Tilapia: Aquaculture, biology and health management

Authors: DEHAL, XU - Retired ARS Employee; Shoemaker, Craig

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 2/5/2024
Publication Date: 12/23/2024
Citation: Xu, De-Hai and Shoemaker, C.A. Concurrent infections of tilapia, pp. 598-622. In: Thompson, K., Shoemaker, C., and Little, D.C. (eds.) Tilapia: Aquaculture, biology and health management. CABI, Wallingford, UK. 861 pp. 2025. (Book Chapter) https://doi.org/10.1079/9781800629455.0012
DOI: https://doi.org/10.1079/9781800629455.0012

Interpretive Summary: Tilapia are intensively cultured worldwide and are affected by bacterial, parasitic, fungal, and viral pathogens. Concurrent infections occur when fish are infected by two or more pathogens either from homologous group, such as dual or multiple bacterial species or from heterologous group, such as parasitic and bacterial pathogens. This book chapter, summarizes studies of concurrent infections in tilapia by various pathogens, evaluates the impact of concurrent infection on fish disease susceptibility, and explores the effects of concurrent infection on fish immune responses. Concurrent infections naturally occur in different species of tilapias. Results from experimental trials demonstrate that (1) concurrent infection in tilapia by two or more pathogens enhance disease development and increase fish mortality; (2) parasitism of tilapia enhance bacterial invasion and increase bacterial load in fish; (3) parasites serve as vectors to carry bacterial pathogens into fish; (4) concurrent infections cause stress response and increase fish susceptibility to pathogen infection; and (5) concurrent infection results in immune suppression. In studies of concurrent infection by parasites and bacteria, parasite treatment reduced bacterial load in fish, improved vaccine efficacy and increased fish survival. More research is needed to better understand the impacts of concurrent infection on tilapia culture for improved health management strategies to limit the impact caused by multiple pathogens.

Technical Abstract: Tilapia are intensively cultured worldwide and are affected by bacterial, parasitic, fungal, and viral pathogens. Concurrent infections occur when fish are infected by two or more pathogens either from homologous group, such as dual or multiple bacterial species or from heterologous group, such as parasitic and bacterial pathogens. In this chapter, we present a summary of studies on concurrent infection of tilapia by various pathogens, evaluate the impact of concurrent infection on fish disease susceptibility, and explore the effects of concurrent infection on fish immune responses. Concurrent infections naturally occur in different species of tilapias. Results from experimental trials demonstrate that (1) concurrent infection in tilapia by two or more pathogens enhance disease development and increase fish mortality; (2) parasitism of tilapia enhance bacterial invasion and increase bacterial load in fish; (3) parasites serve as vectors to carry bacterial pathogens into fish; (4) concurrent infections cause stress response and increase fish susceptibility to pathogen infection; and (5) concurrent infection results in immune suppression. In studies of concurrent infection by parasites and bacteria, parasite treatment reduced bacterial load in fish, improved vaccine efficacy and increased fish survival. More research is needed to better understand the impacts of concurrent infection on tilapia culture for improved health management strategies to limit the impact caused by multiple pathogens.