RETROSPECTIVE REVIEW OF MORTALITY IN CAPTIVE PINK PIGEONS (NESOENAS MAYERI) HOUSED IN EUROPEAN COLLECTIONS: 1977-2018

Liver and Let Die? A Retrospective Analysis of Secretarybird Mortality in European Zoos

The secretarybird (Sagittarius serpentarius) is a threatened African raptor species, and as such requires conservation attention. While the species is managed under a European Association of Zoos and Aquaria (EAZA) Ex-situ Programme (EEP), no studies of mortality are currently available. A retrospective mortality project was therefore conducted to identify the most common causes of death in captive secretarybirds, with a view to informing management decisions. Data were collected by requesting the postmortem reports from zoos where secretarybirds had died and combining this with the existing data recorded in the Zoological Information Management System. Overall, 167 birds were recorded as having died within the EEP population, of which post-mortem information was available for 51 (30.54%) individuals. Trauma was the most common cause of death identified (22 birds, 13.17%), with infection appearing as the second most prevalent cause (15 birds, 8.98%). One incidental finding at postmortem was that many (9) birds showed evidence of liver damage, with reports of bacterial hepatitis, staphylococcal infection, lesions, and dark coloration. Further research into liver complications and diet composition for secretarybirds may therefore have value in reducing mortality. Similarly, investigating strategies to reduce trauma caused by other enclosure occupants or conspecifics may have value in lengthening lifespans for this endangered species.

EVALUATION OF MORTALITY CAUSES AND PREVALENCE OF RENAL LESIONS IN ZOO-HOUSED CHAMELEONS: 2011-2022

Of the 202 species of Chamaeleonidae, 38.6% are globally threatened. Currently, nearly a thousand individual chameleons from 36 different species are kept in zoological institutions worldwide. The objectives of this study were to assess the main mortality causes of chameleons in zoological institutions, the prevalence of renal lesions at necropsy, and the environmental factors associated with renal lesions. An online survey was sent to 245 zoological institutions worldwide to collect information about species and sex distribution, necropsy results, and husbandry parameters. Necropsy reports of the last 10 yr were requested from participating institutions (n = 65) when available. Mortality causes were classified into three categories (open diagnosis, infectious, and noninfectious), and noninfectious causes were further subdivided into seven categories (renal, reproductive, myoarthroskeletal, digestive, ophthalmologic, denutrition/multisystemic, and neoplastic). The prevalence of renal lesions was recorded. Multiple linear regression models were used with the prevalence of renal diseases as the dependent variable, and exhibit minimum and maximum hygrometry; exhibit highest and coolest temperature; as well as minimum, mean, and maximum hygrometry of the geographical area as independent variables, combining all chameleon species with similar environmental requirements. Results were obtained for 14 species (n = 412 individuals). The main mortality causes were infectious (46.8%), noninfectious renal (11.4%), and noninfectious reproductive (10.7%) diseases, with all cases of fatal reproductive diseases reported in females. Of the individuals that underwent renal histopathology, 41.7% displayed renal lesions. There was a tendency towards higher renal lesion prevalence in zoos located in areas with lower mean hygrometry (P = 0.05). Further research studies about infectious, renal, and reproductive diseases of Chamaeleonidae are warranted.

A RETROSPECTIVE ANALYSIS OF THE MORBIDITY AND MORTALITY OF CAPTIVE NORTHERN BALD IBIS (GERONTICUS EREMITA), AFRICAN SACRED IBIS (THRESKIORNIS AETHIOPICUS), AND SCARLET IBIS (EUDOCIMUS RUBER) HOUSED AT THE LONDON ZOO FROM 2000 TO 2020

