Facts of LifeBy WHO- Yemen Program [Archives:2005/833/Health]

April 14 2005

Foodborne and waterborne health risks in Yemen
Many important infectious diseases (such as brucellosis, cholera, cryptosporidiosis, giardiasis, hepatitis A and E, legionellosis, leptospirosis, listeriosis, schistosomiasis and typhoid fever) are transmitted by contaminated food and water.

For travellers, the main health problem associated with contaminated food and water is “travellers' diarrhoea”, which can be caused by a wide range of infectious agents. Travellers' diarrhoea is the most common health problem encountered by travellers and may affect up to 80% of travellers to high-risk destinations. Even a brief episode of severe diarrhoea may spoil a holiday or ruin a business trip. Diarrhoea may be accompanied by nausea, vomiting, and fever. Travellers' diarrhoea is primarily the result of consumption of contaminated food, drink, or drinking-water. Contamination in such cases is due to the presence of disease-producing microorganisms. A wide range of different bacteria, viruses, and some parasitic and fungal infections may cause travellers' diarrhoea.

Illness is also caused by certain biological toxins found in seafood. The main diseases in this group are caused by poisoning from:

– paralytic shellfish

– neurotoxic shellfish

– amnesic shellfish

– ciguatera toxin

– scombroid fish

– puffer fish

The toxins involved in these poisonings come from microorganisms consumed by or otherwise contaminating the fish.

Poisonous chemicals may also contaminate food and drink. However, the ill-effects are generally the result of long-term exposure and do not represent a significant health risk for travellers. Sporadic misuse of chemicals also occurs, such as the use of textile dyes in foodstuffs, which may give an unusually bright colour to the contaminated food.

The safety of food, drink and drinking-water depends mainly on the standards of hygiene applied locally in their preparation and handling. In countries with low standards of hygiene and sanitation and poor infrastructure for controlling the safety of food, drink and drinking-water, there is a high risk of contracting travellers' diarrhoea. In such countries, travellers should take precautions with all food and drink, including that served in good-quality hotels and restaurants, to minimize any risk of contracting a foodborne or waterborne infection. While the risks are greater in poor countries, locations with poor hygiene may be present in any country.

Another potential source of waterborne infection is contaminated recreational water, particularly sewage-polluted seawater or fresh water in lakes and rivers, as well as water in swimming pools and spas where filtering and disinfection are inadequate or even non-existent. Bathing in contaminated water may result in ingestion of diarrhoea-producing microorganisms and other infectious agents.

It is particularly important that people in more vulnerable groups, i.e. infants and children, the elderly, pregnant women and people with impaired immune systems, take stringent precautions to avoid contaminated food and drink and unsafe recreational waters.

Travellers should:

– avoid consumption of potentially contaminated food or drink;

– avoid contact with potentially contaminated recreational waters;

– know how to treat diarrhoea;

– carry oral rehydration salts and water-disinfecting agents.

Precautions for avoiding unsafe food and drink

– Avoid cooked food that has been kept at room temperature for several hours.

– Eat only food that has been cooked thoroughly and is still hot.

– Avoid uncooked food, apart from fruit and vegetables that can be peeled or shelled, and avoid fruits with damaged skins.

– Avoid dishes containing raw or undercooked eggs.

– Avoid food bought from street vendors.

– Avoid ice cream from unreliable sources, including street vendors.

– In countries where poisonous biotoxins may be present in fish and shellfish, obtain advice locally.

– Boil unpasteurized (raw) milk before consumption.

– Boil drinking-water if its safety is doubtful; if boiling is not possible, a certified, well-maintained filter and/or a disinfectant agent can be used.

– Avoid ice unless it has been made from safe water.

– Avoid brushing the teeth with unsafe water.

– Bottled or packaged cold drinks are usually safe provided that they are sealed; hot beverages are usually safe.