Transboundary and Emerging Diseases最新文献

Pasteurella multocida (P. multocida), a significant animal pathogen, causes swine pneumonia and atrophic rhinitis, primarily associated with serogroups A, D, and F. Although serogroups A and D are prevalent in pigs and well-established causes of these diseases, the pathogenicity and genomic characteristics of porcine serogroup F remain poorly characterized. Here, we isolated a virulent P. multocida strain—AH01, from pigs with fatal acute respiratory disease in Anhui, China. It was characterized as a capsular Type F, lipopolysaccharide (LPS) antigen Type L3 isolate of sequence type (ST) 9. To evaluate the pathogenicity of this strain, pigs were challenged intratracheally with AH01 (6 × 10⁹ CFU), inducing acute pyrexia, dyspnea, anorexia, and rapid mortality (≤12 h postinfection, hpi). PacBio SMRT (Single-Molecule Real Time) sequencing generated a complete 2.27-Mbp chromosome (40.3% GC content; 2058 CDSs). Annotation identified 254 potential virulence-associated genes, 47 different drug resistance phenotypes, and three genomic islands (GIs). Comparative genomics revealed a novel 16.7-kb specific region insertion encoding zonula occludens toxin (Zot) and general secretion pathway protein D (GspD), potentially facilitating epithelial barrier disruption. Furthermore, polymorphisms in LPS outer core biosynthesis genes natC and gatF were characterized across strains avian Pm70, porcine AH01, and HN07. Strain AH01 harbors a single-nucleotide deletion (natC position 760), causing a frameshift and premature stop. Both porcine strains AH01 and HN07 exhibited a 216-bp N-terminal extension in gatF compared to avian Pm70 strain, indicating host-specific or strain-dependent LPS biosynthetic divergence. Collectively, these findings provide critical insights into the pathogenicity and genomic basis of porcine-derived P. multocida serogroup F.

Peste des petits ruminants (PPRs) is an economically significant disease affecting small ruminants. Owing to its impact on livestock and rural livelihoods, Ethiopia joined the global PPR eradication program and implemented risk-based vaccination strategies in 2018. However, gaps remain in understanding the geographic distribution, seasonal trends, and impact of this disease. To address these gaps, a repeated cross-sectional study was conducted between September 2018 and August 2024 in the North Shewa Zone to confirm PPR outbreaks via rapid antigen detection methods, specifically the pen-side test and dipstick technique. In addition, a retrospective analysis was performed to assess the spatial and temporal distributions of outbreaks, along with associated morbidity, mortality, and case fatality rates. The results revealed 48 confirmed PPR outbreaks over 6 years, occurring in 15 out of 24 districts, with an average of 8 outbreaks annually and a 0.33 proportion of affected districts, indicating low and localized spread. A total of 192 clinical samples were collected from symptomatic sheep and goats, all of which tested positive for PPRV. In total, 6415 PPR cases were documented, with a morbidity rate of 0.72%, a mortality rate of 0.11% (951 deaths), and a case fatality rate of 14.82%. Kewet had the highest number of outbreaks (7), whereas Mojana-Wedera recorded the highest number of cases (2718). Seasonally, 60% of the outbreaks occurred during the long rainy season, leading to 4472 cases and a fatality rate of 16.79%. Yearly trends showed consistent patterns, with 2023 having the highest number of outbreaks (15) and 2021 having the fewest (5). The year 2024 had the highest number of cases (2706). Despite continued viral circulation, the low morbidity and mortality rates, relative to the high transmissibility and fatality rates of the PPR in naïve populations (infection rates of up to 100% and mortality rates of 10%–90%), reflect significant control progress. While PPR remains endemic in the North Shewa Zone, the reduced incidence and clinical impact indicate measurable advancements toward eradication. Nonetheless, recurrent outbreaks across seasons and districts necessitate sustained, adaptive interventions. The study recommends strengthening surveillance, enhancing postvaccination sero-monitoring, and optimizing vaccine allocation to accelerate eradication.

