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Malaria FAQ
Rabies risk

FAQ About Malaria     


             This information only applies to Thailand and other Southeast Asian countries, since malaria in different parts of the world may have some specific characteristics.

What is malaria?

          Malaria is an infection caused by protozoa and can be fatal. Four kind of malaria parasites infect human: Plasmodium falciparunP. vivaxP.ovalae and P.malariae. Recently, malaria in monkey (P. knowlesi) has been reported in human also.

Is malaria a common disease? And is there any malaria in Thailand? 

         Yes, WHO estimates 300-500 million cases of malaria occur and more than 1 million die each year. Most case occur in Africa.
         In Thailand, only hilly or forested areas are endemic. There is no malaria transmission in urban areas. Most cases are from the borders especially Thai – Myanmar and Thai – Cambodia borders.
         There is no risk in municipal areas or major tourist resorts such as Bangkok, Chiangmai, Pattaya, Phuket and Samui.


How is malaria transmitted?

            Usually, people get malaria from infected female Anopheles mosquito bites. Only specific species of mosquito can transmit malaria. When the infected mosquito bites, it releases the infective stage (sporozoite) into the human bloodstream. It take some time for the parasite to develop and multiply. After that, the person will have the signs and symptoms of malaria

             Because the malaria is found in human blood, it can also be transmitted by blood transfusion, organ transplantation, sharing needles / syringes contaminated with infected blood.

             Malaria is not transmitted from person to person like a cold or flu. You cannot get malaria from casual contact with malaria-infected person.

What are the signs and symptoms of malaria? 

          The symptoms of malaria include fever, chills, headache, muscle pain, loss of appetite. Nausea, vomiting and diarrhea may also occur. Malaria may cause pallor and jaundice (yellow coloring of the eyes and skin). Infection with P. falciparum, if not promptly treated, may cause kidney failure, seizure, coma and leading to death.

How soon will a person feel sick after being bitten by an infected mosquito? 

          For most people, symptoms begin 7 days to 8 weeks after infection. Two kinds of malaria i.e. P.vivax and P.ovalae can remain dormant in the liver for several months up to 4 years.



How do I know if I have malaria?

         If you become ill with a fever with chill, headache, malaise, nausea and vomiting during or after traveling in malaria risk area, you should seek medical care. You should tell your healthcare provider that you have been traveling in the malaria risk area. The common diagnostic test is blood exam for malaria parasite.

What is the treatment of malaria? 

            Malaria is a treatable disease treatment should be done early. The type of drugs and length of treatment depend on which kind of malaria is diagnosed, how severe it is and other factors in each patient.
            The important point is that you should be treated by a qualified medical doctor. Over-the-counter drug is risky especially in the border areas, since most of them are fake.

How to protect yourself ? 

            If you are traveling into the malaria risk area, the best prevention method is to protect yourself against mosquito bite.    


Here are some useful tips: 

         - Always sleep under a bed net (preferably a permethrin - impregnated one )
         - Use mosquito repellents, ask for “ Yah tah gahn young “ (ยากันยุง ) which is Thai for “ mosquito repellent ”.
         - Repellents are available as chemical such as DEET, or natural products e.g. Tropmed herbal Repellent cream, which is DEET – free repellent.         


What is the recommended antimalarial prophylactic drug in Thailand? 

           Chemoprophylaxis is NOT recommended in Thailand. Where malaria is multi – drug resistant. No anti – malaria drugs can fully protect you against malaria. Moreover, you may have unpleasant side effect from the drug. Counseling with a qualified medical doctor is highly recommended .

Dengue Hemorrhagic Fever

        The causative agent of dengue hemorrhagic fever (DHF) is dengue virus, of which there are 4 serotypes. When a person is infected with dengue virus for the first time, clinical signs and symptoms are usually mild. However, if he/she is reinfected with a different type of dengue virus, severe conditions such as bleeding or shock will occur and can be fatal. This disease is usually found in children less than 15 years of age.

