Transboundary and Emerging Diseases

Foot-and-mouth disease (FMD) virus is one of the most feared and most consequential pathogens of livestock worldwide. It can be spread rapidly by the transboundary movement of animals, animal products and byproducts. In January 2025, Germany detected its first FMD outbreak since 1988 in extensively reared water buffalo on a small farm in the state of Brandenburg, directly outside Berlin, the federal capital. Immediate control measures including a standstill for movements of susceptible animals and pre-emptive culling were implemented by the veterinary authorities. Whole-genome sequencing identified the virus as serotype O, topotype ME-SA, lineage SA-2018 and revealed extensive recombination, but cross-neutralization assays suggested good heterologous protection by an O/PanAsia-2 vaccine strain. Epidemiological back-calculation placed the time of virus introduction in late December 2024. Although the entry route remains unresolved, human-associated introduction is most likely. Network analysis revealed minimal farm connectivity, and simulations predicted low potential for onward transmission, which is consistent with the outbreak being ultimately restricted to a single herd. This event underscores the constant and unpredictable risk of introduction of the virus. Early detection through increased awareness and comprehensive differential diagnostics as well as the international collaboration of veterinary services, laboratories and experts are essential in the face of the global presence of FMD.

Zoos may serve as sentinel sites for zoonotic vector-borne diseases. West Nile virus (WNV) and Usutu virus (USUV) are closely related orthoflaviviruses transmitted between Culex mosquitoes and a bird reservoir. Both viruses can also infect mammals, including humans, where they may cause symptoms and, more rarely, hospitalization and death. However, serological cross-reactivity between WNV and USUV complicates their differential diagnosis. Here, we aimed to reconstruct the dynamics of emergence of WNV in a zoo located in a newly affected area in Europe, using ELISA and Virus Neutralization Test (VNT) serological analysis of 1707 animal sera collected between 2015 and 2024. Combining this data in a model accounting for cross-reactivity with USUV, we estimated yearly forces of infection (FOI) by both viruses, and thus found that WNV likely circulated in the area one year prior to the first cases reported to the passive surveillance system. Our results also showed that, in the zoo, mammals and reptiles had a lower risk of infection than birds (relative risk of 0.14 [0.05; 0.28]), and that the exposure of birds to water (aquatic lifestyle or proximity to stagnant water) affected the risk. Finally, we estimated diagnosis parameters, including the sensitivity of the VNT (80.4% [76.5%; 84.3%]), the expected VNT titer value, and the level of serological cross-reactivity between viruses during the VNT. To conclude, our modelling framework allowed to disentangle the co-circulation of two closely related viruses, a crucial point in ensuring the reliable sentinel surveillance of these vector-borne zoonotic pathogens.

BackgroundIn 2021, the Los Angeles County (LAC) Department of Public Health suspected a leptospirosis outbreak in LAC affecting over 200 client-owned dogs. ObjectiveTo characterize the outbreak and describe microbiologic findings, risk factors, diagnostic test performance, and outcomes in dogs diagnosed with leptospirosis at two specialty practices. MethodsLeptospira culture isolates from four cases were subjected to serotyping and whole genome sequencing (WGS); WGS was also performed on one enriched genome isolate. After the outbreak, data were gathered on 59 cases through record review and compared to the background hospital population (controls, n=15,536). ResultsAll isolates were Leptospira interrogans serovar Canicola, but each was distinct based on WGS. Cases clustered in space and in time. Cases evaluated during the outbreak peak had increased odds of exposure to indoor congregate facilities (ICFs). None of 47 dogs with known leptospirosis vaccination history were completely vaccinated. Leptospira real-time PCR on blood and urine and initial serologic testing using the microscopic agglutination test and point-of-care tests were positive in 15/56 (27%), 49/54 (91%) dogs, 22/29 (76%), and 27/35 (77%) dogs respectively. Fifty-four (92%) of 59 dogs survived to discharge; some remained azotemic. No associated human cases were identified. Conclusions and Clinical ImportanceL. interrogans serovar Canicola was associated with a leptospirosis outbreak in unvaccinated dogs from LAC, which had public health implications given widespread dog ownership rates. Data analysis suggested multiple infection sources, including ICFs. Urine PCR was the most sensitive diagnostic test. Such outbreaks might be prevented through more widespread vaccination.

