Browsing by Author "Gartrell BD"

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A single genotype of Chlamydia psittaci (ST27) found in multiple species of birds in a zoological collection in New Zealand
(Taylor and Francis Group on behalf of the New Zealand Veterinary Association, 2025-06-02) Gedye K; Kulkarni P; Soon XQ; Pas A; Jensen M; Gartrell BD
Aims: To investigate the genotypes of Chlamydia psittaci in birds associated with two clusters of disease from a zoological collection in New Zealand. Materials and methods: Samples were collected over two time periods from birds resident at Auckland Zoo (Auckland, NZ). In 2016, two little penguins/kororā (Eudyptula minor) showed respiratory disease on admission to the zoo hospital. Post-mortem samples of liver and lung were collected from the penguins and from 10 other birds from the zoo’s collection that died without clinical signs. Further, 128 conjunctival, choanal and cloacal swabs were collected from 27 different bird species, all housed within the zoo and without clinical signs. In 2019, a cluster of deaths of four diamond doves (Geopelia cuneata) and two superb parrots (Polytelis swainsonii) occurred in one mixed-species aviary. Twenty post-mortem samples were collected from these birds and other birds that died around the same time across the zoo. DNA was extracted from all samples and initially tested for C. psittaci using a high-resolution melting quantitative PCR (HRM qPCR) protocol. We applied multi-locus sequence typing (MLST) on 10 C. psittaci-positive samples from four different avian species, including one sample from 2016 (little penguin) and nine post-mortem samples from 2019. Results: C. psittaci was detected in 14/140 (0.10; 95% CI = 0.061–0.161) of the samples from 2016 from seven species. A penguin sample was sequenced aligning with ompA genotype B and was later characterised by MLST as C. psittaci strain ST27. With the exception of the sample from the sick penguin, the positive results yielded very low DNA copy numbers in the HRM qPCR, potentially indicating latent infections. In the 2019 cluster, C. psittaci was detected in 9/20 post-mortem samples from three bird species (diamond dove, superb parrot, and zebra finch (Taeniopygia guttata)). All nine sample sequences aligned with ompA genotype B and were characterised by MLST as C. psittaci strain ST27. Conclusions and clinical relevance: C. psittaci was present within the zoological collection in a variety of bird species associated with two disease clusters. Most of these infections were asymptomatic, but a cluster of deaths due to avian chlamydiosis in 2019 affecting three species of birds was due to a single genotype, ST27, that was also present in a wild penguin in 2016. This provides evidence of pathogenicity in birds for this genotype.
Biochemical and haematological reference intervals for 3–4-week-old kiwi chicks (Apteryx mantelli) reared in captivity
(Taylor and Francis Group, 2025-08-12) Scheltema EM; Howe L; Pickard KMO; Fletcher MC; Gartrell BD; Singh PM; Morgan KJ
Aims: To establish biochemical and haematological 95% reference intervals (RI) for juvenile North Island brown kiwi (Apteryx mantelli) chicks using parametric analysis. Methods: Blood samples were collected from healthy 3–4-week-old, captive-reared North Island brown kiwi chicks (n = 32; male = 19, female = 13). Concentrations of total plasma protein (TPP), uric acid, glucose, phosphorus, calcium, albumin, globulin, potassium, and sodium and activities of aspartate aminotransferase and creatine kinase (CK) were measured using an automated VetScan VS2 laboratory analyser and the Abaxis Avian-Reptilian Profile Plus. Total and differential white blood cell counts were determined manually on blood smears prepared with a modified Wright-Giemsa stain. TPP was also measured manually using a refractometer, and packed cell volume (PCV) was measured using microhaematocrit tubes. RI were calculated using parametric and non-parametric methods depending on the distribution of the data. Confidence intervals (90%) around upper and lower bounds of the RI were calculated to assess certainty of the intervals. Results: Biochemical (n = 28; male = 17; female = 11) and haematological (n = 22; male = 14, female = 8) 95% RI were generated for juvenile North Island brown kiwi. The 90% CI of the upper or lower limits of the majority of the RI generated were > 0.2 times the RI, reflecting the relatively small sample size. There was no evidence of a difference in mean biochemical values collected from sedated vs. un-sedated, and male vs. female chicks. However, the concentration of phosphorus was higher (p = 0.034) in samples that were analysed > 1 hour after collection (2.097 (SD 0.202) mmol/L) compared to samples analysed < 1 hour after collection (1.856 (SD 0.349) mmol/L). Conclusions: This data provides the first comprehensive biochemical and haematological RI generated for Apteryx spp. chicks carried out under uniform collection and sample handling protocols, making the results robust and applicable to other captive-reared kiwi chicks. Clinical relevance: In comparison to published RI from adult kiwi (Doneley 2006; Morgan 2008), kiwi chicks in this study had lower PCV, TPP and uric acid concentrations, and higher CK activities, white cell counts and lymphocyte counts. These RI are of value to wildlife veterinarians and conservation managers assessing the health of individual kiwi chicks, and for population-level comparison of birds of different ages and living in different managed or wild habitats.
