What's The Doctor Says
By: ELIZABETH Polyclinic, Monivong Blvd., Phnom Penh. ( March, 2003 Volume 3 No.3 )

Travelers to Cambodia are often concerned about mosquito-borne diseases such as Malaria and the dreaded Dengue Hemorrhagic Fever. Here are some facts about the two illnesses.


Malaria is introduced from the bite of a malaria-infected mosquito. When a mosquito bites an infected person, it ingests microscopic malaria parasites found in that person's blood. The malaria parasites grow in the mosquito for about a week or more before infection is passed to another person. After about a week, the mosquito then bites another person and the parasites go from the mosquito into the next person's blood. The parasites then travel to the liver where they grow and multiply. During this period when the parasites remain in the liver, the person may not feel sick yet. The parasites leave the liver and enter the red blood cells; this may take from as little as 8 days to as many as several months. Once inside the red blood cells, the parasites grow and multiply.
The red blood cells then burst, freeing the parasites to attack other red blood cells at the same time releasing toxins into the blood, making the person feel sick. If a mosquito bites this person while the parasites are in his or her blood, it will ingest the tiny parasites. After a week or more, the mosquito can infect another person again.
For most people, symptoms begin 10 days to 4 weeks after infection although in some cases, a person may feel ill as early as 8 days or up to 1 year later. The symptoms of malaria include fever and flu-like illness, including shaking chills, headache, muscle aches, and tiredness. Nausea, vomiting, and diarrhea may also occur. Because of the loss of red blood cells, Malaria may cause anemia and jaundice (yellow coloring of the skin and eyes). One type of malaria, P. Falciparum, if not promptly treated, may cause kidney failure, seizures, mental confusion, coma, and even death. Two other types of malaria, the P. Vivax and P. Ovale, can relapse as some parasites can rest in the liver for several months up to 4 years after a person is bitten by an infected mosquito. When these parasites come out of hibernation and begin invading red blood cells, the person starts to become sick.
Any traveler who becomes ill with a fever or flu-like illness while traveling or even up to 1 year after returning home, should immediately seek professional medical care. Malaria is diagnosed by looking for the parasites in the blood. A drop of blood is stained onto a slide and placed under a microscope to spot the parasites. Malaria can be cured with prescription drugs. The type of drugs and length of treatment depend on which kind of malaria is diagnosed and where the patient was infected. The age of the patient and how severely ill the patient was at start of treatment are also important factors.

Dengue Hemorrhagic Fever

Dengue viruses are transmitted by mosquitoes which are most active during the day. These vector mosquitoes are found near human habitations and are often present indoors. Epidemic transmission is usually seasonal, during and shortly after the rainy season.
Dengue fever is characterized by sudden onset, high fever, severe headaches, joint and muscle pain, nausea/vomiting, and rash. The rash may appear 3-4 days after the onset of fever. Infection is diagnosed by a blood test that detects the presence of the virus or antibodies. The illness may last up to 10 days, but complete recovery can take 2-4 weeks. Dengue is commonly confused with other infectious illnesses such as influenza, measles, malaria, typhoid, leptospirosis, and scarlet fever. The symptoms of dengue can be treated with bed rest, fluids, and medications to reduce fever, such as acetaminophen.
Travelers should alert their physician of any fever illnesses occurring within 3 weeks after leaving an endemic area. There is no known vaccine for dengue fever; therefore, the traveler should avoid mosquito bites by wearing long sleeves and long pants. Travelers are advised to use mosquito repellents on skin and clothing and to bring an aerosol insecticide for use indoors if there are no bed-nets. The risk of dengue is generally higher in urban areas.

If you suffering any of the above symptoms, call 012 85 48 48 or go to Elizabeth Polyclinic at 364-366 Monivong Boulevard, Phnom Penh for immediate medical attention.