Pacific Gulls (Larus pacificus) as Potential Vectors of Coxiella burnetii in an Australian Fur Seal Breeding Colony

Brett R Gardner; Jasmin Hufschmid; John Stenos; Mythili Tadepalli; Grace Sutton; Aymeric Fromant; Yonina Eizenberg; Johanna J Geeson; John P Y Arnould

doi:10.3390/pathogens12010122

Pacific Gulls (Larus pacificus) as Potential Vectors of Coxiella burnetii in an Australian Fur Seal Breeding Colony

Pathogens. 2023 Jan 11;12(1):122. doi: 10.3390/pathogens12010122.

Authors

Brett R Gardner¹, Jasmin Hufschmid¹, John Stenos², Mythili Tadepalli², Grace Sutton³, Aymeric Fromant⁴, Yonina Eizenberg^{3

4}, Johanna J Geeson³, John P Y Arnould³

Affiliations

¹ Melbourne Veterinary School, The University of Melbourne, Parkville, VIC 3030, Australia.
² Australian Rickettsial Reference Laboratory, University Hospital Geelong, Bellerine Street, Geelong, VIC 3220, Australia.
³ School of Life and Environmental Sciences, Deakin University, Geelong, VIC 3125, Australia.
⁴ Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 CNRS-La Rochelle Université, 79360 Villiers-en-Bois, France.

Abstract

Recently, Coxiella burnetii has been described as a novel pathogen potentially contributing to decreased pup production in Australian fur seals (AusFS, Arctocephalus pusillus doriferus). Pacific gulls (PGs, Larus pacificus) are known to scavenge AusFS placental material during the fur seal breeding season. It is hypothesized that PGs may act as vectors for this pathogen. In the present study, cloacal swabs, oral swabs and serum were collected from PGs on Kanowna Island (KI, an AusFS breeding colony) and a nearby island, Seal Island (SI), not occupied by pinnipeds. All sample sets were evaluated with qPCR for the com1, htpAB and IS1111 markers. Most oral and cloacal swabs from KI tested positive on both the com1 (94.1%; 88.2%) and htpAB targets (76.5%; 76.5%). Amplification was very low from the SI oral swabs and cloacal swabs. Only the KI serum samples had amplification (17.7% for both com1 and htpAB). There was no IS1111 amplification in either colony. The results demonstrate that PGs can potentially act as vectors for the spread of C. burnetii. In some birds, C. burnetii was detectable in the serum, indicating that gulls can experience bacteraemia. It appears that different feeding strategies in the same species within the same ecosystem can have profound effects on the prevalence of pathogens. Further studies are required to better understand the epidemiology and potential risks of this organism.

Keywords: abortion; marine mammal gestational loss; oral cloacal swabs; placenta; sea bird; southeastern Australia; zoonoses.

Grants and funding

The costs and logistics of fieldwork were funded by Deakin University. Molecular work was funded by the Australian Rickettsial Reference Laboratory. The research was supported and funded in part by the University of Melbourne and the Merle Ivy Research Scholarship.