Background and Aim: Canine distemper (CD) caused by the CD virus (CDV) has a high mortality rate that severely affects dog populations and other terrestrial carnivores worldwide. However, the genetics of CDV strains circulating in various regions in Vietnam, especially the Mekong Delta, remains unclear. This study aimed to characterize the molecular status of CDV strains circulating in the Mekong Delta, Vietnam. Materials and Methods: Ocular/nasal swabs were collected from 550 dogs with clinically suspected CDV infection from veterinary clinics in three Vietnamese provinces. A reverse transcription-polymerase chain reaction on the part of the hemagglutinin gene was performed. A phylogenetic tree was constructed to analyze the relationship between the detected CDV and GenBank sequences. Results: The molecular study demonstrated that 4.18% (23/550) of the dogs were positive for CDV. The clinical findings revealed that the positive dogs exhibited clinical signs of distemper. The phylogenetic analysis indicated that the identified CDV sequences were clustered in the same branch with the genotype Asia-1 and distantly related to the vaccine strains. Notably, the CDV sequences detected in this study were grouped with the sequences previously found in southeast Vietnam; however, they were distant from those found in the north. Conclusion: The present study confirmed the presence of CDV and to the best of our knowledge, highlighted for the first time that the CDV strains circulating in the Mekong Delta of Vietnam belong to the genotype Asia-1. Keywords: canine, distemper virus, hemagglutinin gene, phylogenetic analysis, Vietnam.

Canine distemper virus (CDV) is a highly contagious pathogen and causes a fatal systemic disease in domestic dogs and wild carnivores worldwide. Despite CDV infections being monitored globally, studies on CDV in Vietnam seem to be limited. This study, therefore, investigated the epidemiological, clinical, and molecular characteristics of CDV in the Mekong Delta (MD) region of Vietnam. A total of 6687 ocular/nasal swabs were collected from CDV-suspected dogs across seven cities/provinces. CDV infection was detected in 6.19% (414 dogs) of suspected dogs using a commercially available rapid kit, with infection associated with age, roaming status, and vaccination status. Hematological and blood biochemical analysis of CDV-infected dogs revealed anemia, leukopenia, neutrophilia, thrombocytopenia, a slight increase in aspartate aminotransferase (AST) levels, and a significant increase in blood urea nitrogen (BUN) levels. Molecular characterization of partial hemagglutinin (H) and fusion (F) genes exhibited high nucleotide and amino acid homology with the Asia-1 genotype. Phylogenetic analysis confirmed that the field sequences were clustered into the Asia-1 genotype together with the neighboring countries. These findings provide important insights into the current epidemiological, clinical, and molecular features of CDV circulating in Vietnam.

Background: Lumpy skin disease (LSD) is caused by a virus belonging to the genus Capripoxvirus, exhibiting clinical symptoms ranging from mild signs to the development of nodules. LSD emerged in Asia and Southeast Asia, including Vietnam, in October 2020 and has since spread throughout the region, resulting in productivity and economic losses. Aim: This study aimed to investigate the virus-causing papular dermatitis in cattle from the Mekong Delta region of Vietnam by analyzing its GPCR gene and assessing its evolutionary relationship with sequences in the GenBank database. Methods: Blood samples (n=180) were collected from cattle farms in Ben Tre, Tien Giang, and Tra Vinh provinces. PCR targeting the P32 antigen gene was utilized to detect LSDV presence, and GPCR gene amplification was performed to assess genetic variability. Results: LSDV was detected in 8.33% (15/180) of the samples using PCR targeting the P32 antigen gene. Each sample that tested positive for LSDV demonstrated complete amplification of the GPCR gene. Sequence alignments and phylogenetic analyses of the GPCR gene revealed that Mekong Delta LSDV isolates shared genetic similarities and possessed a 12-nucleotide insertion comparable to strains from China in 2019 and Northern Vietnam in 2020. Conclusion: This study provides preliminary insights into the molecular characteristics of LSDV in cattle from the Mekong Delta region of Vietnam. The observed genetic relatedness to other LSDV sequences from Asia and Southeast Asia underscores the importance of regional surveillance and control measures. These findings contribute to the development of effective strategies for LSDV control and prevention.

