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. 2024 Nov 21;20(1):524.
doi: 10.1186/s12917-024-04375-3.

Infectious keratoconjunctivitis in European bison (Bison bonasus) in Poland: risk factors, epidemiology and anatomopathological changes with analysis of potential role of Thelazia nematodes in the disease development

Katarzyna Filip-Hutsch  1 , Aleksander W Demiaszkiewicz  2 , Tomasz Hutsch  3   4 , Karolina Duk  4 , Daniel Klich  5 , Anna M Pyziel  6 , Paulina Balińska  2 , Krzysztof Anusz  6
Affiliations

Infectious keratoconjunctivitis in European bison (Bison bonasus) in Poland: risk factors, epidemiology and anatomopathological changes with analysis of potential role of Thelazia nematodes in the disease development

Katarzyna Filip-Hutsch et al. BMC Vet Res. .

Abstract

Background: Infectious keratoconjunctivitis (IKC) is a common ocular disease of ruminants worldwide. Recently, an outbreak of infectious keratoconjunctivitis was observed in the European bison in Poland. Hundreds of animals show conjunctival congestion, corneal opacity, and ulceration, leading to total blindness. The present study aimed to examine the ocular changes of European bison and patterns of the disease occurrence with special emphasis on the role of Thelazia nematodes in the development of IKC.

Results: The eyes of 131 European bison, showing ocular signs and clinically healthy, were collected in Poland in 2021 - 2022 and subjected to parasitological and histopathological examination. Histopathology showed varying lesions, including corneal erosions or ulcers, diffuse purulent infiltrates to lymphocytic infiltration in the cornea, and lymphocytic or mixed conjunctivitis with CALT stimulation. The severity of ocular changes was higher in European bison from mountain areas and during the winter season. Two species of Thelazia nematodes - T. skrjabini and T. gulosa have been isolated from eyes. Prevalence of infection reached over 66.4%, and the infection intensity ranged from 1 to 16 nematodes per individual. Although nematodes of the genus Thelazia were prevalent in European bison, their occurrence did not correspond with the severity of ocular changes.

Conclusions: The results of our studies allowed to identify patterns related to the first outbreak of infectious keratoconjunctivitis in European bison. Living in mountain areas and winter season were the most predisposing factors for the development of ocular changes. Despite the high prevalence of Thelazia nematodes in the present study, their role in forming ocular lesions was not confirmed.

Keywords: Bison bonasus; Eyeworm; IKC outbreak; Ocular lesions.

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Conflict of interest statement

Declarations. Ethics approval and consent to participate: The authors confirm that the ethical policies of the journal, as noted on the journal’s author guidelines page, have been adhered with accordance to Directive 2010/63/EU of The European Parliament and of The Council of 22 September 2010 on the protection of animals used for scientific purposes. All European bison were legally culled on the basis of permission from the General Directorate for Environmental Protection in Poland. The decision of General Directorate for Environmental Protection was implemented by the Regional Head Offices of National Forests, which supervised animals sacrifice. European bison as wild animals, were culled by professional hunters with respect to the animals welfare and safety rules, in the presence of qualified veterinarians. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Intensity of infection of Thelazia nematodes in female and male European bison
Fig. 2
Fig. 2
The severity of macroscopic ocular changes observed in European bison scored from 0 to 3, with 0 for healthy eyes, 1 for increased lacrimation and/or mild conjunctivitis, 2 for animals with moderate to severe clinical signs of IKC and 3 for severe changes (deformation of the eyeball)
Fig. 3
Fig. 3
Severity of macroscopical and histopathological changes in European bison of the Lowland and the Lowland-Caucasian line
Fig.4
Fig.4
Intensity of histopathological changes in IKC in the European bison. Presentation of the cascade of severity of pathological changes in the cornea and conjunctiva according to the applied scalar severity assessment system. Legend of the scalar assessment of the severity of histopathological changes for the cornea: No changes—sum of points: 0–5; Minimal—sum of points:6–12; Slight—sum of points: 13–19; Moderate—sum of points: 20–26; Severe—sum of points: more than 27; for conjunctiva: No changes—sum of points: 0–10; Minimal—sum of points: 11–20; Slight—sum of points: 21–30; Moderate—sum of points: 31–40; Severe—sum of points: more than 41
Fig.5
Fig.5
Types of histopathological changes observed in the conjunctiva in IKC in the European bison. A-C – conjunctival epithelium in magnification × 400; D-F – conjunctival stroma in magnification × 100. Black arrow—mononuclear cell infiltration, White arrow—hyperplastic goblet cells, Blue arrow—fibrosis of the conjunctival stroma and the formation of connective tissue bundles, Red star – exfoliation and delamination of the conjunctival epithelium, Yellow star—stimulated lymphatic follicles
Fig. 6
Fig. 6
Types of histopathological changes observed in the cornea in IKC in the European bison. A-C – corneal stroma in magnification × 100; D-F – corneal epithelium in magnification × 400. Black arrow—mononuclear cell infiltration, Red arrow—neovascularization, White arrow—edema and delamination of corneal stroma fibers, Blue arrow—epidermal metaplasia of the corneal epithelium, Red star – necrosis of corneal epithelium, Yellow star—layered necrosis of the subepithelial corneal stroma fibers
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References

    1. Postma GC, Carfagnini JC, Minatel L. Moraxella bovis pathogenicity: an update. Comp Immunol Microbiol Infect Dis. 2008;31:449–58. - PubMed
    1. Angelos JA. Moraxella bovoculi and infectious bovine keratoconjunctivitis: cause or coincidence? Vet Clin North Am Food Anim Pract. 2010;26:73–7. - PubMed
    1. Gupta S, Chahota R, Bhardwaj B, Priyanka P, Verma S, Sharma M. Identification of Chlamydiae and Mycoplasma species in ruminants with ocular infections. Lett Appl Microbiol. 2015;60:135–9. 10.1111/lam.12362. - PubMed
    1. Sánchez Romano J, Mørk T, Laaksonen S, Ågren E, Nymo IH, Sunde M, Tryland M. Infectious keratoconjunctivitis in semi-domesticated Eurasian tundra reindeer (Rangifer tarandus tarandus): microbiological study of clinically affected and unaffected animals with special reference to cervid herpesvirus 2. BMC Vet Res. 2018;14:15. - PMC - PubMed
    1. Degiorgis MP, Frey J, Nicolet J, Abdo EM, Fatzer R, Schlatter Y, et al. An outbreak of infectious keratoconjunctivitis in Alpine chamois (Rupicapra r. rupicapra) in Simmental-Gruyères, Switzerland. SAT Schweiz. Arch Für Tierheilkd. 2000;42:520–7.

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