Page 228 - Vessel Sanitation Program 2018 Operations Manual

VSP 2018 Operations Manual

13.4 Acute Gastroenteritis Outbreak Investigation

13.4.1 Introduction

13.4.1.1 Introduction
OUTBREAKS of AGE aboard cruise ships are relatively infrequent
occurrences. Since implementation of the cooperative program between
the cruise industry and VSP, the OUTBREAK rate on vessels has steadily
declined each year.

13.4.1.2 Vigilance

Ongoing vigilance and rapid OUTBREAK detection and response are still
warranted. Because so many people share the same environment, meals,
and water, disease can often spread quickly to passengers and crew
members on the vessel and overwhelm the vessel’s medical system. The
infection can also continue unabated between cruises if proper
interventions are not instituted.

13.4.1.3 Consultation

An OUTBREAK of AGE occurs aboard a vessel when the number of
cases is in excess of expected levels for a given time period. When the
cumulative proportion of REPORTABLE CASES of AGE reaches 2%
among passengers or 2% among crew and the vessel is within 15 days of
arrival at a U.S. port, the vessel must submit a special report to VSP. This
provides an early opportunity for consultation to potentially avert more
illness among passengers and crew members.

13.4.1.4 Monitoring
In most instances, a 2% proportion of illness will not lead to an
investigation aboard the vessel but will provide the opportunity to discuss
and monitor illness patterns and collaboratively develop intervention
strategies. VSP staff members are always available to discuss disease
TRANSMISSION and intervention questions.

13.4.1.5 Investigation
OUTBREAKS of AGE aboard cruise ships are relatively infrequent
occurrences. If the proportion of illness in either passenger or crew
populations crests VSP’s 3% OUTBREAK threshold or for subsequent
voyages that crest the 2% or 3% thresholds, an onboard investigation may
occur.

13.4.1.6 Special Circumstances
Under special circumstances, when an unusual AGE pattern or disease
characteristic is found, an investigation may be conducted when the
proportion of cases is less than 3%. These special circumstances may

Annex 13.4: Acute Gastroenteritis Outbreak Investigation; 175