Serious Illnesses Malaria and Dengue Fever

Serious Illnesses Malaria and Dengue Fever
Serious Illnesses |
Malaria and Dengue Fever
Health Manual

                 p. 2

                 Dengue Fever
                 p. 5

                 p. 7
Insect-borne diseases are spread by insects. Insects, such as mosquitoes, that
live and breed in water can cause diseases with rashes and flulike symptoms,
diarrhea, and even death. Malaria and dengue fever are two examples of insect-
borne diseases.


The best way to prevent malaria and dengue fever is to prevent mosquito bites.
The following methods prevent mosquito bites and, therefore, malaria and
dengue fever.

                                                    A mosquito net is a very good way to
                                                    protect people from getting malaria (but
                                                    not necessarily dengue fever). Malarial
                                                    mosquitoes usually bite from sunset to
                                                    sunrise. Although mosquito nets do not
                                                    kill mosquitoes, they can protect you
                                                    from being bitten when you are
                                                    underneath them.

Malaria is particularly dangerous for young children and pregnant women. It is
therefore very important that they use mosquito nets. Young children and
pregnant women should go to sleep early (under mosquito nets) to avoid
mosquito bites during the evening.

Mosquito nets will not prevent malaria unless they are used correctly:
»     Torn sections must be repaired.
»     Mosquito nets should be hung up properly to cover the sleeping area and
      should be low enough to allow netting to be tucked in under the mattress or
      mat where the person sleeps.
» Mosquitoes that are trapped inside the net should be killed with insecticide
      spray or by hand.
Mosquito nets provide much better protection if they are treated with a special
insecticide. This insecticide is not harmful to people if it is used correctly, but it
kills mosquitoes and keep them away from the house. Treated nets also kill
bedbugs and other insects. Insecticides are useful, but they are dangerous if
used incorrectly. You must receive special training before you can advise people
on how to treat nets with insecticides. Cover the baby’s cradle with
treated mosquito netting or a thin cloth.

A single mosquito net provides protection only for those sleeping under it, but
screening the house will protect the whole family. Screening is effective in
protecting against both malaria and dengue fever. Effective screening is possible
only in houses that are well constructed and maintained. Various materials
(usually metal or plastic) can be used for screening. Screens should be placed in
openings to the house (such as windows and doors). Frequent inspection is

    Malaria: A Manual for Community Health Workers, World Health Organization,

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necessary to detect damage to the screens and to make repairs promptly.
Another way of keeping out mosquitoes is to use curtains made from netting or
similar materials. These curtains must be treated regularly with a special
insecticide and they must be hung up in such a way that they cover all the
openings to the house.

                                               Repellents are chemicals that you apply to
                                               the skin to keep mosquitoes away; they
                                               general prevent mosquitoes from landing
                                               on your body. Repellents are generally
                                               sold in pharmacies and some other shops.

                                               Repellents are very useful early in the
                                               evening. They are usually active for five to
                                               eight hours, then they have to be applied
                                               again. Repellents are helpful in protecting
                                               against malaria and dengue fever.

                                                When mosquito coils burn, their smoke
                                                keeps mosquitoes away. If mosquitoes fly
                                                through the smoke, they may even be
                                                killed. The coils are not very expensive
                                                and (like the repellents) are especially
                                                useful early in the evening when people
                                                sit outdoors. Mosquito coils can help
                                                protect you from both malaria and dengue

                                                  In some cases, medicine can protect us
                                                  from getting malaria. Some medicines
                                                  can only be taken for a limited period of
                                                  time. Pregnant women and people with
                                                  HIV may want to take medicines to
                                                  prevent malaria. Talk to a doctor first to
                                                  decide which medicine is best for you.

Prevent Mosquito Breeding

The best way to prevent malaria and dengue fever is to prevent mosquitoes in
the first place. Mosquitoes breed in water that is not flowing. Clean up old tires,
cans, and barrels—anywhere water gathers. Keep water containers covered.
Stock ponds with mosquito-eating fish.


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Mosquitoes lay eggs in standing water. It takes about seven days for mosquito
eggs to hatch. By getting rid of standing water once a week, or by making water
move and flow, you will interrupt mosquito breeding, which in turn means that
they no longer spread diseases.

