What is malaria?
Malaria is a serious and sometimes fatal
disease caused by a parasite. Patients with malaria typically are
very sick with high fevers, shaking chills, and flu-like illness.
Four kinds of malaria parasites can infect humans:
Plasmodium falciparum, P. vivax, P. ovale,
and
P. malariae.
Infection with any of the malaria species can
make a person feel very ill; infection with
P. falciparum,
if not promptly treated, may be fatal. Although malaria can be a
fatal disease, illness and death from malaria are largely
preventable.
Is malaria a common disease?
Yes. The World Health Organization estimates
that each year 300-500 million cases of malaria occur and more than
1 million people die of malaria. About 1,300 cases of malaria are
diagnosed in the United States each year. The vast majority of cases
in the United States are in travellers and immigrants returning from
malaria-risk areas, many from sub-Saharan Africa and the Indian
subcontinent.
Is malaria a serious disease?
Yes.
Malaria is a
leading cause of
death and disease
worldwide, especially in developing countries. Most deaths occur in
young children. For example, in
Africa, a child dies from malaria every 30 seconds. Because malaria
causes so much illness and death, the disease is a great drain on
many national economies. Since many countries with malaria are
already among the poorer nations, the disease maintains a vicious
cycle of disease and poverty.
Wasn’t malaria eradicated years ago?
No, not in
all parts of the world. Malaria has been eradicated from many
developed countries with temperate climates. However, the disease
remains a major health problem in many developing countries, in
tropical and subtropical parts of the world.
An
eradication
campaign
was started in the 1950s, but it failed globally because of problems
including the resistance of mosquitoes to insecticides used to kill
them, the resistance of malaria parasites to drugs used to treat
them, and administrative issues. In addition, the eradication
campaign never involved most of Africa, where malaria is the most
common.
Where does malaria occur?
Malaria typically is found in
warmer regions
of the world -- in tropical and subtropical countries. Higher
temperatures allow the
Anopheles
mosquito to thrive. Malaria parasites, which grow and develop inside
the mosquito, need warmth to complete their growth before they are
mature enough to be transmitted to humans.
Malaria occurs in over
100 countries and territories. More than 40% of the world’s
population is at risk. Large areas of Central and South America,
Hispaniola (the Caribbean island that is divided between Haiti and
the Dominican Republic), Africa, the Indian subcontinent, Southeast
Asia, the Middle East, and Oceania are considered malaria-risk
areas.
Yet malaria does not occur in all warm
climates. For example, economic development and public health
efforts have eliminated malaria from the southern United States,
southern Europe, Taiwan, Singapore, and all of the Caribbean islands
(except Hispaniola). Some Pacific islands have no malaria because
Anopheles
mosquitoes are not found there.
How People Get Malaria (Transmission)
How is malaria transmitted?
Usually, people get malaria by being bitten by
an infected female
Anopheles mosquito. Only
Anopheles
mosquitoes can transmit malaria and they must have been infected
through a previous blood meal taken on an infected person.
When a mosquito bites,
a small amount of blood is taken which contains the microscopic
malaria parasites. The parasite grows and matures in the mosquito’s
gut for a week or more, then travels to the mosquito’s salivary
glands. When the mosquito next takes a blood meal, these parasites
mix with the saliva and are injected into the bite.
Once in the blood, the
parasites travel to the liver and enter liver cells to grow and
multiply. During this "incubation period", the infected person has
no symptoms. After as few as 8 days or as long as several months,
the parasites leave the liver cells and enter red blood cells. Once
in the cells, they continue to grow and multiply. After they mature,
the infected red blood cells rupture, freeing the parasites to
attack and enter other red blood cells. Toxins released when the red
cells burst are what cause the typical fever, chills, and flu-like
malaria symptoms.
If a mosquito bites this infected
person and ingests certain types of malaria parasites
("gametocytes"), the
cycle of
transmission
continues.
Because the malaria
parasite is found in red blood cells, 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 fetus before or during
delivery ("congenital" malaria).
