Truth be told, I really do like the murder mystery genre. In medicine, that particular type of drama is usually absent. Nevertheless, it is fascinating when epidemiologists can track down an agent responsible for multiple deaths and widespread illness. The latest example: Listeria monocytogenes (NEJM 2013; 369: 944-53).
This recent report isolated Listeria monocytogenes as the agent responsible for 147 outbreak-related cases in 28 states; there were 33 deaths. The investigators used multistage epidemiological, trace-back, and environmental studies. Molecular finger printing of the cases identified five distinct patterns which defined the outbreak cases. By comparing the outbreak cases to sporadic cases using the “Listeria initiative,” the authors were able to determine that uncut cantaloupe ingestion was much more common among the outbreak-related cases. Subsequently, the source of the contaminated cantaloupe were traced back to a Colorado farm that had switched to a different cleaning method in 2011.
Other data:
- Only 7 cases (5%) were pregnancy-associated; 1 miscarriage occurred
- The median age was 77 years in this cohort.
- Most of the deaths were in the elderly, with only 2 deaths occurring in individuals less than 60
- 143 patients required hospitalization
While this report discussed 147 outbreak-related cases, there were undoubtedly many more outbreak-related cases which were unidentified due to milder illness.
Bottomline: this report provides a framework for identifying outbreaks of contaminated produce. It reinforces the need for good agricultural practices to minimize food borne-pathogen infections. It is a good read.
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gutsandgrowth 