Global Study Quantifies Pathogen Prevalence in Traditional Food Markets; Seafood Showed Most Contamination
A global systematic review and meta-analysis of nearly 2.8 million samples quantified the prevalence of foodborne and zoonotic pathogens in traditional food markets, with the greatest levels of contamination observed in fish and seafood markets.
Published in The Lancet Global Health, the study included 247 studies comprising 597 pathogen detection records from 41 countries across 16 regions. The researchers analyzed studies published between January 2000 and October 2025 that reported the detection of zoonotic or foodborne pathogens in traditional/informal food markets or related settings, including wet markets, farmers’ markets, live animal or live bird markets, and seafood markets.
The researchers used the term “market-source pathogens” to mean bacteria, viruses, and parasites with known or plausible zoonotic or foodborne potential detected in animal, food, environmental, or human samples from traditional markets.
Parasites Lead Pathogen Prevalence
Overall, the global pooled prevalence of market-source pathogens was 15.32 percent. By pathogen type, parasites had the highest pooled prevalence at 27.05 percent, followed by bacteria at 19.41 percent and viruses at 8.40 percent.
Among regions represented by at least ten studies, Southeast Asia had the highest pooled prevalence, at 23.09 percent, followed by South Asia at 15.52 percent. East sub-Saharan Africa had a pooled prevalence of 14.54 percent.
Fish and Seafood Markets Show Highest Pathogen Prevalence
Significant differences were observed based on market and sample type. Fish and seafood markets had the highest pooled pathogen prevalence, at 37.87 percent. By comparison, prevalence was 16.44 percent in wet markets and 9.37 percent in live animal markets.
Similarly, fish and seafood samples had the highest pooled prevalence at 32.39 percent, followed by raw meat at 24.74 percent and environmental samples at 18.10 percent.
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Lower prevalence was observed in samples of cooked foods (8.70 percent), worker samples (7.93 percent), mixed samples (6.10 percent), and samples of fruits and vegetables (5.54 percent). According to the researchers, the results suggested a gradient of decreasing contamination from animal and environmental reservoirs to cooked foods and humans.
Notable Pathogen–Sample Pairs Emerge
Several specific pathogen–sample combinations also stood out. Vibrio parahaemolyticus in fish and seafood had a pooled prevalence of 37.71 percent, while Salmonella in raw meat had a pooled prevalence of 28.95 percent. Influenza A virus was detected at a pooled prevalence of 35.41 percent in environmental samples and 10.5 percent in live animal samples.
In wet markets specifically, V. parahaemolyticus had a pooled prevalence of 28.8 percent, compared with 10.55 percent for Salmonella. In live animal markets, influenza A virus had a pooled prevalence of 15.44 percent.
Researchers Call for One Health Market Surveillance
Overall, the researchers characterized traditional food markets as persistent multipathogen hotspots at the human–animal–environment interface. They called for standardized, prospective, multi-pathogen surveillance under a One Health framework, as well as studies that simultaneously measure market contamination and human infections.
The findings also highlighted potential points for targeted intervention, including live animal handling, slaughter areas, wastewater management, environmental sanitation, raw product handling, and cold-chain infrastructure.
