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Staying a step ahead of travel-related illnesses

Knowing the causes, symptoms, and treatments for travel-related illnesses is the kind of information that you hope you won't have to use — but that you'll be very glad to have if a need for it arises. The most common travel-related illness — traveler's diarrhea — and the most serious threat to those traveling to tropical and subtropical regions — malaria. In addition, there is a brief synopsis of an array of other conditions that you may or may not be familiar with but that you could well encounter while you're traveling.Knowing the causes, symptoms, and treatments for travel-related illnesses is the kind of information that you hope you won't have to use — but that you'll be very glad to have if a need for it arises.

Below is detailed information on two conditions: the most common travel-related illness — traveler's diarrhea — and the most serious threat to those traveling to tropical and subtropical regions — malaria. In addition, there is a brief synopsis of an array of other conditions that you may or may not be familiar with but that you could well encounter while you're traveling.
Traveler's diarrhea (TD) is the most common complaint of travelers and can be encountered anywhere in the world. Any travel involves some risk of acquiring diarrhea, but the risk is much higher in certain areas. The U.S. Centers for Disease Control and Prevention (CDC) estimates that between 30 and 50 percent of travelers will develop TD during a one- to two-week stay in high-risk areas. The best defense is to develop safe eating and drinking habits when you're visiting such areas.

Prevention: Most cases of TD can be avoided by eating only food that is not just cooked but is steaming hot, that has a high acid content (like citrus fruits — oranges, grapefruits, etc.), that has a high sugar content (like jellies or syrups), or that is dry (like bread).

Any foods that are moist and warm or served at room temperature are potentially unsafe. This includes sauces, salads, and anything served buffet-style. Citrus fruits and any fruits that you peel are safe (assuming your hands and utensils are clean). Unpeelable fruits (like grapes, berries, etc.) are not safe. An unpeeled tomato is not safe, but a tomato that you peel is safe. Watermelons are sometimes injected with water to make them heavier, so they should be considered unsafe.

Untreated water is not safe, but bottled drinks, wine, and beer can be considered safe. Bottled water must have an intact seal at the time of purchase to be considered safe. Children sometimes refill water bottles at a town well and resell them as supposedly safe water.

Following these simple precautions will give you a better than even chance of avoiding diarrhea, even in high-risk areas. Antidiarrheal medication can slightly improve your chances, but the medication is not without its own risks; its side effects can include dizziness, constipation and nausea. Between 30 and 50 percent of travelers in high-risk areas who don't take preventive medication get diarrhea. But not taking the medication offers different benefits: It's more convenient, you avoid any side effects and it costs you nothing.

Bismuth subsalicylate (better known by the brand name Pepto-Bismol) has been shown to decrease the incidence of diarrhea significantly when taken prophylactically, as a preventive measure; the standard prophylactic regimen is 2 ounces of the liquid form four times a day, or two tablets four times a day, for no longer than three weeks. But do not ever give Pepto-Bismol to children under 12 years of age, or to those between 12 and 19 for chicken pox or flu, because of the possible risk of a condition known as Reye's syndrome. And you should avoid Pepto-Bismol if any of the following conditions pertain to you:
* You're allergic to or intolerant of aspirin.
* You're taking an anticoagulant (a blood thinner).
* You have renal insufficiency, gout, or are taking probenecid or methotrexate.
* You have any type of bleeding disorder.
* You have a history of peptic ulcer.
Treatment: While TD may cause you discomfort, it is not usually life-threatening, it is easily treated with over-the-counter medications, and it will go away (eventually) even without treatment. Most travel physicians do not advise taking antibiotics to prevent diarrhea, because serious reactions to the antibiotics are about as common as serious diarrhea. More importantly, the widespread use of antibiotics has led to significant resistance on the part of microorganisms, making treatment less effective for individuals who do fall ill.

The CDC advises that "prophylactic antimicrobial agents are not recommended for travelers" to prevent TD. However, once an individual has contracted TD, the CDC recommends some specific medications. Because bacterial causes of TD far outnumber other microbial causes, practical treatment with an antibiotic directed at intestinal bacterial pathogens remains the best therapy. The effectiveness of any particular antimicrobial depends on the specific microbe that's causing the ailment and on its antibiotic sensitivity. First-line antibiotics include ciprofloxacin and levofloxacin and other members of the fluoroquinolone family of drugs. However, increasing microbial resistance to fluoroquinolones may limit their usefulness in some destinations, such as Thailand and Nepal. In addition, the U.S. Food and Drug Administration recently issued a so-called black-box warning about these drugs, noting a significant risk of tendon rupture (in fact, several potentially associated Achilles ruptures have been reported to DAN). An alternative antibiotic is azithromycin. And rifaximin has been approved for the treatment of TD caused by noninvasive strains of E. coli.

