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We investigate the subnational impact of trade on water use in the contiguous United States (CONUS). We develop an econometric model employing the instrumental variable (IV) approach to understand the causal impact of previous-year trade on current-year water use. Specifically, our analysis focuses on irrigated area and irrigation water use by water source (surface, groundwater, and total) across states in the CONUS for 2012–13, 2017–18, and 2022–23. We find that at the subnational scale, trade openness reduces groundwater withdrawals during droughts; a unit increase in previous-year trade openness results in a 2%–2.5% and 1.4%–2% reduction in groundwater irrigation withdrawals during 2012–13 and 2022–2023, respectively. This effect is identified as being driven by reductions in irrigated area and shifts towards advanced irrigation technologies. These findings enhance our understanding of how trade influences water use at the subnational scale and may provide helpful insights to policymakers.

Swine transboundary diseases pose significant challenges in East and Southeast Asia, affecting Taiwan, Japan, and the Philippines. This review delves into strategies employed by these islands over the past two decades to prevent or manage foot and mouth disease (FMD), classical swine fever (CSF), and African swine fever (ASF) in domestic pigs and wild boars. Despite socio-economic differences, these islands share geographical and climatic commonalities, influencing their thriving swine industries. Focusing on FMD eradication, this study unveils Taiwan’s success through mass vaccination, Japan’s post-eradication surveillance, and the Philippines’ zoning strategy. Insights into CSF in Japan emphasize the importance of wild boar control, whereas the ASF section highlights the multifaceted approach implemented through the Philippine National ASF Prevention and Control Program. This review underscores lessons learned from gained experiences, contributing to a comprehensive understanding of swine disease management in the region.

Classical swine fever virus (CSFV) shares high structural and antigenic homology with bovine viral diarrhea virus (BVDV) and border disease virus (BDV). Because all three viruses can infect swine and elicit cross-reactive antibodies, it is necessary to differentiate among them with regard to serological diagnosis of classical swine fever. To understand the mechanism of cross-reactivity, it is important to define common or specific epitopes of these viruses. For this purpose, epitope mapping of six monoclonal antibodies (mAbs) was performed using recombinant expressed antigenic domains of CSFV and BDV E2 proteins. One CSFV-specific conformational epitope and one CSFV and BDV common epitope within domain B/C of E2 were identified. Site-directed mutagenesis confirmed that residues G725 and V738/I738 of the CSFV-specific epitope and P709/L709 and E713 of the second epitope are important for mAbs binding. Infection of CSFV in porcine cells was significantly reduced after pre-incubation of the cells with the domain B/C of E2 or after pre-incubation of CSFV with the mAbs detecting domain B/C. 3D structural modeling suggested that both epitopes are exposed on the surface of E2. Based on this, the identified epitopes represent a potential target for virus neutralization and might be involved in the early steps of CSFV infection.

Porcine teschovirus (PTV) is an OIE-listed pathogen with 13 known PTV serotypes. Heterologous PTV serotypes frequently co-circulate and co-infect with another swine pathogen, causing various symptoms in all age groups, thus highlighting the need for a pan-PTV diagnostic tool. Here, a recombinant protein composed of a highly conserved “RNNQIPQDF” epitope on the GH loop of VP1, predicted in silico, and a tandem repeat of this epitope carrying the pan DR (PADRE) and Toxin B epitopes was constructed to serve as a PTV detection tool. This recombinant GST-PADRE-(RNNQIPQDF)n-Toxin B protein was used as an immunogen, which effectively raised non-neutralizing or undetectable neutralizing antibodies against PTV in mice. The raised antiserum was reactive against all the PTV serotypes (PTV–1–7) tested, but not against members of the closely related genera Sapelovirus and Cardiovirus, and the unrelated virus controls. This potential pan-PTV diagnostic reagent may be used to differentiate naturally infected animals from vaccinated animals that have antibodies against a subunit vaccine that does not contain this epitope or to screen for PTV before further subtyping. To our knowledge, this is the first report that utilized in silico PTV epitope prediction to find a reagent broadly reactive to various PTV serotypes.

