Results-driven Aquatic Animal Health Specialist and R&D Leader with over 20 years of combined experience across multinational pharmaceutical corporations (Virbac), world-class research institutions (UC Davis, University of Queensland), and national research institutes (RIA2). Proven track record in aquatic vaccine development, fish/shrimp disease diagnostics, teleost immunology, and commercial field trial execution. Expert in bridging cutting-edge academic research with commercial product pipelines to drive business growth across warm-water aquaculture zones globally.

First Detection of Francisella orientalis in Farmed Tilapia (Oreochromis spp.) in Northern Vietnam:                                                                                                                                                                     

Tilapia aquaculture in Vietnam is rapidly expanding, with a national production target set at 400,000 tonnes by 2030. However, seasonal disease outbreaks during cooler months (20-26°C) cause significant economic losses. In March 2025, elevated mortality (10-40%) occurred in Nile tilapia (Oreochromis niloticus) and red tilapia (Oreochromis spp.) cultured in Bac Ninh and Hai Duong provinces, Northern Vietnam. This study aimed to identify the primary causative agent responsible for these outbreaks.

 Diseased fish displaying exophthalmia, body hemorrhage, and white visceral nodules in the kidney and spleen were collected for diagnostic investigation. Bacterial isolation from anterior kidney, posterior kidney, and spleen tissue was performed on modified Thayer-Martin agar and Cysteine Heart Agar supplemented with 2% bovine hemoglobin (CHAH) incubated at 25-26 °C for 5-7 days. Suspected colonies were subjected to Gram staining and duplex PCR using species-specific primer pairs (F11/R5 and FnoF1/FnoR1). Representative isolates were further confirmed by 16S rRNA gene sequencing and BLAST analysis against GenBank database references.

Gram-negative, short rod-shaped bacteria forming small, smooth, off-white colonies emerged on CHAH after 5-7 days. Duplex PCR confirmed all 6 tested isolates as Francisella orientalis (Fno), displaying expected amplicons at 1,140 bp (genus-specific) and 203 bp (Fno-specific). The 16S rRNA gene sequences shared 100% identity with reference to Fno strains in GenBank.

This investigation provides the first confirmed detection of Francisella orientalis in cultured tilapia in Northern Vietnam. The findings highlight the emerging threat of francisellosis during cooler spring temperatures and underscore the urgent need for enhanced health monitoring, biosecurity measures, and diagnostic surveillance in Vietnamese tilapia f