The standard treatment regimen for TD is three days on an antibiotic. However, if treatment is initiated promptly, a shorter course, sometimes just a single-dose therapy, may reduce the duration of the illness to a few hours.

Pepto-Bismol is also useful in the treatment as well as the prevention of diarrhea, but less so than antibiotics. The dosage for treating TD is 1 ounce every 30 minutes, not to exceed 8 ounces in 24 hours or a total of eight doses. You should wait at least two hours after taking an antibiotic before taking Pepto-Bismol, since it will retard the absorption of the antibiotic. And note also the prohibitions above regarding Pepto-Bismol.

Self-treatment of TD, if it occurs, is possible with a little preparation. The following items are required:
* A thermometer
* An antidiarrheal medication, such as loperamide (Imodium) or diphenoxylate (Lomotil)
* Pepto-Bismol
* An antibiotic prescribed by a physician
Any sign of illness requires quick action. Immediately after a bloody or watery stool, take your temperature. If you have a fever — a temperature at or above 100°F (38°C) — or a bloody stool, take only the antibiotic. If you have no fever or bloody stool, take both Pepto-Bismol (1 ounce of the liquid form or two tablets every 30 minutes for a total of eight doses) and/or an antidiarrheal. If you have nausea, vomiting, and/or cramps, you may take an antibiotic along with Pepto-Bismol and an antidiarrheal. This will usually relieve symptoms in 12 to 15 hours. Avoid using antidiarrheal medication in children under 2 years of age.

Significant dehydration usually does not occur in adults; nevertheless, be sure to drink plenty of fluids. If you are having fewer than eight episodes of watery stool per day, continue with your regular diet, supplemented with clear broth, salted crackers, and 2 to 3 liters of clean water daily. Avoid dairy products and beverages that contain high levels of sugar, such as nondiet soft drinks.

Rehydration beverages containing electrolytes, such as Gatorade, are also appropriate in cases of TD. The best strategy is to take liberal quantities of an oral rehydration solutions (ORS). World Health Organization ORS solutions are widely available at stores and pharmacies in most developing countries and can even be purchased at open-air stores.

If your symptoms do not improve within 48 hours, you should seek medical attention because of the possibility of a parasitic infection. Treatments for TD do not eradicate parasites like Giardia intestinalis (which causes a condition known as giardiasis); antimicrobial drugs are needed to get rid of Giardia.Description: Appendicitis is an inflammatory condition of the appendix caused initially by blockage of the appendix by intestinal debris. This blockage leads to increased swelling and bacterial overgrowth, creating conditions of infection, inflammation and low blood flow to the appendix. These conditions increase the risk of appendiceal perforation, however spontaneous resolution has (rarely) been reported. It most commonly presents in patients between the ages of 10-40.

Symptoms/Diagnosis: The classical presentation of appendicitis is severe pain in the right lower quadrant of the patient's abdomen, at a point between the umbilicus and the anterior iliac prominence (known as McBurney's point). Pain may start at the umbilicus and localize after several hours to this point. Anorexia generally presents with appendicitis. Direct rebound tenderness at the right lower quadrant is often present. Fever and indirect rebound tenderness may also be present. In females pregnancy should always be ruled out.

Treatment: If appendicitis is suspected the patient should be evacuated to the nearest medical facility with surgical capability. In the interim, commonly available antibiotics with good Gram-negative bacteria coverage (ciprofloxacin, metronidazole, or doxycycline) should be used to reduce the incidence of infectious complications. Acetaminophen may be given for symptomatic relief. Intravenous access should be obtained and fluids administered via this route. With the exception of medications the patient should not consume anything by mouth.

Prevention: There is little that can be done to prevent the condition. Ignoring symptoms can lead to worsening of the condition especially if they are occurring when ashore.

Impact on Boating: Appendicitis is a surgical disease with a time sensitive treatment course. Delay can increase the risk of complications (perforation, abscess, sepsis). Any patient with a suspicion of having appendicitis should be evacuated immediately for medical workup and treatment. Time from symptom onset to evaluation at a medical treatment facility should not exceed 6 hours.