Differences in body composition between urban and rural Mallards, Anas platyrhynchos
(1/01/2020) Jarman TE; Gartrell BD; Battley PF
Anthropogenic feeding of wildlife provides a valuable opportunity for people to engage with animals, but such feeding has the potential to be detrimental to the species involved. Ducks are frequently fed at urban ponds globally, yet the health impacts of an urban lifestyle for birds are poorly documented. We studied urban and rural Mallards (Anas platyrhynchos) in the Manawatū-Whanganui region (New Zealand). Mallards are opportunistic omnivores that have a phenotypically flexible gastrointestinal system. As urban Mallards consume considerable amounts of low-fibre, high carbohydrate foods via anthropogenic feeding, we predicted that urban Mallards would have smaller gastrointestinal tract organs and higher fat levels than rural ducks. We compared gross body composition of Mallards in a modified environment with high levels of feeding by humans and in rural habitats. We also evaluated other health-associated aspects including fat deposit size, liver fat content and haemosiderin (liver iron deposit) levels. Contrary to predictions, urban birds had larger gizzards and caeca and were no fatter than rural birds; rural birds additionally had larger pectoralis major muscles. These differences are probably associated with broader ecological and behavioural factors than with the provision of anthropogenic food per se [in particular the presence of hard foods (acorns and nuts) for urban birds, and higher flight activity of rural birds]. Longer caeca in urban birds could, however, relate to immunity rather than microbial fermentation of cellulose. Overall, while the nature of the local environment does affect Mallard physiology, no detrimental effects of urban living were evident in this study.
Folliculectomy for the treatment of pre-ovulatory follicular stasis in three illegally captured West Coast green geckos (Naultinus tuberculatus) to enable wild rehabilitation.
(Taylor and Francis Group, 2024-07-30) Gartrell BD; Jolly M; Cree A; Short E; Hori T
CASE HISTORY: In 2023, the New Zealand Department of Conservation seized 63 endemic reptiles that were being held without a permit. This group included three adult female West Coast green geckos (Naultinus tuberculatus) that had been illegally removed from the wild 2 years earlier. They had been held in an outdoor enclosure with a pair of goldstripe geckos (Woodworthia chrysosiretica). CLINICAL FINDINGS: On physical examination, all three geckos had at least two soft palpable masses in the coelom. Repeated ultrasonographic examination over several months confirmed the diagnosis of pre-ovulatory follicular stasis (POFS) in each gecko, and in subsequent weeks, more ovarian follicles developed in each animal. LABORATORY FINDINGS: All three geckos were negative on culture of cloacal swabs for Salmonella spp., and negative on PCR assay of a cloacal flush for Cryptosporidium spp., despite other reptiles in the seized group showing positive results for multiple Salmonella spp., and one other gecko being positive for Cryptosporidium parvum, subtype IIcA5G3. TREATMENT AND OUTCOME: For all three geckos, para-midline ventral coeliotomy was performed under general anaesthesia, and folliculectomy of degenerate ovarian follicles was performed. Post-operative complications were seen in all three animals, which developed suture-line infections following disruption of normal skin shedding and entrapment of shed keratin in the surgical sites. A second surgery was undertaken to remove impacted keratin and caseous inflammatory material from the surgical wounds of all three animals and buried sutures were placed to close the coelomic wounds. The geckos were treated with 20 mg/kg ceftazidime IM every second day for 2 weeks post-operatively. Subsequent ecdysis (skin shedding) occurred without complication and the geckos were released back to the wild 10 months after admission. CLINICAL RELEVANCE: The recommended treatment for POFS in reptiles is ovariectomy, which is not appropriate for wild animals. The use of folliculectomy to resolve preovulatory follicular stasis should be considered for animals where retaining reproductive ability is essential.