         Aedes aegypti is the main mosquito vector that transmits the dengue virus from person to person. When a female A. aegypti feeds on a dengue virus infected person, the viruses multiply in the insect body and remain there for the whole life span of the mosquito, approximately 1-2 months. Viruses are then transferred to another person being bitten by an infected mosquito. 
         A. aegypti can be found both inside and outside houses. They prefer to feed during the day. Their breeding places are containers with clear water, for example, jars, vases, ant traps, dishes, cans, pots, flower pots, tires, etc. The prevalence of DHF increases in the rainy season when the mosquito vectors are abundant and children often stay indoors during the day. However, in big cities such as Bangkok, this disease occurs sporadically all year round.
        Approximately 80-90% of persons infected with dengue virus for the first time are asymptomatic. Hign fever, headache, muscle and joint pain, and minute bleeding spots under skin may be found in some cases. A second infection with a different type of dengue virus, however, causes more severe conditions, which can be divided into 3 phases :
       1. Initial febrile phase- patients suffer continuous high fever, which may cause febrile convulsion in some children. Other symptoms are anorexia, nausea, vomiting and abdominal pain. Facial flush and hemorrhagic spots over the body, arms and legs are common. This phase usually lasts 2-7 days.
      2. State of shock- the fever has subsided at this stage; patients feel drowsy with profuse sweating, cold hands and feet, weak but rapid pulse rate, pain at the right coastal margin, reduced urine output, and easy bleeding such as nose-bleed, vomiting of blood and bloody stool. In severe cases, blood pressure drops drastically resulting in shock and can lead to death. This phase lasts 24-48 hours;
      3. Recovery phase- patients' conditions are improved as shown by good appetite, normal blood pressure, strong and slow pulse, and normal urine output. Bleeding spots under skin are still present over the body in some cases.
 denguehemorrhagic (3).jpg
            Standard criteria of the World Health Organization for the diagnosis of DHF are high fever, easy bleeding (positive tourniquet test, bruises, nose-bleed, gum bleeding, etc.), abdominal pain at the right costal margin because of the enlargement of the liver, shock, decreased platelets, and hemoconcentration. Serological and/or virological investigations may be performed to confirm the diagnosis
denguehemorrhagic (4).jpg 
             There is no specific antiviral treatment. Symptomatic and supportive measures are most important. To lower the temperature during the febrile phase, acetaminophen should be given. Aspirin must not be used since it is known to cause bleeding. An antiemetic can also be given to prevent nausea and vomiting. Juice or oral rehydration solution in small amounts given frequently are helpful. Close observation for early signs of shock is necessary. The critical period is at the transition from the febrile to the afebrile phase. Parents should be advised about the warning signs of shock, such as, reduced urination, restlessness or drowsiness, coldness of extremities, or fainting. If these symptoms occur, the patient should be hospitalized immediately.


The goal for the prevention and control of DHF is the control of mosquito vectors by several means, such as :

1.Preventing children/adults from being bitten by a mosquito vector; using a bed-net, even during the day, is advisable.

2.Eliminating breeding places of mosquito vectors inside and around houses


FAQ about Travelers'diarrhea    



What’s Travelers’ diarrhea?

        Travelers' diarrhea is the most common illness affecting travelers. Every countries is at risk for travelers' diarrhea. But most cases occur in developing countries of Latin America, Africa, the Middle East, and Asia. In Thailand, prevalence of travelers' diarrhea is much lower nowadays, due to better sanitary conditions.


What causes travelers’ diarrhea? 

         Germ in the unclean food or drink can cause travelers' diarrhea.The most common causative agent is enterotoxigenic Escherichia coli (ETEC). Other pathogens can cause travelers' diarrhea such as campylobacter, salmonella, shigella, vibrio spp., and many kinds of intestinal parasites.

What are the common symptoms of traveler’s diarrhea?

            The onset of travelers' diarrhea usually occurs within the first week of travel, but it may occur at any time while traveling. It also can occur shortly after you get home.
            Diarrhea usually occurs abruptly. The illness results in increasing frequency and amount of loose or watery stool. It usually causes 5-10 bowel movements each day. Other common symptoms are abdominal pain, nausea, vomiting, bloating, and fever.

What is the natural course of disease?

          Even without treatment, travelers' diarrhea usually subsides with in 2-5 days. Most cases are mind. Some cases may having dehydration, fatique, and high grade fever, mayrequired hospitalization.

What is the treatment of travelers’ diarrhea? 

           Whenever possible, you should have your stool checked to find the causative pathogen. Most travelers' diarrhea is treated with appropriate antibiotics and supportive treatment. Oral rehydration is recommended to replace the lost fluid and electrolytes. Hospitalized cases usually require intravenous fluid rehydration.


What about the antimotility drug?

          Antimotility agents (e.g. loperamide) can reduce diarrhea by slowing the bowel movement. Since diarrhea is the body’s defense mechanism to get rid of the pathogen from the gastrointertinal tract, therefore antimotility agents may reduce the clearance of the pathogen and lead to systemic toxicity in the patient. However, these agents may be useful in reducing diarrhea while traveling.