Porcine epidemic diarrhea virus (PEDV) causes severe diarrhea and a high rate of mortality in suckling pigs. The epidemic of PEDV that occurred after 2013 was caused by non-insertion and deletion of S gene (S-INDEL) PEDV strains. During this epidemic, a variant of the non-S-INDEL PEDV strain with a large deletion of 205 amino acids on the spike gene (5-17-V) was also found to co-exist with a non-S-INDEL PEDV without deletion (5-17-O). Herein, we describe the differences in the complete genome, distribution, virulence, and antigenicity between strain 5-17-O and variant strain 5-17-V. The deletion of 205 amino acids was primarily located in the S1O domain and was associated with milder clinical signs and lower mortality in suckling pigs than those of the 5-17-O strain. The 5-17-V strain-induced antibody did not completely cross-neutralize the 5-17-O strain. In conclusion, the deletion in the S1 region reduces the virulence of PEDV and influences the virus-neutralizing activities of the antibody it induces.

Classical swine fever (CSF) is a highly contagious swine disease caused by the classical swine fever virus (CSFV), wreaking havoc on global swine production. The virus is divided into three genotypes, each comprising 4–7 sub-genotypes. The major envelope glycoprotein E2 of CSFV plays an essential role in cell attachment, eliciting immune responses, and vaccine development. In this study, to study the cross-reaction and cross-neutralizing activities of antibodies against different genotypes (G) of E2 glycoproteins, ectodomains of G1.1, G2.1, G2.1d, and G3.4 CSFV E2 glycoproteins from a mammalian cell expression system were generated. The cross-reactivities of a panel of immunofluorescence assay-characterized serum derived from pigs with/without a commercial live attenuated G1.1 vaccination against different genotypes of E2 glycoproteins were detected by ELISA. Our result showed that serum against the LPCV cross-reacted with all genotypes of E2 glycoproteins. To evaluate cross-neutralizing activities, hyperimmune serum from different CSFV E2 glycoprotein-immunized mice was also generated. The result showed that mice anti-E2 hyperimmune serum exhibited better neutralizing abilities against homologous CSFV than heterogeneous viruses. In conclusion, the results provide information on the cross-reactivity of antibodies against different genogroups of CSFV E2 glycoproteins and suggest the importance of developing multi-covalent subunit vaccines for the complete protection of CSF.

Classical swine fever (CSF) is a systemic hemorrhagic disease affecting domestic pigs and wild boars. The modified live vaccine (MLV) induces quick and solid protection against CSF virus (CSFV) infection. Maternally derived antibodies (MDAs) via colostrum could interfere with the MLV’s efficacy, leading to incomplete protection against CSFV infection for pigs. This study investigated CSFV transmission among experimental piglets with various post-MLV immune statuses. Nineteen piglets, 18 with MDAs and 1 specific-pathogen-free piglet infected with CSFV that served as the CSFV donor, were cohabited with piglets that had or had not been administered the MLV. Five-sixths of the piglets with MDAs that had been administered one dose of MLV were fully protected from contact transmission from the CSFV donor and did not transmit CSFV to the piglets secondarily exposed through cohabitation. Cell-mediated immunity, represented by the anti-CSFV-specific interferon-γ-secreting cells, was key to viral clearance and recovery. After cohabitation with a CSFV donor, the unvaccinated piglets with low MDA levels exhibited CSFV infection and spread CSFV to other piglets through contact; those with high MDA levels recovered but acted as asymptomatic carriers. In conclusion, MLV still induces solid immunity in commercial herds under MDA interference and blocks CSFV transmission within these herds.

