Widespread Disease in Hedgehogs (Erinaceus europaeus) Caused by Toxigenic Corynebacterium ulcerans

Abstract

Toxin-producing Corynebacterium ulcerans, a causative agent of diphtheria in humans, was isolated from 53 hedgehogs in Belgium during the spring of 2020. Isolates showed low levels of acquired antimicrobial drug resistance. Strain diversity suggests emergence from an endemic situation. These findings stress the need for raising public awareness and improved wildlife disease surveillance.

Keywords: Belgium; Corynebacterium ulcerans; Erinaceus europaeus; Flanders; antimicrobial resistance; bacteria; diphtheria; disease; hedgehogs; toxigenic; zoonoses.

Figure 1

Toxigenic Corynebacterium ulcerans as cause of widespread disease in hedgehogs (Erinaceus europaeus), Flanders, Belgium. A) Locations of 81 hedgehogs with lesions on the head or limbs from 4 regions in Flanders, Belgium, who were tested for C. ulcerans. Green, blue, black, and yellow indicate proportion of positive animals; gray indicates proportion of negative animals. Regions: A, Geraardsbergen; B, Merelbeke; C, Herenthout; D, Oudsbergen. Scale bar = 50 km. B) Representative clinical state with necrotizing facial dermatitis in 1 male hedgehog from Merelbeke. C) Ulcerative dermatitis with suppurative exudation and inflammation extending into the subcutis and underlying skeletal muscles. Hematoxylin and eosin stained; scale bar = 100 μm. D) Microcolonies of gram-positive bacilli in suppurative exudate. Gram stain; scale bar = 10 μm.

Figure 2

Dendrogram of Fourier-transformed infrared spectra of Corynebacterium spp. strains obtained from hedgehogs (Erinaceus europaeus), Flanders, Belgium, compared with spectra from several C. ulcerans isolates, including isolates from free-roaming red foxes (Vulpes vulpes) and wild boars (Sus scrofa scrofa) (1) and other well characterized and available isolates from animals and humans. Additional details for isolates were determined by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (8). Country of origin: BEL, Belgium (region: Ge, Geraardsbergen [green]; Me, Merelbeke [blue]; Ou, Oudsbergen [yellow]); BE, Berlin; BY, Bavaria; DEU, Germany. NT, no tox gene; NTTB, nontoxic but tox-bearing (these are isolates that have the toxin gene, but do not produce toxins); T, type strain; Tox, toxigenic; tox-w, toxigenic (weak).