Transmissible Spongiform Encephalopathies (TSEs) or prion diseases are a fatal group of infectious, inherited and spontaneous neurodegenerative diseases affecting human and animals. They are caused by the conversion of cellular prion protein (PrP^C) into a misfolded pathological isoform (PrP^Sc or prion- proteinaceous infectious particle) that self-propagates by conformational conversion of PrP^C. Yet by an unknown mechanism, PrP^C can fold into different PrP^Sc conformers that may result in different prion strains that display specific disease phenotype (incubation time, clinical signs and lesion profile). Although the pathways for neurodegeneration as well as the involvement of brain inflammation in these diseases are not well understood, the spongiform changes, neuronal loss, gliosis and accumulation of PrP^Sc are the characteristic neuropathological lesions. Scrapie affecting small ruminants was the first identified TSE and has been considered the archetype of prion diseases, though atypical and new animal prion diseases continue to emerge highlighting the importance to investigate the lesion profile in naturally affected animals. In this report, we review the neuropathology and the neuroinflammation of animal prion diseases in natural hosts from scrapie, going through the zoonotic bovine spongiform encephalopathy (BSE), the chronic wasting disease (CWD) to the newly identified camel prion disease (CPD).

Q fever is caused by the pathogen Coxiella burnetii and is a zoonosis that naturally infects goats, sheep, and cats, but can also infect humans, birds, reptiles, or arthropods. A survey was conducted for the detection of antibodies against C. burnetii in a sample of 617 free-ranging wild ruminants, 358 wild boar (Sus scrofa) and 259 red deer (Cervus elaphus), in east–central Portugal during the 2016–2022 hunting seasons. Only adult animals were sampled in this study. Antibodies specific to C. burnetii were detected using a commercial enzyme-linked immunosorbent assay (ELISA; IDVet^®, Montpellier, France) according to the manufacturer’s instructions. The seroprevalence of C. burnetii infection was 1.5% (n = 9; 95% confidence interval [CI]: 0.7–2.8%). Antibodies against C. burnetii were detected in 4/358 wild boar (1.1%; 95% CI: CI: 0.3–2.8%) and 5/259 red deer (1.9%; 0.6–4.5%). Results of the present study indicate that antibodies against C. burnetii were present in wild boar and red deer in Portugal. These findings can help local health authorities to focus on the problem of C. burnetii in wildlife and facilitate the application of a One Health approach to its prevention and control.

A survey to determine the occurrence of Mycobacterium avium subsp. paratuberculosis (MAP) in wild carnivores in Portugal was conducted by testing samples from road-killed animals between 2009 and 2012. Postmortem examinations were performed and tissues were collected from wild carnivores representing four families and six different species, with a total of 74 animals analyzed. Cultures were performed by using Löwenstein-Jensen and Middlebrook 7H11 solid media and acid-fast isolates were identified by polymerase chain reaction (PCR) and mycobactin dependency characteristics. Tissues were also screened for MAP by directly extracting DNA and testing for the MAP-specific sequences. The occurrence of infected animals (an animal had at least one tissue that was positive for culture or direct PCR) was 27.0% (n = 20). MAP was isolated from culture of 25 tissue samples (3.8%) and was detected by direct PCR in 40 (6.0%) samples. Infection was recorded in 5/6 studied species: 7/49 (14.3%) red foxes (Vulpes vulpes), 3/3 (100%) beech martens (Martes foina), 2/4 (50.0%) Eurasian otters (Lutra lutra), 7/15 (46.7%) Egyptian mongooses (Herpestes ichneumon), and 1/1 (100%) European badger (Meles meles). These species represent three different taxonomic families: Canidae (14.3% were positive), Mustelidae (75.0% were positive), and Herpestidae (46.7% were positive). The results of this study confirm the presence of MAP infection in wild carnivores in Portugal.

We report granulomatous lymphadenitis in red deer (Cervus elaphus) in Portugal caused by coinfection with Corynebacterium pseudotuberculosis, Mycobacterium bovis, and Mycobacterium avium subsp. paratuberculosis, as demonstrated by molecular methods.

Hepatitis E virus (HEV) is a zoonotic foodborne virus with an annual infection prevalence of 20 million human cases, which seriously affects public health and economic development in both developed and developing countries. To better understand the epidemiology of HEV in Central Portugal, a cross-sectional study was conducted from 2016 to 2023 with sera samples from wild ungulates. The seroprevalence and risk factors for HEV seropositivity were evaluated in the present study. Specifically, antibodies against HEV were determined by a commercial enzyme-linked immune-sorbent assay (ELISA). Our results show that in the 650 sera samples collected from 298 wild red deer and 352 wild boars in Portugal, 9.1% red deer and 1.7% wild boar were positive for antibodies to HEV. Regarding age, the seropositivity in juvenile wild ungulates was 1.3%, whereas it was 7.2% in adults. Logistic regression models investigated risk factors for seropositivity. The odds of being seropositive was 3.6 times higher in adults than in juveniles, and the risk was 4.2 times higher in red deer than in wild boar. Both wild ungulate species were exposed to HEV. The higher seroprevalence in red deer suggests that this species may make a major contribution to the ecology of HEV in Central Portugal. Further research is needed to understand how wildlife affects the epidemiology of HEV infections in Portugal.