Dr. CAI Wenlong

Assistant Professor
BSc, MSc, MVM, PhD
Office Address
Room 1A-502, 5/F, Block 1, To Yuen Building, 31 To Yuen Street, City University of Hong Kong
Office Tel
Office Fax

Dr. Wenlong (Colin) Cai joined City University of Hong Kong in October 2021 as an Assistant Professor in Aquatic Animal Health in the Department of Infectious Diseases and Public Health.

He obtained both MSc and PhD degrees from the School of Fisheries, Aquaculture and Aquatic Science at Auburn University (Auburn, AL, USA), and he also held a joint master’s degree in Veterinary Medicine (MVM) from Shanghai Ocean University (Shanghai, China). His doctoral research involved the study of virulence factors of warm water fish pathogens, and the mechanism of action for a live-modified vaccine against columnaris disease in catfish. Afterwards, he became a postdoctoral fellow and adjunct faculty at the Atlantic Veterinary College (AVC) at University of Prince Edward Island (PE, Canada), where he worked on fish immune response to pathogen co-infection and functional feed.

He has also served as the chief bacteriology diagnostician for the Aquatic Animal Disease Diagnostic Laboratory at Auburn University in Alabama (USA), and the coordinator for annual hatchery checks (bacterial and virology sections) for state hatcheries in the southeastern United States. Dr. Cai is a full member of the State Key Lab of Marine Pollution, and he currently serves as the Associate Editor of Journal of Aquatic Animal Health (JAAH).

The fish disease is the overall result and interaction among the host, pathogens, and surrounding environment. Dr. Cai’s research covers a broad range of topics related to Aquatic Animal Health, including bacterial virulence factors, fish immune pathway analysis, and the impact of functional feeds on co-infections. In addition, his research involves evaluating the effect of microplastics in teleost fish and developing methods for microplastic removal in the marine environment.

Zhong L., Liu S., Zuo F.Y.,…Xiong, Y.L., W. Cai# and X.L., Huang#. 2023. The IL17 signaling pathway: A potential signaling pathway mediating gill hyperplasia and inflammation under ammonia nitrogen stress was identified by multi-omics analysis. Science of The Total Environment, 867.

Cai, W., Kumar, S., Umasuthan, U., Caballero Solares, A., Carvalho, L. A., Whyte, ., ... & Fast, M. D. 2021. Transcriptome analysis of Atlantic salmon (Salmo salar) skin in response to sea lice and infectious salmon anemia virus co-infection under different experimental functional diets. Frontiers in Immunology, 5535. DOI:

Cai, W.; Arias, C.R. Deciphering the Molecular Basis for Attenuation of Flavobacterium columnare Strain Fc1723 Used as Modified Live Vaccine against Columnaris Disease. Vaccines 2021, 9, 1370.

Cai, W., L. De La Fuente, and C.R. Arias. 2013. Biofilm formation by the fish pathogen Flavobacterium columnare: development and parameters affecting surface attachment. Applied and Environmental Microbiology. 79: 5633-5642.  DOI:

Cai W., L. De La Fuente, and C.R. Arias. 2019.Transcriptome analysis of the fish pathogen Flavobacterium columnare in biofilm suggests calcium role in pathogenesis. BMC Microbiology. 19 (1): 151.

Ksepka S. J.M.Rash, W. Cai, S.A. Bullard. 2021. Detection of Myxobolus cerbralis (Hofer, 1903) (Bivalvulida:Myxobolidae) in two non-Tubifex tubifex oligochaetes in the southeastern united states. Disease of Aquatic Organisms. 143:51-56.

Cai, W. and C.R. Arias. 2019. Draft genome sequences of Flavobacterium columnare ARS1 and BGFD27 strains isolated from channel catfish (Ictalurus punctatus). Microbial Resource Announcement. 8 (26): e00648-19.

A.M. Declercq*, W. Cai*, E. Naranjo, W. Thongda, V. Eeckhaut, E. Bauwens, C. Arias, L. De La Fuente, B. Beck, M. D. Lange, E. Peatman, F. Haesebrouck, J. Aerts, A. Decostere. 2019. Evidence that the stress hormone cortisol regulates biofilm formation differently among Flavobacterium columnare isolates. Veterinary Research. 50:24. (*Shared first co-authorship).

Cai, W., E. Willmon, F.B. Valverde, C.L. Ray, T. Hanson, and C.R. Arias. 2018. Biofilm and sediment are major reservoirs of virulent Aeromonas hydrophila (vA h) in catfish production ponds. Journal of Aquatic Animal Health. 31:112-120.

Ray, C.L., W. Cai, E. Willmon, and C.R. Arias. 2018. Fish are not alone: Characterization of the gut and skin microbiomes of wild-caught Largemouth Bass (Micropterus salmoides), Bluegill (Lepomis macrochirus), and Spotted Gar (Lepisosteus oculatus). SDRP Journal of Aquaculture, Fisheries & Fish Science. 2 (2). DOI: 10.25177/JAFFS.2.2.RA.459

Cai, W., and C.R. Arias. 2017. Biofilm formation on aquaculture substrates by selected bacterial fish pathogens. Journal of Aquatic Animal Health. 29:95-104.

Zhang, X., W. Cai, Z. Tao, and C.R. Arias. 2014. Survival of fish pathogenic strains of Aeromonas hydrophila under starvation. Journal of Aquatic Animal Health. 26.3: 190-193.

Arias, C.R., W. Cai, E. Peatman, and S.A. Bullard. 2012. Catfish hybrid Ictalurus punctatus x I. furcatus exhibits higher resistance to columnaris disease than the parental species. Diseases of Aquatic Organisms. 100: 77-81.

Arias, C.R., S. LaFrentz, W. Cai, and O. Olivares-Fuster. 2012. Adaptive response to starvation in the fish pathogen Flavobacterium columnare: cell viability and ultrastructural change. BMC Microbiology. 12: 266-288.