Reference: Schwartz's Manual of Surgery McGraw-Hill 2006Malaria has caused more deaths worldwide than any other infectious disease. It is the most serious infectious-disease threat for anyone traveling to the tropics. The disease is found primarily in subtropical and tropical regions of the world, where environmental conditions favor a stable, infected population of Anopheles mosquitoes. Malaria is prevalent in large areas of Central and South America, Mexico, Hispaniola, Haiti, the Dominican Republic, sub-Saharan Africa, the Middle East, the Indian subcontinent, southern and Southeast Asia, and Oceania. Major cities in Asia and South America are nearly malaria-free, though cities in Africa, India, and Pakistan are not. There is less risk of malaria at altitudes above 4,900 feet (1,500 meters).

The serious health risk represented by malaria cannot be overemphasized. Prophylaxis (preventive measures) are essential and include both the avoidance of mosquito bites and the administration of prophylactic drugs. The malaria parasite, a protozoan, is transmitted to humans by the bite of an infected female Anopheles mosquito, usually between dusk and dawn.

Prevention: Personal protection is the best way to prevent malaria and other insect-transmitted diseases. This means staying in well-screened areas when you're indoors, wearing clothes that cover most of your body when you're outdoors, and using mosquito nets when you're sleeping. You should also use insecticides and repellents on your clothing, tents and nets, as well as personal repellents containing at least 30 percent DEET (note, however, that concentrations above 30 percent do not add significantly to its protective effect or duration). Standard preparations last about four hours; longer-acting preparations are available. Picaridin is an effective alternative.

Travelers to malarious areas should also take prophylactic drugs, which must be obtained by prescription. Dosage recommendations may vary depending upon the drug susceptibilities of local malaria strains. Most of the drugs used for prophylaxis are safe and well tolerated. But as with any drug, some serious side effects and toxic reactions may occasionally occur. The severity of malaria, however, justifies temporary mild side effects.

There are a few considerations specific to divers. The prophylactic drug mefloquine (also known by the brand name Lariam) very occasionally causes side effects that mimic the symptoms of decompression sickness. Individuals taking mefloquine are prohibited from diving in some countries, in which case another drug can be substituted.

But if a diver traveling to an area with a high risk of malaria is unable to take any prophylactic antimalarial due to side effects, the trip should be canceled; the risk is too great that the diver may contract malaria and even die because of the lack of appropriate prophylaxis.

Treatment: Despite the most stringent preventive measures, it is still possible to contract malaria. The symptoms may not develop until long after your trip, so prophylaxis should be continued for four weeks following your return home. If you develop flu-like symptoms (any illness with chills, fever and headache) during a trip in a malarious area or within several months after your last exposure, seek medical attention immediately. It is important to mention your possible exposure to malaria when you do so. The appropriate treatment, usually an antimalaria drug, will depend on several factors, including the severity of your symptoms and the strain of the malaria parasite causing your disease.Amebiasis: This disease is caused by the protozoan Entamoeba histolytica. The most common symptom is diarrhea, which may become painful and bloody. The disease is transmitted by person-to-person contact through the fecal-oral route or by ingesting contaminated food or water. There is no vaccine, making safe food and water practices key to preventing the disease. Treatment should be obtained from a specialist in infectious diseases or tropical medicine.

Cholera: A bacterial disease, cholera is transmitted through food or drinking water contaminated with Vibrio cholerae. Modern sanitation practices have drastically reduced its incidence in most parts of the world. Cholera vaccination is still required by some countries, but it is not medically recommended, as travelers rarely develop cholera, even in endemic areas (there are only 2 cases for every 1 million travelers to endemic areas). The vaccine is no longer available in the U.S., but there are currently two manufacturers of oral cholera vaccines in other countries. Both variants require two doses and an interval of two to four weeks for immunity to develop. Furthermore, they offer incomplete protection and so should not replace standard protective measures: regular hand-washing, good sanitation practices, and safe food and water practices .

Giardiasis: This is a parasitic disease caused by Giardia intestinalis. Those who eat and drink in areas with poor sanitation are at increased risk. Symptoms occur one to two weeks after ingestion; they include, in various combinations, diarrhea, abdominal cramps, bloating, fatigue, weight loss, flatulence, anorexia and/or nausea; symptoms usually last more than five days. There is no vaccine or prophylaxis, making safe food and water practices key to preventing the disease. For treatment, consult a specialist in infectious diseases or tropical medicine.

