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.

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.

Between 2016 and 2023, a cross-sectional study was conducted in the central region of Portugal in order to better understand the epidemiology and public health risks resulting from the handling and consumption of game animals infected with Brucella spp. The seroprevalence and risk factors for Brucella spp. seropositivity were evaluated. Antibodies against Brucella spp. were determined using a commercial enzyme-linked immunosorbent assay (ELISA) according to the manufacturer’s instructions. Results showed that in the 650 serum samples collected from red deer (n = 298) and wild boars (n = 352) in Portugal, 21.7% (n = 141; 95% CI: 18.6–25.1%) tested positive. Wild boar had a significantly higher prevalence (35.5%; 95% CI: 30.5–40.8%) than red deer (5.4%, 95% CI: 3.1–8.6%; p ≤ 0.001). Risk factors for seropositivity were investigated using multivariable logistic regression models. The odds of being seropositive was 8.39 (95% CI: 4.75–14.84; p ≤ 0.001) times higher in wild boar than in red deer. Correlations between sex, age, body condition, and seropositivity could not be observed. The higher seroprevalence in wild boar suggests that this species may primarily contribute to the Brucella spp. ecology in central Portugal.

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 the Centre of 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 collected from 298 wild red deer and 352 wild boars from Portugal, 9.1% red deer (95% confidence interval [CI]: 6.312.9%) and 1.7% wild boar (95% CI: 0.63.3%) were positive for antibodies to HEV. Regarding age, the seropositivity in juvenile wild ungulates was 1.3% (95% CI: 0.273.72%) and 7.2% in adults (95% CI: 4.910.11%). Logistic regression models investigated risk factors for seropositivity. The odds of being seropositive was 3.6 higher in adults than in juveniles (95% CI: 1.7218.11%) and the risk was 4.2 higher in red deer than in wild boar (95% CI: 1.64–10.69%). Both wild ungulate species were exposed to HEV. The higher seroprevalence in red deer suggests that this species may have a major contribution to the ecology of HEV in the Centre of Portugal. Further research is important to understand how wildlife affects the epidemiology of HEV infection in Portugal.

Tularemia is a zoonotic disease caused by the highly contagious bacterium Francisella tularensis, with rabbits, hares, and rodents considered as primary reservoirs. Clinical manifestations in humans can range from mild to life-threatening, depending on the mode of exposure (ingestion, inhalation, skin contact, injection, or tick bite), with high fever being a common feature. The primary aim of the present research was to evaluate the circulation of F. tularensis and the potential infection among wild boar (Sus scrofa) and red deer (Cervus elaphus) from the central region of Portugal. A total of 368 samples (including serum and organ samples) were collected from 184 wild boar and 184 red deer. For serological analysis, two commercially available enzyme-linked immunosorbent assay (ELISA) kits were used to detect immunoglobulin M (IgM) and G (IgG) antibodies to F. tularensis. Antibodies to F. tularensis (IgG and IgM) were detected in one adult male wild boar, corresponding to a seroprevalence of 0.54% (1/184, 95% confidence interval [95% CI]: 0.01–3.0%). No antibodies to F. tularensis were detected in red deer. Molecular detection by PCR was negative in the seropositive animal, in which submandibular lymph node, liver, and spleen samples were analysed targeting the 16S rRNA gene. These findings indicate exposure of wild boar to F. tularensis in central Portugal, suggesting a sporadic presence of the pathogen. Although no evidence of active infection was detected in the analysed tissues, the presence of seropositive individuals highlights the need for further investigation. Despite the very low seroprevalence observed, the zoonotic potential of F. tularensis supports the importance of continued surveillance within a One Health perspective.