Parasitology of one of the world's foremost aquaculture fish species lacks a One Health Approach

Abstract

With the growing global demand for Nile tilapia (Oreochromis niloticus) as an affordable source of animal protein, the adoption of semi-intensive and intensive farming systems has increased. However, this has also led to a higher risk of parasites, diseases, and mortality among Nile tilapia, as well as environmental impacts. To address these challenges, it is crucial to understand the biology and ecology of these parasites in an ever-changing environment and tackle their pathogenicity. Currently, Oreochromis niloticus is known to harbor approximately 276 species of parasites, making it the African fish with the highest number of reported protists and metazoans. However, the available knowledge on these parasites is fragmented, with only around 340 peer-reviewed articles published on the topic to date. This lack of comprehensive information highlights the need for a One Health approach, which is currently lacking in the study of Nile tilapia parasites and necessitates the need for an appropriate account on the interconnectedness of human, animal and environmental health. A review was conducted to identify protists, metazoans, fungi, bacteria and viruses that have proven impacts on Nile tilapia health and production, as well as those that pose a zoonotic risk and have the potential to serve as environmental indicators. From the synthesis, only 94 peer-reviewed papers met the inclusion criteria. These studies were carried out in only 24 out of more than 140 countries where Nile tilapia is produced, showing the relatively low number of research on the effects and environmental correlates of these parasites. When comparing the number of formally described parasite species to the few number of studies documenting their effects, there is a significant knowledge gap. The current information on these parasites is not yet ready for practical use by stakeholders involved in Nile tilapia production and management. Therefore, there is a need for descriptive and experimental studies to bridge this knowledge gap between farmers, fisheries policy makers, veterinarians, researchers and consumers. By adopting a One Health approach and conducting further research, stakeholders can gain valuable insights into the effective management of Nile tilapia fish health and diseases in today's world. This approach will provide information that is essential for sustainable Nile tilapia production, addressing both the environmental integrity, the health and well-being of the fish, and the people who consume them.