Porcine epidemic diarrhea (PED) virus (PEDV) is a highly contagious intestinal infection that primarily affects suckling pigs. The interaction about the innate immune evasion of PEDV in intestinal epithelium and microRNA (miRNA) remains unclear. A strain of PEDV belonging to the G2a genotype, designated FJND 2022, was successfully isolated and confirmed. Then, the miRNA profile in exosomes-derived from intestinal porcine epithelial cell line (IPEC) infected with PEDV FJND 2022 for 48 h was evaluated. In exosomes from PEDV-infected IPECs, 34 miRNAs showed differential expression relative to blank cells. A total of 7762 target genes of those differentially expressed miRNAs were forecast, and the miR-193a-5P and its target mRNA interleukin (IL)22 and porcine β-defensin 1 (pBD1) attracted our interest. After infection with PEDV for 48 h, the mRNA levels and protein levels of IL22 and pBD1 were both notably downregulated, while the mRNA level of miR-193a-5P was significantly decreased. When IPECs were pretreated with the mimic of miR-193a-5P and then infected with PEDV, the mRNA levels of IL22 and pBD1 were significantly increased while the viral load of PEDV was significantly reduced. However, siRNA-mediated knockdown of IL22 abrogated the capacity of miR-193a-5p mimic pretreatment to restore pBD1 expression. Furthermore, the inhibitor of miR-193a-5P was pretreated with IPECs infected with PEDV, resulting in a notable downregulation of IL22 and pBD1 expression, and a significant upregulation of the virus load of PEDV. Finally, we also found that the expression levels of IL22, pBD1, and miR-193a-5P were notably reduced in the small intestinal epithelium of suckling piglets infected with PEDV for 48 h. Therefore, in this study we reveal that PEDV downregulates the miR-193a-5P expression in the intestinal epithelium to evade the antivirus of IL22/pBD1, which provides new insights into PEDV molecular pathogenesis and immune evasion mechanisms.

Tick-borne viruses (TBVs) represent a serious risk to global public and animal health. Despite the remarkable species diversity of ticks documented in Urumqi and its adjacent regions of China, scientific investigations into TBVs in this ecologically significant area have been strikingly scarce. In this study, we conducted metagenomic sequencing on 752 Hyalomma asiaticum (H. asiaticum), including questing ticks from Wujiaqu and blood-feeding ticks collected from sheep and horses in the Changji area. A total of 11 different RNA viruses were detected, belonging to six viral families and some unclassified families, with double-stranded RNA viruses being the most prevalent (49.1%), including Totiviridae and Sedoreoviridae. Single-stranded RNA viruses accounted for 11.9% of the virome, encompassing Chuviridae, Flaviviridae, Rhabdoviridae, and Phenuiviridae. Notably, 39.0% of the viral sequences remained unclassified, highlighting a substantial reservoir of uncharacterized viral diversity. Genomic and phylogenetic characterizations were performed on six highly abundant viruses, including Bole tick virus 1, Mivirus boleense, Bole tick virus 4, Lonestar tick totivirus, Hubei toti-like virus 24, and a novel strain of Hulunbuir Totiv tick virus 1. However, their zoonotic potential requires further investigation. By integrating cytochrome c oxidase subunit Ⅰ (COI) gene-based tick species identification with viral metagenomics, this study provided a comprehensive assessment of tick species and TBVs diversity in Urumqi and its surrounding areas, China. These results provide new insights into both the genetic diversity of tick-borne RNA viruses and their phylogenetic connections, while also expanding knowledge about the geographical distribution patterns of these pathogens.

Bovine tuberculosis (TB), primarily caused by Mycobacterium bovis, is a chronic infectious disease of cattle with significant public health and economic implications due to its zoonotic potential and impact on livestock productivity. The control of the disease is hindered by complex epidemiological dynamics and the chronic, and often slow-progressing nature of the disease. The recurrent outbreaks of bovine TB in endemic areas are common and threaten the success of eradication programs. To address this issue, long-term reemergent outbreaks in Catalonia (Northeastern Spain) were retrospectively investigated in depth. In 2009, an outbreak caused by M. bovis spoligotype SB0120 was detected in four extensively managed cattle herds. Following intensive eradication measures, all herds recovered the officially TB-free status by 2012. In 2021, 9 years later, a new outbreak involving the same spoligotype was detected in three herds located in the same area, one of which had been affected in the previous outbreak. Extensive sampling of TB-positive slaughtered cattle and hunted wild ungulates was conducted. Whole genome sequencing (WGS) of M. bovis isolates from cattle affected in both outbreaks, as well as from two culture-positive wild boars was performed. Epidemiological and phylogenetic analyses were conducted to elucidate the origin and transmission dynamics of the outbreaks. The results revealed a long-term residual infection in the cattle herd that linked the first and second outbreaks. This herd was also the most likely source of transmission of M. bovis to wild boars. Since residual infections can jeopardize the final stages of the eradication in low-prevalence settings, thorough investigation of reemerging strains is essential for risk assessment and for guiding TB control decisions.

