Swine enteric coronaviruses (SECoVs), including transmissible gastroenteritis virus (TGEV), porcine epidemic diarrhea virus (PEDV), porcine deltacoronavirus (PDCoV), and swine acute diarrhea syndrome coronavirus (SADS-CoV), are major enteric pathogens causing severe diarrhea, dehydration, high neonatal mortality, and substantial global economic losses. Rapid viral evolution and recombination continually generate antigenically diverse variants that limit cross-protection and undermine vaccine efficacy, particularly for PEDV genogroup II strains that now dominate worldwide circulation. This review synthesizes current knowledge on epidemiology, diagnostic innovations, and emerging vaccine platforms, with emphasis on advances since 2022. Recent progress includes molecular surveillance tools, rapid point-of-care diagnostics, and next-generation vaccine technologies such as mRNA-based and virus-like particle platforms. However, significant knowledge gaps persist regarding viral evolution dynamics, co-infection synergies, and zoonotic spillover potential, particularly following documented human infections with PDCoV. Effective long-term control requires integrated genomic surveillance, strengthened farm-level biosecurity, rationally designed multivalent vaccines targeting conserved epitopes, and harmonized international surveillance systems to reduce outbreak risk and enhance pandemic preparedness at the human–animal interface.

Porcine epidemic diarrhea (PED) continues to inflict devastating losses on global swine production. By systematically reviewing and meta-analysing 32 high-quality studies, we quantified the protective efficacy of PED vaccines and dissected how core variables shape that protection. Using fecal scores as the endpoint, we pooled effect sizes under a random-effects model and explored sources of heterogeneity through subgroup analyses. This analysis showed a pooled effect size (Hedges’ g) of −5.80, confirming that vaccination markedly alleviates diarrheal severity. Moreover, substantial heterogeneity was detected across studies. Stratified analyses revealed that vaccine type, vaccination target, vaccination route, and vaccination frequency are the principal sources of variation, all of which significantly influence vaccine efficacy. Conventional inactivated or live-attenuated formulations still dominate the field, but recombinant live-viral platforms are emerging. Piglets and sows represent the most responsive immunological targets. A two-dose regimen consistently outperforms a single injection, and delivery via intranasal, oral or intramuscular routes offers distinct advantages that can be exploited to maximise mucosal and systemic immunity. Overall, the optimal impact on PED prevention and control is achieved when the vaccine is correctly chosen and paired with an appropriate immunization protocol and delivery route.

Porcine transmissible gastroenteritis virus (TGEV) is a highly contagious pathogen causing severe diarrhea in pigs, particularly piglets, leading to significant economic losses. Distinguishing TGEV from the genetically similar porcine respiratory coronavirus (PRCV) remains challenging due to their high genomic homology. In this study, we developed a one–pot assay combining recombinase-aided amplification (RAA) and CRISPR/Cas13a technology, targeting the TGEV S gene. This method was optimized for sensitivity and specificity, with orthogonal tests determining the optimal reagent concentrations. The assay achieved a detection limit of 4.13 copies/µL within 40 min at 37 °C, demonstrating no cross-reactivity with other porcine viruses. Clinical validation on 140 samples showed 100% concordance with RT–qPCR and RT–PCR results. Since the established method is completed in a single reaction tube, it eliminates the need for step-by-step operations, simplifying the process and reducing the risk of cross–contamination and false positives in subsequent tests. Overall, this assay shows promising potential for TGEV detection.

