT11 was recovered from hedgehogs across England and Scotland, consistent with endemic infection. PT66 was isolated from Scotland only, possibly indicating a recent emergence event. People infected with ST183 were four times more likely to be aged 0-4 years than people infected by the more common ST11 S. Enteritidis. Evidence for human ST183 infection being non-foodborne included stronger correlation between geographic and genetic distance, and significantly increased likelihood of infection in rural areas, than for ST11. These results are consistent with hedgehogs acting as a source of zoonotic infection.

Streptococcus pyogenes Infection in a Free-Living European Hedgehog (Erinaceus europaeus).

Streptococcus pyogenes, a common pathogen of humans, was isolated from the carcass of a free-living European hedgehog (Erinaceus europaeus) found in northern England in June 2014. The animal had abscessation of the deep right cervical lymph node, mesenteric lymph nodes and liver. The S. pyogenes strain isolated from the lesions, peritoneal and pleural cavities was characterised as emm 28, which can be associated with invasive disease in humans. This is the first known report of S. pyogenes in a hedgehog and in any free-living wild animal that has been confirmed by gene sequencing. As close associations between wild hedgehogs and people in England are common, we hypothesise that this case might have resulted from anthroponotic infection.

Aprocta cylindrica (Nematoda) infection in a European Robin (Erithacus rubecula) in Britain.

A European Robin (Erithacus rubecula) found dead in England had marked blepharitis and periocular alopecia associated with Aprocta cylindrica (Nematoda: Aproctidae) and concurrent mixed fungal infections. Aprocta cylindrica should be considered a differential diagnosis in periocular abnormalities of robins and other insectivorous, migratory passerines in Western Europe.

Epidemiological evidence that garden birds are a source of human salmonellosis in England and Wales.

The importance of wild bird populations as a reservoir of zoonotic pathogens is well established. Salmonellosis is a frequently diagnosed infectious cause of mortality of garden birds in England and Wales, predominantly caused by Salmonella enterica subspecies enterica serovar Typhimurium definitive phage types 40, 56(v) and 160. In Britain, these phage types are considered highly host-adapted with a high degree of genetic similarity amongst isolates, and in some instances are clonal. Pulsed field gel electrophoresis, however, demonstrated minimal variation amongst matched DT40 and DT56(v) isolates derived from passerine and human incidents of salmonellosis across England in 2000-2007. Also, during the period 1993-2012, similar temporal and spatial trends of infection with these S. Typhimurium phage types occurred in both the British garden bird and human populations; 1.6% of all S. Typhimurium (0.2% of all Salmonella) isolates from humans in England and Wales over the period 2000-2010. These findings support the hypothesis that garden birds act as the primary reservoir of infection for these zoonotic bacteria. Most passerine salmonellosis outbreaks identified occurred at and around feeding stations, which are likely sites of public exposure to sick or dead garden birds and their faeces. We, therefore, advise the public to practise routine personal hygiene measures when feeding wild birds and especially when handling sick wild birds.

Prevalence of Salmonella spp. and thermophilic Campylobacter spp. in the small Asian mongoose (Herpestes javanicus) in Barbados, West Indies.

From April to July 2005, rectal swabs were collected from 48 free-ranging small Asian mongooses (Herpestes javanicus) on the east and south coasts of Barbados and analyzed for Salmonella and Campylobacter spp. Salmonella was recovered in 21.12% (7/33) of mongooses at the east-coast site and 26.67% (4/15) at the south-coast site. Four serotypes were isolated: Salmonella enterica serovar Rubislaw, Kentucky, Javiana, and Panama. One east-coast sample of 11 tested for Campylobacter was positive (9.09%). These results indicate that mongooses in Barbados are carriers and shedders of Salmonella and Campylobacter spp. and are a potential wildlife reservoir for these enteropathogens.

What caused the UK's largest common dolphin (Delphinus delphis) mass stranding event?

On 9 June 2008, the UK's largest mass stranding event (MSE) of short-beaked common dolphins (Delphinus delphis) occurred in Falmouth Bay, Cornwall. At least 26 dolphins died, and a similar number was refloated/herded back to sea. On necropsy, all dolphins were in good nutritive status with empty stomachs and no evidence of known infectious disease or acute physical injury. Auditory tissues were grossly normal (26/26) but had microscopic haemorrhages (5/5) and mild otitis media (1/5) in the freshest cases. Five lactating adult dolphins, one immature male, and one immature female tested were free of harmful algal toxins and had low chemical pollutant levels. Pathological evidence of mud/seawater inhalation (11/26), local tide cycle, and the relative lack of renal myoglobinuria (26/26) suggested MSE onset on a rising tide between 06:30 and 08∶21 hrs (9 June). Potential causes excluded or considered highly unlikely included infectious disease, gas/fat embolism, boat strike, by-catch, predator attack, foraging unusually close to shore, chemical or algal toxin exposure, abnormal weather/climatic conditions, and high-intensity acoustic inputs from seismic airgun arrays or natural sources (e.g., earthquakes). International naval exercises did occur in close proximity to the MSE with the most intense part of the exercises (including mid-frequency sonars) occurring four days before the MSE and resuming with helicopter exercises on the morning of the MSE. The MSE may therefore have been a "two-stage process" where a group of normally pelagic dolphins entered Falmouth Bay and, after 3-4 days in/around the Bay, a second acoustic/disturbance event occurred causing them to strand en masse. This spatial and temporal association with the MSE, previous associations between naval activities and cetacean MSEs, and an absence of other identifiable factors known to cause cetacean MSEs, indicates naval activity to be the most probable cause of the Falmouth Bay MSE.

Pulsed-field gel electrophoresis supports the presence of host-adapted Salmonella enterica subsp. enterica serovar Typhimurium strains in the British garden bird population.

Salmonellosis is a frequently diagnosed infectious disease of passerine birds in garden habitats within Great Britain with potential implications for human and domestic animal health. Postmortem examinations were performed on 1,477 garden bird carcasses of circa 50 species from England and Wales, 1999 to 2007 inclusive. Salmonellosis was confirmed in 263 adult birds of 10 passerine species in this 11-year longitudinal study. A subset of 124 fully biotyped Salmonella enterica subsp. enterica serovar Typhimurium isolates was examined using pulsed-field gel electrophoresis to investigate the hypothesis that these strains are host adapted and to determine whether this molecular technique offers greater resolution in understanding the epidemiology of Salmonella Typhimurium infection than phage typing alone. For the two most common phage types, definitive type (DT) 40 and DT56v, which together accounted for 97% (120/124) of isolates, pulsed-field gel electrophoresis groupings closely correlated with phage type with remarkably few exceptions. A high degree of genetic similarity (>90%) was observed within and between the two most common pulsed-field gel electrophoresis groups. No clustering or variation was found in the pulsed-field gel electrophoresis groupings by bird species, year, or geographical region beyond that revealed by phage typing. These findings support the hypothesis that there are currently two host-adapted Salmonella phage types, S. Typhimurium DT40 and DT56v, circulating widely in British garden birds and that the reservoir of infection is maintained within wild bird populations. Large-scale multilocus sequence typing studies are required to further investigate the epidemiology of this infection.