Mosquitoes may breed in the following:
»       Freshwater or brackish (slightly salty) water, especially if it is stagnant or
»       Open streams with very slow-flowing water along their banks
»       Pools of water left in a riverbed after the rains have ended or as a result of
        poor water management
»       Swamps, rice fields, and reservoirs
»       Small ponds, pools, borrow pits, canals, and ditches with stagnant water in
        and around villages
»       Animal hoofprints filled with water
»       Cisterns (water tanks) for storage of water
»       Anything that may collect water (plant pots, old car tires, etc.)

Remember: The mosquitoes that bite you usually breed within two kilometers
(one and a quarter miles) of where you live. Individuals and communities can
reduce mosquito breeding by doing the following:
»       Use sand to fill in pools, ponds, borrow pits, and hoofprints in and around the
»       Remove discarded containers that might collect water.
»       Cover cisterns (water tanks) with mosquito nets or lids.
»       Clear away vegetation and other matter from the banks of streams to speed
        up the flow of water.

Pools of water may be caused by leaking taps, spilled water around pipes and
wells, or poor drains. These pools can be eliminated by repairs or improvements
to the water supply or drainage system. Elimination of mosquito breeding in large
expanses of water (or in areas where small pools of water are abundant after the
rains) usually requires major engineering works. Whenever you have a problem,
ask your supervisor for advice; if he or she does not know the answer
immediately, specialists in malaria and environmental health can be contacted for
advice and help.


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Dengue Fever
Dengue fever (dengue or breakbone fever) is a leading cause of illness and
death in many tropical areas. It is transmitted by mosquitoes. There are different
kinds of dengue fever. Dengue hemorrhagic fever (DHF) is a more severe form
of dengue infection that can lead to death.

Dengue fever is caused by a virus spread by a
black mosquito with bands of white dots that
look like white stripes from a distance (see
figure to the right). Their legs are also striped.
This mosquito is sometimes called the “yellow
fever mosquito” because it can also carry
yellow fever. Dengue fever usually occurs
during the hot, rainy season. It is most
common in cities, in places where water
collects, and where there is poor drainage.

The first time a person gets dengue fever, she can usually recover with rest and
lots of liquids. But when a person gets it a second time, it can be much more
dangerous and may even cause death.


When a person first becomes sick, he or she gets a sudden high fever with chills,
severe body aches (dengue fever is sometimes called bone-break or breakbone
fever), a headache, and sore throat. The person feels very ill and weak. After
three to four days, the person usually feels better for a few hours to two days.
Then illness returns for one or two more days, often with a rash that begins on
the hands and feet. The rash spreads to the arms, legs, and body (but usually
not the face).

Babies, young children, older people, or people with weak immune systems
(such as people with HIV/AIDS) are especially at risk of contracting a more
severe form of dengue fever called hemorrhagic dengue. If not treated right
away, this form of dengue fever causes bleeding from the skin and can lead to

Generally, younger children and those with their first dengue infection have a
milder illness than older children and adults. Symptoms include:
»   Severe headaches
»   Severe pain behind the eyes
»   Fever
»   Rash
»   Mild bleeding from the nose or gums
» Joint, muscle, and bone pain
Just when you think you are getting better, the sickness returns for another day
or two.


There is no medication to cure dengue fever, but acetaminophen pain relievers—
do not use aspirin or ibuprofen—will make you feel better. You should also rest,
drink plenty of fluids, and see a health care provider. If vomiting and severe
abdominal pain develop, in the first 24 hours after the fever declines, you should
go immediately to a doctor or health clinic. If small dark spots appear (which
show there is bleeding into the skin), go to a hospital immediately.

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When a person is infected with dengue fever, recognizing it early and taking the
above steps right away can greatly lower the risk of developing severe disease.

Prevention and Control

The best way to protect yourself from dengue fever is to prevent mosquito bites.
The mosquito that spreads dengue fever breeds in clean, standing water. Unlike
the malarial mosquito, the dengue mosquito bites mostly during the day. For this
reason, bed nets have little effect except for small children or older people who
sleep during the day. Dengue mosquitoes usually stay in shady, dark places,
such as under tables or beds or in dark corners. To learn other ways to protect
yourself, see prevention (p. 2).

    “Dengue Frequently Asked Questions,” Centers for Disease Control and Prevention,

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Malaria is an infection of the blood that causes chills and high fever. It is spread
by mosquitoes. The mosquito sucks up the malarial parasites in the blood of an
infected person and injects them into the next person it bites. Malarial parasites
are so small that they can only be seen under a microscope. They feed on the
blood cells, multiply inside them, and destroy them. Then that person becomes
sick. People with HIV are twice as likely to catch malaria.

