Porcine parvovirus (PPV) is the main pathogen of reproductive disorders. In recent years, a new type of porcine parvovirus has been discovered and named porcine parvovirus 2 to 7 (PPV2–PPV7), and it is associated with porcine circovirus type 2 in pigs. Codon usage patterns and their effects on the evolution and host adaptation of different PPV sub-types are still largely unknown. Here, we define six main sub-types based on the Bayesian method of structural proteins of each sub-type of PPV, including PPV2, PPV3, PPV4, PPV5, PPV6, and PPV7, which show different degrees of codon usage preferences. The effective number of codons (ENC) indicates that all PPV sub-types have low codon bias. According to the codon adaptation index (CAI), PPV3 and PPV7 have the highest similarity with the host, which is related to the main popular tendency of the host in the field; according to the frequency of optimal codons (FOP), PPV7 has the highest frequency of optimal codons, indicating the most frequently used codons in its genes; and according to the relative codon deoptimization index (RCDI), PPV3 has a higher degree. Therefore, it is determined that mutational stress has a certain impact on the codon usage preference of PPV genes, and natural selection plays a very decisive and dominant role in the codon usage pattern. Our research provides a new perspective on the evolution of porcine parvovirus (PPV) and may help provide a new method for future research on the origin, evolutionary model, and host adaptation of PPV.

Chikungunya virus (CHIKV) infection is often linked to acute interstitial nephritis (AIN) in fatal cases. Given the global spread of CHIKV and the lack of targeted antiviral treatments, there is an urgent need for effective therapeutic strategies against CHIKV-induced AIN. This study explored the therapeutic potential of salidroside (Sal) using an integrative approach involving network pharmacology, molecular docking and in vitro validation. Network pharmacology analysis identified 18 overlapping targets between Sal and AIN, including TNF, IL6 and AKT1. Molecular docking revealed strong binding affinities between Sal and key pathway proteins (Vina scores < –6), notably TNF, IL6 and BCL2. In vitro assays using CHIKV-infected 293T cells demonstrated that Sal (7.8125–2000 μM) enhanced cell viability by 8.9–25.9%, with the greatest effect observed at 1000 μM, without significantly altering viral replication. Mechanism analysis using the KEGG and FerrDB databases implicated apoptosis and ferroptosis in CHIKV-induced AIN pathogenesis. RT-qPCR analysis confirmed that Sal significantly downregulated ferroptosis-related genes (IL-6, IL-1β, SIRT1, PARP1, HMOX1) and apoptosis-associated markers (Bax, TNF-α, PARP1) in infected cells. Consistent with these findings, molecular docking demonstrated that Sal binds strongly to the ferroptosis-related protein GPX4 (Vina score: –6.3) and the apoptosis regulator NFKB1 (Vina score: –6.0). These results suggest that Sal is a promising therapeutic candidate for the treatment of CHIKV-induced AIN.

Fu-Zheng-Xuan-Fei formula (FF) is a prescription that has been clinically used through the basic theory of traditional Chinese medicine (TCM) for treating viral pneumonia. Although FF possesses a prominent clinical therapeutic effect, seldom pharmacological studies have been reported on its anti-influenza B virus (IBV) activity. Influenza is an acute infectious respiratory disease caused by the influenza virus, which has high annual morbidity and mortality worldwide. With a global decline in the COVID-19 control, the infection rate of influenza virus is gradually increasing. Therefore, it is of great importance to develop novel drugs for the effective treatment of influenza virus. Apart from conventional antiviral drugs, TCM has been widely used in the clinical treatment of influenza in China. Therefore, studying the antiviral mechanism of TCM can facilitate the scientific development of TCM. Madin-Darby canine kidney cells (MDCK) and BALB/c mice were infected with IBV, and FF was added to evaluate the anti-IBV effects of FF both in vitro and in vivo by Western blotting, immunofluorescence, flow cytometry, and pathological assessment. It was found that FF exhibited anti-viral activity against IBV infection both in vivo and in vitro, while inducing macrophage activation and promoting M1 macrophage polarization. In addition, FF effectively regulated the signal transducer and activator of transcription (STAT) signaling pathway-mediated Th17/Treg balance to improve the lung tissue damage caused by IBV infection-induced inflammation. The findings provided the scientific basis for the antiviral mechanism of FF against IBV infection. This study shows that FF is a potentially effective antiviral drug against IBV infection.