A probabilistic risk assessment of Cryptosporidium exposure among Baltimore urban anglers

In some urban settings, recreational fishing in industrialized waterways may pose a substantial health risk due to the presence of pathogenic microbes such as Cryptosporidium, a pathogen that produces a moderate to fatal gastrointestinal illness in humans. This pilot study examined the risk of exposure to Cryptosporidium based on fish samples and hand wash samples taken from urban anglers. Information regarding fishing frequency and consumption were also collected through an interview questionnaire to further characterize this risk. There were a total of 56 anglers interviewed and 46 fish and hand wash samples collected (18 hand wash samples and 28 fish samples). It was determined that the mean probability of infection using the U.S. Environmental Protection Agency's (EPA) dose-response model for Cryptosporidium and the fish and hand wash samples was 0.11 and 0.81, respectively. Among the positive fish samples, this mean probability was found to be 0.41. Depending on a variety of confounding factors, such as immunity, pre-existing illnesses and other host specific factors, this probability indicated that on average 1 to 8 out of 10 anglers could become infected. The current fish consumption advisories in Maryland and elsewhere provide no apparent information in regard to any microbiological contaminant. This pilot study provided data for possible modifications and improvements to be made to policy and risk communication regarding the potential health risks due to Cryptosporidium exposure from fishing.