Browsing by Author "Grimwood RM"

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Evidence for a Role of Extraintestinal Pathogenic Escherichia coli, Enterococcus faecalis and Streptococcus gallolyticus in the Aetiology of Exudative Cloacitis in the Critically Endangered Kākāpō (Strigops habroptilus)
(John Wiley and Sons Ltd, 2025-04-19) French RK; Waller SJ; Wierenga JR; Grimwood RM; Hodgkinson-Bean J; Digby A; Uddstrom L; Eason D; Kākāpō Recovery Team; Argilla LS; Biggs PJ; Cookson A; French NP; Geoghegan JL
The kākāpō is a critically endangered flightless parrot which suffers from exudative cloacitis, a debilitating disease resulting in inflammation of the vent margin or cloaca. Despite this disease emerging over 20 years ago, the cause of exudative cloacitis remains elusive. We used total RNA sequencing and metatranscriptomic analysis to characterise the infectome of lesions and cloacal swabs from nine kākāpō affected with exudative cloacitis, and compared this to cloacal swabs from 45 non-diseased kākāpō. We identified three bacterial species—Streptococcus gallolyticus, Enterococcus faecalis and Escherichia coli—as significantly more abundant in diseased kākāpō compared to healthy individuals. The genetic diversity observed in both S. gallolyticus and E. faecalis among diseased kākāpō suggests that these bacteria originate from exogenous sources rather than from kākāpō-to-kākāpō transmission. The presence of extraintestinal pathogenic E. coli (ExPEC)-associated virulence factors in the diseased kākāpō population suggests that E. coli may play a critical role in disease progression by facilitating iron acquisition and causing DNA damage in host cells, possibly in association with E. faecalis. No avian viral, fungal nor other parasitic species were identified. These results, combined with the consistent presence of one E. coli gnd sequence type across multiple diseased birds, suggest that this species may be the primary cause of exudative cloacitis. These findings shed light on possible causative agents of exudative cloacitis, and offer insights into the interplay of microbial factors influencing the disease.
Oral and Faecal Viromes of New Zealand Calves on Pasture With an Idiopathic Ill-Thrift Syndrome
(John Wiley and Sons Ltd, 2025-07-28) Grimwood RM; Darnley JA; O’Connell JP; Hunt H; Taylor HS; Lawrence KE; Abbott MBW; Jauregui R; Geoghegan JL; Zhai S-L
Since 2015, an idiopathic ill-thrift syndrome featuring diarrhoea and, in some cases, gastrointestinal ulceration has been reported in weaned New Zealand dairy calves. Similar syndromes have been described in the British Isles and Australia, but investigations in New Zealand have yet to identify a specific cause. Notably, the viromes of affected calves remain understudied. We conducted metatranscriptomic analyses of oral and faecal viromes in 11 calves from a dairy farm in Taranaki, New Zealand, experiencing an outbreak of this syndrome. This included nine calves showing clinical signs. Our analysis identified 18 bovine-associated viruses across two DNA and three RNA viral families, including six novel species. Oral viromes were dominated by Pseudocowpox virus, which was detected in all calves with oral lesions. Faecal viromes were more diverse, featuring adenoviruses, caliciviruses, astroviruses and picornaviruses. Bovine bopivirus, from the Picornaviridae family and previously unreported in New Zealand, was significantly associated with calves showing oral lesions and diarrhoea, indicating a possible link to disease, though its role remains unclear. The diverse viral communities of the calves complicate the identification of a single causative agent. Importantly, no novel viruses were significantly associated with the syndrome, and the viromes closely resembled those found in cattle globally. These findings suggest the syndrome likely has a multifactorial origin involving nutritional, management and environmental factors rather than being driven primarily by known or novel viruses. Further, research across regions and seasons is recommended to clarify the role of viruses in idiopathic ill-thrift among New Zealand calves.
Total infectome investigation of diphtheritic stomatitis in yellow-eyed penguins (Megadyptes antipodes) reveals a novel and abundant megrivirus.
(Elsevier B.V., 2023-11-01) Wierenga JR; Grimwood RM; Taylor HS; Hunter S; Argilla LS; Webster T; Lim L; French R; Schultz H; Jorge F; Bostina M; Burga L; Swindells-Wallace P; Holmes EC; McInnes K; Morgan KJ; Geoghegan JL
First identified in 2002, diphtheritic stomatitis (DS) is a devastating disease affecting yellow-eyed penguins (Megadyptes antipodes, or hoiho in te reo Māori). The disease is associated with oral lesions in chicks and has caused significant morbidity and mortality. DS is widespread among yellow-eyed penguin chicks on mainland New Zealand yet appears to be absent from the subantarctic population. Corynebacterium spp. have previously been suspected as causative agents yet, due to inconsistent cultures and inconclusive pathogenicity, their role in DS is unclear. Herein, we used a metatranscriptomic approach to identify potential causative agents of DS by revealing the presence and abundance of all viruses, bacteria, fungi and protozoa - together, the infectome. Oral and cloacal swab samples were collected from presymptomatic, symptomatic and recovered chicks along with a control group of healthy adults. Two novel viruses from the Picornaviridae were identified, one of which - yellow-eyed penguin megrivirus - was highly abundant in chicks irrespective of health status but not detected in healthy adults. Tissue from biopsied oral lesions also tested positive for the novel megrivirus upon PCR. We found no overall clustering among bacteria, protozoa and fungi communities at the genus level across samples, although Paraclostridium bifermentans was significantly more abundant in oral microbiota of symptomatic chicks compared to other groups. The detection of a novel and highly abundant megrivirus has sparked a new line of inquiry to investigate its potential association with DS.