Various hazards to health may be associated with coastal waters, freshwater lakes and rivers, ponds, pools and spas during recreational or occupational activities: unknown waters can be a cause of accidents, disease or infection and envenomation from bites and stings from marine animals. Travelers need to be aware of the precautions and the risks to avoid illness and injury. 

1. Risks Associated with Coastal and Fresh Waters

Coastal waters may be contaminated with fecal matter or by pathogens naturally present, or carried in by people or animals. Infection can be spread through ingestion, inhalation or contact. Diarrheal disease, acute febrile respiratory disease and ear infections are the most common consequences.

Freshwater lakes, rivers, and streams may be contaminated with schistosomiasis (for more information see outline #36). Travelers are at risk in most tropical areas, especially so in Africa. Safaris, where streams must be crossed are hazardous and water sports are particularly risky because they may involve exposure to surface water over a large area. Dams and deep water, even far offshore are not exempt. Fresh water may also spread leptospirosis, where contaminated by the urine of infected rodents. Most commonly found in the tropics, leptospirosis is of greatest public health importance in South East Asia and Latin America notably Thailand. Infection occurs through contact with contaminated water, wet soil or vegetation. Bacteria penetrate through the skin and mucosa and cause a systemic reaction, the severity of which may range from asymptomatic to fulminant: it is often misdiagnosed as meningitis or encephalitis.

1.1 Precautions around Coastal and Fresh Waters

1) While swimming in the sea is usually safe, always ensure the swimming area is not close to sewage works or highly populated areas with no proper sanitary facilities.

2) Avoid swallowing any contaminated water

3) Avoid swimming or wading with what might serve as entry points (cuts and abrasions) for germs.

4) Protect nasal membranes from germs by wearing nose plugs, when entering untreated water venues.

In areas endemic for schistosomiasis

1) Avoid contact (swimming, boating, rafting) with potentially contaminated fresh water: even a minimal exposure to fresh water in an endemic area poses a risk for the traveler.

2) Remember that seawater as a rule does not pose a risk for schistosomiasis, but infection may be acquired near the mouths of rivers and in brackish waters

3) Remember that risk is highest along lake shores and in slow moving bodies of water such as irrigation ditches and flooded paddy fields.

4) In case of accidental exposure, dry the skin vigorously to avoid penetration

5) Avoid drinking, washing or washing clothes that may contain cercariae. Water can be treated to remove cercariae by paper filtering or use of iodine or chlorine or by storing in a snail free environment for 48 hrs.

6) Do not cross streams at points where there is much human contact...cross upstream.

7) Wear long trouser and sleeves and dry out immediately in the sun after crossing.

8) Rubber boots and wet suits are protective but must be dried quickly in the sun after use (the larvae die quickly on removal from water and cannot survive drying).

In areas endemic for leptospirosis

1) Avoid swimming or wading in waters including canals, ponds, rivers, streams and swamps potentially contaminated with animal urine.

2) Avoid all direct or indirect contact with rodents.

3) Clothing that prevents contact with surface water should be worn.

4) Tetracycline (200mg /week) has been used as chemoprophylaxis for well- defined, high risk populations.

2. Risks Associated with Swimming Pools and Spas 

In swimming pools and spas infections causing diarrhea, gastroenteritis and throat and ear infections can occur, though rarely, if treatment and disinfection are inadequate. The parasites Giardia, Cryptosporidium, hepatitis A and Norwalk virus may be a more serious  problem because of their resistance to chlorine. Most common are superficial foot infections such as  tinea pedis and plantar’s warts which can contaminate swimming pool surroundings. Eye irritation and conjunctivitis may result from chemical irritation. Spas and whirlpools may become contaminated with Legionella (see outline #35).

2.1 Precautions around Swimming Pools and Spas 

1) Check the cleanliness and hygiene standards of a hotel: this is generally a good indication that its pool /spa are likely safe.

2) Be aware that pool maintenance should include chlorine measurements taken at least twice daily (at slow and peak usage times) if not continuous, a good filtration system, properly  trained  staff, a dependable supply of chemicals and spare parts, and regular inspections by local health departments.

3) To minimize exposure to legionella in travelers, some experts recommend staying out of the bathroom for the first minute after turning on the warm water for showers (hot water temperatures above 60˚ inactivate the bacteria).  Proper disinfection in spas and hot tubs in recreational areas will minimize legionella infection.

3. Risks Associated with Marine Creatures

Marine hazards include animals that envenom and those that bite, puncture, or shock but do not envenom. They are predominantly found in tropical and warm temperate oceans.

Venomous sea creatures to avoid are: sponges, jelly fish, Portuguese man-of war, stinging corals, sea anemones, cone shells, sea urchins, starfish, stingrays, sea snakes, stonefish and scorpion fish, some of which may cause death (see # 34 for more details on envenomation). Contact with venomous organisms may produce excruciating pain and a wide range of symptoms ranging from an  irritant dermatitis to coma and death. A minor contact with jelly fish larvae will manifest itself as seabather’s eruption (swimmer’s itch), a jellyfish larvae found mainly in the Carribean. The  sting of the box jellyfish, found in the shallow waters off Australia’s coast can kill within 2 minutes. Of note, clostridium tetani has been cultured from sea sponges.

