Infectious Agents : Bacteria / Virus / Protozoa
Incidence rates are equal for Male and Female
In short-term travelers, bouts of TD do not appear to protect against future attacks, and >1 episode of TD may occur during a single trip
|INCUBATION PERIOD||6-72 HOURS||6-72 HOURS||1-2 WEEKS|
|SYMPS||can range from mild cramps and urgent loose stools to severe abdominal pain, fever, vomiting, and bloody diarrhea||SAME
although with norovirus vomiting may be more prominent
|Protozoal diarrhea, such as that caused by Giardia intestinalis or E. histolytica, generally has a more gradual onset of low-grade symptoms, with 2–5 loose stools per day|
|Last for||3-7 days||2-3 days||Weeks -months|
Food & Water Precautions
1. Select food with care : Raw food is especially likely to be contaminated. Raw or undercooked meat, fish, and shellfish can carry various intestinal and systemic pathogens.In areas where hygiene and sanitation are inadequate or unknown, travelers should avoid consuming salads; uncooked vegetables; raw, unpeeled fruits; and unpasteurized fruit juices. Fruits that can be peeled are safest when peeled by the person who eats them. Produce should be rinsed with safe water. Foods of animal origin, including meat and eggs, should be thoroughly cooked; milk and milk products, including milk used in soft cheese, should be pasteurized. In restaurants, inadequate refrigeration and lack of food safety training among staff can result in transmission of pathogens. Consumption of food and beverages obtained from street vendors has been associated with an increased risk of illness. In general, foods that are fully cooked and served hot are safest, as are foods people carefully prepare themselves.
2. Wash Hands : Travelers should wash their hands with soap and water before preparing food, before eating, after using the bathroom or changing diapers, before and after caring for someone who is ill, and after contact with animals or their environments. If soap and water are not available, use an alcohol-based hand sanitizer (with ≥60% alcohol) and wash hands with soap and water as soon as they become available. Hand sanitizer is not very effective against Cryptosporidium or norovirus and does not work well when hands are visibly dirty or greasy.
3. Infant Formula : The safest way to feed an infant aged <6 months is to breastfeed exclusively. If the infant is fed formula prepared from commercial powder, the powder should be reconstituted with hot water at a temperature of ≥158°F (≥70°C). This precaution will kill most pathogens with which the infant formula may have been contaminated during manufacturing or through handling after opening. To ensure that the water is hot enough, travelers should prepare formula within 30 minutes after boiling the water. The prepared formula should be cooled to a safe temperature for feeding (for example, by placing the bottle upright in a bath of safe water and safe ice [see below], keeping the bath water below the nipple ring) and used within 2 hours of preparation. Bottles and nipples should be washed and then sterilized (in boiling water or in an electric sterilizer). Travelers may wish to pack enough formula for their trip, because manufacturing standards vary widely around the world.
4. Drinking Water : Travelers should avoid drinking or putting into their mouths tap water unless they are reasonably certain it is safe. Many people choose to disinfect or filter their water when traveling to destinations where safe tap water may not be available. Tap water that is safe for drinking is still not sterile and should not be used for sinus or nasal irrigation or rinsing, including use in neti pots and for ritual ablution unless it is further disinfected by the traveler. Tap water should never be used to clean or rinse contact lenses. Water that looks cloudy or colored may be contaminated with chemicals and will not be made safe by boiling or disinfection. In these situations, travelers should use bottled water if it is available.In areas where tap water may be unsafe, only commercially bottled water from an unopened, factory-sealed container or water that has been adequately disinfected should be used for drinking, preparing food and beverages, making ice, cooking, and brushing teeth.
5. Other Beverages : Beverages made with water that has just been boiled, such as tea and coffee, are generally safe to drink. When served in unopened, factory-sealed cans or bottles, carbonated beverages, commercially prepared fruit drinks, water, alcoholic beverages, and pasteurized drinks generally can be considered safe. Because water on the outside of cans and bottles may be contaminated, they should be wiped clean and dried before opening or drinking directly from the container.Beverages that may not be safe for consumption include fountain drinks or other drinks made with tap water and iced drinks. Because ice might be made from contaminated water, travelers in areas with unsafe tap water should request that beverages be served without ice.
6. Recreational Water : Pathogens that cause gastrointestinal, respiratory, skin, ear, eye, and neurologic illnesses can be transmitted by contaminated recreational water in inadequately treated pools, water playgrounds (splash pads or spray parks) or hot tubs/spas, or in freshwater or marine water. Recreational water contaminated by human feces from swimmers, sewage, animal waste, or wastewater runoff can appear clear but still contain disease-causing infectious or chemical agents. Ingesting even small amounts of such water can cause illness.