Human leptospirosis is a disease of public health importance in Thailand, but the animal species involved in the transmission cycle have not been fully uncovered. This study investigated Leptospira infection in dogs and terrestrial micromammals in rural Nan Province, Thailand, and the pathogen diversity. Sera from 95 seemingly healthy dogs and kidney samples from 399 micromammals were analyzed using real-time PCR for Leptospira detection, followed by conventional PCR and sequencing of infecting Leptospira. We investigated environmental factors associated with Leptospira infection in micromammals, using data collected during trapping. Real-time PCR revealed ongoing infection in 8.4% (8/95) of dogs and 10.0% (40/399) of terrestrial micromammals, with 12 infected species including Bandicota indica, Berylmys berdmorei, Berylmys bowersi, Mus cervicolor, Mus cookii, and Hylomys suillus. In this qPCR-positive micromammals, three pathogenic Leptospira species were identified: L. interrogans, L. weilii, and L. borgpetersenii. This represents the first confirmed detection of L. weilii in rodents in Thailand. Infected micromammals were found in agricultural and forest habitats but not in human settlements. Our study demonstrates potential complex leptospirosis epidemiology in rural Thailand, with multiple species serving as pathogenic Leptospira reservoirs across diverse habitats, and some shared pathogen diversity with human leptospirosis cases in Thailand. Free-roaming dogs may serve as bridge hosts, transmitting zoonotic Leptospira from micromammals to humans by visiting both animal habitats and human settlements. These findings emphasize the need for integrated One Health surveillance approaches to control leptospirosis in rural communities.

Introduction Nontyphoidal Salmonella enterica (NTS) is a major zoonotic enteric pathogen. Animal contact-related NTS outbreaks have increased in the United States of America (U.S.) over the last decade. Geospatial analysis can identify locations with elevated risk of NTS outbreaks where public health authorities can focus their NTS prevention and intervention efforts. Methods We analyzed NTS outbreak data reported from individual states to the Centers for Disease Control via the National Outbreak Reporting System between 2009 and 2022 across the continental contiguous U.S. A geospatial analytical framework that included disease mapping, spatial interpolation, and global and local clustering methods was applied to identify regions with high NTS outbreak rates. Results A total of 104 NTS single-state outbreaks were reported to the National Outbreak Reporting System (NORS) during the study period. The mean annual incidence rate was 0.02 NTS outbreaks per million person-years. The primary animal contact categories associated with these outbreaks were mammals (cattle, pigs, sheep, and horses), birds (backyard chickens, ducklings, and turkeys), and reptiles (turtles and lizards). Exposure settings included farms, fairgrounds, agricultural feed stores, veterinary clinics, dairy/agricultural settings, and residential settings. The local cluster detection methods consistently identified areas with significantly high NTS animal contact-related outbreak rates in the Mountain West, Midwest, and Northeast of the US. Conclusion NTS animal contact-related single-state outbreaks revealed distinct spatial clustering across the United States, with potentially higher risks in the Mountain West, Midwest, and Northeast. Diversity of animal-contact sources and exposure settings depicted complex transmission dynamics of NTS. Focused prevention and control programs in these areas are needed to mitigate the burden of NTS outbreaks.

