Managing a Gastrointestinal Outbreak on Board
Each AGE case is identified and managed promptly under the applicable plan; in VSP, 2% triggers a special report and 3% or an unusual pattern triggers outbreak/investigation criteria, separately for passengers and crew.
Operational Explanation
Under CDC VSP 2025 §4.1.1.1, a reportable case is reported to the master, medical staff or other designated staff and involves diarrhea (at least three loose stools within 24 hours or above the person’s normal), or vomiting with at least one of: one loose stool within 24 hours, abdominal cramps, headache, muscle aches or fever ≥38 °C. This is a reporting definition; clinical and public-health action may be needed before it is met.
Regulatory Reference
VSP covers ships carrying at least 13 passengers on international voyages calling at a US port. Special reports at 2% and again at 3% require the ship to be within 15 days of expected US arrival; calculate passengers and crew separately. The 2% report also requires telephone notification. Submit the routine report 24–36 hours before arrival, including zero cases; an update at least four hours before arrival is required if counts change. Keep receipts and reports for 12 months. Apply section 4.2 counting rules for long or segmented voyages. CDC VSP 2025, §4.2.
The International Health Regulations cover more than certificates: Article 28 also addresses advance reporting of suspected infectious illness or public health risks; Article 37 concerns the ship health declaration under the arrival State’s requirements. Article 39 governs sanitation certificates, valid for up to six months and extendable by one month in specified circumstances. A valid certificate does not replace reporting a health event. WHO IHR.
VSP thresholds are not universal IHR thresholds. For European ports, check SHIPSAN guidance and competent-authority requirements; do not present technical guidance as a uniform EU reporting law.
For SHIPSAN use the European Manual, third edition, January 2026: distinguish LEG requirements, recommended ST standards and competent-authority duties.
SHIPSAN third edition §2.10 (ST) recommends an initial report to the next port at 2% and an update at 3%, separately for passengers and crew. An outbreak remains an increase above the expected level for ship, period and itinerary; it is not automatically defined by a VSP percentage.
Scope of Application
VSP reporting rules apply within their own scope. SHIPSAN §2.10 also recommends reports at 2% and 3%, with its own recipients and conditions. Check IHR, port-health requirements and the ship plan separately; do not automatically extend the VSP regime to other contexts.
Procedure / How to Complete It
- Apply both limbs of the case definition.
- Manage and isolate each case under the plan without waiting for a threshold.
- For VSP ships, special-report at 2% and treat 3% or an unusual pattern under outbreak/investigation criteria.
- Outside VSP apply competent-authority requirements.
Practical Example
A passenger reports vomiting and abdominal cramps to designated staff: the reportable definition is met without three loose stools. Start plan measures promptly and calculate passenger and crew rates separately.
What Typically Goes Wrong
An incomplete definition, waiting for a threshold before managing a case, extending VSP percentages beyond jurisdiction, or presenting dynamic statistics without a date and as causal proof leads to wrong decisions.
Common Mistakes Mistake Library
| Mistake | Consequence | How to avoid it |
|---|---|---|
| Waiting for a percentage threshold before applying the plan’s measures to an individual AGE case | Delayed identification, management and containment | Manage every case immediately under the applicable plan; within VSP scope, treat 2% as the special-report/support threshold and 3% or an unusual pattern as an outbreak/investigation criterion, calculated separately for passengers and crew |
| Syndromic surveillance based only on spontaneous reports | Cases are underestimated and response is delayed | Maintain active surveillance and apply plan measures from the first case |
What the PSCO Checks
Operational Tips
- Start case measures and the plan response without waiting for 2%.
- Within VSP scope only, use 2% for the special report and CDC support and 3% or an unusual pattern for outbreak and investigation.
- Calculate and document passenger and crew rates separately and cooperate with the competent health authority.
Preparation checklist
- Both AGE limbs applied
- Case measures started promptly
- 2% and 3% confined to VSP scope
- Passengers/crew calculated separately
- Local requirements checked
FAQ
Related Topics
Last substantive revision of this page: 16 September 2026 · page fingerprint d85ae9beb333