Bich Ngoc Tran

Background and Aim: Canine hepatobiliary disorders are frequently encountered in small animal practice; however, prospective clinic-based studies integrating ultrasonographic phenotyping with infectious molecular screening remain limited in tropical Southeast Asia. This study aimed to determine the frequency of ultrasonographically detected hepatobiliary abnormalities, identify associated host factors, characterize ultrasonographic phenotypes, and assess infectious etiologies in dogs with suspected hepatobiliary disease in southern Vietnam. Materials and Methods: A prospective observational study was conducted at the Veterinary Teaching Clinic, Can Tho University, Vietnam, between January and November 2025. Among 1,278 canine presentations, 111 dogs meeting predefined clinical and clinicopathologic criteria underwent abdominal ultrasonography, and 63 dogs with confirmed hepatobiliary abnormalities were enrolled. Hematologic and serum biochemical analyses were performed in all enrolled dogs. Cases classified with a hepatitis ultrasonographic phenotype underwent conventional polymerase chain reaction (PCR) screening of ethylenediaminetetraacetic acid (EDTA)- anticoagulated blood samples targeting vector-borne pathogens, Leptospira spp., and canine adenovirus type 1. Ultrasonographic phenotypes were categorized as hepatitis, hepatic lipidosis, or cirrhosis. Univariable logistic regression was used to evaluate host-associated risk factors, and hierarchical clustering analysis was applied to assess co-occurring clinical and imaging abnormalities. Results: Hepatobiliary abnormalities were identified in 63/1,278 dogs (4.93%) and in 63/111 clinically suspected dogs (56.76%). Ultrasonographic positivity was significantly associated with exotic breed (odds ratio [OR] = 2.29), age >8 years (OR = 13.93), obesity (OR = 4.78), and underweight body condition (OR = 3.38). Hepatitis was the predominant ultrasonographic phenotype (57.14%), followed by hepatic lipidosis (30.16%) and cirrhosis (12.70%). Dogs with hepatitis commonly exhibited anorexia, vomiting, diffuse hepatic hypoechogenicity, hepatomegaly, and gallbladder abnormalities. PCR screening detected infectious agents in 55.56% of hepatitis cases, including vector-borne pathogens (41.67%), Leptospira spp. (8.33%), and canine adenovirus type 1 (5.56%). Dogs with hepatic lipidosis showed diffuse hepatic hyperechogenicity and hepatomegaly, whereas cirrhosis cases demonstrated heterogeneous hepatic echotexture, ascites, and vascular abnormalities consistent with portal hypertension. Conclusion: Ultrasonography effectively identified distinct hepatobiliary imaging phenotypes in dogs and provided a practical diagnostic framework for referral-based clinical settings in resource-limited regions. Integration of ultrasonography with clinicopathologic evaluation and targeted PCR screening enhanced preliminary etiologic assessment, particularly in dogs with inflammatory hepatopathies. Older age and abnormal body condition were important host-associated factors linked with ultrasonographic positivity. Although imaging-based classification may assist clinical triage, histopathological confirmation remains necessary for definitive diagnosis. Keywords: canine adenovirus type 1, cirrhosis, hepatic lipidosis, hepatobiliary disease, hepatitis, polymerase chain reaction, ultrasonography, vector-borne pathogens.

Osteoarthritis is a common knee joint disease that significantly affects pet health, especially among domestic dogs. Bone marrow mesenchymal stem cells (BMSCs) are multipotent cells capable of differentiating into multiple lineages and self-renewing. However, their limited quantity and proliferative capacity during laboratory cultivation present challenges. In this study, BMSCs were isolated from the bone marrow of immature dogs and evaluated for various biological characteristics. Researchers assessed their ability to form colonies (Colony Forming Unit—CFU), stability of cellular morphology, proliferative capacity, expression of stem cell markers, and potential for differentiation into other cell types. The results indicated that the isolated cells exhibited colony-forming ability with a CFU-f of 5 ± 1 colonies per million mononuclear cells. The cells maintained stable morphology through the 8th passage and showed a doubling time of less than 42 hours. Additionally, these BMSCs expressed surface markers CD90 and CD105 while lacking CD34 and CD45, and they successfully differentiated into bone, cartilage, and fat cells. These findings encourage continued research into the clinical use of canine BMSCs for joint repair. In conclusion, this study presents a successful method for isolating and culturing canine BMSCs, highlighting their potential application in treating degenerative knee diseases.

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.

Ehrlichia canis ( E. canis ) is a tick‐borne, obligate intracellular bacterium that causes canine monocytic ehrlichiosis (CME), a widely distributed infectious disease in dogs with variable clinical severity. While the 16S rRNA gene has been commonly used for detection, limited data are available on the genetic diversity of the immunogenic p28 outer membrane protein gene, particularly in Southeast Asia. Eighty‐three canine blood samples were collected from various districts in Ho Chi Minh City, Vietnam, and screened using polymerase chain reaction (PCR) assays targeting the 16S rRNA and p28 genes. Ten representative p28‐positive samples were selected for Sanger sequencing. Phylogenetic relationships were inferred using the maximum likelihood method. Genetic variability was assessed through nucleotide and amino acid entropy analysis. Of the 83 samples, 40 (48.19%) were positive for both 16S rRNA and p28 genes. Phylogenetic analysis of p28 sequences revealed three major clades, with all Vietnamese strains clustering within clade 3 and showing a 97%–100% nucleotide identity with global references. Entropy analysis identified 50 high‐variability nucleotide sites H ( x ): 0.206–1.013 and 20 amino acid positions H ( x ): 0.206–1.264, including a prominent substitution at position 145 (S ⟶ D/T), suggesting a potential immunogenic variability. This study provides the first detailed molecular characterization of the p28 gene in E. canis from Vietnam, demonstrating both high genetic conservation and localized variation within clade 3. These findings enhance the understanding of regional strain diversity and may inform future diagnostic or vaccine development efforts targeting the p28 protein.

| 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.