Cetacean pathology is a cornerstone for population and marine ecosystem health monitoring, allowing clear differentiation among natural and anthropogenic threats. Previous studies in the Canary Islands reported natural causes of death in 59.4% (1999-2005) and 81% (2006-2012) of stranded cetaceans, versus anthropogenic causes in 33.3% and 19%, respectively. This study aimed to determine the causes of death (CD), pathologic findings, and epidemiological patterns of 316 cetaceans stranded in the Canary Islands between 2013 and 2018. The CDs were classified in pathologic entities (PEs) emphasizing natural versus anthropic origins. Of 316 animals, 224 (70.9%) from 18 species were suitable for pathological investigations. Among natural PEE, natural pathology associated with good nutritional status (NP-GNS) and natural pathology associated with significant loss of nutritional status (NP-LNS) represented 43/224 (19.2%) and 36/224 (16%) cases, respectively. Natural pathology with undetermined nutritional status (NP-UNS) occurred in 19/224 (8.5%) animals. Intra- and interspecific traumatic interactions (ITI) represented 30/224 (13.4%) cases, followed by neonatal/perinatal pathology (NPN) 19/224 (8.5%) and live-stranding stress and/or capture myopathy (LS-CM) 18/224 (8%). Infectious and parasitic diseases predominated in natural PEs. Anthropogenic PEs included interaction with fishing activities (IFA) in 17/224 (7.6%) cases, vessel collisions (VC) in 9/22 (4%) cases, and foreign body-associated pathology (FBAP) in 3/224 (1.3%) animals. Overall, anthropogenic causes accounted for 12.9% of deaths, natural causes for 73.6%, and the CD could not be established in 30/194 (13.4%) cases. This study reaffirms the trends concerning recognized PEs (NP-GNS, NP-LNS, NP-UNS, ITI, NPN, LS-CM, IFA, VC, and FBAP), expands the body of knowledge on cetacean pathology in the Canary Islands, and reports novel findings including mixed infections, clostridiosis in uncommon species, uremic syndrome secondary to urethral nematodiasis, gas embolism in unusual species, epibiont stomatitis, congenital musculo-skeletal malformations, or neoplastic processes. These findings advance understanding of cetacean mortality patterns and support conservation and management strategies.

This study aimed to evaluate DARO Systems detection of Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) against serum and oral fluid surveillance methods within a controlled study consisting of one PRRSV infected seeder pig and 46 naive nursery pigs. Findings showed DARO Systems comprehensive herd-level surveillance approach detected PRRSV earlier than traditional testing methods.

Mycoplasma bovis was first detected in cattle in New Zealand in 2017, prompting an eradication programme that incorporated extensive surveillance and a test-and-cull policy. Genome sequence data and phylodynamic models were used to inform decision making throughout the eradication programme. Isolates from 697 cattle on 126 farms were collected and sequenced between July 2017 and December 2023. Phylodynamic models were used to estimate the time of most recent common ancestor, the effective reproduction number (Reff) and effective population size, and long-range and local between-farm transmission dynamics. The analysis revealed the dramatic impact of movement restrictions and culling up to early 2020, with a sharp reduction in the Reff to less than 1 in 2018/9 and the extinction of two of three major lineages in 2020. This was followed by three-years of residual infection in farms in the South Island, associated with persistent infection of a large feedlot farm and nearby farms. The comprehensive dataset of genomic and epidemiological data provided a unique opportunity to study the dynamics of a country-wide outbreak of a single-host pathogen from first detection to potential eradication, underlining the utility of integrated genomic surveillance during an outbreak response. Author summaryThe economically important cattle pathogen, Mycoplasma bovis, was first detected in New Zealand in 2017. This led to a large-scale, successful control programme aimed at eradication of the pathogen. The decision to undertake an eradication programme was informed by initial analyses of whole genome sequences from isolates collected as part of the surveillance programme. The analysis showed that the bacteria had entered New Zealand relatively recently and was unlikely to be widespread. Over the subsequent years, genome sequencing and modelling of transmission dynamics informed important policy decisions made by the New Zealand Government and the cattle industry, and helped to monitor progress of the eradication programme. The impact of the detection, movement control and culling programme was profound, with sharp reductions in transmission between 2018 and 2020. This was followed by a long tail of localised infection in the South Island, involving transmission from a large feedlot farm. Provisional eradication was achieved after depopulation of this feedlot. This analysis highlights the role of genomic surveillance and modelling to inform decision making during an infectious disease outbreak.

