Epidemiology for public health practice.

Analyze the response to the epidemic in terms of effectiveness (consider addressing questions such as how fast was the response, how long did it take to contain it, was the number of people who investigated really necessary, is the situation resolved).

Discuss ways to reduce the incidence of such an outbreak (research how outbreaks of this disease occurred and how to prevent them). Nettye Johnson Discussion Cruise ships are ripe settings for outbreaks of infectious disease. Two elements of the epidemiologic triangle are inherent with cruises; i.e., the large number of people (hosts) living in close closed quarters (environment) for a prolonged period during the cruise.

If the third epidemiological triangle element (an infectious agent) is introduced, disease can easily spread (Friis and Sellers, 2014). To examine the epidemiological approach used for infectious disease in a cruise ship environment, I reviewed articles detailing epidemiological studies of passenger and crew illness at a busy Caribbean cruise port (Marshall, Morris, & Unwin, 2016) and a food-borne outbreak of gastroenteritis on a cruise ship in Hawaii (Herwalt, Lew, Moe, Lewis, Humphrey, Monroe, & Glass, 1994). Aspects related to the study and reporting of those incidents In the Caribbean cruise port example data was secured using a public health monitoring system at each port of entry.

A retrospective descriptive study of passenger and crew registers and illness logs indicated that between January 2009 and December 2013, there were 1,031 cases of illness from 4 million people (3 million passengers and 1 million crew members). The communicable illness event rate was 15.7 per 100,000 passengers and higher among the crew at 24.0 per 100,000. The predominant illnesses were gastroenteritis and influenza. These two illnesses accounted for 93% and 87% of communicable disease events in passengers and crew respectively.

This study did not find a cause of the illnesses. The researchers propose further study is needed to determine the exact cause (Marshall et al., 2016). The study of the gastroenteritis outbreak on a Hawaiin ship was smaller in scale as it addressed illnesses on a single 682-foot ship. Sickness broke out on the first 7-day trip of this boat. A crew member anonymously reported the incident to the Hawaiian Department of Health and the CDC conducted an epidemiological investigation of the second voyage.

Investigation methods included questionnaires, a case-controlled study conducted via phone interviews, and serology and bacteriology analysis of serum and fecal specimens from passengers and crew. On this trip, 41% of the 527 passengers experienced gastroenteritis from the Norwalk virus. The identified cause of the outbreak was food served during the voyage (Herwaldt, et al., 1994). Participants that worked these outbreaks Many individuals and agencies worked together to track, study, and contain these outbreaks. Cruise ship staff was involved in the recording of data in the registers and illness logs.

Passengers contributed via self-reporting of sickness and compliance with sanitation, hygiene, quarantine and other measures outlined to contain the illness. Agency involvement in these cases includes the Hawaiin Department of Health, the Barbados Port Health Department, Environmental Health Officers (Port Health) who monitors and documents sick passengers on ships in Barbados waters, the Vessel Sanitation Program (VSP) charged to monitor sanitation and health practices on cruise ships to lower outbreaks, the Centers for Disease Control and Prevention, and laboratories at the Hawaiin DOH, and Baylor College of Medicine who tested collected specimens.

An interesting note about the Hawaiin outbreak: VSP was not contacted in this case because the smaller ship did not use foreign ports, but the CDC was called in for investigation by the Hawaiin Department of Health.

References Friis, R. H. and Sellers, T. A. (2014). Epidemiology for Public Health Practice. Burlington, MA: Jones and Bartlett Learning. Herwaldt, B. L., Lew, J. F., Moe, C. L., Lewis, D. C., Humphrey, C. D., Monroe, S. S., & Glass, R. I. (1994).

Characterization of a variant strain of Norwalk virus from a food-borne outbreak of gastroenteritis on a cruise ship in Hawaii. Journal of Clinical Microbiology, 32(4), 861-866. Marshall, C. A., Morris, E., & Unwin, N. (2016).

An epidemiological study of rates of illness in passengers and crew at a busy Caribbean cruise port. BMC Public Health, 16(1), 1-6. doi:10.1186/s12889-01991-3 Response should be at least 250 words with at least two scholarly sources to support your response.

Introduction to Epidemiology Ashford University Text:Friis, R. H. and Sellers, T. A. (2014).