Low occurrence of Salmonella spp. in wild birds from a Swiss rehabilitation centre

Correlates of Co-Infection with Coccidiosis and Avian Malaria in House Finches (Haemorhous mexicanus)

Pathogens have traditionally been studied in isolation within host systems; yet in natural settings they frequently coexist. This raises questions about the dynamics of co-infections and how host life-history traits might predict co-infection versus single infection. To address these questions, we investigated the presence of two parasites, a gut parasite (Isospora coccidians) and a blood parasite (Plasmodium spp.), in House Finches (Haemorhous mexicanus), a common passerine bird in North America. We then correlated these parasitic infections with various health and condition metrics, including hematological parameters, plasma carotenoids, lipid-soluble vitamins, blood glucose concentration, body condition, and prior disease history. Our study, based on 48 birds captured in Tempe, Arizona, US, in October 2021, revealed that co-infected birds exhibited elevated circulating lutein levels and a higher heterophil:lymphocyte ratio (H/L ratio) compared to those solely infected with coccidia Isospora spp. This suggests that co-infected birds experience heightened stress and may use lutein to bolster immunity against both pathogens, and that there are potentially toxic effects of lutein in co-infected birds compared to those infected solely with coccidia Isospora sp. Our findings underscore the synergistic impact of coparasitism, emphasizing the need for more co-infection studies to enhance our understanding of disease dynamics in nature, as well as its implications for wildlife health and conservation efforts.

Low Occurrence of Salmonella spp. in Wild Animals in Bahia, Brazil-Population Assessment and Characterization in the Caatinga and Atlantic Forest Biomes

Salmonella spp. are known to persist in the environment. Wild animals are believed to act as important reservoirs, with antimicrobial resistance frequently occurring in the environment. However, little is known about the role of the wildlife in Bahia as a reservoir for Salmonella in Brazil. This study aimed to isolate and characterize Salmonella spp. from wildlife in the Atlantic Forest and Caatinga biomes considering indicators such as the animal species, degree of anthropization, sampling area, and feeding habits. Convenience wildlife sampling and characterization were conducted, followed by microbiological and molecular identification of Salmonella isolates, serotyping, and antimicrobial susceptibility testing. A total of 674 fecal samples were collected from 12 municipalities during 2015-2021, and 4 were positive for the following Salmonella species: Salmonella enterica subspecies enterica serovar Agona (n = 1), Salmonella enterica subsp. enterica serogroup O:16 (n = 2), and Salmonella enterica subsp. enterica serovar Muenchen (n = 1). Antimicrobial susceptibility analysis revealed that one isolate was resistant to six antibiotics, including extended-spectrum penicillins and beta-lactamase inhibitors. These results indicated a low frequency of Salmonella spp. in the sampled forest fragments. The presence of Salmonella in wild animals increases the risk to public health and biodiversity and indicates that they can act as sentinels of environmental contamination or indicators of preservation.

Antimicrobial Susceptibility of Commensal E. coli Isolated from Wild Birds in Umbria (Central Italy)

The role of wildlife, including birds, in antimicrobial resistance is nowadays a speculative topic for the scientific community as they could be spreaders/sources of antimicrobial resistance genes. In this respect, we aimed to investigate the antimicrobial susceptibility of 100 commensal Escherichia coli strains, isolated from wild birds from an Umbrian rescue centre and admitted to the Veterinary Teaching Hospital of Perugia (Central Italy) mainly for traumatic injuries. The possible presence of Salmonella spp. and ESBL-producing E. coli was also estimated. The highest prevalence of resistance was observed for ampicillin (85%) and amoxicillin/clavulanic acid (47%), probably due to their extensive use in human and veterinary medicine. Seventeen out of the one hundred E. coli isolates (17%) displayed a multidrug-resistance profile, including the beta-lactam category, with the most common resistance patterns to three or four classes of antibiotics. Resistance to ciprofloxacin, cefotaxime and ceftazidime exhibited values of 18%, 17% and 15%, respectively. Eight out of the hundred E. coli isolates (8%) were ESBL and seven showed multidrug resistance profiles. Salmonella spp. was not isolated. Resistance to third-generation cephalosporins, also detected in long-distance migratory birds, suggests the need for monitoring studies to define the role of wild birds in antimicrobial resistance circuits.