Borealpox virus (BRPV; formerly Alaskapox) is an orthopoxvirus that has caused seven reported human infections in Alaska since 2015, including a fatal case in 2023. The natural reservoir of BRPV is unknown, although previous investigations have raised the possibility of wild small mammals transmitting the virus to humans, either through direct contact or via domestic cats and dogs. To understand which species may be involved in the maintenance and/or spillover of BRPV in Alaska, we trapped and sampled wild small mammals (including voles, shrews, and squirrels) in 2021 and 2024 near reported human case locations in Fairbanks and the Kenai Peninsula, respectively. We found evidence of previous exposure to orthopoxviruses in five species (including the House Mouse, Mus musculus) and detected BRPV DNA as well as viable virus in Northern Red-backed Voles (Clethrionomys rutilus). Further, screening of tissues from historical museum specimens revealed BRPV DNA in C. rutilus specimens collected in Denali National Park and Preserve in 1998 and 1999, 17 years before the first reported human case of BRPV. Phylogenomic analysis of all human and animal BRPV isolates strongly supports the hypothesis of local human infections through multiple spillover events. These findings suggest C. rutilus as a possible reservoir species for BRPV and indicate that BRPV has been present in Alaskan wild small-mammal populations for at least 25 years. Our study highlights the potential of museum collections to elucidate the temporal, spatial, and host ranges of emerging pathogens. Further museum- and field-based sampling will clarify the true geographic range of BRPV, which is closely related to Old World orthopoxviruses and may be circulating beyond North America.

Dromedary camels are the main reservoir for Middle East respiratory syndrome coronavirus (MERS-CoV), a re-emerging infectious disease with pandemic potential. Somalia harbours approximately 32% of dromedary camels globally. We investigated current and past MERS-CoV infections among occupationally-exposed workers in slaughterhouses, dairy farms, livestock markets and a quarantine station. Sera and nasopharyngeal/oropharyngeal swabs from 770 workers were analysed for MERS-CoV antibodies by Enzyme-Linked Immunosorbent Assay (ELISA) and virus neutralization and for viral RNA by Real Star(R) MERS-CoV Reverse Transcription Polymerase Chain Reaction (RT-PCR). One farm worker with no travel history in the Qardo district, Karkar region, Puntland was sero-positive by ELISA and virus neutralization, providing the first-ever evidence of zoonotic spillover of MERS-CoV to humans in Somalia. This finding highlights the need to strengthen MERS-CoV surveillance across Somalia, along with an urgent need to strengthen national laboratory capacity and integrate MERS into diagnostic algorithms to generate accurate and reliable infection data and studies to understand the socio-cultural and potential risk factors for MERS-CoV.

Background: Although the relaxation of COVID-19 containment measures in China has altered the transmission dynamics of respiratory pathogens, regional data on post-pandemic epidemiological characteristics remain limited.Objective: This study aimed to investigate the pathogen spectrum and epidemiological characteristics of acute respiratory infections (ARIs) in Quzhou City from 2023 to 2024, providing a scientific basis for local prevention and control strategies.Methods: A total of 2,800 respiratory specimens were collected from November 2023 to July 2024, comprising 1,960 influenza-like illness (ILI) cases from outpatient/emergency departments and 840 severe acute respiratory infection (SARI) cases from inpatient departments. All samples were tested for 13 common respiratory pathogens using multiplex fluorescence quantitative PCR. Etiological and epidemiological analyses were performed based on detection results and case information. Results: The overall ARI positivity rate was 59.28% (1,660/2,800), with a male-to-female ratio of 1.07:1 (1,447/1,353). The three most prevalent pathogens were influenza virus (Flu, 23.21%, 650/2,800), Streptococcus pneumoniae (SP, 13.14%, 368/2,800), and adenovirus (ADV, 8.39%, 235/2,800). Single pathogen infections accounted for 73.55% (1,221/1,660) of positive cases, while co-infections with two or more pathogens accounted for 26.45% (439/1,660), yielding an overall co-infection rate of 15.68% (439/2,800). No significant gender difference was observed in detection rates. However, significant differences were found across case types, temporal periods, age groups, and geographic regions (P < 0.01). Children aged [&le;]5 years exhibited the highest positivity rate (78.00%, 378/525), while adults aged [&ge;]65 years showed the lowest (34.53%, 144/417). Among surveillance regions, Kaihua County had the highest positivity rate (72.47%), and Changshan County the lowest (40.55%). Conclusions: Multiple respiratory pathogens and co-infections are prevalent in Quzhou City, with distinct age-specific and seasonal patterns. These findings underscore the need for continuous multi-pathogen surveillance and integrated prevention strategies for influenza and other respiratory infectious diseases in the post-pandemic era.

