Malaria updates and prevention Malaria updates and prevention Malaria affects 500 million people worldwide and
kills at least 2 million per year. Over one million
Africans die of Malaria yearly (mostly children).
30,000 Europeans and North Americans are affected.
Sometimes Malaria may be easy to recognize, but it
can also sometimes be difficult to diagnose. In
travelers, over 1300 cases are reported each year
with most of these having used no chemoprophylaxis.
It is important to stress to travelers the importance
of Malaria precautions if they are going to countries
where it is present.
Malaria Parasites
Malaria is caused by a parasite transmitted by
certain species of mosquitoes. Plasmodium falciparum,
vivax, oval, or malaria are the four different
species. The mosquito contracts the Malaria parasite
when biting an infected person; a gamocyte form
enters the mosquito and breeds internally creating
oocytes and then sporocites.
These then travel to the salivary glands of the
mosquito, which will be passed to people with the
next bite. These sporocites can penetrate the liver
of an infected human within 45 minutes. Within 9-16
days the sporocites differentiate into merozites,
which invade red blood cells and liver cells.
Blood cells will then rupture releasing gametocytes
and merozites, which cause the cycle of fevers and
chills in the human host.
Mosquitoes carrying Malaria Anopheles mosquitoes are
responsible for the transmission of Malaria.
Anopheles mosquitoes are sometimes identifiable by
the way they bite (head downward when biting), as
compared with Culex mosquitoes (stand parallel when
biting). Female mosquitoes of the Anopheles type bite
at night or twilight. Urbanization may create areas
where mosquitoes may breed close to people (stagnant
water).
Mosquitoes don't travel more than two miles from
where they are bred. Weird exceptions are airport
Malaria, acquired by passengers being bitten by
mosquitoes indoors during stopovers. Wind could also
blow mosquitoes further away. Only female mosquitoes
drain blood. Males survive off of nectars and fluids.
Symptoms
Sometimes Malaria may be easy to recognize, but it
can also sometimes be difficult to diagnose.
Symptoms of Malaria may be very subtle like flu like
attacks, fever and chills, which may lead to multi-
organ failure and death. It is important to note that
Malaria medication /will lessen symptoms of Malaria
but will not guarantee immunity. Malaria
/hemoprophylaxis helps prevent life threatening
Malaria that will kill people before they are able to
seek medical attention.
Any symptoms should be investigated with a thick and
thin malarial smear. This can still lead to
misdiagnosis, as a smear may not "catch" parasites on
microscopic analysis.
If Malaria is suspected, one normal smear does not
rule it out. It is generally assumed that any
returning traveler with fever has Malaria until
proven otherwise. Many other infectious diseases may
also manifest themselves with flu-like symptoms but
Malaria is the one diagnosis not to miss.
Many other mosquitoes co-exist with the Anopheles
mosquito-Aedes aegypti, Culex, Haemogogus, Sabethes,
and Masonia, which cause other diseases like Yellow
fever, Filariasis, viral Encephalitis, Dengue and
other hemorrhagic fevers. Other insects (Tse-Tse
flies, black flies, deerflies, sand flies, lice,
ticks and mites) cause a variety of illnesses many of
which have no known vaccine or medication to prevent
illness as well as no good treatment. General
recommendations are to avoid all insect bites
similarly as to malarial mosquitoes.
The A, B, C and D
approach to Prevention
of Malaria:
This new way of emphasizing the risk for travelers
simplifies the issues important for Malaria
prevention.
A is for Awareness. All travelers going to areas of
risk should be informed.
B is for Bite Avoidance, which involves behavior as
well as chemical and barrier methods.
C is for Compliance with Medication. It is not enough
to just prescribe the correct medication but also
stress the importance of taking the medication
correctly. Practitioners must be prepared to discuss
the pros and cons of different choices so that
clients will actually take the medication they
receive.