Lumpy skin disease (LSD) is an emerging transboundary viral disease and an economically important disease of domestic ruminants worldwide caused by the LSD virus (LSDV). LSD was first confirmed in Vietnam on 13 October 2020 and continuously spread to almost every province. This study highlighted the molecular characterization and phylogenetic analysis of LSDV occurring in Ben Tre province of Vietnam during 2023. Nasal swabs were collected in cattle from 70 outbreaks of LSD in seven districts of Ben Tre province to amplify the GPCR gene via the PCR method. The nucleotide and amino acid identities of LSDV between the field sequences in Ben Tre province and the reference sequences in GenBank were very high (98.4–99.6% and 99.7–100%, respectively), however, the nucleotide and amino acid identities between the field sequences and vaccine sequence were low (78.7–79.0% and 78.0–78.2%, respectively). Phylogenetic analysis according to the GPCR gene revealed that all the field sequences were clustered into the same group with the LSDV collected from cattle in other provinces in Vietnam and those in the neighboring countries including China and Thailand, and distinguished from the GTPV and SPPV recruited from the GenBank database. Moreover, multiple alignments of the field LSDV sequences in Ben Tre province and reference sequences from the previous studies in China, Thailand, and Vietnam showed a tight homology in the GPCR region. The present study expanded basic knowledge of the molecular characteristics of LSDV in Ben Tre province and Vietnam.

Nghiên cứu được tiến hành nhằm đánh giá tình hình chăn nuôi heo, dịch bệnh truyền nhiễm và thực hành vệ sinh thú y liên quan đến bệnh dịch tả heo Châu Phi (African swine fever – ASF) trên heo tại tỉnh Cà Mau. Số liệu thứ cấp về tình hình chăn nuôi và dịch bệnh được thu thập thông qua điều tra hồi cứu; số liệu sơ cấp thực trạng vệ sinh thú y được thu thập thông qua điều tra cắt ngang và phỏng vấn trực tiếp đối với 79 hộ chăn nuôi heo. Kết quả cho thấy, tổng đàn heo của tỉnh Cà Mau giảm mạnh vào năm 2019 (giảm 22,98%) và 2020 (giảm 25,63%) so với năm 2018 do ảnh hưởng của bệnh ASF. Dịch bệnh trên heo trong giai đoạn 2019 – 2020 chủ yếu là do ASF gây ra. Quy mô chăn nuôi heo chủ yếu là quy mô nông hộ (89,87%), chăn nuôi heo hướng thịt (89,87%), kinh nghiệm chăn nuôi lâu năm (>10 năm) (50,63%), hệ thống chuồng hở (63,29%), người chăn nuôi sử dụng thức ăn hỗn hợp (91,14%) và nước giếng (89,87%). Bên cạnh đó, người chăn nuôi tại địa phương có quan tâm về thực hành vệ sinh thú y để phòng ngừa lây nhiễm bệnh ASF.

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.

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.

Nghiên cứu được thực hiện nhằm đánh giá tỷ lệ tiêm phòng và đáp ứng miễn dịch sau tiêm của bệnh cúm gia cầm độc lực cao type A/H5 (H5 highly pathogenic avian influenza, H5 HPAI) trên đàn gia cầm của tỉnh Đồng Tháp giai đoạn 2019–2020. Nghiên cứu được tiến hành thông qua thu thập số liệu hồi cứu tình hình tiêm phòng và đáp ứng miễn dịch sau tiêm từ Chi cục Chăn nuôi, Thú y và Thủy sản tỉnh Đồng Tháp. Kết quả cho thấy tỷ lệ tiêm phòng cúm gia cầm type A/H5 có sự khác nhau giữa các huyện/thành phố giai đoạn 2019–2020. Có 6 trong 12 huyện/thành phố có tỷ lệ đàn gia cầm được tiêm phòng dưới 70%. Tỷ lệ tiêm phòng trên vịt cao hơn gà ở các huyện/thành phố. Tỷ lệ đàn đạt bảo hộ sau tiêm phòng tăng từ 59,46% (năm 2019) lên 84,62% (năm 2020). Tỷ lệ bảo hộ trên vịt tăng từ 77,78% (2019) đến 89,05% (2020), cao hơn gà (50,0% năm 2019 và 60,61%, năm 2020). Kết quả nghiên cứu là cơ sở để đánh giá tình hình tiêm phòng và đáp ứng miễn dịch sau tiêm phòng H5, từ đó giúp triển khai các phương án nâng cao công tác tiêm phòng tại các địa phương nhằm kiểm soát hiệu quả H5 HPAI tại tỉnh Đồng Tháp.