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International Travelers + Infectious diseases

What is altitude illness?

mountain.jpgAltitude illness is a condition which occurs in many travelers making rapid ascents to high altitudes. It is commonly referred to as acute mountain sickness (AMS). It most often occurs at altitudes of 3,000 meters (approximately 10,000 feet) or more. In some individuals, it has been reported as low as 2,500 meters (8,000 feet).

We suspect that altitude illness is caused by the body's reaction to lower levels of oxygen found at high altitudes. The disease may occur several hours to days after ascending to high altitudes. Symptoms range from mild to severe.

Classic, high risk areas of the world for altitude illness include any mountain range over 10,000 feet, such as the Alps, Andes, or Himalayas. In addition, travelers to areas of North American, East Africa, and the polar regions are at risk.

Symptoms of altitude illness

Altitude illness can range from mild to severe.

Mild symptoms

  • Headache
  • Fatigue
  • Sleep disturbance
  • Appetite loss
  • Nausea
  • Difficulty breathing

Severe symptoms

  • Shortness of breath while resting
  • Rapid pulse at rest (>100-110 beats per minute or BPM)
  • Decreased urination
  • Visual changes
  • Severe headache
  • Loss of coordination
  • Mental confusion
  • Productive cough

The last group of symptoms may represent fluid accumulation in the brain (high altitude cerebral edema) or lungs (high altitude pulmonary edema). In these severe cases, the disease can be fatal if not treated rapidly and requires descent to lower altitudes. Luckily, in most travelers, altitude illness is mild and does not become severe.

Asthma does not increase the risk of altitude illness. In fact, people with asthma often do well at altitude since there is less pollution in the air.

Prevention of altitude illness

The best prevention is slow ascent. In general, ascent of altitudes of no more than 1,000 feet (300 meters) per day above 10,000 feet is recommended. Upon arrival at altitude, you should avoid strenuous activity until you fully acclimatize.

Maintain fluid intake to avoid dehydration and follow the maxim, "climb high and sleep low." Avoid alcohol, cigarettes and sedatives (including narcotics).

Use of coca tea or coca leaves

The active ingredient in coca leaves is a mild stimulant that may help you stay alert and hydrated. This may make you feel better at altitude. Unfortunately, it does not prevent altitude illness.

coca.jpgGingko biloba or Viagra™ (sildenafil)

It is unknown whether these two medications are effective in preventing altitude sickness, and therefore, their use is not recommended.

Fitness level

Physical conditioning does not protect against altitude illness. Susceptibility is based on your body's response to altitude and is not reflective of aerobic capacity.

Treating altitude illness

If slow ascent is not possible or if you have a history of recurrent altitude illness, preventive medications may be needed. An example is Mt. Kilimanjaro (19,340 feet), which is often climbed in less than seven days.

Acetazolamide (Diamox)

The drug of choice to prevent altitude illness is acetazolamide. Take this medication 24 hours before ascent above 10,000 feet through 24-48 hours after you reach peak altitude. Avoid this medication if you have a history of sulfa antibiotic allergy, liver or kidney disease, or severe lung disease. Acetazolamide may cause tingling of the lips, fingers and toes, frequent urination, and a metallic taste with carbonated beverages.

Dexamethasone

If you cannot take acetazolamide, dexamethasone can be used. If you've had adverse reactions to steroids or have diabetes, this drug may not be safe for you. Dexamethasone can cause headaches, nausea, dizziness, abdominal pain, and can suppress your immune function if used over a long period of time.

Treating severe altitude illness

If symptoms of acute mountain sickness develop, you should stop your ascent, rest and get adequate fluids and calories. If altitude illness symptoms worsen, rapid descent to lower altitudes should begin as soon as possible. You should also see a medical professional.

Oxygen, use of hyperbaric chambers and medications may be needed.

Additional resources

 

Authored by: Hall Health Center Travel Clinic staff

Reviewed by: Hall Health Center Travel Clinic staff (AT), May 2014


Traveler's diarrhea is the most common infectious disease experienced by international travelers. It can be caused by bacteria (most common), viruses or parasites that have been ingested through contaminated food or drink. Traveler's diarrhea can be mild to extreme in severity.

Preventing traveler's diarrhea

Remember: boil it, cook it, peel it, or forget it! In other words, if you don't boil, cook, or peel your food, you could get sick.