Toxoplasma gondii is a globally prevalent zoonotic parasite with multiple life stages and transmission routes, including ingestion and transplacental transmission. It is a major cause of abortion in sheep, goats and pigs, among other production animals, worldwide. While Type II strains are common in livestock in North America and Europe, non-archetypal, non-clonal genotypes are highly prevalent in South America. This study aimed to determine the molecular epidemiology of T. gondii strains causing sheep abortion in Uruguay. Phylogenomic analyses confirmed significant divergence among typed strains and revealed similarities with genotypes previously detected in the human population. Two novel strains, were isolated and characterized, uncovering the connection between their genetic makeup and phenotypes. Differences in virulence could be correlated to differences in gene copy number of the pseudo kinase ROP5 - further highlighting this virulence factor as relevant in wild strains. Whole-genome sequencing further confirmed the divergence among Uruguayan isolates, uncovering at least three distinct evolutionary origins. Overall, our findings highlight the circulation of virulent non-clonal lineages with links to human infections and underscore the importance of furthering genomic surveillance in South America to better understand Toxoplasmas transmission dynamics, pathogenic potential, and zoonotic risk.

IntroductionDiagnostics have become the fundamental backbone of HIV prevention, treatment and long-term retention in care, and are critical to achieving the 95-95-95 UNAIDS targets. To effectively reach underserved and remote populations, diagnostic technologies must be cost-effective, robust, user-friendly and suitable for settings with limited infrastructure. Among available testing modalities, rapid diagnostic tests (RDTs) play a central role in expanding HIV testing coverage. Earlier generations of RDTs were limited by their inability to detect acute HIV, with limited ability to detect p24 antigen (Ag), an early marker of HIV infection, which is expected to shorten the diagnostic window to two-to-three weeks. The introduction of fourth-generation RDTs, which detects both chronic and acute HIV infection through p24 Ag detection, was designed to ensure that the traditional diagnostic window of two-to-three months is shortened to approximately two-to-three weeks. However, integrating these assays into existing testing algorithms requires clear evidence that they meet high standards of quality and performance. This systematic review aims to assess the performance of WHO-prequalified fourth-generation Ag/Ab RDTs. MethodsWe performed a systematic search across six databases to identify studies evaluating Ag/Ab RDTs against laboratory reference standards in individuals aged 12 years and older, spanning 1 January 2010 to 31 December 2025. Outcomes were limited to measures of diagnostic accuracy. A meta-analysis focusing exclusively on WHO-prequalified fourth-generation RDTs was performed using a bivariate random-effect model. Results1,932 records were screened, of which 31 diagnostic accuracy studies from 19 countries were included. 15 studies used US-only approved products, 12 used WHO-prequalified products and four used commercially discontinued products. The pooled sensitivity of WHO-prequalified Ag/Ab RDTs for acute HIV infection (AHI) was 94% (95% CI: 86%-99%). An RNA threshold of [&ge;] 1,000,000 copies/mL was used as a proxy for high viraemia and used as a cut-off for the following analyses. The cut-off based analysis is considered more suited to decision-making, as it focuses on cases most likely to be associated with higher viraemia and greater potential for detection during the p24 Ag window. When using enzyme immunoassay (EIA) as the reference standard, the pooled p24 Ag sensitivity was 76% (95% CI: 62%-88%), and the pooled p24 Ag sensitivity when using nucleic acid amplification test (NAAT) as the reference standard was 75% (95% CI: 41%-97%). In the general population, the pooled sensitivity for p24 antigen detection was 77% (95% CI: 60%-92%). Amongst risk populations, only three studies had available raw data, and the pooled sensitivity was 62% (95% CI: 10%-97%). In plasma and serum specimens, pooled p24 Ag sensitivity was 74% (95% CI: 57%-88). DiscussionCollectively, these findings indicate that WHO-prequalified fourth-generation Ag/Ab RDTs can function as a scalable frontline screening tool, particularly in low- and middle-income countries, while offering incremental holistic detection through p24 Ag. Their effective deployment, however, depends on maintaining standard algorithm safeguards, including repeat testing and targeted laboratory referral when acute infection is suspected. ConclusionsResults from this meta-analysis support the use of WHO-prequalified fourth-generation Ag/Ab RDTs for general population screening. From a programmatic perspective, the added value of WHO-prequalified fourth-generation RDTs lies in their ability to combine rapid, decentralized access to testing, with incremental yet impactful improvements in holistic detection.

