There have been numerous outbreaks of waterborne disease associated with ships. From 1970 to 2003, there were over 100 outbreaks of disease, with 21 of them being associated with water and 33 of them of unknown origin, some of which could have also been associated with water. Over 6000 people became ill from the known outbreaks of waterborne disease. Seven outbreaks were due to enterotoxigenic Escherichia coli. Three of the outbreaks were due to norovirus. One outbreak was due to Salmonella typhi. One outbreak was due to non-typhoidal Salmonella. One outbreak was due to Cryptosporidium species. One outbreak was due to Giardia lamblia. One outbreak was traced to chemical poisoning. Five outbreaks were of unknown origin. These data may be at the low end of what is occurring, since numerous times reporting is not necessarily uniform and accurate. (See endnote 38.)
The number of outbreaks of disease aboard cruise ships from 2004 through May 14, 2015 has been established as well as the causative agent if known, but the number of people affected is not listed nor a determination whether the outbreak was due to food contamination, water contamination, or a combination of both. If the reader wishes to delve further into the next data released, contact the CDC Vessel Sanitation Program. (See endnote 17.)
Outbreaks of waterborne disease can occur from: contaminated water sources where there might be high turbidity, various chemicals present, as well as increased levels of microorganisms; defective filters; contaminated hoses; contaminated water hydrants; cross-connections with non-potable water when loading or aboard the ship; defective backflow preventers at loading or aboard the ship; and sick people especially food service workers who may be spreading the microorganisms to drinks or food.
Contamination of the water supply even though it is safe to start with can occur readily aboard ship because the potable water system is hooked up to provide water supply lines to swimming pools, whirlpools, hot tubs, bathtubs, showers, garbage grinders, hospital and laundry equipment, boiler feed water tanks, and toilets. It also may be hooked up to the salt water ballast systems, bilge or other wastewater, international shore connections, and hospital and laundry equipment.
Best Practices for Preventing Disease Spread by Use of Potable Water Facilities (See endnote 38)
- • Develop and implement a water safety plan for each cruise ship and each port. The plan should include an assessment of the entire water system from procurement to treatment to storage, to ensure a safe water source at the point of consumption by people; a hazard analysis of all steps in the water system and means of correcting problem areas; the use of acceptable water treatment technologies; a management plan in writing including appropriate control measures and corrective actions; and a monitoring system in accordance with the plan and meeting the highest level of requirements for chemicals and microorganisms as established by the appropriate official agency, US EPA, CDC, World Health Organization, and the national health agencies of other countries adhering to World Health Organization standards.
- • Clean and disinfect all water holding tanks before filling with freshwater and after emptying existing remaining water in tanks.
- • Determine the safety and security of all potable water being brought to the ship. Also determine if the means of transportation of the water is safe and secure and not contaminated.
- • Test all incoming waters to determine if they meet acceptable microbiological, chemical, physical, and radiological standards as set by the US EPA, CDC, World Health Organization or nation states where the regulations are equal to or better than those of the World Health Organization.
- • Have appropriate water treatment processes and equipment aboard all ships to be used for ensuring that the potable water is safe.
- • Determine if the water once treated can become contaminated aboard ship during storage and distribution and if so immediately correct the situation and decontaminate the equipment.
- • Frequently inspect all back flow prevention devices to ensure that contaminated water will not be merged with potable water. This can especially be a problem in the event of a fire on board the ship.
- • Document and maintain the records of all inspections of the water system, the various tests being conducted, the sources of the water, and any outbreaks of waterborne disease.
- • When bringing seawater on board ship either for a fresh seawater swimming pool or as a source of potable water after treatment, do not take it from ports or other areas where there is a considerable amount of traffic.
- • Where hoses are used to deliver potable water from a municipal or private supply at the dock to the ship, mark the hoses with a distinct color of blue to indicate potable water use only and provide signs at reasonable distances and around corners to alert people not to use them for any other purpose than a clean water connection. Protect the inlet and outlet of the hoses when not in use.
- • Do not use water boats or barges for any other purpose except delivery of potable water to the ship and make sure that the tanks and pipes or hoses are kept clean at all times and not used for any other purpose except delivery of potable water.
- • Have the appropriate public health authorities test the water source on a frequent as well as emergency basis. This is especially important in the event of any flooding. Keep all hydrants and other attachments above flood stage in ports where the water will be used as a potable water source.
- • If a water source is questionable and there is no other available, then the water must be first filtered with high-efficiency filtration systems, treated through the use of water treatment systems, and appropriately disinfected before bringing aboard ship. Retest the water before using it as a potable water supply.
- • Use appropriately trained individuals in all aspects of the delivery, storage, treatment, and use of potable water.
- • Label all non-potable water outlets as unfit for human consumption.
- • It is of greatest significance to have highly trained individuals under close supervision making all repairs to pipes and hoses as well as the operation of the hoses when needed.
- • Frequently inspect and test all water systems aboard ship to ensure the safety of the potable water supply.