Other prevention tips include:

  • Wash your hands with soap and water or use alcohol-based hand sanitizers before eating.
  • If you're having coffee, tea, or other drinks that require water for preparation, use bottled or disinfected water.
  • Don't use tap water for drinking or brushing your teeth, and be sure to avoid ice. Drink bottled water with an intact seal or purify water yourself.bottled water.jpg
  • Avoid unpasteurized dairy products.
  • Avoid food of questionable preparation or origin (like buffets).
  • Avoid food from street vendors.
  • Steer clear of food that has been rewarmed (like quiche).
  • To clean vegetables, start with boiled water, and add bleach (2-4 drops per liter of water). You may also use enough iodine tablets to make the water the color of dark tea. Soak veggies in the water for several hours, and then drain produce and rinse again with clean water.

Treating traveler's diarrhea

Traveler's diarrhea can range from mild to severe. Treatment varies based on severity.

Mild diarrhea

Mild traveler's diarrhea is characterized by 3-4 unformed stools in 24 hours with mild cramping.

intestines.jpgRecommended treatment:

  • Drink plenty of clear fluids or consider the use of Oral Rehydration Solution (ORS) or Ceralyte. (Appropriate for adults and children.)
  • Loperamine (Imodium AD) will decrease diarrhea for about 4 hours, allowing you to travel or sleep. Follow the directions on the box of loperamine. Not to be used for children under 12 or if you have bloody diarrhea.
  • Try to eat as soon as possible. It's best to start with easily digested foods, like bananas, rice, applesauce and toast. Avoid milk products for 72 hours after last diarrhea.

Moderate diarrhea

Symptoms of moderate traveler's diarrhea include increased frequency of unformed bowel movements with one or more of the following: Fever up to 101° F, abdominal pain, nausea or vomiting.

Recommended treatment:

  • Drink plenty of clear fluids or consider the use of Oral Rehydration Solution (ORS) or Ceralyte. (Appropriate for adults and children.)
  • Loperamine (Imodium AD) will decrease diarrhea for about 4 hours, allowing you to travel or sleep. Follow the directions on the box of loperamine. Not to be used for children under 12 or if you have bloody diarrhea.
  • Prior to your trip, an antibiotic will be prescribed for you depending on your history and destination. It is important to discuss all your medications with your provider before taking antibiotics, as some drugs reduce the efficacy of antibiotics, or cause unpleasant side effects:
    • Ciprofloxacin (Cipro), which should be taken in conjunction with Loperamine (Imodium AD). Not to be used in pregnant or breastfeeding women, or in children under 18.
    • Azithromycin (Zithromax), the preferred medication for children under 18. It may be dispensed as a powder to allow a parent or guardian to administer it as a liquid. Azithromycin should be taken with food to avoid stomach upset.
    • Rifaximin (Xifaxan), which is used for individuals who are not able to tolerate other antibiotics.

Severe diarrhea

Severe traveler's diarrhea is moderate diarrhea with or without abdominal cramping/pain, fever, blood in stool, dehydration. You can take antibiotics if you have severe diarrhea, but if symptoms worsen seek medical care. These symptoms could indicate a more severe infection, such as giardia or amoebiasis.

Diarrhea in children

Young children (under age 5) are particularly susceptible to becoming dehydrated from diarrhea. Do not use loperamine (Imodium AD) in children.

If a breastfeeding infant has diarrhea, continue breastfeeding. An infant or toddler should have at least one wet diaper every 4-6 hours. If there is a longer period between wet diapers, the child needs more fluids and should be seen by a health care provider. Parents and guardians should have a low threshold for seeking medical help if a child in their care experiences vomiting and diarrhea.

Additional resources

 

Authored by: Hall Health Center Travel Clinic staff

Reviewed by: Hall Health Center Travel Clinic staff, May 2014


What is malaria?

Malaria is the most significant parasitic disease threat you will face in most tropical and subtropical countries. It is a microscopic blood- borne parasite transmitted to humans by the bites of infected mosquitoes.  There are 300 to 500 million cases a year of malaria worldwide —approximately 1000 a year are reported in U.S. travelers. 

Symptoms can include: fever and flu-like symptoms, chills, generalized muscle aches and pains, tiredness, headache, abdominal pain, and even diarrhea.  Symptoms usually begin 1 to 2 weeks after an infected bite, but onset can be as late as 4 or more weeks afterwards in some cases.  If left untreated, malaria can cause anemia, jaundice, kidney failure, coma, and death. 