Enterohemorrhagic Escherichia coli O157:H7 (EHEC) is an important zoonotic pathogen that disrupts intestinal epithelial barrier integrity and induces excessive inflammatory responses, thereby leading to impaired growth performance and intestinal injury. EHEC is also an important cause Hemolytic Uremic Syndrome (HUS) in children and older adults. In pig production, chitosan is considered a promising alternative to antibiotics due to its bioadhesive and antimicrobial properties, but the effects and underlying mechanisms of chitosan (COS) under pathogenic challenge remain to be elucidated. One hundred and eight pigs were randomly divided into three treatments: an unchallenged control group (CON), an EHEC-challenged control group (ECON), and an EHEC-challenged group supplemented with 100 mg/kg COS (ECOS). Results show that EHEC challenge increased the feed conversion ratio (FCR), increased inflammatory cytokine levels, disrupted intestinal morphology, and downregulated tight junction and nutrient transporter gene expression (P<0.05). Dietary COS supplementation significantly improved average daily gain (ADG) and FCR during day 6-14 (P<0.05). Moreover, COS reduced fecal shedding of total E. coli (P = 0.085) and EHEC, attenuated systemic inflammation by decreasing serum TNF- and IL-6 levels, and enhanced humoral immunity as indicated by increased IgA and IgM concentrations (P<0.05). Importantly, COS alleviated EHEC-induced intestinal injury by restoring villus height and villus-to-crypt ratio, with enhanced mucosal digestive enzyme activities, and upregulated expression of tight junction proteins (ZO-1 and occludin) and nutrient transporters (SGLT-1 and PEPT1) (P<0.05). In conclusion, these findings indicate that dietary COS improves growth performance in EHEC-challenged weaned pigs, with enhanced intestinal barrier integrity and nutrient transport capacity.

Measurement of antibody responses to viral infection is essential for surveillance, diagnostics, epidemiological research, and natural history of infection studies. However, current methods to detect virus-specific antibodies are often resource-intensive and impractical for deployment in outbreak settings or in field-based studies. This manuscript presents two economical, high-throughput immunoassays--the cytoblot immunoassay (CBA) and strip immunoblot assay (SIA)--for detecting and quantifying anti-lymphocytic choriomeningitis mammarenavirus (LCMV) antibodies in mouse serum. To validate, we tested serum from acutely or persistently experimentally infected mice. Both assays detected LCMV-specific IgG and IgM antibodies with high sensitivity and specificity across multiple timepoints. By facilitating the study of immune responses in rodent reservoirs, these tools can enhance our understanding of zoonotic viral transmission, provide scalable platforms for outbreak preparedness, and serve as adaptable models for the development of rapid serological assays for other viral pathogens.

Background: Leptospirosis is a neglected tropical disease with substantial public health impact in Brazil, closely associated with socio-environmental vulnerabilities and climatic extremes. This study analyzed the epidemiological profile, spatiotemporal distribution, and climatic influences on leptospirosis incidence and lethality in Brazil from 2015 to 2024. Methods: An ecological time-series study was conducted using secondary data from the Notifiable Diseases Information System (SINAN). Variables included geographic region, probable infection environment, occupational, and educational level (ISCED-2011). The spatiotemporal correlation between disease incidence and El Nino-Southern Oscillation (ENSO) anomalies was assessed using the Oceanic Nino Index (ONI) and Spearman's rank correlation coefficient. Results: A total of 31,397 cases were notified, with an annual average of 3,140 cases. The South and North regions exhibited the highest incidence rates, while the Northeast and Southeast presented lethality rates above the national average (9.20%). A marked reduction in notifications occurred during the COVID-19 pandemic. Contaminations occurred predominantly in the domiciliary environment (64%). Rural workers (27.45%) and civil construction workers (18.63%) were the most affected occupational groups, with a higher incidence among illiterate and low-education populations. Climatic analysis revealed a positive spatial correlation between El Nino intensification and leptospirosis incidence in the South and Southeast, and a negative correlation in specific Northeastern states. Conclusion: The dynamics of leptospirosis in Brazil are complex and multifactorial, strongly influenced by macroclimatic variations and driven by deficits in basic sanitation and urbanization. Mitigating the disease burden requires sustained, region-specific public health strategies, targeted infrastructure improvements, and enhanced epidemiological surveillance to address underreporting.

