Epidemiological surveillance reveals major pathogen dynamics in Brazilian Nile tilapia aquaculture from 2023 to 2025
- 1Pathovet Labs , ,
Abstract
Introduction
Brazil is among the world's largest producers of Nile tilapia (Oreochromis niloticus), a species increasingly challenged by a complex of cocirculating pathogens that threatens production sustainability.Methods
We conducted a structured epidemiological surveillance program across the three main tilapia-producing macro-regions of Brazil (Southeast, Central-West, and Northeast) between 2023 and 2025. A total of 26,057 diagnostic samples, generating 68,514 pathogen-specific tests, were analyzed for Aeromonas spp., Edwardsiella spp., Flavobacterium spp., Francisella orientalis, Infectious Spleen and Kidney Necrosis Virus (ISKNV), Lactococcus spp., and Streptococcus spp. using standardized bacteriological, real-time PCR, and MALDI-TOF MS protocols, and antimicrobial susceptibility (minimum inhibitory concentration, MIC) was determined for four antimicrobials. Generalized linear models (with a farm-clustered mixed-model sensitivity analysis), time-series analysis (ADF stationarity, ARIMA), co-detection network analysis, and Gamma-log MIC modelling were applied.Results
The cumulative overall detection positivity rate (DPR) was 18.1%, with Flavobacterium spp. showing the highest cumulative positivity (21.6%) on the smallest testing base, and Lactococcus spp. (18.4%), ISKNV (23.3%), and Streptococcus spp. (15.2%) representing the dominant, most widely sampled agents; S. agalactiae serotype Ia was not detected by serotype-specific qPCR. Detection was structured principally by macro-region and pathogen-specific temporal dynamics, whereas host developmental stage exerted a heterogeneous, generally weak influence. Five of the seven pathogens showed stationary, endemically compatible dynamics; Streptococcus spp. was non-stationary, consistent with active geographic expansion into the Northeast, whereas non-stationarity in Flavobacterium spp. reflected sampling instability rather than directional change. Quarterly aggregation minimized forecast error among the frequencies evaluated. Co-detection was predominantly independent, with only a weak module linking the three dominant agents. Antimicrobial resistance was structured by pathogen and antibiotic, with significant pathogen-specific interactions, and the fry stage showed higher MICs.Discussion
These findings reframe the historically Streptococcus-centered view of Brazilian tilapia health and, within the constraints of a structured but non-probabilistic design, provide a descriptive, data-driven baseline to inform regionalized early-warning systems and rational antimicrobial stewardship in Brazilian tilapia aquaculture.
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BibTeX
@article{cardosoguimaraes2026epidemiological,
title = {{Epidemiological surveillance reveals major pathogen dynamics in Brazilian Nile tilapia aquaculture from 2023 to 2025}},
author = {Mateus Cardoso-Guimarães and Miguel Frederico Fernandez-Alarcon and Rodolfo Correa and Mariene Miyoko-Natori and Renata Galetti and Adrielli Brito de Souza and Ana Cristina Squizatto and Rafael Silva and Luana Araújo de Almeida and Thaise Mota Sátiro and Ricardo Ildefonso and Marco Rozas-Serri},
journal = {Frontiers in veterinary science},
year = {2026},
month = oct,
doi = {10.3389/fvets.2026.1944605},
url = {https://europepmc.org/article/PMC/PMC13726547},
note = {CC BY},
}
RIS
TY - JOUR
TI - Epidemiological surveillance reveals major pathogen dynamics in Brazilian Nile tilapia aquaculture from 2023 to 2025
AU - Mateus Cardoso-Guimarães
AU - Miguel Frederico Fernandez-Alarcon
AU - Rodolfo Correa
AU - Mariene Miyoko-Natori
AU - Renata Galetti
AU - Adrielli Brito de Souza
AU - Ana Cristina Squizatto
AU - Rafael Silva
AU - Luana Araújo de Almeida
AU - Thaise Mota Sátiro
AU - Ricardo Ildefonso
AU - Marco Rozas-Serri
PY - 2026
DA - 2026/10/19
JO - Frontiers in veterinary science
DO - 10.3389/fvets.2026.1944605
UR - https://europepmc.org/article/PMC/PMC13726547
AB - Introduction Brazil is among the world's largest producers of Nile tilapia (Oreochromis niloticus), a species increasingly challenged by a complex of cocirculating pathogens that threatens production sustainability.Methods We conducted a structured epidemiological surveillance program across the three main tilapia-producing macro-regions of Brazil (Southeast, Central-West, and Northeast) between 2023 and 2025. A total of 26,057 diagnostic samples, generating 68,514 pathogen-specific tests, were analyzed for Aeromonas spp., Edwardsiella spp., Flavobacterium spp., Francisella orientalis, Infectious Spleen and Kidney Necrosis Virus (ISKNV), Lactococcus spp., and Streptococcus spp. using standardized bacteriological, real-time PCR, and MALDI-TOF MS protocols, and antimicrobial susceptibility (minimum inhibitory concentration, MIC) was determined for four antimicrobials. Generalized linear models (with a farm-clustered mixed-model sensitivity analysis), time-series analysis (ADF stationarity, ARIMA), co-detection network analysis, and Gamma-log MIC modelling were applied.Results The cumulative overall detection positivity rate (DPR) was 18.1%, with Flavobacterium spp. showing the highest cumulative positivity (21.6%) on the smallest testing base, and Lactococcus spp. (18.4%), ISKNV (23.3%), and Streptococcus spp. (15.2%) representing the dominant, most widely sampled agents; S. agalactiae serotype Ia was not detected by serotype-specific qPCR. Detection was structured principally by macro-region and pathogen-specific temporal dynamics, whereas host developmental stage exerted a heterogeneous, generally weak influence. Five of the seven pathogens showed stationary, endemically compatible dynamics; Streptococcus spp. was non-stationary, consistent with active geographic expansion into the Northeast, whereas non-stationarity in Flavobacterium spp. reflected sampling instability rather than directional change. Quarterly aggregation minimized forecast error among the frequencies evaluated. Co-detection was predominantly independent, with only a weak module linking the three dominant agents. Antimicrobial resistance was structured by pathogen and antibiotic, with significant pathogen-specific interactions, and the fry stage showed higher MICs.Discussion These findings reframe the historically Streptococcus-centered view of Brazilian tilapia health and, within the constraints of a structured but non-probabilistic design, provide a descriptive, data-driven baseline to inform regionalized early-warning systems and rational antimicrobial stewardship in Brazilian tilapia aquaculture.
SN - 2297-1769
ER -