Necropsy (n = 144) and medical (n = 121) records of captive northern bald ibis (NBI; Geronticus eremita), African sacred ibis (ASI; Threskiornis aethiopicus), and scarlet ibis (SCI; Eudocimus ruber) housed at the Zoological Society of London's London Zoo (LZ) from 2000 to 2020 were reviewed. Pododermatitis was a common cause of morbidity in all species (79 cases in 247 examinations). Trauma (58 of 144), the majority being caused by suspected collisions with stationary objects in the zoo's habitats, infectious diseases (32 of 144), predominantly valvular endocarditis (10 of 32), and aspergillosis (9 of 32) were major causes of mortality. The odds of a morbidity being related to toxicosis were 4.4 times greater in NBI than for ASI (95% CI, 1.5-13.3; P < 0.05); all cases in the NBI were plumbism. Overall, females of all species had 3.4 times greater odds of undetermined morbidity than males (95% CI, 1.5-7.9; P < 0.05), and the majority (16 of 25) were birds that were thin without an apparent cause. Nestlings had 11.3 times greater odds of nutritional morbidity than adults (95% CI, 1.7-73.0) and 5.5 times greater than juveniles (95% CI, 0.7-41.0; P < 0.05). These data have identified areas that require further study in the population of NBI, ASI, and SCI held at LZ.

The microbiota in feces of domestic pigeons in Seoul, Korea

In Korea, feral pigeons pose significant public health risks because they carry various zoonotic pathogens. Human population density is a significant factor in zoonotic disease events. Seoul is one of the largest cities by population density among developed countries and where most of the homeless population in Korea exists. We designed this study to compare the microbiota of pigeon feces by regional characteristics and the presence of homeless individuals. Therefore, this study used 16S rRNA amplicon sequencing to detect possible pathogenic microbes and assess the current risk of zoonosis in Seoul, South Korea. Pigeon fecal samples (n = 144) obtained from 19 public sites (86 and 58 fecal samples from regions in and outside Seoul, respectively) were examined. Potentially pathogenic bacteria were also detected in the fecal samples; Campylobacter spp. was found in 19 samples from 13 regions, Listeriaceae was found in seven samples, and Chlamydia spp. was found in three samples from two regions. Principal coordinates analysis and permutational multivariate analysis of variance revealed a significant difference in bacterial composition between the regions in Seoul (n = 86) and outside Seoul (n = 58) and between the regions with (n = 81) and without (n = 63) homeless individuals. Overall, this study identified various potentially pathogenic microorganisms in pigeon feces at public sites in South Korea. Moreover, this study demonstrates that the microbial composition was influenced by regional characteristics and homelessness. Taken together, this study provides important information for public health strategic planning and disease control.

Birds Kept in the German Zoo "Tierpark Berlin" Are a Common Source for Polyvalent Yersinia pseudotuberculosis Phages

Yersinia pseudotuberculosis is an important animal pathogen, particularly for birds, rodents, and monkeys, which is also able to infect humans. Indeed, an increasing number of reports have been published on zoo animals that were killed by this species. One option to treat diseased animals is the application of strictly lytic (virulent) phages. However, thus far relatively few phages infecting Y. pseudotuberculosis have been isolated and characterized. To determine the prevalence of Y. pseudotuberculosis phages in zoo animals, fecal samples of birds and some primates, maras, and peccaries kept in the Tierpark Berlin were analyzed. Seventeen out of 74 samples taken in 2013 and 2017 contained virulent phages. The isolated phages were analyzed in detail and could be allocated to three groups. The first group is composed of 10 T4-like phages (PYps2T taxon group: Myoviridae; Tevenvirinae; Tequatrovirus), the second group (PYps23T taxon group: Chaseviridae; Carltongylesvirus; Escherichia virus ST32) consists of five phages encoding a podovirus-like RNA polymerase that is related to an uncommon genus of myoviruses (e.g., Escherichia coli phage phiEcoM-GJ1), while the third group is comprised of two podoviruses (PYps50T taxon group: Autographiviridae; Studiervirinae; Berlinvirus) which are closely related to T7. The host range of the isolated phages differed significantly. Between 5.5 and 86.7% of 128 Y. pseudotuberculosis strains belonging to 20 serotypes were lysed by each phage. All phages were additionally able to lyse Y. enterocolitica B4/O:3 strains, when incubated at 37°C. Some phages also infected Y. pestis strains and even strains belonging to other genera of Enterobacteriaceae. A cocktail containing two of these phages would be able to lyse almost 93% of the tested Y. pseudotuberculosis strains. The study indicates that Y. pseudotuberculosis phages exhibiting a broad-host range can be isolated quite easily from zoo animals, particularly birds.