The devastating swine disease, porcine reproductive and respiratory syndrome (PRRS), can only be caused by live PRRS virus (PRRSV) infection. However, the most commonly used detection methods cannot discriminate PRRSV infectivity. Here we developed a triplex propidium monoazide (PMA) qPCR assay for differential detection of infectious PRRSV isolates (NADC34-like PRRSV-2, NADC30-like PRRSV-2, and HP-PRRSV-2) prevalent in China. First, the PRRSV inactivation strategy was selected by comparing distinct inactivation methods. Subsequently, we optimized PMA pretreatment parameters and concentrations of primers and probes. The triplex PMA-qPCR assay displayed favorable specificity, sensitivity, and reproducibility. Moreover, 452 clinical samples (environmental feces, lungs, lymph nodes (LNs), and sera) were submitted to differential detection by triplex qPCR and triplex PMA-qPCR assays. A total of 83 PRRSV-positive samples were detected by the triplex qPCR assay, including 25 NADC34-like, 48 NADC30-like, and 15HP-PRRSV-2-positive samples (two samples were coinfected by NADC34-like and NADC30-like PRRSV-2, while three samples were coinfected by NADC30-like and HP-PRRSV-2). Meanwhile, 65 samples were identified by the PMA-qPCR method, including 21 NADC34-like, 36 NADC30-like, and 9HP-PRRSV-2 positive samples (one sample was coinfected by NADC34-like and NADC30-like PRRSV-2). No PRRSV could be isolated from the 18 qPCR-positive but PMA-qPCR-negative samples. Overall, this study provides the first triplex PMA-qPCR assay for rapid discrimination of live PRRSV isolates in clinical samples, particularly in environmental feces.

Foot-and-mouth disease (FMD) is a highly contagious and serious transboundary disease affecting cloven-hoofed animals. Myanmar is a critical area for FMD outbreaks in Southeast and East Asian regions because of its geographical location bordering South Asian countries and its cattle industry. Phylogenetic characterization and pathogenicity in susceptible animals of circulating viruses in Myanmar are essential to prepare the rapid and accurate diagnosis and implement effective FMD prevention. This study analyzed a total of 34 vesicular epithelial samples collected from FMD cases in northern, central, and southern Myanmar between 2016 and 2022. Phylogenetic analysis of VP1 nucleotide sequences revealed multiple serotypes and topotypes between 2016 and 2019, including serotype O/Middle East-South Asia (ME-SA) topotype (O/ME-SA/Ind-2001e) and Southeast Asia (SEA) topotype, and serotype A/ASIA topotype. Subsequently, all viruses across Myanmar detected from 2019 to 2022 belonged to O/ME-SA/Ind-2001e. Phylogenetic analysis of the whole genome sequence showed that O/ME-SA/Ind-2001e viruses detected after 2019 were classified into a different genetic group with those of 2016 isolates in Myanmar. Based on phylogenetic analysis, one representative strain from 2019 that was genetically similar to viruses detected from 2019 to 2022 and to a 2022 Indonesian isolate was selected for pathogenicity testing in comparison with a 2016 strain closely related to viruses from neighboring countries. Both strains were used for experimental infection in pigs and showed similar pathogenicity. The 2019 strain was additionally tested in cattle and caused typical FMD pathogenicity, including vesicular development and virus excretion. Viral genes and antibodies in infected animals were detectable using existing diagnostic methods, which are considered useful for identifying currently circulating viruses. These results elucidate the subtypes of FMD viruses (FMDVs) circulating in Myanmar, their phylogenetic relationships with viruses from neighboring Asian countries, their pathogenicity, and the applicability of available diagnostic methods. It offers insights into appropriate control strategies against FMD in Southeast and East Asian regions.