Viremia is a key step in CSF pathogenesis and serum remains a preferred testing sample for detecting the antibody, antigen, or nucleic acid. [...]serum itself may become a vehicle of disease spread [11], not only for CSF virus (CSFV) but also for others such as porcine reproductive and respiratory syndrome virus (PRRSV) [12], so that inactivation of viruses while not disturbing antibody detection is key to prevent such risk [11]. MLV has the further disadvantage of overloading the immune system, when multiple infections with various viral and bacterial pathogens, such as PRRSV, occur regularly in the field [12]. [...]more is not necessarily better” for a busy immune system, wherein killed or subunit CSF vaccines are suitable [12]. [...]experimentally infecting sows at mid-gestation showed newborn viremic piglets launching CD8+-T cell and interferon (IFN) -alpha responses to CSFV [4], and fast and solid immunity for sows is required for prevention of congenital viral persistence. Fun-In Wang1,* and Chia-Yi Chang2 1School of Veterinary Medicine, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan 2OIE Reference Expert for CSF, Animal Health Research Institute, Council of Agriculture, Executive Yuan, 376 Chung-Cheng Road, Tansui, New Taipei City

In Taiwan, the prevalent CSFV population has shifted from the historical genotype 3.4 (94.4 strain) to the newly invading genotype 2.1 (TD/96 strain) since 1996. This study analyzed the competition between these two virus genotypes in dual infection pigs with equal and different virus populations and with maternally derived neutralizing antibodies induced by a third genotype of modified live vaccine (MLV), to simulate that occurring in natural situations in the field. Experimentally, under various dual infection conditions, with or without the presence of maternal antibodies, with various specimens from blood, oral and fecal swabs, and internal organs at various time points, the TD/96 had consistently 1.51−3.08 log higher loads than those of 94.4. A second passage of competition in the same animals further widened the lead of TD/96 as indicated by viral loads. The maternally derived antibodies provided partial protection to both wild type CSFVs and was correlated with lower clinical scores, febrile reaction, and animal mortality. In the presence of maternal antibodies, pigs could be infected by both wild type CSFVs, with TD/96 dominating. These findings partially explain the CSFV shift observed, furthering our understanding of CSFV pathogenesis in the field, and are helpful for the control of CSF.

Bluetongue is an infectious viral hemorrhagic disease of domestic and wild ruminants that has a considerable economic impact on domestic ruminants. There are currently at least 29 serotypes of bluetongue virus (BTV) in the world. Noteworthily, the pathogenesis among BTV serotypes is different, even in the same animal species. In this study, BTV2/KM/2003 and BTV12/PT/2003 were used to investigate the differential immunological effects on bovine peripheral blood mononuclear cells (PBMCs). The BTV viral load and the expression of cytokine messenger RNA (mRNA) in PBMCs were measured by fluorescence-based real-time reverse-transcription PCR (qRT-PCR). The immunofluorescence assay (IFA) was applied to detect BTV signals in monocyte-derived macrophages (MDMs). The SWISS-MODEL and IL-4pred prediction tools were used to predict the interleukin 4 (IL-4)-inducing peptides in BTV-coat protein VP2. Synthetic peptides of VP2 were used to stimulate PBMCs for IL-4-inducing capability. This study demonstrated that the cytokine profiles of BTV-induced PBMCs were significantly different between BTV2/KM/2003 and BTV12/PT/2003. BTV2 preferentially activated the T helper 2 (Th2) pathway, represented by the early induction of IL-4, and likely fed back to inhibit the innate immunity. In contrast, BTV12 preferentially activated the innate immunity, represented by the induction of tumor necrosis factor -α (TNF-α) and interleukin 1 (IL-1), with only minimal subsequent IL-4. The BTV nonstructural protein 3 antibody (anti-BTV-NS3) fluorescent signals demonstrated that monocytes in PBMCs and MDMs were the preferred targets of BTV replication. Bioinformatics analysis revealed that the capability to induce IL-4 was attributed to the tip region of the VP2 protein, wherein a higher number of predicted peptide segments on BTVs were positively correlated with the allergic reaction reported in cattle. Synthetic peptides of BTV2-VP2 induced significant IL-4 within 12–24 h post-infection (hpi) in PBMCs, whereas those of BTV12 did not, consistent with the bioinformatics prediction. Bovine PBMCs and synthetic peptides together seem to serve as a good model for pursuing the BTV-induced IL-4 activity that precedes the development of an allergic reaction, although further optimization of the protocol is warranted.