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Research article - Peer-reviewed, 2018

Pathology of natural Francisella tularensis subsp holarctica infection in two yellow-necked mice (Apodemus flavicollis)

Hestvik, Gete; Uhlhorn, Henrik; Mattsson, Roland; Westergren, Eva; Sodersten, Fredrik; Akerstrom, Sara; Gavier-Widen, Dolores

Abstract

Background: Tularemia is a zoonosis caused by the bacterium Francisella tularensis. It has a wide host range, which includes mammals, birds and invertebrates. F. tularensis has often been isolated from various species of small rodents, but the pathology in naturally infected wild rodent species has rarely been reported.Case presentation: Herein, we describe the pathology of tularemia in two naturally infected wild yellow-necked mice (Apodemus flavicollis). To visualize F. tularensis subsp. holarctica, indirect immunofluorescence and immunohistochemistry were applied on tissue sections. Real time polymerase chain reaction detected the bacterium in samples from liver and spleen in both mice. The only finding at necropsy was splenomegaly in one of the mice. Histological examination revealed necrotic foci in the liver associated with mild inflammation in both mice. Immunohistochemistry and indirect immunofluorescence showed bacteria disseminated in many organs, in the cytoplasm of macrophages, and intravascularly.Conclusions: The two yellow-necked mice died of an acute disease caused by tularemic infection disseminated to many organs. Further investigations of naturally infected small rodents are important to better understand the variability in pathological presentation caused by infection by F. tularensis subsp. holarctica, as well to elucidate the importance of small rodents as transmitters and/or reservoirs.

Keywords

Apodemus flavicollis; Francisella; Immunohistochemistry; Pathology; Tularemia; Small rodent; Yellow-necked mouse

Published in

Acta Veterinaria Scandinavica
2018, volume: 60, article number: 26
Publisher: BIOMED CENTRAL LTD

Authors' information

Hestvik, Gete
Swedish University of Agricultural Sciences, Department of Biomedical Science and Veterinary Public Health
Hestvik, Gete
National Veterinary Institute (SVA)
Uhlhorn, Henrik
National Veterinary Institute (SVA)
Mattsson, Roland
National Veterinary Institute (SVA)
Westergren, Eva
National Veterinary Institute (SVA)
Åkerström, Sara
National Veterinary Institute (SVA)
Gavier-Widen, Dolores (Gavier Widén, Dolores)
National Veterinary Institute (SVA)
Gavier-Widen, Dolores (Gavier Widén, Dolores)
Swedish University of Agricultural Sciences, Department of Biomedical Science and Veterinary Public Health

UKÄ Subject classification

Clinical Science

Publication Identifiers

DOI: https://doi.org/10.1186/s13028-018-0381-9

URI (permanent link to this page)

https://res.slu.se/id/publ/95259