Penyakit malaria
Malaria
is a life-threatening mosquito-borne blood disease caused by a Plasmodium
parasite.
It is transmitted to humans through the bite of the Anopheles mosquito.
Once
an infected mosquito bites a human, the parasites multiply in the host's liver
before infecting and destroying red blood cells.
In
some places, malaria can be treated and controlled with early diagnosis.
However, some countries lack the resources to do this effectively.
Currently,
no vaccine is licensed for use in the United States or globally, although one
is available in Europe.
Malaria
was eliminated from the U.S. in the early 1950s, but between 1,500 and 2,000 cases
still occur each year, mostly in those who have recently traveled to
malaria-endemic areas.
Fast facts on malaria:
Here are some key points about the malaria. More detail is in
the main article.
· Malaria
is typically spread by mosquitoes.
· Symptoms
resemble those of flu, but, without
treatment, the effects can sometimes be long-term and fatal.
· Travelers,
hikers, and campers can protect themselves with medication, pest control,
clothing, and nets.
·
What
is malaria?
Over 100 types
of Plasmodium parasite can infect a variety of species. They replicate at
different rates, and this affects how quickly the symptoms escalate, and the
severity of the disease.
Five types of
Plasmodium parasite can infect humans. They are found in different parts of the
world. Some cause a more severe type of malaria than others.
Symptoms
Malaria
symptoms can be classified into two categories: uncomplicated
and severe malaria.
Uncomplicated
malaria
This
is diagnosed when symptoms are present, but there are no signs to indicate
severe infection or dysfunction of the vital organs.
This
form can become severe malaria if left untreated, or if the host has poor or no
immunity.
Symptoms
of uncomplicated malaria typically last 6 to 10 hours and recur every second
day. Some strains of the parasite can have a longer cycle or cause mixed
symptoms.
As
symptoms resemble those of flu, they may be undiagnosed or misdiagnosed in
areas where malaria is less common.
In
uncomplicated malaria, symptoms progress as follows, through cold, hot, and
sweating stages:
·
a sensation of cold with shivering
·
seizures sometimes occur in younger people with the disease
·
sweats, followed by a return to normal temperature, with tiredness
In
areas where malaria is common, many patients recognize the symptoms as malaria
and treat themselves without visiting a doctor.
Severe
malaria
In
severe malaria, clinical or laboratory evidence shows signs of vital organ
dysfunction.
Symptoms
of severe malaria include:
·
fever and chills
·
impaired consciousness
·
prostration, or adopting a prone position
·
multiple convulsions
·
deep breathing and respiratory distress
·
abnormal bleeding and signs of anemia
·
clinical jaundice and evidence
of vital organ dysfunction
Severe
malaria can be fatal without treatment.
Causes
Malaria
happens when a bite from the female Anopheles mosquito
infects the body with Plasmodium. Only the Anopheles mosquito
can transmit malaria.
The
successful development of the parasite within the mosquito depends on several
factors, the most important being humidity and ambient temperatures.
When
an infected mosquito bites a human host, the parasite enters the bloodstream
and lays dormant within the liver.
The
host will have no symptoms for an average of 10.5 days, but the malaria parasite will begin
multiplying during this time.
The
new malaria parasites are then released back into the bloodstream, where they
infect red blood cells and multiply further. Some malaria parasites remain in
the liver and are not released until later, resulting in recurrence.
An
unaffected mosquito becomes infected once it feeds on an infected individual.
This restarts the cycle.
Diagnosis
Early
diagnosis is critical for a patient's recovery.
Anyone showing signs of malaria
should be tested immediately.
The
World Health Organization (WHO) strongly advise confirmation of the parasite
through microscopic laboratory testing or by a rapid diagnostic test (RDT),
depending on the facilities available.
No
combination of symptoms can reliably distinguish malaria from other causes, so
a parasitological test is vital for identifying and managing the disease.
In
some malaria-endemic areas, such as sub-Saharan Africa, the disease's severity
can cause mild immunity in a large proportion of the local population.
As
a result, some people carry the parasites in their bloodstream but do not fall
ill.
Treatment
Treatment
aims to eliminate the Plasmodium parasite from the patient's bloodstream.
Those
without symptoms may be treated for infection to reduce the risk of disease
transmission in the surrounding population.
Artemisinin-based
combination therapy (ACT) is recommended by the WHO to treat uncomplicated
malaria.
Artemisinin
is derived from the plant Artemisia annua, better
known as sweet wormwood. It is known for its ability to rapidly reduce the
concentration of Plasmodium parasites in the bloodstream.
ACT
is artemisinin combined with a partner drug. The role of artemisinin is to
reduce the number of parasites within the first 3 days of infection, while the
partner drugs eliminate the rest.
Expanding
access to ACT treatment worldwide has helped reduce the impact of malaria, but
the disease is becoming increasingly resistant to the effects of ACT.
In
places where malaria is resistant to ACT, treatment must contain an effective
partner drug.
The
WHO has warned that no alternatives to artemisinin are likely to become
available for several years.
Prevention
There
are several ways to keep malaria at bay.
Vaccination
Research
to develop safe and effective global vaccines for malaria is ongoing, with one vaccine already licensed for use in Europe.
No vaccine is yet licensed in the U.S.
It
is essential to seek medical attention for suspected symptoms of malaria as
early as possible.
Prevention:
Advice for travelers
While malaria is not endemic to the U.S., travel to many
countries around the world entails a risk.
Travelers
are advised to:
·
find out what the risk of malaria is in the country and city or
region they are visiting
·
ask their doctor what medications they should use to prevent
infection in that region
·
obtain antimalarial drugs before leaving home, to avoid the risk
of buying counterfeit drugs when away
·
consider the risk for individual travelers, including children,
older people, pregnant women, and the existing medical conditions of any
travelers
·
ensure they will have access to preventative tools, many of
which are available to purchase online. These include insect repellants, insecticides, pre-treated bed nets, and
appropriate clothing
·
be aware of the symptoms of malaria
In
emergency situations, local health authorities in some countries may carry out "fogging," or spraying areas
with pesticides similar to those used in household sprays.
The
WHO points out that these are not harmful for people, as the concentration of
pesticide is only strong enough to kills mosquitoes.
While
away, travelers should, where possible, avoid situations that increase the risk
of being bitten by mosquitoes. Precautions include taking an air-conditioned
room, not camping by stagnant water, and wearing clothes that cover the body at
times when mosquitoes are most likely to be around.
For
a year after returning home, the traveler may be susceptible to symptoms of
malaria. Donating blood may also not be possible for some time.
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