Gut microbiota of the threatened takahē: biogeographic patterns and conservation implications
(BioMed Central Ltd, 2022-12) West AG; DeLaunay A; Marsh P; Perry EK; Jolly M; Gartrell BD; Pas A; Digby A; Taylor MW
BACKGROUND: The Aotearoa New Zealand takahē (Porphyrio hochstetteri), once thought to be extinct, is a nationally threatened flightless rail under intensive conservation management. While there has been previous research into disease-related microbes in takahē, little is known about the microbes present in the gastrointestinal tract. Given the importance of gut-associated microbes to herbivore nutrition and immunity, knowledge of these communities is likely to be of considerable conservation value. Here we examined the gut microbiotas of 57 takahē at eight separate locations across Aotearoa New Zealand. RESULTS: Faecal samples, taken as a proxy for the hindgut bacterial community, were subjected to 16S rRNA gene amplicon sequencing using Illumina MiSeq. Phylogenetic analysis of > 2200 amplicon sequence variants (ASVs) revealed nine main bacterial phyla (Acidobacteriota, Actinobacteriota, Bacteroidota, Campilobacterota, Firmicutes, Fusobacteriota, Planctomycetota, Proteobacteria, and Verrucomicrobiota) that accounted for the majority of sequence reads. Location was a significant effect (p value < 0.001, 9999 permutations) that accounted for 32% of the observed microbiota variation. One ASV, classified as Lactobacillus aviarius, was present in all samples at an average relative abundance of 17% (SD = 23.20). There was strong evidence (p = 0.002) for a difference in the abundance of the genus Lactobacillus between locations. A common commensal bacterium previously described in takahē, Campylobacter spp., was also detected in most faecal samples. CONCLUSIONS: Location plays a pivotal role in the observed variation among takahē gut bacterial communities and is potentially due to factors such as supplemental feeding and medical treatment experienced by birds housed in captivity at one of the eight sampled sites. These data present a first glimpse of the previously unexplored takahē gut microbiota and provide a baseline for future microbiological studies and conservation efforts.
Health impacts of poor water quality on an endangered shorebird breeding programme in Aotearoa New Zealand.
(Taylor and Francis Group, 2024-02-04) Gartrell BD; Hunter S; Collen R; Jolly M; McInnes K; Richardson A; Reed C; Ward R; Pita A
CASE HISTORY: Two clusters of mortality among endangered tūturuatu/tchūriwat'/shore plover (Thinornis novaeseelandiae) have occurred at captive breeding facilities around New Zealand in recent years. In the first, four chicks died at Pūkaha National Wildlife Centre (Mount Bruce, NZ) in February 2016, and in the second five adult birds at the Cape Sanctuary (Cape Kidnappers, NZ) died in 2022. CLINICAL FINDINGS: In 2016, four chicks were noted to become weak, have increased vocalisations and closed eyes prior to death. The remaining chicks were treated for 5 days with amoxycillin/clavulanate orally twice daily. Water containers and brooders were cleaned and disinfected with chlorhexidine. No further mortality was seen.In the 2022 cluster, three adult breeding birds died acutely and five others showed inappetence, weight loss and diarrhoea approximately 10 days after heavy rains flooded the local river. The five birds were treated with amoxycillin/clavulanate orally twice daily and oral fluids for 5 days. Two birds died and three survived. No breeding occurred in the aviaries in the following season. PATHOLOGICAL FINDINGS: In 2016, the chicks showed pulmonary changes ranging from congestion and oedema to heterophilic inflammation consistent with septicaemia.In 2022, the adult birds showed proliferation of bacteria in the distal small intestine associated with mucosal ulceration and heterophilic infiltration. Acid-fast staining of the caecal contents in one bird showed organisms consistent with Cryptosporidium spp. LABORATORY FINDINGS: Aerobic bacterial cultures of the lung and liver of two affected chicks carried out in 2016 showed heavy growth of Plesiomonas shigelloides. The same organism was cultured from water trays and holding tanks containing water boatmen (Sigara arguta) on which the chicks were fed.In 2022, cultures from the livers of three dead birds each showed a mixed bacterial growth with differing dominant organisms (Aeromonas sobria, Hafnia alvei, Citrobacter freundii and an Enterococcus sp.). PCR and sequencing confirmed Cryptosporidium parvum in the caecum of one bird. Fresh faeces from 24 breeding birds from the captive breeding facilities were negative by PCR for Cryptosporidium spp.The captive breeding facilities obtain water for the aviaries and aquatic invertebrates to feed to the chicks from local freshwater sources. Water quality testing at the Cape Sanctuary revealed concentrations of faecal indicator bacteria in excess of safe drinking water guidelines, with peaks following heavy rainfall. CLINICAL RELEVANCE: Fluctuations in water quality associated with mammalian faecal bacteria can adversely affect bird health and impact on captive rearing of endangered wildlife.