Getah virus (GETV), Japanese encephalitis virus (JEV), West Nile virus (WNV), and African horse sickness virus (AHSV) are mosquito-borne viruses threatening the health of racehorses. However, the systematic surveillance of these viruses among Shanghai racehorses remains lacking. Therefore, molecular and serological surveillance was conducted for these viruses in racehorses and mosquitoes at horse farms in Shanghai, China, during 2022 to assess their prevalence. Among 11,140 mosquitoes collected from seven farms across four districts, Culex tritaeniorhynchus and Anopheles sinensis were identified as the dominant species. RT-qPCR detected GETV in four mosquito pools (FX1-6, PD1-32, PD1-45, and PD1-57) and JEV in three pools (SJ1-4, PD1-22, and JS1-9), while WNV and AHSV remained undetected. Two GETV strains (SH202201 and SH202202) were isolated and phylogenetically classified as genotype III (GIII). Serological surveys of 182 horse serum samples revealed an overall GETV antibody positivity rate of 28.6%. The positivity rate demonstrated significant age-dependency (41.7% in horses >15 years) and seasonal variation (45.1% in autumn vs. 12.1% in spring). JEV seroprevalence rates were 12.6%, exhibiting significant seasonal differences. No antibodies positive for WNV and AHSV were detected. These results indicate that the threat of WNV and AHSV to racehorses in Shanghai is currently very small, while GETV represents the primary arboviral risk. Implementing targeted surveillance for GETV during high-risk seasons (autumn) and in key regions (Fengxian), while enhancing surveillance for JEV, WNV, and AHSV, is crucial for safeguarding equine health and promoting the sustainable development of the equestrian industry.

Strongyloidiasis caused by Strongyloides papillosus is a significant parasitic disease affecting the health and productivity of small ruminants globally. In this study, a novel recombinase-aided amplification (RAA) combined with lateral flow dipstick (LFD) assay was developed and validated for the rapid and specific detection of S. papillosus infection in goats and sheep, targeting the 18S ribosomal RNA (18S rRNA) gene. A total of 815 fecal samples were collected from nine provinces in China, encompassing major goats and sheep production regions. The RAA-LFD assay exhibited high sensitivity, with a minimum detection limit of 15 eggs per gram (EPG) of feces. Clinical fecal examination yielded a positive rate of 62.30% (433/695), while the RAA-LFD assay achieved a positive rate of 58.28% (475/815), indicating that the diagnostic accuracy of the RAA-LFD assay is consistent with that of fecal examination. Compared with conventional fecal examination, the RAA-LFD assay offers superior rapidity, portability, and sensitivity, presenting a valuable diagnostic tool for large scale epidemiological surveillance and point-of-care applications, particularly in resource constrained environments.

Bartonella species are known as candidates for zoonotic transmission, and cats serve as the main reservoir for Bartonella henselae, the primary causative agent of cat scratch disease (CSD). However, research on the transmission of bartonellosis to humans remains very limited. In East Asia, there is a lack of comprehensive studies regarding the prevalence of B. henselae infection and its associated risk factors among companion cats, their owners, and individuals working in veterinary professions. This study aimed to investigate both the molecular and seroprevalence of B. henselae in veterinary personnel and companion cats in South Korea, along with a questionnaire-based analysis of transmission risk factors. Blood and saliva samples were collected from humans, whereas blood, saliva, claw, and fecal samples were obtained from cats. Seroprevalence and molecular prevalence were measured for all these samples. Additionally, participants were required to complete an epidemiological information questionnaire related to CSD. The study enrolled 300 veterinary professionals and 126 companion cats owned by them. The serum IgG prevalence in humans was 64.6% (190/294), whereas, in cats, it was 5.5% (6/108). The molecular prevalence in human blood and saliva was 3% (9/298) and 1.7% (5/298), respectively. In cats, it was 10.1% (12/119) for blood, 0% (0/123) for saliva, 1.7% (2/119) for nails, and 4.5% (5/112) for feces. Phylogenetic analysis of the PCR-positive samples confirmed that all of them were B. henselae. This study demonstrates that Bartonella species are widespread among veterinary professionals in South Korea, highlighting their significance as zoonotic pathogens. Given the potential for indirect transmission from cats, enhancing awareness of Bartonella exposure risk among veterinary personnel is warranted, along with emphasizing preventive education for cat owners, including strict ectoparasite control.