Malaria occurs more often during hot, rainy seasons. The mosquito that causes
malaria tends to bite at dusk or during the night. That is why it is so important to
sleep under an insecticide-treated bed net or use other prevention methods in
the evening.

Malaria is one of the most serious diseases to affect people in countries with
tropical and subtropical climates. It is particularly dangerous for young children
and for pregnant women and their unborn children, although others may be
seriously affected in some circumstances.

Malaria is a curable and preventable disease, but it still kills many people. The
main reasons for this are:
»      Some people do not come for treatment until they are very ill because: They
       do not realize they might have malaria (people often think they have a cold,
       influenza, or other common infection); they do not realize that malaria is very
       dangerous; or they live far away from health care facilities.
»      People living far from health services will often go to local medicine vendors
       (sellers) for advice, which is not always appropriate, or to buy medicines,
       which are not always effective.
»      Many people do not know what causes malaria or how it is spread, so they
       are not able to protect themselves from the disease.

Effects of Malaria

It is often difficult to tell whether a sickness is caused by malaria or some other
disease because the symptoms of malarial are similar to those of many other
diseases. Therefore, if the patient’s condition has not improved within two days
after the start of an adequate malaria treatment, he or she needs urgent care in
the nearest clinic or hospital.

Malaria is especially dangerous in pregnant women and, in particular, young
children (under five years old). If a pregnant woman or young child gets malaria,
severe illness may rapidly develop and may even result in death. Such patients
need special care in addition to standard malaria treatment.

In areas where malaria is very common, people may get the disease several
times during their lives. This gives them some resistance to the disease, and
their attacks of malaria often become less severe as they get older. However,
adults who come from areas where malaria is not common can become very ill
with malaria just like children.

  Malaria: A Manual for Community Health Workers, World Health Organization,

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How Malaria Spreads

Malaria can affect anyone who has been bitten by an infected mosquito. That
said, some people are more likely to get infected with malaria or will become
more ill than others. For example, people with HIV are twice as likely to catch
malaria. Small children may have more severe reactions to malaria. Because of
this, malaria is one of the leading causes of death in children under the age of
five. Children who are breast-fed, however, are less likely to get malaria. Also,
malaria can be very dangerous for pregnant women.

When a mosquito bites an infected person, a small amount of blood is taken in
which contains microscopic malarial parasites. About 1 week later, when the
mosquito takes its next blood meal, these parasites mix with the mosquito's
saliva and are injected into the person being bitten.

Because the malarial parasite is found in red blood cells of an infected person,
malaria can also be transmitted through blood transfusion, organ transplant, or
the shared use of needles or syringes contaminated with blood. Malaria may also
be transmitted from a mother to her unborn infant before or during delivery
("congenital" malaria).


The symptoms of malaria vary from very mild to very severe, depending on
several factors. For example, in areas where malaria is very common, adults with
the disease might have just a slight increase in body temperature. However,
pregnant women and, in particular, young children often have a severe illness
with many symptoms and signs, and they may even die.

The typical malarial attack has three stages.

»      Stage 1: The person will have chills and a headache that will last for 15
       minutes to one hour.
»      Stage 2: The chills will be followed by a fever of about 40°C or higher. The
       person will be weak or flushed (red skin), and may become delirious (not in
       his right mind). The fever may last several hours or even days.
»      Stage 3: Finally, the person will begin to sweat, and his temperature will go
       down. After an attack the person will feel weak but may feel OK.

If the person does not get treated, Stages 1, 2, and 3 will repeat usually every
two days. Usually malaria causes fevers every two or three days (depending on
the kind of malaria), but in the beginning it may cause fever daily. Also,
the fever pattern may not be regular or typical. For this reason anyone who
suffers from unexplained fevers should have his blood tested for malaria.

If someone has these symptoms, it is important to take him or her to a health
center immediately where a health worker can give the sufferer medicine to treat
malaria. Different medicines cure malaria in different regions. Be sure the patient
takes the entire course of medicine the health worker gives him or her.

Chronic malaria often causes anemia and the spleen to enlarge. For people
with HIV it can cause them to get sick faster.

    Where There Is no Doctor, Hesperian Health Guides.

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In young children, anemia and paleness can begin within a day or two. In
children with malaria affecting the brain (cerebral malaria), fits may be followed
by periods of unconsciousness. Also, the palms may become a blue-gray color,
and breathing may be rapid and deep. (Note: Children who have not been
breast-fed are more likely to get malaria.)

