The Bagaza virus (BAGV) belongs to the genus Orthoflavivirus (Ntaya serocomplex) and emerged in Europe, Spain, in 2010. The natural transmission cycle of this virus is perpetuated by Culex spp. mosquitoes and viraemic birds. The ability of BAGV to cause infection in several game birds from the family Phasianidae has been well-studied. BAGV is antigenically similar to other orthoflaviviruses from the Japanese encephalitis serocomplex, such as the West Nile and Usutu viruses, a circumstance which can lead to cross-reactivity in less specific serological techniques (e.g., ELISA). Severe implications in animal health has already been described, but some aspects of the dynamics of transmission and the limits of zoonotic potential of BAGV still need to be clarified. Further investigation focused on epidemiological surveillance in high-risk areas would be beneficial for prevention and control of new outbreaks. The present study is a systematic review of the BAGV reports in Europe.

Wild birds may be involved in the transmission of agents of infectious diseases, including zoonoses, a circumstance which raises a number of public and animal health issues. Migratory bird species play a significant role in the introduction of tick-borne pathogens to new geographic areas, contributing to the dissemination of various etiological agents. This preliminary study aimed to assess the occurrence of four potentially zoonotic pathogens (Hepatozoon spp., Borrelia spp., Babesia spp. and Theileria spp.) in the wild birds of Portugal. Blood and tissue samples were taken from 103 birds admitted at wildlife rehabilitation centers. Through the use of conventional PCR, our findings indicate no evidence of the circulation of these pathogens among the studied bird populations in the region. In the One Health context, it is relevant to understand how faraway avian populations play a role in the epidemiology of infectious diseases. Further molecular studies are needed to deepen the knowledge of avian piroplasmosis, borreliosis and hepatozoonosis.

Emerging infectious diseases are a major threat to biodiversity and an important public health issue. Flaviviruses are the cause of several emerging vector-borne zoonotic arboviruses whose distribution is currently increasing in Europe. The evidence that West Nile virus (WNV) circulates in resident and migratory species has implications for both animal and public health and should therefore be studied in depth. USUTU (USUV), Bagaza (BAGV) and tick-borne encephalitis virus (TBEV) are other viruses that are beginning to spread more widely. An integrated surveillance program, namely in birds, is essential for reducing the risk of infection in human populations within the One Health principles. In the present study, wild birds admitted to wildlife rehabilitation centers in Portugal were sampled. Two hundred eight blood samples were assayed serologically for antibodies to flaviviruses by using a commercial ELISA kit. An overall seroprevalence of 19.6% (95% confidence interval [CI]: 13.7–26.7%) was observed. Antibodies against flaviviruses were detected in 13 (35.1%) different species of wild birds. Accipitriformes (26.7%; 95% CI: 18.5–36.2%) and Strigiformes (26.7%; 95% CI: 14.6–42.0%) were the orders with the highest seroprevalence rates recorded. There were no statistically significant differences (p = 0.725) between the geographical regions (NUTS II) studied, but a statistically significant difference (p = 0.017) was found between sex (male: 34.4%; female: 4.8%). A higher seroprevalence was detected in adults (32.1%) than in juvenile birds (9.3%) (p = 0.014), and age was considered a risk factor for flavivirus infection in wild birds (odds ratio 1.4; 95% CI: 0.5–4.0). More epidemiological studies are needed in Portugal since the actual spread of the genus Flavivirus throughout the country is unknown.

Coxiella burnetii is a highly infectious zoonotic pathogenic bacterium that has a major economic impact in the livestock industry throughout the world and causes unpredictable outbreaks in humans worldwide. Although it is known that birds are potential reservoirs of C. burnetii, their role in the epidemiological cycle of the pathogen has not been fully verified. Due to its non-specific symptoms and clinical signs, it is certainly an underdiagnosed disease. The objective of this study was to obtain more information on C. burnetii prevalence in wild birds in Portugal. Blood, plasma, and other tissue samples were obtained from wild birds admitted at wildlife rehabilitation centres in Portugal in the scope of passive surveillance. Antibodies specific to C. burnetii were screened using a commercial enzyme-linked immunosorbent assay according to the manufacturer’s instructions. Evidence of C. burnetii infection was sought based on the detection of bacterial DNA. No positive results were found, either in terms of antibodies to C. burnetii or molecular biology. These serological findings do not indicate the endemic circulation of C. burnetii in wild birds, which can be considered relevant information. However, a more complete and serialized approach over time is necessary to be able to make real inferences about the endemicity of the pathogen in the country and its dispersion among wild avian populations. qPCR results were also negative, a finding suggesting that this host population may not play a significant role in the transmission dynamics of C. burnetii. Given the importance of wild bird species as natural reservoirs of this zoonotic bacterium, we consider these data useful for multidisciplinary work in the prevention and control of Q fever, following a One Health approach.

Climate change is regarded as a critical issue for public health. Each year, its impact on human and animal health becomes increasingly evident as the risk of zoonosis transmission is exacerbated by extreme weather events and the movement of vectors into new areas. These changes are causing extensive consequences, affecting human health, the environment, and the global economy. Therefore, collective action is considered essential to mitigate the effects of climate change and safeguard public health for future generations. This study investigates the perceptions, knowledge, and practices of Portuguese citizens concerning vector-borne zoonoses and their connection to climate change. A descriptive cross-sectional study was carried out by distributing a survey to 147 individuals. The findings indicated that, on average, 80% of participants were aware of zoonoses, with the least recognised vector-borne zoonoses identified as the chikungunya virus and West Nile virus. Approximately 93% of the study population reported that they perceived temperatures in the warmer months have risen each year, with more than half of the participants noting an increase in the prevalence of vectors in the country during these months in recent years. Additionally, the results demonstrated that the majority of participants, about 93%, believed that veterinarians provided inadequate information regarding vector-borne zoonoses. The findings further revealed that the sampled population was unprepared for the realities increasingly faced in Europe and Portugal, with only 42% of participants reporting the use of preventive measures, such as repellents, against vectors. Consequently, there is a need for enhanced education and awareness campaigns, as well as a more proactive role from veterinarians in disseminating information and prevention strategies.

West Nile virus (WNV) is an arbovirus mainly transmitted by Culex spp., which causes a worldwide zoonotic disease. This pathogen is endemically maintained in a life cycle with birds acting as reservoirs and humans and horses as accidental and dead-end hosts. Sporadic WNV outbreaks have been reported in Europe and the potential impact of WNV infection on populations of threatened or endangered birds of prey is considerable. Surveillance programs are needed for early detection of this virus. All four species of vultures present in Europe are considered protected species. As scavengers, vultures are at the top of the food chain, and can be susceptible to and negatively affected by pathogens like WNV. In a conservation perspective, the impact of WNV in European vultures, alone or concomitantly with other factors, should be addressed. This review of documented cases can be considered a state point.