Continuing Source
Continuing source outbreaks are characterized by the sustained presence of an infectious agent, often leading to a continuous or intermittent series of cases over an extended period. [1]
Contents
Definition and Characteristics
A continuing source outbreak occurs when a common source of exposure to a pathogen persists over time, resulting in an ongoing transmission of the disease. The outbreak may be localized or widespread and may involve a single or multiple transmission routes. Examples of continuing source outbreaks include waterborne diseases caused by contaminated water supply or foodborne diseases stemming from the persistent contamination of food products.
The following characteristics are often associated with continuing source outbreaks:
- Cases occur over an extended period without a distinct pattern.
- Transmission may be direct or indirect and involve multiple exposure pathways.
- Identification and elimination of the source can be challenging due to its persistence.
- Affected individuals may have varying exposure levels, leading to a wide range of disease severity.
Challenges in Investigating Continuing Source Outbreaks
- Identifying the source
- Continuing source outbreaks often involve complex and persistent exposure pathways, making it challenging to pinpoint the exact source of infection.
- Heterogeneous exposure
- Varying exposure levels among affected individuals can lead to a wide range of disease severity, further complicating the investigation.
- Prolonged time frame
- The extended duration of continuing source outbreaks can make it difficult to establish the temporal relationship between exposure and disease onset.
- Multiple transmission routes
- The presence of multiple transmission routes can complicate the identification of the primary source and mode of transmission.
Examples of Continuing Source Outbreaks
Here are four examples of continuing source outbreaks, along with literature references for further reading:
- Legionnaires' Disease Outbreak in Flint, Michigan (2014-2015)
- During the Flint water crisis, there was a notable increase in cases of Legionnaires' disease, a severe form of pneumonia caused by the bacterium Legionella pneumophila. The contamination of the water supply with Legionella was attributed to the city's switch to the Flint River as its primary water source, which led to a significant decline in water quality. The outbreak resulted in at least 87 cases and 12 deaths. [2]
- Salmonella Typhimurium Outbreak Linked to Peanut Butter (2008-2009)
- A widespread outbreak of Salmonella Typhimurium infections occurred in the United States, affecting over 700 individuals across 46 states. The source of the outbreak was traced to contaminated peanut butter products from a single processing facility. The contamination was likely due to persistent issues with sanitation and the presence of rodents in the facility. [3]
- Hepatitis A Outbreak Linked to Frozen Strawberries (2016)
- A multistate outbreak of hepatitis A infections in the United States was traced back to frozen strawberries imported from Egypt. The contaminated strawberries were used in smoothies served at a popular restaurant chain. The outbreak affected at least 143 people across nine states and resulted in 56 hospitalizations. [4]
- Cryptosporidiosis Outbreak in Milwaukee, Wisconsin (1993)
- The largest waterborne disease outbreak in U.S. history occurred in Milwaukee, Wisconsin, when over 400,000 people became ill due to Cryptosporidium parvum, a protozoan parasite. The outbreak was attributed to the contamination of the city's water supply, resulting from inadequate water treatment and heavy rainfall that led to the overflow of contaminated water into Lake Michigan. [5]
References
- ↑ This text was originally written by ChatGPT4.0 and edited by Arnold Bosman
- ↑ Zahran, S., McElmurry, S. P., Kilgore, P. E., Mushinski, D., Press, J., Love, N. G., ... & Swanson, M. S. (2018). Assessment of the Legionnaires' disease outbreak in Flint, Michigan. Proceedings of the National Academy of Sciences, 115(8), E1730-E1739.
- ↑ Cavallaro, E., Date, K., Medus, C., Meyer, S., Miller, B., Kim, C., ... & Braden, C. (2011). Salmonella Typhimurium Infections Associated with Peanut Products. New England Journal of Medicine, 365(7), 601-610.
- ↑ Foster, M., Ramachandran, S., Myatt, K., Donovan, D., Bohm, S., Fiedler, J., ... & Miller, K. (2018). Hepatitis A Virus Outbreaks Associated with Drug Use and Homelessness — California, Kentucky, Michigan, and Utah, 2017. MMWR. Morbidity and Mortality Weekly Report, 67(43), 1208-1210.
- ↑ Mac Kenzie, W. R., Hoxie, N. J., Proctor, M. E., Gradus, M. S., Blair, K. A., Peterson, D. E., ... & Davis, J. P. (1994). A massive outbreak in Milwaukee of cryptosporidium infection transmitted through the public water supply. New England Journal of Medicine, 331(3), 161-167.
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