Haemophilus parasuis (H. parasuis, HPS) is a prominent pathogenic bacterium in pig production. Its infection leads to widespread fibrinous inflammation in various pig tissues and organs, often in conjunction with various respiratory virus infections, and leads to substantial economic losses in the pig industry. Therefore, the rapid diagnosis of this pathogen is of utmost importance. In this study, we used recombinase polymerase amplification (RPA) and clustered regularly interspaced short palindromic repeats (CRISPR) technology to establish a convenient detection and analysis system for H. parasuis that is fast to detect, easy to implement, and accurate to analyze, known as RPA-CRISPR/Cas12a analysis. The process from sample to results can be completed within 1 h with high sensitivity (0.163 pg/μL of DNA template, p < 0.05), which is 10⁴ -fold higher than the common PCR method. The specificity test results show that the RPA-CRISPR/Cas12a analysis of H. parasuis did not react with other common pig pathogens, including Streptococcus suis type II and IX, Actinobacillus pleuropneumoniae, Escherichia coli, Salmonella, Streptococcus suis, and Staphylococcus aureus (p < 0.0001). The RPA-CRISPR/Cas12a assay was applied to 15 serotypes of H. parasuis clinical samples through crude extraction of nucleic acid by boiling method, and all of the samples were successfully identified. It greatly reduces the time and cost of nucleic acid extraction. Moreover, the method allows results to be visualized with blue light. The accurate and convenient detection method could be incorporated into a portable format as point-of-care (POC) diagnostics detection for H. parasuis at the field level.

Mycoplasma, reticuloendotheliosis virus (REV), avian leukosis virus (ALV), chicken infectious anemia virus (CIAV), bovine polyomavirus (BPV), bovine viral diarrhea virus (BVDV), and porcine circovirus (PCV) are considered common contaminants in live veterinary vaccines against Newcastle disease virus (NDV), fowlpox virus (FPV), infectious bursal disease virus (IBDV), classical swine fever virus (CSFV), pseudorabies virus (PRV), and porcine reproductive and respiratory syndrome virus (PRRSV). In the past five years, Getah virus (GETV), an arbovirus affecting many farming mammals, was reported as a new contaminant in live PRRSV vaccines in two previous studies, which arouses our considerable interest. Therefore, in this paper, we aim to analyze and discuss the source, biological hazard, and genomic characteristics of these contaminating GETV strains further.

Getah virus (GETV), a mosquito-borne virus capable of infecting multiple economically important animal species, poses a potential epidemic risk. In May 2024, one pig farm from Heyuan, Guangdong Province, China, suffered reproductive disorders in sows and diarrhea in newborn piglets. Out of the six blood samples that were collected, three tested strongly positive for GETV, yielding a positivity rate of 50%. Moreover, a GETV strain (designated GDHYLC2024) was successfully isolated and identified. The viral titer of GDHYLC2024 was 10^7.687 TCID₅₀/mL in Vero cells. Its genome was composed of 11,688 bases in length. Interestingly, compared with GDHYLC23, it had no unique 32-nucleotide repeat insertion in 3′ non-coding region. However, phylogenetic analysis showed that GDHYLC2024 and GDHYLC23 clustered in genotype III. Animal infection experiments demonstrated that the GDHYLC2024 strain was highly pathogenic to 4-day-old piglets, which caused obvious clinical symptoms including fever, depression, anorexia, periorbital edema, ataxia, and three deaths out of a total of five individuals in the infection group. This study reported re-emergence of GETV in the same region of Guangdong Province, China. The above findings suggest that GETV continuously poses a threat to farm pig’s health and has genetic diversity.

Viruses have evolved numerous mechanisms to target key metabolic pathways in the host, thereby reshaping host metabolism to establish a metabolic environment conducive to their replication. We previously observed that pseudorabies virus (PRV) infection upregulates cellular glycolysis, but the mechanism is not clear. Here, our results showed that PRV infection significantly upregulated the mRNA levels of HK2 and MCT4. Upon HIF-1α inhibition, the PRV-induced upregulation of glycolytic genes was reversed. Concurrently, PRV infection promoted the accumulation of intracellular mitochondrial ROS (mROS), whereas mROS inhibition blocked HIF-1α activation. Furthermore, both HIF-1α and mROS inhibition significantly reduced PRV replication. In conclusion, we revealed that PRV activates HIF-1α by inducing mROS accumulation, thereby upregulating key glycolytic genes to promote viral replication. This study provides novel evidence for the metabolic regulatory mechanisms underlying PRV infection and identifies potential targets for PRV and other herpesvirus control.