Chronic Wasting Disease Monitoring in Italy 2017-2019: Neuropathological Findings in Cervids

Abstract

Chronic wasting disease (CWD) is a prion disease that affects cervids; it is classified under transmissible spongiform encephalopathies (TSEs). CWD is particularly contagious, making its eradication in endemic areas very difficult and creating serious problems for cervid conservation and breeding. It has recently become an emerging public health risk to be managed by health authorities. Starting in 2017, active CWD surveillance in Italy has intensified with the monitoring of wild and farmed cervids. The present study summarizes findings from a histopathological survey of the brains from wild ruminants collected via CWD monitoring between 2017 and 2019. A total of 113 brains from 62 red deer (Cervus elaphus) and 51 roe deer (Capreolus capreolus) were submitted for analysis at the National Reference Center for Animal Encephalopathies (CEA) to determine major patterns of neuropathological lesions and correlated pathogens. Brain lesions were detected in 20 animals, 10 brain samples were unsuitable for examination, and 83 presented no lesions. Neuropathological examination revealed non-suppurative encephalitis or meningoencephalitis in most cases (15/20). This brain study revealed evidence for the absence of CWD in Italy and provided a reference spectrum of neuropathological lesions for differential diagnosis in cervids.

Keywords: CEA; TSE; cervids; chronic wasting disease; encephalopathy; neuropathological lesions; prion.

Figure 1

CWD cases in Norway, Sweden, and Finland reported since 2016.

Figure 2

Flowchart for sample testing.

Figure 3

Neuropathological analysis of brain samples from 62 red deer and 51 roe deer.

Figure 4

Neuropathological lesions. (A). Severe lymphoplasmacytic meningitis in the frontal cortex (red deer). HE; 20×. (B). Perivascular cuffing of mononuclear cells in the frontal cortex (red deer). HE; 20×. (C). Diffuse and severe suppurative meningoencephalitis characterized by infiltrate of polymorphonuclear cells (roe deer). HE; 10×. (D). Foci of gliosis in the parietal cortex (red deer). HE; 20×.