Tilapia culture is an important source of income and nutrition to many rural families. Since 2000, the production of tilapia increased and reached domestic and global markets. Major farmed species is Nile tilapia (Oreochromis niloticus), in earthen ponds and cage cultures. Intensification contributed to global tilapia disease outbreaks, with bacterial infections causing mortalities and morbidities, threatening sustainable production. At tilapia farms, high nutrient concentrations, water temperature and fish densities enhance bacterial growth including virulent bacterial clones and potential zoonotic bacteria. Global warming favours this. This review respectively provides a comprehensive overview of the most common and emerging bacterial pathogens, diseases, clinical presentations and diagnostics of tilapia, including bacteria and diseases with zoonotic potential. First, common bacterial disease outbreaks, including streptococcosis, motileAeromonassepticaemia, francisellosis, columnaris disease and vibriosis are described. Then, information on emerging bacterial infections of concern for tilapia, like edwardsiellosis throughEdwardsiella ictaluriandE.tarda, as well asAeromonas schubertiiis provided. Reports of infectious bacterial tilapia disease outbreaks from other bacteria, includingLactococcus garvieae,Aerococcus viridans,Pseudomonasspp.,Mycobacterium marinumandChlamydiaspp., and others are reviewed. Furthermore, bacteria with zoonotic potential, likeStreptococcus agalactiaeST283,S.iniae,Aeromonassp.,E.tarda,Vibrio vulnificuspathovar (pv)piscisandM.marinumare included in the review, to provide the most current overview of the disease risks affecting production and post‐harvest stages. Additionally, the status and risks of antimicrobial resistance in bacteria from tilapia and other cultured fish through imprudent use of antibiotics, and its future at a global level are provided.

Tilapia lake virus (TiLV) is a recently described virus affecting wild and farmed tilapines. At present, it has been reported on three continents (Asia, Africa and South America) and the number of countries where the agent has been detected is likely to increase rapidly as a result of increased awareness, surveillance and availability of diagnostic methods. Any lack of openness regarding the TiLV status of a translocating live tilapia population destined for aquaculture may inadvertently contribute to the spread of the agent. Currently, there is no cure for viral diseases in aquaculture and while vaccines and selective breeding have proved successful in reducing the severity of some viral diseases, there are currently severe knowledge gaps relating to TiLV and no effective, affordable vaccines are yet available. This paper summarizes the published scientific information on TiLV and highlights important issues relating to its diagnosis, mitigation and control measures. While there have been no scientific studies on the socio‐economic impact of TiLV, it may pose a significant threat particularly to small‐scale fish farmers’ livelihoods and wild tilapine populations if left uncontrolled. To aid disease investigations, the authors propose case definitions for suspected and confirmed cases of TiLV infections.