Leveraging an existing whole-genome resequencing population data set to characterize toll-like receptor gene diversity in a threatened bird
(John Wiley and Sons, Ltd, 2022-10) Magid M; Wold JR; Moraga R; Cubrinovska I; Houston DM; Gartrell BD; Steeves TE; Hohenlohe PA
Species recovery programs are increasingly using genomic data to measure neutral genetic diversity and calculate metrics like relatedness. While these measures can inform conservation management, determining the mechanisms underlying inbreeding depression requires information about functional genes associated with adaptive or maladaptive traits. Toll-like receptors (TLRs) are one family of functional genes, which play a crucial role in recognition of pathogens and activation of the immune system. Previously, these genes have been analysed using species-specific primers and PCR. Here, we leverage an existing short-read reference genome, whole-genome resequencing population data set, and bioinformatic tools to characterize TLR gene diversity in captive and wild tchūriwat'/tūturuatu/shore plover (Thinornis novaeseelandiae), a threatened bird endemic to Aotearoa New Zealand. Our results show that TLR gene diversity in tchūriwat'/tūturuatu is low, and forms two distinct captive and wild genetic clusters. The bioinformatic approach presented here has broad applicability to other threatened species with existing genomic resources in Aotearoa New Zealand and beyond.
Suspected brodifacoum poisoning in tuatara (Sphenodon punctatus)
(Taylor and Francis Group on behalf of the New Zealand Veterinary Association, 2025-05-04) Mehta S; Booth L; Hunter S; Jolly M; Gartrell BD
Case history: Between June 2017 and April 2019, three captive tuatara from a zoological facility in the South Island of New Zealand were found unwell and admitted to veterinary care. One other tuatara from the same facility was found dead from misadventure in May 2019. Clinical findings: All three unwell tuatara showed clinical signs of lethargy, mucous membrane pallor, and dehydration, with haematoma formation/swelling in dependent parts of the body. Fine needle aspiration and cytology of the swellings showed common features of peripheral blood, with variable other cytological findings. Haematology confirmed marked anaemia in Case 1 (PCV 5%; reference range 22–53%) and Case 2 (PCV 1%) and suspected mild anaemia in Case 3 (PCV 27%). Case 1 died 6 weeks after initial presentation, whereas Cases 2 and 3 died soon after presentation. Pathological findings: Post-mortem examination showed general pallor of soft tissues in the three tuatara with clinical signs of coagulopathy. There was haemorrhage in the bladder wall of Case 1, while Cases 2 and 3 had haematomas (subcutaneous in Case 2 and peri-oesophageal in Case 3). The pathological diagnosis in Case 4 was death by asphyxiation following burrow collapse. Retrospective analysis showed brodifacoum was present in liver tissue at a concentration of 0.26 mg/kg in Case 3, and in skeletal muscle tissue at concentrations of 0.019 mg/kg in Case 2 and 0.035 mg/kg in the non-clinical case (Case 4). Diagnosis: The clinical signs and post-mortem findings were consistent with anticoagulant poisoning in three tuatara, and tissue concentrations of brodifacoum demonstrated exposure in three animals, including one animal with no clinical signs of coagulopathy (Case 4). Definitive diagnosis was prevented, however, by inconsistent toxicology testing and a limited understanding of toxicity thresholds in reptiles in general, and tuatara specifically. Clinical relevance: This case series suggests that tuatara are susceptible to anticoagulant poisoning and this has implications for both the captive management of tuatara, and also the use of rodenticides in tuatara habitat, such as offshore islands and mainland sanctuaries.
Ventral dermatitis in rowi (Apteryx rowi) due to cutaneous larval migrans.
(2015-04) Gartrell BD; Argilla L; Finlayson S; Gedye K; Gonzalez Argandona AK; Graham I; Howe L; Hunter S; Lenting B; Makan T; McInnes K; Michael S; Morgan KJ; Scott I; Sijbranda D; van Zyl N; Ward JM
The rowi is a critically endangered species of kiwi. Young birds on a crèche island showed loss of feathers from the ventral abdomen and a scurfy dermatitis of the abdominal skin and vent margin. Histology of skin biopsies identified cutaneous larval migrans, which was shown by molecular sequencing to be possibly from a species of Trichostrongylus as a cause of ventral dermatitis and occasional ulcerative vent dermatitis. The predisposing factors that led to this disease are suspected to be the novel exposure of the rowi to parasites from seabirds or marine mammals due to the island crèche and the limited management of roost boxes. This is the first instance of cutaneous larval migrans to be recorded in birds. Severe and fatal complications of the investigation resulted in the death of eight birds of aspergillosis and pulmonary complications associated with the use of bark as a substrate in hospital. Another bird died of renal failure during the period of hospitalisation despite oral and intravenous fluid therapy. The initiating cause of the renal failure was not determined. These complications have the potential to undermine the working relationship between wildlife veterinarians and conservation managers. This case highlights that intensive conservation management can result in increased opportunities for novel routes of cross-species pathogen transmission.