Transboundary and Emerging Diseases最新文献

Schmallenberg virus (SBV) is a Culicoides-borne Orthobunyavirus causing congenital malformations and reproductive losses in ruminants, with substantial economic and livestock health impacts across Europe. While outbreaks have been linked to specific climatic and environmental conditions, the drivers of SBV transmission in endemic regions remain poorly defined. It is unclear to what extent spatial variation in SBV seroprevalence reflects environmental risk factors in temperate regions with intensively managed livestock systems such as those in Germany. Spatially explicit generalised additive models (GAMs) and predictive risk mapping are, hence, applied to investigate whether landscape, climate or host availability influence SBV exposure risk in sheep flocks across five German federal states. Serological data were obtained from 70 sheep flocks (n = 2723 animals; autumn 2017 to spring 2018) and 69 environmental variables were used in the spatial risk analysis. Environmental heterogeneity showed limited explanatory power for SBV seroprevalence. The final GAM explained 50.6% of deviance and identified cattle density as the strongest positive predictor (odds ratio [OR] = 1.01, p < 0.001), while nature reserve coverage (OR = 0.13, p = 0.015) and summer temperature during the wettest quarter (OR = 0.95, p = 0.021) were negatively associated. No spatial clustering was detected, and the predicted risk surface revealed only modest regional variation. These findings suggest that farm-level factors and cattle-associated vector habitats are more relevant to SBV transmission than broader climatic or land use gradients in ecologically uniform settings. The diffuse spatial pattern underscores a general vulnerability of German ruminants to Culicoides-borne viruses and supports the need for targeted surveillance and farm-focused vector control. This modelling framework may assist in future risk assessments for emerging arboviruses under changing climate and agricultural conditions.

Larvae of ascaridoid nematodes, particularly Anisakis spp., are common parasites of commercially important marine fishes and may represent a zoonotic hazard following ingestion of raw or undercooked seafood. We investigated the ascaridoid fauna of the sympatric European hake (Merluccius merluccius) and greater forkbeard (Phycis blennoides) from the Ionian Sea (Eastern Mediterranean), integrating host biometric and seasonal drivers with molecular identification and quantitative risk assessment (QRA) for the zoonotic Anisakis pegreffii. Anisakis pegreffii was the dominant species in both hosts, followed by Hysterothylacium aduncum; other detected taxa included A. typica, A. ziphidarum, Skrjabinisakis physeteris, and H. fabri. In both hosts, the larval abundance exhibited marked seasonal peaks in summer and correlated more strongly with host liver and gonad condition indices, suggesting that seasonality, togheter with host physiological state, rather than size alone, modulates infection levels. Most larvae were found in the visceral non edible parts of the fish, while only a small proportion of these were detected in skeletal muscles (2.6% in hake and 0.6% in forkbeard), primarily in the anterior ventral fillet portion. QRA indicated a low per-meal probability of anisakiasis from untreated hake (~1 case per 52,609 meals). These findings highlight species-specific, trophically mediated infection patterns and reinforce that European hake and greater forkbeard represent minor but nonnegligible sources of zoonotic risk. Preventive measures, including immediate evisceration, proper freezing or cooking, and selective fillet trimming, are recommended to minimize human exposure.

Ticks are major vectors of numerous pathogens affecting both livestock and humans. In Senegal, data on the diversity of tick-borne pathogens (TBPs) in ruminant-associated ticks remain limited. In total, 1703 ticks were collected from goats, sheep, and cattle across three ecological zones of Senegal (Sudanian, Sahelian, and Sudano-Sahelian). Tick species were identified morphologically, and 300 individuals were screened for 36 microorganisms using a high-throughput microfluidic real-time PCR system. DNA was successfully extracted and amplified from 289 ticks. The most abundant species were Rhipicephalus evertsi evertsi (32.3%), Hyalomma truncatum (19.6%), R. guilhoni (15.6%), H. rufipes (11.6%), and Amblyomma variegatum (11.0%). Among the screened ticks, 226 (78.9%) were positive for at least one microorganism. True pathogens of veterinary and/or zoonotic importance included Anaplasma ovis (30.8%), Coxiella spp. (23.9%), Rickettsia aeschlimannii (13.1%), Theileria spp. (11.1%), and Ehrlichia canis (4.8%), with sporadic detections of Anaplasma marginale, A. bovis, and Babesia spp. (0.3% each). In addition, non-pathogenic Francisella-like endosymbionts (FLEs) were detected at high prevalence (37.4%) across all ecological zones. The presence of TBPs and/or endosymbionts was significantly associated only with the tick’s host in the multivariable logistic regression model. Ticks collected from goats (OR = 7.82; p = 0.024) and sheep (OR = 7.70; p = 0.015) were significantly more likely to be infected than those collected from cattle (reference group). A total of 96 cases of microorganism co-occurrence were recorded across different tick species. Co-infections were more frequent in ticks collected from the Sudano-Sahelian zone (48.2%) and in those from sheep (32.0%). None of the detected microorganism species showed a significant associated with tick sex. This study represents the first large-scale molecular survey of TBPs in ruminant-associated ticks in Senegal, revealing both a high diversity of pathogens and a widespread presence of tick endosymbionts. While endosymbionts, such as FLEs, are not known to be pathogenic, their abundance may influence tick physiology and vector competence. The detection of zoonotic pathogens, such as E. canis and R. aeschlimannii, underscores the need to strengthen tick surveillance and investigate their potential public health implications.