ABSTRACPorcine respiratory diseases caused by extraintestinal pathogenic Escherichia coli (ExPEC) pose a severe threat to swine production and public health; however, research on respiratory tract-isolated ExPEC remains limited. This study comprehensively analyzed the genomic characteristics and antibiotic resistance gene (ARG) transfer potential of 441 ExPEC strains isolated from porcine lungs across 21 Chinese provinces (including 53 newly isolated strains from 2022-2024 and 388 NCBI-deposited strains). Phylogenetic analysis revealed that 84% of the isolates belonged to phylogroups A, B1, and C, with ST410, ST101, and ST88 as the predominant STs. The strains exhibited extensive ARG diversity, harboring 111 distinct ARG subtypes, with sul2 (81.4%), floR (73.5%), and tet (A) (68.0%) being the most prevalent. Importantly, critical "last-resort" antibiotic resistance genes (e.g., blaNDM-1/5, the mcr family, and tet (X4)) were also detected. Notably, 77.2% of the ARGs presented horizontal transfer potential, with plasmids (especially IncF family replicons) serving as core vectors, followed by integrons and transposons. Cooccurrence network analysis identified aph (3)-Ib, aph (6)-Id, sul2, and floR as core subnetworks driving multidrug resistance dissemination. Pangenomic analysis confirmed an open genome architecture, with core genes accounting for only 6%, reflecting the strains capacity to acquire exogenous genetic material via horizontal transfer. From the One Health perspective, these transferable ARGs can spread to the environment and humans through fecal discharge and the food chain. These findings underscore the importance of monitoring and controlling ExPEC infections in swine, as such strains can as reservoirs of ARGs, pose potential risks to human health, and may even act as sources of pathogenic agents responsible for human infections. IMPORTANCEPorcine respiratory ExPEC-induced diseases threaten swine production and public health, yet respiratory tract-isolated ExPEC research remains scarce. This study comprehensively analyzed 441 porcine lung ExPEC strains across 21 Chinese provinces, uncovering their dominant phylogroups, high ARG diversity (111 subtypes) and the presence of "last-resort" antibiotic resistance genes. We identified 77.2% of ARGs with horizontal transfer potential, plasmids (especially IncF family) as core vectors, and a core ARG subnetwork driving multidrug resistance. The open pangenome (6% core genes) highlights ExPECs strong capacity to acquire exogenous genes. These findings fill the research gap of respiratory ExPEC, clarify ARG transmission mechanisms in swine ExPEC, and provide critical genomic data for One Health-based AMR surveillance and control, guiding targeted strategies to mitigate ARG spread from swine to humans and the environment.

Avian influenza virus (AIV) epidemiology is well-documented in temperate regions but remains poorly understood in isolated ecosystems like tropical oceanic islands. On these islands, seabirds nest in dense interspecific colonies where the role of different species as reservoirs and dispersers of AIV may vary greatly. Here, we examine the role of noddies (Anous spp.) as potential reservoirs for low pathogenic AIV and evaluate their potential as sentinel species for highly pathogenic AIV introduction on tropical oceanic islands. We analyzed blood samples from 11 seabird species across eight islands in the southwestern Indian Ocean (2015-2020). Noddies exhibited high, stable seroprevalence (30-45%), comparable to reservoir host species in temperate regions. The detection of two N7-positive noddies, sampled the same year on two distinct islands, provided direct molecular evidence that AIV actively circulates on these island colonies. While most other species showed low exposure, Bridled Terns (Onychoprion anaethetus) had exceptionally high seroprevalence (80%), though their reservoir status requires further investigation due to limited sampling. Given noddies consistent exposure and regional distribution, we recommend prioritizing islands with large noddy populations for AIV surveillance. Continued investigation of viral dynamics within and among islands is now called for to elucidate the ecological drivers of AIV maintenance and transmission.

