Porcine reproductive and respiratory syndrome virus (PRRSV) continues to pose a major challenge to swine production in Vietnam because of its rapid evolution and genetic diversity. Here, we analyzed 69 PRRSV-positive samples collected from 20 provinces in Vietnam between 2021 and 2026 using ORF5 gene sequencing to characterize the genetic diversity of circulating strains. Phylogenetic analysis demonstrated the co-circulation of multiple PRRSV-2 lineages (L1, L3, L5, L8, and L10), together with a limited presence of PRRSV-1, indicating a genetically diverse PRRSV population within the analyzed diagnostic samples. Among the PRRSV-2 strains, lineage 8 (L8), particularly sub-lineage L8E, was the most frequently detected, whereas lineage 10 (L10) accounted for 24.6% of the sequenced isolates and was detected only in samples collected from 2023 onwards. Independent maximum-likelihood phylogenetic and pairwise ORF5 distance analyses showed that the Vietnamese L10 strains formed a distinct monophyletic cluster within lineage 10. Analysis of the GP5 protein identified amino acid variation in previously described antigenic regions, providing descriptive information on the genetic diversity of circulating Vietnamese PRRSV strains. Collectively, these findings provide updated insights into the molecular epidemiology of PRRSV in Vietnam and highlight the value of continuous molecular surveillance for monitoring the emergence and distribution of PRRSV lineages.
Nguyen Tuan Anh Mai, Thi Chau Giang Tran, Thi Thu Hang Vu et al.· The Veterinary Journal· 0 citations
African swine fever virus (ASFV) genotype II is a highly virulent pathogen; however, its effects on the female reproductive system remain poorly understood. This study investigated the pathogenesis of ASFV genotype II in female pigs, focusing on viral dynamics and reproductive tissue damage. Pigs were intramuscularly inoculated with a highly pathogenic ASFV strain (103 HAD50). Clinical signs developed rapidly, with fever exceeding 41 °C at 3-4 days post-infection (dpi), followed by 100% mortality within 9 dpi. Viraemia was detected at 3 dpi, peaked at 6 dpi, and remained high until death, indicating rapid systemic dissemination. ASFV-specific antibodies were undetectable at 6 dpi, with only limited seroconversion observed at the terminal stage. ASFV DNA was detected in all reproductive organs (real-time PCR Ct values: 21.89-27.9). Severe gross and histopathological lesions were identified, including vascular congestion, haemorrhage, inflammatory infiltration, endometrial desquamation, glandular necrosis, and ovarian follicular degeneration. The co-occurrence of high viral loads and marked tissue damage, particularly in the ovaries and endometrium, indicates direct viral involvement in reproductive pathology. These findings demonstrate that ASFV genotype II causes rapid systemic infection and significant reproductive tissue damage, highlighting its potential impact on reproductive performance in swine.
The Viet Hoang Nguyen, Viet Dung Nguyen, Ngoc Duong Vu et al.· The Veterinary Journal· 0 citations