Marine animals to avoid include sharks, barracudas and eels as well as the crocodiles  which inhabit rivers and estuaries in many tropical countries. Aquatic or water leeches are found only in fresh water, primarily in North Africa, western Asia, Indonesia and southern Europe. They are acquired by drinking or bathing in infested water  They can attack swimmers and crawl into the mouth, nostrils, eyes and other small openings into the body.

3.1 Precautions around Marine Creatures

1) Ensure tetanus-diphtheria is up to date prior to departure.

2) Check for books on the local sea creatures; also check with local authorities and always follow their advice.

3) Divers should educate themselves on appropriate behavior toward dangerous sea creatures. 

4) Avoid passing close by, handling, interfering with or treading on a venomous animal during wading, swimming snorkeling, diving or exploring the sea-shore. If a jelly fish is sighted stay at a distance since tentacles trail.

5) Do not place fingers  in crevices or holes where sea animals may reside.

6) Wear footgear  when walking in shallow waters or at the water’s edge: shuffling will help to scare off a stingray hidden in the sand. 

7) Consider wearing protective clothing against jelly fish stings: a “stinger suit”, mask or goggles.

8) Avoid the water during seasons when large numbers of jellyfish are washed inshore.

9) To help prevent seabather’s eruption, wash with soap and water after swimming.

10) When fishing, always cut away sea snakes, scorpion fish or anything that you are unfamiliar with.

11) Seek medical advice after a sting or bite by a poisonous animal.    

4. Risks of Drowning and Injury  

Of the hazards associated with recreational waters, the most important are drowning and impact injuries. Swimming in unknown currents and the consumption of alcohol around recreational waters are often associated with drownings. With intoxication there is lack of risk awareness, and this may lead to hypoglycemia, nausea, vomiting, and/or hypothermia, confusion and loss of consciousness. In swimming pools drowning is associated with slip-trip-fall accidents or getting caught close to outlets where suction is strong. Children can drown in relatively small volumes of water, most often due to lack of adult supervision. Lacerations from rocks, coral, glass, and metal are common in beach sports. Water sports, particularly surfing, are a frequent cause of injury among  travelers.

4.1 Precautions to Avoid Drowning and Injury 

Around recreational waters

1) Adopt safe behavior in all recreational waters.

2) Respect yellow or red flags on the beach indicating swimming is dangerous or not allowed.

3) Ask the local people about river or sea currents; be aware of weather conditions and forecasts.

4) Use a personal floating device when boating, skiing or using personal water craft. 

5) Be aware of weather conditions and forecasts when swimming and boating

6) Avoid excessive alcohol consumption:  in cold surroundings alcohol can be exceedingly dangerous.

7) Never dive or jump into an unfamiliar body of water: first determine the depth (min.9 ft.) the terrain, and any hidden obstacles; never jump on someone else.

8) Ensure constant adult supervision of children no matter how small the volume of water.

9) Learn CPR and First Aid: immediate treatment (such as a hot bath for immersion hypothermia) is most important.

Around pools, look for

1) Depth markings that are clear.

2) Non-slip pool surrounds (this is the most frequent cause of accidents). 

3) Appropriate fencing on bridges across pool areas for children.

4) Children’s areas physically separated from adult areas to prevent children from entering deep water accidentally .

5) Clear signs listing pool safety rules for guests.

References

Martinez, L. (Executive Editor). International Travel and Health. Published by the World Health Organization (WHO). 2002.

Keystone, J.S. (Editor) Don't drink the water.....The complete traveller's guide to staying healthy in warm climates. 5^th Edition.  Co-published by the Canadian Public Health Association and the Canadian Society for International Health. 2000

Dawood, R. Traveller's Health. Oxford, Great Britain: Oxford University Press.1986

Strickland, T. Hunter's Tropical Medicine and Emerging Infectious Diseases. 8th Edition. Philadelphia: Saunders, 2000.

Health Information for International Travel 2001-2002. Published by the Centers for Disease Control and Prevention (CDC). Atlanta, Georgia: U.S. Department of Health and Human Services, Public Health Service, 2001

Robin, M.R. and Dessery, B.L. The Medical Guide for Third World Travelers.  San Diego, California, USA. K-W Publications. 1990

Lockie, C.; Walker, E.; Calvert, L.; Cossar, J.; Raeside, F.; Knill-Jones, R. (Editors). Travel Medicine and Migrant Health. UK: Churchill Livingstone, 2000.

Submitted by:

Pauline Delorme RN

Tel: 613 236-6163. Fax: 613 238-7230.

pdelorme@idrc.ca