This study is the first to report Blastocystis sp. in dairy cattle from Terceira Island, part of the Azores Archipelago. Blastocystis sp. is an enteric protozoan with high genetic diversity and is associated with both zoonotic and non-zoonotic subtypes (STs). The present survey aimed to fill the gap in knowledge regarding the occurrence and genetic characterization of Blastocystis sp. isolates in Holstein-Friesian cattle in this geographical area. A total of 116 stool samples were thus collected from dairy cows, and Blastocystis sp. DNA was detected using qPCR. The results revealed a 14.7% occurrence rate (17/116), with seven STs identified including ST3, ST5, ST7, ST10, ST14, ST25, and ST42, with variable frequency. Some of these STs (ST5, ST7, ST10, and ST14) are potentially zoonotic, underscoring their potential public health significance. However, the low frequency of Blastocystis sp. in this animal cohort possibly attributed to the extensive grazing system practiced on Terceira Island and the limited presence of zoonotic isolates, suggests a minimal risk of transmission from cattle to humans. This study highlights the importance of further research on the transmission dynamics of Blastocystis sp., particularly in regions with varying farming practices, to better understand its epidemiology and zoonotic potential.

Background: Bovine mastitis (BM) is a major disease affecting dairy herds (DHs), with Serratia marcescens (S. marcescens) being increasingly implicated as a causative agent. The growing concern over antimicrobial resistance (AMR) extends to BM-associated S. marcescens isolates, where resistance patterns are emerging. Methods: Here, four BM Gram-negative isolates were investigated: 1-DH1, 2-DH1, 3-DH2, and 4-DH3. Phenotypic characterization was performed using the Neg-Urine-Combo98 panel on a MicroScan WalkAway Plus system. Whole-genome sequencing (WGS) was performed to characterize and identify AMR and virulence factors (VF) genes and plasmids in isolates 1-DH1, 3-DH2, and 4-DH3, and phylogenomic analyses were conducted for a visual comparison of the genomes. Results: Phenotypically, isolates 1-DH1, 2-DH1, and 4-DH3 were identified as S. marcescens, and 3-DH2 as Serratia odorifera (confirmed as S. marcescens by WGS). A 28.00% (n = 25) prevalence of phenotypic AMR for isolates 1-DH1, 2-DH1, and 4-DH3 against Aug-E, AM, To, Cfx, Crm, Cl, and Fd was shown, and 24.00% (n = 25) for isolate 3-DH2 against Aug-E, AM, To, Crm, Cl, and Fd. The AMR genes AAC(6′)-Ic, aac(6′)-Ic_1, aac(6′)-Ial, H-NS, SRT-2, oqxB, oqxB_1, oqxB25, mexI, CRP, and blaSST-1, and flgH, fliP, fliM, and fliG VF genes were identified in the whole genome of the S. marcescens sequenced isolates 1-DH1, 2-DH1, and 4-DH3. In addition, a phylogenomic analysis of these three isolates revealed that WGS genomes are more closely related to S. marcescens prevenient from environmental sources. Conclusions: This study reports, for the first time, AMR resistance to tobramycin, cefuroxime, colistin, and nitrofurantoin in BM S. marcescens isolates. Genomic analysis revealed the presence of multiple AMR and VF genes, further highlighting the pathogenic potential of these isolates. Phylogenomic analysis revealed that the genome of the three BM S. marcescens isolates is more closely related to environmental S. marcescens strains.

Due to their frequent contact with animals, veterinarians may be at preferential risk of Coxiella burnetii exposure due to occupational contact with livestock. This study assesses the seroprevalence and risk factors associated with C. burnetii seropositivity in Portuguese veterinarians. A cross-sectional study compared IgG anti-C. burnetii in veterinarians’ sera to a demographically matched control group. Univariate and multivariate logistic regression analyses evaluated associations between the demographic, occupational, and biosecurity factors and seropositivity. Seroprevalence among veterinarians was 33.7%, significantly higher (p = 0.0023) than in the controls (17.39%). Univariate analysis identified higher seropositivity in the northern region (p = 0.03), though this association was not significant after adjustment (p = 0.07). Protective measures, including isolating aborting animals from the rest of the herd (adjusted OR [aOR]: 0.35, p = 0.03) and wearing gloves during sample collection (OR: 0.28, p = 0.009), were significantly associated with lower infection risk. Veterinarians face increased C. burnetii exposure, but specific biosecurity practices reduce risk. Strengthening preventive measures, including personal protective equipment (PPE) use and biosecurity training, is essential to mitigate occupational and public health risks. Further research should explore vaccination strategies and molecular epidemiology to improve risk reduction efforts.

Background: Antimicrobial resistance (AMR) is a growing global health concern, driven in part by antibiotic use in animal production systems. Despite its relevance, the microbiome and resistome of small ruminant farm environments remain largely underexplored. Methods: In this study, shotgun metagenomics was applied to environmental samples from 46 sheep, goat and mixed-species farms across 14 municipalities in central Portugal. Results: Microbial profiling revealed a well-preserved microbiome with Pseudomonadota, Actinomycetota, Bacteroidota and Bacillota (syn. Proteobacteria, Actinobacteria, Bacteroidetes and Firmicutes respectively) as the most dominant phylum across different farm types. Regarding AMR, a total of 706 unique antimicrobial resistance genes (ARGs), covering 15 antibiotic classes, were detected. Tetracycline, aminoglycoside and macrolide resistance genes dominated across all samples, forming a conserved core resistome. While overall resistome profiles were broadly similar among farm types, significant differences were observed in specific ARG classes, such as pleuromutilin and fosfomycin. Conclusions: These findings highlight small ruminant farm environments as potential reservoirs of clinically relevant ARGs, including WHO highest priority critically important antimicrobial (HPCIA) resistance genes for macrolides (mph(c), erm(f), erm(b)) and fluoroquinolones (qnrD1), as well as critically important antimicrobial (CIA) resistance genes for glycopeptides (vanR-SC, vanR-O) and aminoglycosides (str, aadA), supporting the need to incorporate these environments into surveillance strategies.

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.

Parasitic infections of the gastrointestinal tract of domestic animals play a major role in the transmission of disease, which in turn may result in financial and productive losses. Notwithstanding, studies on the burden and distribution of diarrheagenic protists in zoological gardens are still insufficient. Given the close animal–animal and animal–human interaction in these settings, Public Health concerns under the One Health context are raised. Using molecular detection tools and phylogenetic analysis, the goal of this study was to assess the occurrence of four potentially zoonotic protists—Balantioides coli, Blastocystis sp., Cryptosporidium spp. and Giardia spp.—in animals residing in zoological parks in Portugal. Occurrence of Eimeria spp. was also assessed because of its veterinary relevance. Although Blastocystis sp. represents most of the positive samples obtained (11.6%; 95% CI: 0.08–0.17), all parasites were detected (B. coli (2.9%; 95% CI: 0.01–0.06), and Cryptosporidium spp., Eimeria spp. and Giardia spp. presented the same prevalence (0.5%; 95% CI: 0.00–0.03)). We also describe the first molecular detection of B. coli in a collared peccary (Tayassu tajacu), of Blastocystis sp. in three different python species, and G. muris in a central bearded dragon (Pogona vitticeps), suggesting the broadening of the host range for these parasites.