         Never use these drug in the patients with fever or mucous-bloody stool. Medical consultation is needed.


Is there any drug can be used to prevent travelers’ diarrhea?

         Taking antibiotics to prevent diarrhea is not recommended. Routine antimicrobial prophylaxis increases the risk for adverse reactions to the travelers and may increase resistance to the organism.


Where can I seek for medical care if I have diarrhea? 

         All hospital in Thailand can take care travelers' diarrhea. Most patients can be treated as outpatients but some patients may need hospitalization. In our clinic, all patients will be requested to collect their stool to check for the pathogen. You may collect your stool before attending our clinic. Use small plastic container collecting device.         


How can I prevent travelers' diarrhea? 

         Travelers' diarrhea is caused by a pathogen in unclean food or drink. Here are some useful tips.

        - Avoid eating food or drinking beverage from uncertain origin.

        - Avoid eating raw or undercooked meat and seafood.

        - Avoid unpasteurized dairy products.

        - Don't drink tap water.

        - Bottled water is probably safe, but be sure the cap and seal are not broken.

        - Bottled carbonated beverages and canned drinks are normally safe.         

Rabies vaccine in Southeast Asia. Is it necessary? 

Well, it depends…..before we will answer the above question. Let’s begin with some practical knowledge of rabies:

1. Rabies is a zoonotic disease (animal borne); you may get rabies when you are bitten/licked by infected animals.

2. It is a fatal disease with no effective treatment available. Once a patient develops symptoms; he/she will eventually die. So it is an untreatable disease.

3. In Thailand and Southeast Asia, dogs and cats are the most important vector for rabies. Unfortunately, there are many stray dogs in many parts of Southeast Asia. 

4. Not all stray dogs are rabid. According to the survey in 2004, only 0.03% of stray dogs in Bangkok carry rabies virus. In general, rabid animals will have some bizzare behaviours (may looked crazy or dump). Unfortunately even normal-looking animal may carry rabies virus also.

5. Whenever you are bitten or licked, please clean the wound with soap and water as much as possible. Good cleansing clearly reduce the chance to get infection. After that, you should seek for medical care immediately. The doctor will give a post-exposure vaccination/treatment.6. If someone never get any vaccination against rabies and are bitten. He/She must have the post-exposure treatment immediately. The treatment include Immunoglobulin and a series of rabies vaccine (5 shots). But if someone have already complete pre-exposure vaccine (3 shots). He/She will require only 2 doses of vaccine (Day 0 and Day 3). Immunoglobulin is not necessary.7. The major factor that we have to consider is the availability of medical care in the destination. Let’s imagine, if you never get pre-exposure vaccine, and you are bitten. You have to find the medical service that equipped with vaccine and immunoglobulin. Unfortunately, immunoglobulin is available in the major cities in Southeast Asia only. So in some cases, they may have to interrupt their trip and fly to Bangkok to get the treatment.8. The advantages of getting rabies vaccine before travel included you will have some protection which could give you some peace of mind, and you are not required to get immunoglobulin when you are bitten. However, you still need to get 2 shot of rabies vaccine.

Let’s go back to the question. Is it necessary to get rabies vaccine before travel in Southeast Asia? As in any vaccine; we have to consider the risk of getting the diseases and the cost/side-effect of vaccine. Benefit of vaccines should clearly outweight the cost and side-effect of vaccine. In that case we’ll recommend the vaccine.

So we’ll come to the most important question. We, all, know that we might get rabies only when we are bitten/licked by animal. So what it the chance for someone to get bitten/licked during travel. Difficult to say? Yes, that’s right. Risk for any individual is not equal. But according to previous researches we have some information;

  • In 1994; a survey in general traveler in Thailand found that the risk of being bitten and being licked were 1.3% and 8.9% respectively, in an average stay of 17 days.
  • Our recent survey (2009) in Khao San Road, we found that 0.7% of backpackers were bitten and 3.6% of backpackers were licked during their trip (average duration of travel = 30 days).

So, are the risk of being bitten high or low in your point of view? Some may say it is high so I would like to get vaccine; while some may say it is low risk for me to be bitten so I will not get the vaccine. By the way, many factors should also be considered such as duration of travel, exact destination, availability of medical care in the destination, traveler’s preference, activity during travel, budget, etc. So it is recommended to have a formal consultation/discussion with your travel doctor in this issue.

For us, we usually consider pre-exposure rabies vaccine in travelers who 
       – will travel in a rural or remote area where standard medical care is not available
       - have high risk activities including cycling, backpacking etc
       - have longer duration of stay (more than 2 wks)

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