Travelers can decrease the risk of malaria by taking certain drugs to prevent a malaria attack (malaria chemoprophylaxis) and by using measures to prevent mosquito bites.  However, in spite of all precautions, travelers occasionally might become infected with malaria.  Therefore, while traveling and up to five years after returning home, travelers should seek medical evaluation for any flu-like illness accompanied by fever.

If you have an extended period of travel or experience numerous mosquito bites in a malaria area, you may need additional anti-malarial medication after your return, to eradicate a possible asymptomatic incubating malaria infection.  If this situation applies to you, continue your prescribed malaria chemo-prophylaxis medication and seek care within two weeks after your return.

You are excluded from blood donation for 1 year after being in a malarious area.

Prevention

Travelers should limit their time outdoors in rural tropical areas between dusk and dawn, when the mosquitoes transmitting malaria are most likely to bite.  When outdoors, prevent mosquito bites by staying in screened areas as much as possible; wearing protective clothing that covers arms and legs; using an insect repellent on exposed skin areas when outdoors; and using a mosquito net where you sleep.  For more detailed information on procedures and products to prevent mosquito and other insect bites, see our health information article or brochure Avoiding Insects.

Drugs against malaria

No anti-malaria drug is 100% effective and drug resistant strains of malaria are being reported throughout the world.  Selection of the most effective regimen depends on itinerary, whether drug resistant malaria is reported at destination areas, age, health, allergies, and other factors. One of the following options may be selected.

1. Chloroquine Phosphate  (Aralen®)

Adult dosage: 500 mg orally once/week for use in areas with chloroquine-sensitive Plasmodium falciparum malaria. Take weekly dose starting 1 week before entering a malaria area, each week while there, and for 4 weeks after leaving the area.

Notes on Chloroquine:

  • Drug interactions can occur with Kaopectate®, methotrexate, metronidazole (Flagyl®), Phenergan®, and cimetidine.
  • Chloroquine can be used with caution in persons who have psoriasis, porphyria, or liver dysfunction, but not in those with retinal degeneration.
  • Chloroquine can decrease the effectiveness of the rabies vaccine given by intra-dermal administration, if taken sooner than 1 week following the last vaccine dose.
  • Chloroquine is considered safe in pregnancy.

2. Hydroxychloroquine Sulfate (Plaquenil®)

Adult dosage: 400 mg (2x 200 mg) orally once/ week—an alternative to chloroquine.

Notes on Hydroxychloroquine:

  • Drug interactions can occur with digoxin and rifampin and possibly with the drugs listed above under Chloroquine.
  • Hydroxychlorquine can be used with caution in persons who have psoriasis, porphyria, or liver dysfunction, but not in those with retinal degeneration.
  • Hydroxychloroquine can decrease the effectiveness of rabies vaccine given by intra-dermal administration, if taken sooner than 1 week following the last dose.

3. Malarone® (Atovaquone/Proguanil)

This drug is recommended for travelers going to areas of chloroquine-resistant Plasmodium falciparum malaria.

Dosing: 1 tab daily. Dose 1 day before through 7 days after leaving area of malaria risk.

Adult dosage: 250mg/100mg

Pediatric dosage: 62.5mg/25mg

Notes on Malarone:

  • Common side effects include mild stomach upset, headache, nausea and mouth ulcerations
  • Serous/rare side effects are hair loss, rash
  • Take with food or milky drink at same time each day
  • Do not take with tetracycline, rifampin, or metoclopramide

4. Doxycycline

Used for patients with intolerance to other antimalarials.

Adult dosage: Take 1 (100mg) tablet daily with evening meal starting 2 days before entering malarious area, each day while in the area and daily for an additional 4 weeks after leaving. Missing even one day's pill can result in malaria.

Notes on Doxycycline:

  • Doxycycline is not to be used by pregnant women or children under 9 years of age.
  • Due to increased sensitivity to the sun, wear a   sunscreen with a high SPF that covers both UVA and UVB.
  • Other potential side effects: vaginal yeast infections; erosion of esophagus if taken immediately before reclining without adequate liquids.
  • Pepto-Bismol® interferes with doxycycline absorption.

