Fever
- Fever in Thailand
A fever occurs when your temperature rises above
its normal range. What's normal for you may be a
little higher or lower than the average temperature
of 37 C. That's why it's hard to say just what a
fever is. But a "significant" fever is usually
defined as an oral or ear temperature of 38 C or a
rectal temperature of 39 C. If you're an adult, a
fever may be uncomfortable, but it usually isn't
dangerous unless it rises above 39 C. For very
young children and infants, however, even slightly
elevated temperatures may indicate a serious
infection. In newborns, a subnormal temperature -
rather than a fever - may be a sign of serious
illness.
COMPLICATIONS
Most people who develop dengue fever
recover completely within 2 weeks. Some, however, may go through several
weeks to months of feeling tired and/or depressed. Others develop severe
bleeding problems. This complication, dengue hemorrhagic fever, is a
very serious illness which can lead to shock (very low blood pressure)
and is sometimes fatal, especially in children and young adults.
Malaria is a serious
and sometimes fatal disease which is widespread in many tropical and
subtropical countries. It is caught by being bitten by an infected
mosquito that is carrying the malaria parasites in its saliva.
The malaria parasite is a microscopic organism called a
Plasmodium
and it belongs to the group of tiny organisms known as protozoans. There
are four types of plasmodium: P. falciparum (the most dangerous), P.
vivax, P. ovale and P. malariae. The species of mosquito that carries
the malaria parasites is the
Anopheles
mosquito.
These
parasites enter the host's
bloodstream when bitten by an infected mosquito and then migrate to the
liver where they multiply before returning back into the bloodstream to
invade the red blood cells. The parasites continue to multiply inside
the red cells until they burst releasing large numbers of free parasites
into the blood plasma causing the characteristic fever associated with
the disease. This phase of the disease occurs in cycles of approximately
48 hours.
The free parasites are then able to infect any mosquito that
feeds on the host's blood during this phase. The cycle then continues as
the parasites multiply inside the mosquito and eventually invade its
salivary glands. (see the plasmodium life cycle below).
Malaria occurs in
over 100 countries and more than 40% of the people in the world are at
risk. Large areas of Central and South America, Hispaniola (Haiti and
the Dominican Republic), Africa, the Middle East, the Indian
subcontinent, Southeast Asia, and Oceania are considered malaria-risk
areas.
Symptoms of malaria include
fever and flu-like illness, including shaking chills, headache, muscle
aches, and tiredness.
Nausea, vomiting, and diarrhea may also occur.
Malaria may cause anemia and jaundice (yellow coloring of the skin and
eyes) because of the loss of red blood cells. Infection with one type of
malaria, P. falciparum, if not promptly treated, may cause kidney
failure, seizures, mental confusion, coma, and death.
For most people, symptoms begin 10 days to 4 weeks after
infection, although a person may feel ill as early as 8 days or up to 1
year later. Two kinds of malaria, P. vivax and P. ovale, can relapse;
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
will become sick.
Any traveler who becomes ill with a fever or flu-like illness
while traveling and up to one year after returning home should
immediately seek professional medical care. You should tell your GP that
you have been traveling in a malaria-risk area.
Malaria can be cured with prescription drugs. The type of drugs
and length of treatment depend on which kind of malaria is diagnosed,
where the patient was infected, the age of the patient, and how severely
ill the patient was at start of treatment.
Anybody traveling to an area
where malaria is endemic is at risk of catching the disease. Lately
there has been an increase in the cases of malaria reported in the UK -
in 1993 there were 1922 reported cases in the UK, including five deaths.
All caught the disease abroad and almost all cases could have been
prevented.
Be aware
of the fact that adventure travelers are usually more exposed to malaria
than ordinary travelers due to the nature of their activities and the
fact that they travel to the more remote locations.
The Malaria
Cycle (Plasmodium life cycle)
Ruptured blood cells release free
parasites (gametocytes) into the
host's bloodstream.
The human host shows the classic malaria symptoms at this stage.
The gametocytes are sucked up by a feeding mosquito and the cycle begins
again.
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