Hepatitis A: "Hep A" is a highly contagious liver disease that's transmitted via contaminated food and water. It is a worldwide problem; the most luxurious resort in a major nation or the most humble dwelling in an impoverished nation can harbor the Hep A virus, though it is more prevalent in areas with poor sanitation. Routine vaccination against Hep A is recommended in the U.S. and other developed nations, typically in a two-dose series (a vaccine is also available for Hep B, but not for any of the other forms of hepatitis). As a result, indigenous populations in undeveloped countries are most likely to acquire Hep A; such infections generally occur early in life and then persist as a chronic condition with few clinical manifestations. However, if an adult traveler from a developed nation contracts the disease, serious complications can occur. As a result, the U.S. Centers of Disease Control and Prevention (CDC) suggests that travelers to areas with high rates of Hep A consider getting revaccinated. It takes from two to four weeks after the vaccine is administered before full immunity develops, so individuals traveling sooner should consider also getting a prophylactic (preventive) dose of immune globulin, but at a different injection site. A blood test that screens for antibodies to the hepatitis A virus is also available; a positive result can prevent unnecessary reimmunization or prophylaxis.

Hepatitis B: This form of hepatitis, also a viral liver disease, is transmitted by contact with infected blood or blood-derived fluids. An effective vaccine is also available for this form of hepatitis and is administered routinely in the U.S. and other developed nations, typically in a three-dose series. But the CDC suggests that travelers to areas with high rates of Hep B consider getting revaccinated — as well as those who might have close personal or sexual contact with an infected individual or who might receive a blood transfusion, share hypodermic needles (or anything else that breaks the skin, such as acupuncture needles), get a tattoo or piercing, or come in contact with unsterilized surgical or dental instruments in an area where the disease is endemic.

Hepatitis C: This form of hepatitis, also a viral liver disease, is, like Hep B, transmitted by contact with infected blood or blood-derived fluids. Symptoms are usually mild or nonexistent but no vaccine is available for Hep C. The risk to travelers is low in general — but those visiting areas where the disease is endemic are advised to avoid close personal or sexual contact with individuals who might be infected and to refrain from receiving blood transfusions, sharing hypodermic needles (or anything else that breaks the skin, such as acupuncture needles), getting a tattoo or piercing, or coming in contact with unsterilized surgical or dental instruments.

Hepatitis E: This form of hepatitis, also a viral liver disease, is transmitted by the fecal-oral route, mainly through contaminated drinking water but in some cases through undercooked meat. It can be distinguished from the other forms of hepatitis by a blood test. There is no vaccine. The best prevention is to follow safe food and water practices in endemic areas.

Japanese b encephalitis: This mosquito-borne disease is relatively rare and for the most part confined to certain areas of Southeast Asia. A vaccine against it is available in the United States but should be considered only for individuals who will be visiting high-risk areas for 30 days or longer.

Leishmaniasis: A parasitic disease, leishmaniasis is transmitted by the bite of phlebotomine sand flies. The skin form of the disease is characterized by open or closed sores that develop weeks to months after the bite. The visceral form of the disease, which affects the internal organs, is characterized by fever, enlargement of the liver and spleen, and anemia; these symptoms develop months to years after the bite. Individuals at greatest risk are those who engage in outdoor nighttime activities in endemic areas. High-risk areas are Bangladesh, Brazil, India and Nepal. Cases have also been reported from northern Argentina to southern Texas, northern Asia, the Middle East, and eastern and northern Africa. Preventive measures include wearing long-sleeved clothing, using insect repellents (preferably containing DEET) on the skin, using permethrin-containing insecticides on clothing, and avoiding outdoor activities at night, when sand flies are active. There is no vaccine; the disease requires treatment from a specialist in tropical diseases.

Leptospirosis: Though found worldwide, leptospirosis has a higher incidence in tropical climes. It affects humans as well as wild and domestic animals and is caused by a bacterium in the Leptospira genus. Animals excrete the bacterium in their urine and feces, contaminating the soil and water. Humans acquire the disease through contact with infected soil or water or with the body fluids of an infected animal. The symptoms of leptospirosis are similar to those of other tropical diseases and include fever, chills, myalgia (muscle pain), nausea, diarrhea, cough and conjunctival suffusion (redness of the membrane covering the eye). If untreated, it may result in kidney or liver failure or other serious complications. Travelers who engage in water sports in endemic areas are at increased risk, especially during periods of flooding. There is no vaccine. The CDC recommends that travelers planning to engage in water sports in tropical or subtropical area consider taking the antibiotic doxycycline (200 milligrams a week) as a prophylactic (preventive measure), beginning one to two days before the expected exposure.