How to Recognize Malaria

You can recognize malaria by asking and looking:

1. Ask questions and listen to what the patient has to say. (If the patient is a
young child, listen to the parent or guardian.)

2. Examine the patient for features of malaria.

If the patient (or parent) does not mention fever, ask whether there has been a
fever at any time during the past two to three days. In some places, it is better to
ask whether the patient has felt hot or cold or whether the child’s body has felt
hot to touch.

Measure the temperature with a thermometer. If the temperature is more than
37°C, the patient has a fever. (If you do not have a thermometer with you, feel
the patient’s forehead with the back of your hand. If the forehead feels hot, the
patient probably has a fever.)

If the patient does not have a fever and has no history of fever during the past
two to three days, the patient does not have malaria. Patients who have had
fever during the last two to three days may have malaria.

The danger signs of malaria are:
»       Changes in behavior, such as convulsions; unconsciousness; sleepiness;
        confusion; and an inability to walk, sit, speak, or recognize relatives
»       Repeated vomiting, inability to retain oral medication, eat, or drink
»       Passage of small quantities of or of dark urine, not passing urine, severe
»       Unexplained heavy bleeding from nose, gums, or other sites
»       High fever (above 39°C)
»       Severe dehydration (loose skin and sunken eyes)
»       Anemia
»       Yellowed whites of the eyes

How to recognize the danger signs:
»       Is the patient unable to drink?
»       Has the patient had convulsions (fits)?
»       Has the patient vomited repeatedly?
»       How much urine has the patient passed? Very little? None at all? Is it dark?
»       Is the patient abnormally sleepy, difficult to wake, or confused?


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»       Does the patient have severe dehydration? (Look for sudden weight loss,
        loose skin, sunken eyes, and a dry mouth. Dehydration is always important
        to recognize—for more details, refer to the notes from your diarrhea course
        or your general course.)
»       Is the patient unable to stand or sit?

If the answer to any of these questions is yes, the patient has severe febrile
disease, probably severe malaria. The patient’s life is in danger. Urgent
treatment is needed at a clinic or hospital to save the patient’s life.


Malaria can be cured with prescription drugs. The type of drugs and length of
treatment depend on the type of malaria, where the person was infected, their
age, whether they are pregnant, and how sick they are at the start of treatment.

Patients having recovered from the first episode of illness may suffer several
additional attacks (“relapses”) after months or even years without symptoms.
Treatment to reduce the chance of such relapses is also available.

»       If you suspect malaria or have repeated fevers, go to a health center if
        possible for a blood test. In areas where an especially dangerous type of
        malaria called falciparum occurs, seek treatment immediately.
»       In areas where malaria is common, treat any unexplained high fever as
»       Take the malaria medicine known to work best in your area.
»       If you get better with the medicine you are given, but after several days the
        fevers start again, you may need another medicine. Get advice from the
        nearest health center.
»       If a person who possibly has malaria begins to have fits or other signs
        of meningitis (e.g. sore neck, high fever, and severe headache), he may
        have cerebral malaria. If possible, inject malaria medicine at once.


Malaria occurs more often during hot, rainy seasons. If everyone cooperates, it
can be controlled. The following measures can help prevent malaria.

Mosquitoes that Carry Malaria

There are many different kinds of mosquitoes, but only malarial mosquitoes can
pass on malarial parasites. All malarial mosquitoes have white and black spots
on their wings (but a mosquito with white and black spots is not necessarily a
malarial mosquito). Only female mosquitoes bite people. Male mosquitoes do not
suck up blood and cannot pass on malarial parasites. Female mosquitoes need
blood to produce eggs. The eggs are very small: you can hardly see them. They
are laid on stagnant or slow-flowing water. Usually the mosquitoes that bite you
are breeding in collections of water within two kilometers (about one and a
quarter miles) of the place where you live.


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Two or three days after the eggs are laid on the water, a mosquito larva will
come out of each egg. The larva feeds on very small animals and plants in the
water and grows until it becomes a pupa. The pupa remains in the water but
does not feed. After a few days the adult mosquito will come out of the pupa and
fly away. If it is a female mosquito, it may bite people and feed on their blood.
After feeding, the mosquito usually rests on a nearby surface before it flies away.
Then it will lay eggs, and everything starts all over again. In tropical countries it
takes 7 to 14 days for a mosquito to grow from an egg to an adult mosquito.

A mosquito egg, larva, or pupa does not contain malarial parasites naturally.
Adult mosquitoes may have malarial parasites in their bodies only if they have
bitten someone who has malaria.

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