Treatment

If you have any of the aforementioned symptoms during or up to 3 years after leaving a malarious area, seek medical counseling. If a fever develops within 3 months after possible exposure, immediately seek medical help. Malaria can be treated if caught early enough, but delay in appropriate therapy can have serious or fatal consequences.

 

Authored by: Hall Health Center Travel Clinic staff

Reviewed by: Hall Health Center Travel Clinic staff (AT), May 2014


What is dengue (deng-gay) fever?

Dengue fever and dengue hemorrhagic fever are viral illnesses transmitted by the bite/sting of a mosquito. The mosquito species that carries dengue virus is active, biting during daylight hours, with a peak of activity just after daybreak, and then again for several hours before dark. These insects are often present indoors, and are common in areas of human habitation, including urban and rural areas throughout the tropical areas of the world.

Symptoms

Symptoms of dengue fever include:

  • Relatively sudden onset of high fever
  • Severe frontal headache
  • Muscle and joint pains
  • Nausea and/or vomiting
  • Rash

On the third or fourth day of the fever, many people will develop a rash on the torso, which then spreads to the arms and legs.

Usually the illness is "self-limited" in travelers and relatively mild, meaning it runs its course over a week or two, though in rare circumstances it can cause severe symptoms.

Another name for this illness is "break-bone fever" due to the extreme bone pain that can accompany this disease.

Treatment

There is no specific treatment for classic dengue fever, and most people recover within 2 weeks. To help with recovery:

  • Get plenty of bed rest
  • Drink lots of fluids
  • Take acetaminophen to reduce fever (not aspirin nor non-steroidal anti-inflammatory products such as aspirin or ibuprofen)

Risk to travelers

International travelers to areas where Dengue Fever occurs are at risk, more so if there is current epidemic activity underway at the time of the trip. Dengue is becoming an increasing health concern worldwide due to spread of significant disease in 2005-2007 in areas of the world without previous recent Dengue Fever.

Luckily, cases of severe Dengue Hemorrhagic Fever are rare, since this typically afflicts only those persons who reside in areas where dengue exists and are subject to repeated infections. Your travel health care adviser will let you know if dengue is a risk for you on your planned travel abroad.

Prevention of dengue fever

Since there is no vaccine against dengue at this time, the best prevention is to avoid getting bitten by mosquitoes in the first place. Follow these tips to prevent being bitten by mosquitoes:

  • Stay in screened or air-conditioned environments as much as possible
  • Use DEET-containing insect repellent on your skin

Your travel health adviser will discuss use of DEET in preventing dengue and other mosquito-borne diseases including malaria during your Travel Clinic visit.

If you have dengue fever

  • Avoid mosquito bites while you have a fever. Don't let mosquitoes bite you. They can infect other members of your family with dengue after biting you.
  • Use mosquito barriers until the fever subsides, to prevent day-biting mosquitoes from biting a sick person, becoming infected, and then biting someone else.
  • Rest in a screened room or under a bed net.
  • Use insect repellents and spray insecticide indoors if there are mosquitoes.

Additional resources

 

Authored by: Hall Health Center Travel Clinic staff

Reviewed by: Hall Health Center Travel Clinic staff (AT), May 2014


mosquito.jpgBy avoiding insect bites during your travels to tropical and subtropical regions, you can prevent the following diseases:

  • Malaria
  • Dengue fever
  • Yellow fever
  • Japanese encephalitis
  • Lyme disease
  • Tick typhus
  • Chagas disease

Care should be taken to protect yourself and your family from most bugs you might encounter. 

Tips to avoid bites and stings

Be aware

  • Learn about the feeding and nesting habits of insects at your destination and take extra precautions and/or minimize activities accordingly. Ask your hosts about seasonal or local pests to be on the lookout for.

Use insect repellant

  • Use an appropriate insect repellent. DEET (N,N-diethylmetatoluamide) has a long and safe track record and is very effective at sufficient concentrations. Hall Health Pharmacy sells DEET insect repellant.
    • The Centers for Disease Control and Prevention (CDC) suggest DEET strengths of up to 30-50%. Concentrations up to 30% are  considered safe in children 2 months and older.  Concentrations greater than 50% do not provide better protection, but may have longer lasting protection. We do not recommend concentrations greater than 50%.  When you purchase insect repellant, check the label for strength information.
  • Repellents containing Picaridin at 7-20% concentrations are also available, and compared to the products above, may be as effective, but need more frequent application.