Meningococcal meningitis: This inflammation of the membranes around the brain and spinal cord can be fatal. Caused by either a bacterium or a virus, it is spread via saliva and other oral secretions; it's rare in the U.S. but endemic in certain regions, especially sub-Saharan Africa. Symptoms include sudden high fever; a severe, persistent headache; a stiff neck; nausea or vomiting; sensitivity to light; drowsiness; joint pain; and confusion. A vaccine that confers some protection against several forms of meningococcal disease is recommended in the U.S. and other developed nations. The World Health Organization issues a weekly bulletin on the incidence of meningitis in endemic areas.

Rabies: Rabies is a viral disease transmitted by the bite of an infected animal — often a bat, raccoon, skunk, fox, or other wild animal. In humans, rabies is rare in the U.S. but prevalent in developing countries (where the disease is often transmitted by dogs, as well as wild animals). The virus infects the central nervous system, and untreated rabies is almost always fatal. However, infection can be prevented by administration of the rabies vaccine immediately after exposure to a rabid animal. The vaccine is not recommended for routine, pre-exposure administration but should be considered by anyone who may come into contact with possibly rabid animals or who is traveling in endemic areas, including Africa, Asia or Central and South America. And whether or not you have been vaccinated, you should seek medical advice immediately if you have contact with a possibly rabid animal.

Schistosomiasis: The Schistosoma parasite has a life cycle that relies on a freshwater snail. The disease is found in rural tropical and subtropical areas, including in the Middle East, Africa, eastern South America (especially Amazonia), and parts of the Caribbean (including Puerto Rico and St. Lucia). If you bathe in or drink fresh water that harbors an infected snail, you may encounter larvae that will penetrate your skin. Schistosomiasis can have serious consequences, including liver and bladder damage. Chlorinated water and salt water are usually safe for swimming. The risk of infection can also be reduced or eliminated by swimming and bathing in (or drinking) water that has been chemically treated; that has been allowed to stand for more than 48 hours; or that has been heated to 122°F (50°C) for more than five minutes (but be sure to let it cool before using it — water hotter than 113°F (45°C) may cause burns).

Smallpox: Smallpox, a sometimes fatal viral disease, was declared eradicated worldwide in 1980, following a concerted global vaccination effort. It is the only infectious disease ever eradicated by vaccines. As a result, vaccination is no longer required or available.

Tuberculosis: A bacterial disease, tuberculosis (TB) usually manifests itself in the lungs; if untreated, it can be fatal. M. Tuberculosis spreads through the air, usually as a result of an infected person coughing or sneezing. The disease's airborne transmission makes it a risk, especially in developing countries. A TB vaccine exists, but it confers variable immunity and is not generally recommended in the U.S. A tuberculin skin test known as the PPD, for purified protein derivative, can be used to determine an individual's tuberculosis infection status. A PPD may be required before a trip to certain regions, with a repeat test about 12 weeks following the trip if the first test was negative. If a negative pretrip test is followed by a positive post-trip test, prophylactic (preventive) treatment may be indicated. If a pretrip test is positive, reinfection is unlikely. An immunity impairment, such as HIV-positive status, can affect the results of the PPD test, however, so be sure to inform your physician of any such impairment.

Typhoid fever: Though rare in the U.S., this life-threatening bacterial illness is still endemic in many countries of the world, where it is predominantly a disease of school-age children and a major public health problem. Travelers are unlikely to contract typhoid fever, but anyone who will be exposed to potentially contaminated food or water in rural or undeveloped areas — especially in Africa, Asia or Latin America — should consider being vaccinated. There are currently three typhoid vaccines available, one oral and two parenteral (given by injection). However, they confer protection in only 50 to 80 percent of recipients, so travelers should still follow safe food and water practices . If you do come down with symptoms of typhoid, including sustained fever, stomach pain, headache, or loss of appetite, the disease can usually be treated with antibiotics.

Yellow fever: Yellow fever is a mosquito-borne viral illness that is potentially fatal; there is no known treatment other than rest and good hydration. A vaccine is available, however, and is advised for anyone visiting an endemic area, including parts of South America and Africa. Visiting some countries in the endemic zone requires a yellow fever vaccination certificate, also called a "yellow card." In addition, some countries outside the endemic zone require a yellow card from anyone traveling from that zone. Doing whatever you can to prevent mosquito bites is also important in the endemic zone. This means staying in well-screened areas when you're indoors, wearing clothes that cover most of your body when you're outdoors, and using mosquito nets when you're sleeping. You should also use insecticides and repellents on your clothing, tents and nets, as well as personal repellents containing at least 30 percent DEET (note that concentrations above 30 percent do not add significantly to its protective effect or duration). Standard preparations last about four hours; longer-acting preparations are available. Picaridin is an effective alternative.


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