D is for (prompt) Diagnosis. Travelers returning from
a malarious area must be assessed correctly for the
possibility of Malaria
Assessing Risk Using the traveler's itinerary, which
includes geographic areas visited, types of
accommodation (resort, camping), duration of stay,
season (rainy, dry or recent human disasters), and
elevation will help practitioners make the decision
in what type of malarial medication to recommend.
Medications should be compatible with the patient's
medical conditions and other medications.
There are several malarial maps published by the CDC
(www.cdc.gov/travel/) and other organizations that
list malarious areas of the world. This information
is constantly being reassessed and updated.
Prevention of Bites
Malarial prevention is best accomplished by avoiding
being bitten. Wear long sleeved shirts and long
pants. Uses insect repellent, sleep under a mosquito
net, use mosquito coils, don't sleep on the ground,
and check for ticks and insect bites daily. Be
knowledgeable of the signs and symptoms of the
disease you may likely encounter where you are
traveling.
DEET works well as a skin protectant.
Permethroid insecticides on clothing and tents
dissuade biting insects. Chemoprophylaxis for the
Prevention of Malaria
Taking an antimalarial drug before, after, and during
exposure to malarious areas should be understood not
to completely protect the traveler from Malaria. The
purpose of antimalarial chemoprophylaxis is to
prevent life-threatening Malaria from killing or
dehabilitating a traveler. It is always implied that
fever in a traveler to a malarious area is Malaria
until proven otherwise and swift steps to accurately
diagnose and treat must be taken. Antimalarials buy
time and in many cases do prevent infections.
All malarial medications have some side effects as
well.
Types of medication to prevent malaria
(chemoprophylaxis) include:
Chloroquine (Aralen): This medication is cheap and
well tolerated but has a bitter taste. It can upset
the stomach and blur vision. There are many areas of
the world where the strains of Malaria are resistant
to Chloroquine.
The adult dose is 500mg once weekly of Chloroquine
phosphate. Previously, Chloroquine was dispensed as
either a salt or base but currently the Chloroquine
phosphate notation is easily understood. Chloroquine
comes as 250mg strength tablets so that travelers
must take 2 tablets once per week, on the same day.
Some suggest taking it on Monday using the pneumonic
"Malaria Mondays" to make it easier to remember to
take on the proper day.
For those having stomach upset, Chloroquine may also
be taken as 250mg twice weekly. The children's dose
is 8.3mg/kg once per week. Children may take
fractions of an adult tablet if this is convenient;
otherwise send the prescription to a Compounding
Pharmacist who will be able to dispense an irregular
dose with precision.
Medication is started one week prior to travel, and
is taken weekly during, and for four weeks after the
trip.
Chloroquine is very safe but it can aggravate
inactive psoriasis.
It is safe for pregnant women to take.
Chloroquine with proguanil was previously used for
pregnant women going to Chloroquine resistant areas,
but this regiment is no longer used.
Mefloquine (Larium): Mefloquine is moderately
expensive but it can be used in Chloroquine resistant
areas although there are now Mefloquine resistant
areas also.
An estimated 25-40% of people experience mild self
limited side effects including stomach upset, strange
dreams, mood changes, insomnia and headaches.
However, these side effects are generally well
tolerated so that the medication schedule is not
interrupted and is properly finished.
Approximately 5% of people have more significant
adverse effects including anxiety, depression,
nightmares, paranoia, and dizziness, which may cause
them to seek medical attention and discontinue the
drug.
Severe side effects occur in 1 in 10,000-13,000
people and may include seizures and psychosis.
If adverse effects will occur, they will normally
manifest themselves after 3 doses of Mefloquine. If a
person is unsure about how they would react to
Mefloquine they may be given a loading dose of
Mefloquine 250mg daily for 3 days. If they do not
experience any problems at this loading dose they
will be unlikely to have any future problems from
taking Mefloquine.
The normal Mefloquine dose for prevention is 250 mg
taken weekly, starting one week prior to departure,
during the trip and for four weeks after the trip.