Analysis of Yersinia pseudotuberculosis Isolates Recovered from Deceased Mammals of a German Zoo Animal Collection

Yersinia pseudotuberculosis is an important pathogen for both humans and animals. It can infect livestock, as well as pets and wild animals. During recent years, a number of reports have described the isolation of Y. pseudotuberculosis from zoo animals, mainly birds and mammals, for which the infection was mostly lethal. Between 2005 and 2019, there were at least 17 cases of deceased mammals, belonging to five different species, which suffered from a Y. pseudotuberculosis infection at the Zoo Wuppertal, Germany. Since only scarce information exists on the properties of Y. pseudotuberculosis from zoo animals, we characterized eight isolates, covering all infected species, in detail. All isolates were members of biotype 1, but belonged to five serotypes, five sequence types (STs), and seven core-genome multilocus sequence types (cgMLSTs). Using pulsed-field gel electrophoresis (PFGE) analysis and whole-genome sequencing (WGS), the seven isolates could be discriminated from each other. They differed significantly regarding their virulence genes and mobile genetic elements. While the virulence plasmid pYV existed in all serotypes (five isolates), a complete high-pathogenicity island (HPI) was detected only in the serotypes O:1a, O:1b, and O:13 (four isolates), but not in O:2a and O:2b. Similarly, the content of other plasmids and prophages varied greatly between the isolates. The data demonstrate that the deceased mammals were infected by seven individual isolates and not by a single type predominating in the zoo animals.

HEALTH SCREENING OF THE EUROPEAN ENDANGERED SPECIES PROGRAM CAPTIVE POPULATION OF THE PINK PIGEON (NESOENAS MAYERI)

The population of the Mauritian pink pigeon (Nesoenas mayeri) fell to fewer than 20 individuals in the 1970s. Following intensive conservation efforts, the free-living population is now estimated to be 470 individuals. However, because of the population bottleneck the species remains at risk of extinction because of genetic loss and inbreeding depression. A European captive population was established in 1977 and a European Endangered Species Program (EEP) was formalized in 1992. As birds in the EEP captive population possess unique alleles not observed in the surviving free-living birds, the EEP management plan recommends transferring EEP birds to Mauritius to improve genetic diversity. Health screening of the current EEP population to identify circulating pathogens was performed. Forty-two birds from three collections in the United Kingdom and one in Jersey were screened for a wide range of pathogens, present clinically or subclinically, including important viruses, bacteria, protozoa, and helminths. Eleven birds tested positive for at least one pathogen: Trichomonas spp. (5), Yersinia kristensenii (2), Yersinia aleksiciae (1), coccidial oocysts (3), and strongyle ova (3). None of the positive birds showed overt signs of clinical disease, although two birds with Trichomonas spp. had suboptimal body condition. Genotyping of one Trichomonas gallinae sample revealed a type-C strain (low pathogenicity). The results from this screening will contribute towards a disease risk assessment, to create a pre-export protocol for translocation of captive EEP birds to Mauritius.

Common bacterial, viral, and parasitic diseases in pigeons (Columba livia): A review of diagnostic and treatment strategies

Pigeons (Columba livia) have been associated with humans for a long time now. They are raised for sport (pigeon race), exhibition (display of fancy breeds), food, and research. Most of the pigeons kept are Racing Homers, trained to compete in the pigeon race. Other breeds, such as Rollers, Nose Divers, Doneks are bred for their aerial abilities. Incorporation of a good preventive medicine program is one of the most critical factors in averting infectious diseases in pigeon flocks. This review summarizes the common bacterial, viral, and parasitic infections in pigeons. The different clinical signs, symptoms, diagnostic strategies, prevention, and treatments were described in this review. Current researches, molecular diagnostic assays, and treatment strategies such as vaccines and drug candidates were included. The information found in this review can provide insights for veterinarians and researchers studying pigeons to develop effective and efficient immunoprophylactic and diagnostic tools for pigeon diagnosis and therapeutics.