Bluetongue (BT) is a vector-borne viral disease caused by the bluetongue virus (BTV), which can affect a variety of wild and domestic ruminants. Due to its significant impact on ruminant health and national economies, BT is classified as a notifiable multispecies disease by the World Organization for Animal Health (WOAH). In China, BT is listed as a Class II multispecies animal disease. This article provides a comprehensive review of the distribution of BTV and its primary insect vector, Culicoides, in China. Since BTV was first reported in China in 1979, BTV antibody-positive samples have been detected in most parts of the country, with a total of 17 serotypes of BTV isolated (BTV-1, 2, 3, 4, 5, 7, 9, 11, 12, 14, 15, 16, 17, 20, 21, 24, and 29). Culicoides are widely distributed across China. Currently, studies have been conducted on climatic factors influencing their distribution and blood-sucking habits. To improve the efficiency of BTV detection in China, various detection methods have been explored, including polymerase chain reaction (PCR), loop-mediated isothermal amplification (LAMP), bio-bar code assay (BCA) for viral detection, as well as enzyme-linked immunosorbent assay (ELISA), agar gel immunodiffusion (AGID) and colloidal gold immunochromatography test strips for antibody detection. Additionally, inactivated vaccines, attenuated vaccines, and recombinant vaccines were also investigated. This review summarizes the current knowledge on BTV vectors, viruses, and surveillance, as well as the development of BT vaccines in China. In light of the current situation of BT in China, it proposes comprehensive prevention and control recommendations, including enhancing awareness of the hazards of BT, implementing an integrated prevention and control technology system, and strengthening research related to BT prevention and control.

In 2023, highly pathogenic avian influenza (HPAI) heavily affected gulls in Europe. In July, a mass mortality event was reported in the black-legged kittiwake (Rissa tridactyla) breeding colony at Ekkerøy in Northern Norway. The cause was confirmed to be infection with the HPAI H5N1 clade 2.3.4.4b virus, genotype EA-2022-BB. We describe the outbreak in kittiwakes, including pathological and virological investigations, and discuss the management and zoonotic potential. With more than 15,000 dead birds reported, we estimate that the outbreak caused a reduction in the kittiwake population at Ekkerøy of at least 50%. Diseased birds exhibited neurological signs. Necropsies of 10 birds revealed a peracute fatal systemic disease, with severe lesions in the brain and pancreas co-localizing with viral RNA and antigen. Vascular expression of α2,3-linked sialic acids (SAs) and viral RNA/antigen may reflect hematogenous viral spread. Further studies should investigate the long-term impact of HPAI on kittiwake populations.

Porcine epidemic diarrhea virus (PEDV), an enteropathogenic coronavirus causing high mortality in neonatal piglets, continues to threaten global swine industries. Frequent mutations in the spike (S) protein of PEDV, particularly in emerging variants, have substantially compromised commercial vaccine efficacy. Despite the emergence of G2c variants dominating recent epidemics, comprehensive studies integrating viral isolation, phylogenetics, structural modeling, cross-neutralizing antibody response, and pathogenicity assessment remain insufficient. In this study, we successfully isolated a G2c strain (AHCZ02) and obtained 69 S gene sequences from nine provinces during 2021–2024. Phylogenetic analysis identified G2c variants as predominant (69.57%, 48/69) in current outbreaks. Structural comparisons revealed four G2c-specific substitutions (N139D, I287M, F345L, and L998M) inducing conformational changes in critical S domains compared to G2a/G2b strains, potentially disrupting immune recognition. The results of serum neutralizing antibody (nAb) test using the AHCZ02 strain showed that G2c-based feedback exposure strategies elicited 3.9-fold higher geometric mean titers (GMTs) than S-INDEL–based approaches. Furthermore, feedback exposure strategies of G2c (GMT = 480–1893) showed 12- to 189.3-fold higher neutralizing activity versus conventional vaccines (GMT = 10–40). Pathogenicity assessment in neonatal piglets revealed 100% mortality within 66 h post-AHCZ02 inoculation, accompanied by hallmark clinical manifestations including profuse watery diarrhea, rapid weight loss, and severe jejunal villus atrophy. Collectively, these findings provide evidence that G2c variants have developed S protein modifications associated with diminished vaccine efficacy, underscoring the need for next-generation vaccines incorporating G2c-specific antigenic determinants, and strengthened virological surveillance systems to effectively monitor and respond to PEDV evolutionary dynamics.