The aim of this study was to evaluate the influence of vitamin and β-glucan supplementations on growth performance of growing-finishing pigs in Ben Tre province. A total of 36 post-weaned piglets (Duroc x Yorkshire-Landrace) with the initial live weight of 17.42 kg±0.26, was allotted into 3 treatments and 4 replications in a completely randomized design. There were three diets, including basal diet (BD) without any addition of β-glucan or vitamin (diet CT), the BD supplemented with vitamin (diet Vit) and the BD supplemented with β-glucan (diet Glu). The results on growth parameters indicated that final live weight (kg), weight gain (kg), and average daily gain (g/head/day) of pigs in the experimental diets were significantly higher (P<0.01) than those in the control treatment. FCR was lowest in Glu and highest in the control (P<0.01). Financial benefit based on feed and veterinary expenses was higher in the vitamin and β-glucan supplement diets than that of the control from 15.74% to 18.98%, respectively.

| Lumpy skin disease (LSD) is an increasing threat to the global cattle industry, and Vietnam is among the countries recently affected. In response to this growing concern, a cross-sectional study was conducted to assess the infection status and risk factors associated with LSD outbreaks in the Mekong Delta. The study documented an LSD outbreak in the Mekong Delta provinces of Tien Giang, Tra Vinh, and Ben Tre between May 2023 and June 2024. A questionnaire-based survey was conducted through face-to-face interviews with farmers impacted by the disease. The collected epidemiological data were analysed, and the LSDV strains were genetically characterised. Out of 1,278 animals clinically examined across 180 farms, 80 tested positive via PCR, resulting in a morbidity rate of 6.26% and a herd prevalence of 37.22%. The morbidity rates in the 19 districts surveyed ranged from 1.45% to 17.95%. Risk factor analysis revealed that unvaccinated animals had the highest incidence rate at 17.94% (P<0.05), with an OR of 5.52 (95%CI: 3.62–8.44). Additionally, calves under six months old have a significantly higher risk of LSD compared to cows aged 6–24 months (OR 1.84, 95%CI: 1.14–3.00) and compared to animals older than 24 months (OR 4.82, 95% CI: 2.73-8.51). Phylogenetic analysis of the P32 gene of LSDV (PP934191-PP934205) indicated 100% similarity with other isolates from China, Russia, and Thailand. The findings of this study provide critical epidemiological insights into the risk factors associated with LSD in the Mekong Delta. This information is essential for government livestock regulators to develop effective prevention and control strategies, thereby mitigating the negative impact of LSD on cattle farming.

Infectious bursal disease is a highly contagious and economically devastating disease in the poultry industry worldwide caused by Infectious bursal disease virus (IBDV). However, the data on epidemiological and molecular characteristics of the IBDV outbreak in broiler flocks in the Mekong Delta of Vietnam is unclear. Herein, the epidemiological data of IBDV–positive flocks over a period of 2015–2018 were recorded and the hypervariable region of the VP2 gene of IBDV was amplified to analyze the local phylogeny. The current investigation showed that the overall morbidity and mortality rates of IBDV–positive flocks were 45% and 4.81%, respectively. The IBDV–positive birds occurred clinical signs and macroscopic findings involved with the very virulent (vv) IBDV outbreak. Epidemiological results revealed that IBDV was frequently infected in broiler flocks at 12–42 days, and birds belonging to Tau Vang and Binh Dinh breeds were more sensitive to IBDV. Also, the morbidity rate of IBDV was dramatically decreased in the open farming system. Flocks with complete vaccination significantly dropped morbidity in comparison with other groups. Regarding phylogenetic analysis, all identified IBDV sequences clustered in the same branch of vv phenotype and closely homology with prior strains circulated in Vietnam and other countries. These findings first indicated the epidemiological characteristics of the IBDV–positive broiler flocks in the Mekong Delta and highlighted the IBDV strain circulating in this region.