If travelers would like to test recreational water before use, CDC recommends pH 7.2–7.8 and a free available chlorine concentration of 2–4 ppm in hot tubs/spas (4–6 ppm if bromine is used) and 1–3 ppm in pools and water playgrounds. Test strips may be purchased at most superstores, hardware stores, and pool supply stores. Pseudomonas, which can cause “hot tub rash” or “swimmer’s ear,” and Legionella can multiply in hot tubs and spas in which chlorine or bromine concentrations are not adequately maintained. Travelers should avoid pools, water playgrounds, and hot tubs/spas where bather limits are not enforced or where the water is cloudy. Additional guidance can be found at www.cdc.gov/healthywater/swimming.
Travelers should not swim or wade 1) near storm drains; 2) in water that may be contaminated with sewage, human or animal feces, or wastewater runoff; 3) in lakes or rivers after heavy rainfall; 4) in freshwater streams, canals, and lakes in schistosomiasis-endemic areas of the Caribbean, South America, Africa, and Asia ;5) in water that might be contaminated with urine from animals infected with Leptospira ; or 6) in warm seawater or brackish water (mixture of fresh and sea water) when they have wounds.
A traveler with an open wound should consider staying out of the water or covering the wound with a water-repellent bandage (often labeled “waterproof”), as seawater and brackish water can contain germs, such as Vibrio spp., that can cause wound infections. If a sore or open wound comes into contact with untreated recreational water, it should be washed thoroughly with soap and water to reduce the chance of infection.
Naegleria fowleri is a parasite found in warm freshwater around the world. To help prevent a rare but fatal infection caused by this parasite, travelers should hold their nose shut or wear a nose clip when swimming, diving, or participating in similar activities in warm freshwater (including lakes, rivers, ponds, hot springs, or locations with water warmed by discharge from power plants and industrial complexes). They should also avoid digging in or stirring up sediment, especially in warm water.This infection has also been linked to use of contaminated tap water for sinus and nasal irrigation.
Travelers’ diarrhea definitions
Mild (acute): diarrhea that is tolerable, is not distressing, and does not interfere with planned activities.
Moderate (acute): diarrhea that is distressing or interferes with planned activities.
Severe (acute): diarrhea that is incapacitating or completely prevents planned activities; all dysentery is considered severe.
Therapy of mild travelers’ diarrhea
- Antibiotic treatment is not recommended in patients with mild travelers’ diarrhea.
- Loperamide or BSS may be considered in the treatment of mild travelers’ diarrhea.
Therapy of moderate travelers’ diarrhea
- Antibiotics may be used to treat cases of moderate travelers’ diarrhea.
- Fluoroquinolones may be used to treat moderate travelers’ diarrhea.
- Azithromycin may be used to treat moderate travelers’ diarrhea.
- Rifaximin may be used to treat moderate, noninvasive travelers’ diarrhea.
- Loperamide may be used as adjunctive therapy for moderate to severe travelers’ diarrhea. Antimotility agents alone are not recommended for patients with bloody diarrhea or those who have diarrhea and fever.
- Loperamide may be considered for use as monotherapy in moderate travelers’ diarrhea.
Therapy of severe travelers’ diarrhea
- Antibiotics should be used to treat severe travelers’ diarrhea.
- Azithromycin is preferred to treat severe travelers’ diarrhea.
- Fluoroquinolones may be used to treat severe, nondysenteric travelers’ diarrhea.
- Rifaximin may be used to treat severe, nondysenteric travelers’ diarrhea.1
- Single-dose antibiotic regimens may be used to treat travelers’ diarrhea.
Treatment for Children
Children who accompany their parents on trips to high-risk destinations can contract TD as well, with elevated risk if they are visiting friends and family. Causative organisms include bacteria responsible for TD in adults, as well as viruses including norovirus and rotavirus. The main treatment for TD in children is ORS. Infants and younger children with TD are at higher risk for dehydration, which is best prevented by the early initiation of oral rehydration. Empiric antibiotic therapy should be considered if there is bloody or severe watery diarrhea or evidence of systemic infection. In older children and teenagers, treatment recommendations for TD follow those for adults, with possible adjustments in the dose of medication. Among younger children, macrolides such as azithromycin are considered first-line antibiotic therapy