Despite long-term vaccination and control efforts, infectious bronchitis virus (IBV) remains a major threat to the global poultry industry, largely due to its high prevalence and extensive genetic diversity. This study aimed to characterize two novel GI-13 (4/91-like) IBV field strains, CK/CH/JS/2302 and CK/CH/AH/2307, isolated from H120-vaccinated broiler flocks in China, in order to elucidate their pathogenicity, genomic characteristics, and evolutionary relationships. Although both isolates belonged to the GI-13 genotype but exhibited divergent pathogenic profiles and evolutionary patterns. CK/CH/JS/2302 exhibited higher virulence, severe respiratory symptoms, tracheal hemorrhage, kidney lesions, and 10% mortality, while CK/CH/AH/2307 induced only mild respiratory signs and slight renal swelling. Phylogenetic analysis revealed that CK/CH/JS/2302 displayed a recombinant genome involving GX-YL5 and IBV/India/ck/01/23, in which the S1 gene was clustered within GI-13 genotype, whereas other genes showed high similarity to domestic GI-7, GI-19, and GI-22 genotypes. In contrast, CK/CH/AH/2307 showed high genomic similarity to the 4/91 vaccine strain without evidence of recombination but still impaired tracheal ciliary activity. Sequence and structural modeling of the S1 protein revealed that amino acid substitutions within hypervariable regions (HVRs) may affect receptor binding and antigenicity, potentially reducing cross-protection from current vaccines. These findings demonstrate the coexistence of a virulent recombinant strain (CK/CH/JS/2302) and a low-pathogenic variant (CK/CH/AH/2307) within the same lineage in China, underscoring the role of recombination and immune selection in IBV evolution. Overall, these findings emphasize the necessity for continuous molecular surveillance and genotype-specific vaccine development to improve protection against emerging 4/91-like IBV variants and reduce the economic losses caused by infectious bronchitis in poultry production.

Transboundary animal diseases (TADs), including zoonoses, can be introduced in non-endemic areas through animal trade and uncontrolled movements during times of conflict and migration. Sheep and goat pox (SGPX) and peste des petits ruminants (PPRs) were, respectively, reported in Europe in 2018 and 2010. EFSA emphasised the risk of spread into Europe through informal trade and unmonitored migration routes that may involve the informal transport of small ruminants. Using a One Health conceptual framework, which considers the interconnectedness of human, animal, and environmental health, this study analysed the epidemic trends of the two selected diseases during 2014–2025, with particular focus on the role of human migrations in influencing their spread along major migratory routes in the Balkan Peninsula. The conceptualisation of animals in migration settings was investigated through the scrutiny of policies and semi-structured interviews to experts and people who travelled the route. The presence of small ruminants, companion and pest animals was confirmed in formal and informal camps. The results underscore the relevance of animals in the migration contexts of the Balkan routes, as well as the risks associated with their presence in settlements in the absence of an adequate management. Our findings seem to suggest that human migration along the Balkan routes is not directly responsible for the spread of TADs, as there is no evidence of significant animal movements accompanying migrants. However, our results show a possible role of informal trade networks following human migration paths along the Balkan route, while a possible role of informal trade networks, following human migration paths along the Balkan route, deserves to be further investigated.

Pasteurella multocida serotype A (PmCQ2), a Gram-negative zoonotic pathogen, causes severe respiratory disease in a variety of domestic and wild animals, leading to high morbidity and mortality and substantial agricultural economic losses. Pyroptosis, a gasdermin-mediated programmed cell death mechanism, facilitates pathogen clearance but exacerbates tissue damage through inflammatory cytokine release. While our prior work established PmCQ2-driven NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome activation, the role of pyroptosis in pulmonary pathology during infection remains unresolved. Here, we demonstrate that PmCQ2 induces macrophage pyroptosis via gasdermin D (GSDMD) cleavage, evidenced by lactate dehydrogenase (LDH) release, membrane pore formation under transmission electron microscopy (TEM), and proteolytic generation of GSDMD-N termini. Pharmacological inhibition of NLRP3 (MCC950) and genetic ablation of caspase-11 significantly attenuated GSDMD activation, IL-1β secretion, and pyroptotic cell death, implicating both canonical (NLRP3/caspase-1) and noncanonical (caspase-11) pathways. Crucially, GSDMD knockout mice exhibited markedly reduced lung injury, evidenced by diminished inflammatory infiltration and preserved alveolar architecture, compared to wild-type (WT) counterparts following PmCQ2 challenge. This study provides the first evidence that PmCQ2 triggers GSDMD-dependent pyroptosis through dual signaling axes, directly linking this inflammatory cell death pathway to pathogen-induced pulmonary damage. Our findings position GSDMD as a central therapeutic target to mitigate tissue injury during P. multocida infection, offering a framework for novel interventions that balance antimicrobial defense and inflammation control in zoonotic pathogens.