Mefloquine is considered a category C drug for
pregnant women in their second and third trimesters
and a Category IIIB drug for the first trimester.
Mefloquine is the only drug available to pregnant
women traveling to Chloroquine resistant areas. It
should also be emphasized that Malaria is often more
severe in pregnant women.
Mefloquine in children
The adult dose is prorated according to weight (kg):
5-14 kg 1/8th adult tablet; 15-19 kg ¼ adult tablet;
20-30kg ½ adult tablet; 31-45kg ¾ adult tablet;
0.45kg one adult tablet weekly.
Children generally tolerate Mefloquine well having
less adverse effects than adults do.
Doxycycline : Doxycycline is effective against all
Malaria strains and is used in areas where Mefloquine
resistance exists.
The dose is one daily pill started 1-2 days before
exposure and continued during the trip and until 4
weeks post travel. Side effects include stomach
irritation and photosensitivity. Doxycycline is well
tolerated but can cause Candida yeast infections in
women. Those taking it are more prone to sun
photosensitivity. Rarely patients experience
esophageal ulcers.
It is recommended to take Doxycycline while in an
upright position with fluids and food and avoid lying
down right after taking the pill.
It is not used in children or pregnant women because
it can discolour developing teeth.
It may be used in children 9 years and older and the
dose is 2mg/kg each day.
Malarone (Atoraquine/ Proquinil) :
Malarone is new, but it
is expensive.
It has fewer side effects than other antimalarials
but can cause nausea and vomiting.
Patients also have reported the occurrence of mouth
ulcers from Malarone.
This drug may be started 2 days before the trip. It
is taken daily and then discontinued 7 days after the
trip. It is discontinued sooner because it is
effective at killing Malaria in the liver. So, there
is no need to take this medication as long as 4 weeks
as with Mefloquine, Chloroquine or Doxycycline.
Malarone is not approved for pregnant women.
Children's dosing is according to weight:
Children 1-20kg 1 Pediatric tablet; 21-30kg 2
pediatric tablets; 31-40kg 3 pediatric tablets; and
>40kg 4 pediatric tablets or one adult tablet.
Other treatments are possible and some are under
investigation.
Self treat Malaria
Self-treatment Malaria kits are available. Many
travelers like the idea of doing self-testing and
then consequently treating themselves. However, large
doses of Malaria drugs in a sick person are not
without side effects. Self-treatment is not
recommended. Instead preventative measures are best
with medication to prevent Malaria and to seek
immediate medical attention if ill.
90% of travelers with Malaria do not become ill until
after they return home. This illusion of good health
may foster urban myths among travelers that Malaria
is not a significant risk, which lead to laxity of
mosquito precautions.
Taking medications to prevent Malaria is not a
perfect solution but is still the overall best way to
prevent Malaria. All of the Malaria medications have
some type of side effects but the benefits they
confer of preventing Malaria far outweigh these
effects.
Information on Malaria
for Patients:
General: Malaria is an infection caused by a parasite
that is transmitted through the bite of an infected
mosquito. Malaria enters the body through the blood
stream. Once in the blood stream parasites travel to
the liver and destroy red blood cells. Other
complications include anemia caused by blood cell
destruction, and the clumping of blood cells which
may cause brain and kidney damage.
Signs & Symptoms
Headaches
Shakes and chills caused by fever
Fatigue
Rapid breathing
Nausea
Extremes sweating with a drop in temperature
Prevention
Prevention is best accomplished by avoiding being
bitten.
The best ways to do this are: wearing long sleeved
shirts and long pants; using insect repellent;
sleeping under a mosquito net; using mosquito coils;
not sleeping on the ground; and checking for ticks
and insect bites daily. Be knowledgeable of the signs
and symptoms of the diseases you may likely encounter
where you are traveling.
Use anti-malarial drugs
Use mosquito netting while in mosquito infested areas
Avoid crowded or unsanitary conditions
Wear long pants and long sleeved shirts.
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