  • When applying both insect repellent and sunscreen, always apply the sunscreen liberally first, wait 10 to 15 minutes if possible, then apply insect repellent.

Dress for success

  • Wear protective clothing such as long sleeves and pants whenever practical.  Shirts should be tucked in.  Foot wear that provides maximum coverage is ideal, including socks, (sandals are not recommended).  Avoid jewelry and bright or dark-colored clothes; the best colors are light green, tan and khaki.
  • Use permethrin on your clothes and gear.
  • Do not walk barefoot.

Insect proof your surroundings

  • When at the beach or pool, lie on a chair or, at the very minimum, on a blanket or long towel.  Do not lay clothes on ground since perspiration or other scents may attract insects.  Shake them vigorously before putting them back on.
  • Sleep in well-screened areas, air-conditioned rooms, or use bed (mosquito) nets.
  • Clothing and bed nets can be impregnated with permethrin insecticide.
  • Avoid using fragrance-containing products such as perfumes, colognes, after-shaves, scented soaps, shaving creams, hair sprays, etc.  Use only unscented hygiene products.

Insect behavior and habits

Mosquitoes

  • Species that carry malaria and Japanese encephalitis bite from dusk till dawn.
  • Species that carry dengue fever, chikungunya fever, and yellow fever bite during daylight hours.
  • Mosquitoes are most active right around dawn and right around dusk, so extra care at those times is necessary.

Ticks

  • Burrow into your skin.
  • Are carried on animals, but picked up by humans from brush, grass, trees.
  • Check your skin at least once daily for presence of ticks if in high risk areas. Armpits and hairline are common places for ticks.
  • Remove ticks with a slow steady tug, pulling perpendicular to the skin at the site of attachment of the tick, using tweezers or a tick remover, if available.

Fleas

  • Especially present on and around animals and in sand and soil.

Product information: What to buy

The following products are used to avoid bites and stings of insects, and thereby reduce the risk of contracting the diseases they carry.   They can be purchased in many pharmacies and outdoor supply stores (e.g., REI), including at Hall Health Pharmacy.  Some specific products are listed for your information.

Repellents for use on the skin

NOTE: Please note that these repellents are to be used only on exposed skin and not under clothing.

DEET repellent – DEET (N, N-diethyl-m-toluamide) is the most effective repellent against mosquitoes, chiggers, ticks, fleas, and biting flies.  Controlled release formulations have longer lasting effectiveness. Avoid contact with eyes, mouth, and synthetic materials. Toxic only if swallowed.

We strongly recommend DEET-containing repellents over all others, based on its proven safety, effectiveness, and ease of use. Look for a minimum concentration of 20% and a maximum concentration of 50%.

Other repellents

Picaridin – available for many years in Europe at 21% concentration. Higher concentrations provide longer duration of protection.

  • Cutter Advanced® sprays containing 7% and 15% picaridin are available.
  • Sawyer Go Ready® spray contains 20% picaridin

Higher concentrations provide longer lasting protection.

Newer repellents

  • Cutter Lemon Eucalyptus® spray contains Oil of Lemon Eucalyptus (PMD), approved by the EPA and CDC as a "biopesticide repellent"
  • Sawyer makes a DEET-free repellent containing IR-3535, another biopesticide repellent approved by the EPA and CDC.

Insecticide for use on clothing and nets

Permethrin is a synthetic chemical analogue of pyrethrum, which is the natural substance found in chrysanthemums. It effectively repels and kills insects. Permethrin is available in various formulations, as a spray for clothing, or as a liquid for “soaking” clothing or bed nets.

See manufacturer’s recommendations for application. Generally, permethrin is effective for 6 washings on clothing. If clothing is ironed after application, permethrin can last up to 12 washings. Some manufacturers offer travel clothing that is already treated with permethrin.

Mosquito nets

Locally, REI sells mosquito nets. Various companies sell mosquito nets and netting on the web. Here is a sampling, in no particular order, and without endorsement.

Military surplus stores also may stock mosquito nets.

Bee stings

Talk to your travel consultant at Hall Health or your personal health care provider if you are allergic to bee stings. The products discussed above may not be effective against bee stings and you should be appropriately prepared to manage a bee sting reaction.

Additional resources

 

Authored by: Hall Health Center Travel Clinic staff

Reviewed by: Hall Health Center Travel Clinic staff (AT), May 2014


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