Research background. Foodborne diseases (FBDs) remain a pressing global public health issue, with courier-based food delivery systems increasingly recognized as potential contamination pathways. In Zambia, despite the Food Safety Act No. 7 of 2019, limited evidence exists on microbial risks in courier-mediated food transport. This study was conducted to assess pathogenic contamination in food carriers used by courier bikers in Lusaka during the 2025/2026 cholera outbreak response. Experimental approach. An analytical cross sectional design was employed. Ninety three food carriers (bags, cooler boxes, and metal containers) were randomly sampled from courier bikers. Swabs from internal surfaces were processed within 24 hours using standard microbiological culture and biochemical identification methods. Statistical analyses (Chi square tests, Pearson correlations, and logistic regression) were applied to determine associations between contamination and operational factors. Results and conclusions. Microbial contamination was detected in 69% of carriers. The most common pathogens were Escherichia coli (30%), coagulase negative Staphylococcus (24%), and Staphylococcus aureus (18%), with additional isolates including Gram-positive bacilli (11%) and Klebsiella pneumoniae (8%). Logistic regression identified cleaning frequency as the strongest predictor of contamination, with infrequent cleaning associated with significantly higher odds ratios (26.5 to 94.7, p < .05). Carrier type also influenced contamination risk, while years in service and certification status were not significant. The findings highlight that inadequate cleaning practices and carrier design are primary drivers of microbiological risks in courier based food delivery systems. Novelty and scientific contribution. This study provides the first empirical evidence of microbial contamination in courier food carriers in Lusaka, Zambia. It underscores the urgent need for strengthened hygiene protocols and routine sanitation enforcement to protect consumers from foodborne pathogens and antimicrobial resistance. The work contributes novel insights into food safety risks in emerging delivery systems, with implications for policy, public health interventions, and consumer protection in Zambia and beyond.

IntroductionAntimicrobial Resistance (AMR) presents a critical public health challenge, particularly in smallholder broiler farming, where antibiotics are often used preventively in the absence of effective biosecurity measures. ObjectiveThis study investigates the adoption of biosecurity practices as a sustainable alternative to antibiotics through Participatory Systems Mapping and Experimental Games. MethodsA participatory mixed-methods study was conducted in southern Bangladesh (September 2024-June 2025). Causal Loop Diagrams (CLDs) were co-created with farmers, dealers, and veterinary officers. Ten broiler farmers from single village were selected via purposive and snowball sampling. Experimental games simulated four production cycles where farmers chose Option A (biosecurity, adopters) or Option B (antibiotics, non-adopters) after several interactive trainings. Key metrics including biosecurity compliance (0-12 scale), mortality, FCR, antibiotic use, outbreak history, and economic outcomes were recorded. ResultsCLD analysis revealed a reinforcing loop of increased antibiotic reliance driven by fear of mortality, and balancing loops involving training, biosecurity practices, and consumer incentives to reduce use. Five farmers chose Option A, and both groups remained stable until Round 4. Adopters had flock sizes of 800-2000 birds (non-adopters, 600-1000; mean for both = 1000), were younger, and more educated compared to non-adopters. At baseline, both groups had similar biosecurity scores (0). Adopters had higher mean outbreaks (2 vs. 1.4), mortality (5.6 vs. 4.2), antibiotic use (3.6 vs. 3), and FCR (1.8 vs. 1.6) compared to non-adopters. By Round 4, adopters improved biosecurity scores by 125%, eliminated outbreaks, reduced mortality by 52.6%, stopped antibiotic use, improved FCR by 13.3%, and gained 71.72% profit per bird compared to non-adopters. Non-adopters, influenced by adopters, increased biosecurity scores by 25%, reducing outbreaks, mortality, antibiotic use, and FCR. Adopters also increased direct sales to consumers, yielding a 10%-16% profit gain per bird each round. ConclusionThis study highlights the successful adoption of biosecurity practices by farmers, replacing antibiotics and improving production outcomes. Farmer-driven adoption of these practices fosters long-term sustainability and supports a healthier planet within the One Health framework.