Mannheimia haemolytica is a primary pathogen causing bacterial pneumonia in cattle and sheep. Multiple PCR targets exist for its identification, but no standardized primer pairs have been widely adopted. This study evaluated the universality of six reported primers (including rpt2) using clinical M. haemolytica isolates. Genus specificity was tested against standard strains of common ruminant pathogenic/commensal bacteria and other Mannheimia species. Four primer sets (gcp, artJ-lktC, lktD, sodA) failed to distinguish M. haemolytica from other Mannheimia species. The rpt2 primer showed suboptimal universality, with 3 of 22 tested isolates yielding negative results. The rpoB primer had favorable universality and specificity, but its 136 bp amplicon was unsuitable for constructing multiplex PCR with M. haemolytica serotyping primers. We identified design flaws in the original rpt2 primer and developed a novel rpt2-N primer. Evaluation confirmed its strong universality, specificity, and sensitivity, as well as compatibility with serotyping primers for multiplex PCR assays. Field testing on three goat farms in the Chongqing region showed markedly higher M. haemolytica positivity rates after sharp temperature drops and transportation. Serotype A2 was confirmed as the dominant serotype in goats in Chongqing. This study systematically assessed multiple PCR identification primers, confirmed the feasibility of rpoB, and resolved the universality limitation of rpt2, providing technical support for rapid and accurate M. haemolytica detection.

Porcine epidemic diarrhea virus (PEDV) continues to undergo persistent genetic evolution and remains highly prevalent in pig herds worldwide. The resulting porcine epidemic diarrhea (PED) causes substantial economic losses to the global commercial swine industry. In this study, 296 clinical specimens were collected from diarrheic piglets across nine districts and counties of Chongqing between 2022–2024 and were screened using RT-qPCR. PEDV-positive specimens were detected in all sampling regions, with an overall positive rate of 48.31% (143/296), indicating widespread circulation and endemic persistence of PEDV throughout Chongqing. Phylogenetic analysis of the S gene from 15 representative field isolates revealed that all strains clustered within the G2c sublineage, implying that G2c has become the predominant epidemic lineage circulating in this region in recent years. Sequence analysis showed that the nucleotide identities of the S gene ranged from 93.37%–94.09% compared with the classic CV777 strain and from 96.79%–97.67% compared with the variant AJ1102 strain. Corresponding amino acid similarities were 92.88%–93.56% and 97.25%–98.05%, respectively. Notably, clear recombination footprints were identified in 11 sequenced isolates, all exhibiting highly identical recombination patterns, likely resulting from crossover events between the major parental strain FR/001/2014 and the minor parental strain CH/GDGZ/2012. Furthermore, ten distinct amino acid substitutions including F536L, D566E and L573S were identified within the COE antigenic domain of the S protein, whereas the SS2, SS6 and 2C10 domains remained highly conserved. Four isolates possessed four novel potential N-glycosylation motifs, including 300 NKTI and 787 NFSV, while two isolates concurrently lost the conserved 341 NLSF glycosylation site. These genetic alterations may influence viral pathogenicity and immune evasion capacity, thereby potentially contributing to the continued predominance and spread of the G2c sublineage in China. Together, this study expands current epidemiological knowledge of PEDV in inland Southwest China, and confirms G2c strains as the dominant circulating variants in local pig populations. These findings provide important molecular insights into the epidemiological trends and evolutionary dynamics of PEDV and offer a valuable reference for the development of more effective prevention and control strategies.

Clostridium perfringens type A causes neonatal clostridial enteritis, hemorrhagic enteritis, and sudden death syndrome in cattle. This study examined a fatal outbreak at a fattening farm housing 58 adult yaks in Southwest China, with an incidence of 22.41% (13/58) and a 100% case fatality rate. Histopathology of deceased yaks showed widespread multi-organ hemorrhage and severe hemorrhagic enteritis. A specific PCR assay amplified the alpha-toxin gene of Clostridium perfringens, while no other pathogens were detected. Clostridium perfringens was isolated from small intestinal contents using TSC agar, designated strain CQ1, and identified as type A through toxinotyping. Whole-genome sequencing revealed that strain CQ1 carries the core alpha-toxin gene along with key accessory virulence determinants (pfoA, colA, and cloSI). Phylogenomic analysis based on core single-nucleotide polymorphisms revealed that strain CQ1 is clustered into a distinct, independent evolutionary lineage with an existing historical yak isolate and a canine-origin isolate. Intraperitoneal challenge in mice confirmed its extreme lethality, causing 100% mortality within 36 h with severe intestinal necrosis. These findings provide fundamental genetic resources for understanding the virulence mechanisms and genetic background of this pathogen and offer critical insights for preventing and controlling clostridial diseases in high-altitude yak farming.