Malaria is not transmitted from person to
person like a cold or the flu. You cannot get malaria from casual
contact with malaria-infected people.
Who is at risk
Who is at risk for malaria?
Anyone can get malaria. Most cases occur in
residents of countries with malaria transmission and travellers to
those countries.
In non-endemic countries, cases
can occur in non-travellers as congenital malaria, introduced
malaria, or transfusion malaria (see above).
Who are the people most at risk of severe and fatal malaria?
Plasmodium falciparum
causes severe and life-threatening malaria; this parasite is very
common in many countries in Africa south of the Sahara. People who
are heavily exposed to the bites of mosquitoes infected with
P. falciparum
are most at risk of dying from malaria. People
who have little or no immunity to malaria, such as young children
and pregnant women; or travelers coming from areas with no malaria,
are more likely to become severely ill and die. Poor people living
in rural areas who lack knowledge, money, or access to health care
are more vulnerable to the disease. As a result of all these
factors, an estimated 90% of deaths due to malaria occur in Africa
south of the Sahara; most of these deaths occur in children under 5
years of age.
How can malaria be
prevented?
If I live in an area where malaria is a problem, how can I prevent
myself and my family from getting sick?
You and your family can
prevent malaria by
-
keeping
mosquitoes from biting you, especially at night
-
taking
antimalarial drugs to kill the parasites
-
eliminating
places around your home where mosquitoes breed
-
spraying
insecticides on your home’s walls to kill adult mosquitoes that
come inside
-
sleeping under
bed nets - especially effective if they have been treated with
insecticide, and
-
wearing insect
repellent and long-sleeved clothing if out of doors at night
Isn't there a malaria vaccine? And if not, why?
There is
currently no malaria vaccine approved for human use. The malaria
parasite is a complex organism with a complicated life cycle. Its
antigens are constantly changing and developing a vaccine against
these varying antigens is very difficult. In addition, scientists do
not yet totally understand the complex immune responses that protect
humans against malaria. However, many scientists all over the world
are working on developing an effective vaccine. Because other
methods of fighting malaria, including drugs, insecticides, and bed
nets, have not succeeded in eliminating the disease, the search for
a vaccine is considered to be one of the most important research
projects in public health.
I
am 4 months pregnant but want to visit a malaria-risk area for 2
weeks. Is it safe to do so?
NVBDCP
advises women who are pregnant or likely to become pregnant to avoid
travel to areas with malaria risk, if possible. Malaria in pregnant
women can be more severe than in nonpregnant women. Malaria can
increase the risk for adverse pregnancy outcomes, including
prematurity, miscarriage, and stillbirth. No preventive drugs are
completely effective. Please consider these risks (and other health
risks as well) and discuss with your health-care provider.
Which are the
malaria high-risk areas in our country?
No area in the
country can be said safe for malaria except place at altitude above
2000-2500 meters (due to unfavorable climatic conditions). The
states of Orissa, West Bengal, Jharkhand, Rajasthan, Madhya Pradesh,
Chhattishgarh, Andhra Pradesh, Maharastra, Gujarat & North Eastern
states (except Sikkim) are high risk States for malaria.
Symptoms and Diagnosis
What are the signs and symptoms of malaria?
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, Plasmodium
falciparum, if not promptly
treated, may cause kidney failure, seizures, mental confusion, coma,
and death.
How soon will a person feel sick after being bitten by an infected
mosquito?
For most people, symptoms begin 10 days to 4
weeks after infection, although a person may feel ill as early as 7
days or as late as 1 year later. Two kinds of malaria,
P. vivax
and
P. ovale,
can relapse. In P.
vivax and
P. ovale
infections, some parasites can remain dormant in the liver for
several months up to about 4 years after a person is bitten by an
infected mosquito. When these parasites come out of hibernation and
begin invading red blood cells (“relapse”), the person will become
sick.
How do I know if I have malaria?
Most people,
at the beginning of the disease, have fever, sweats, chills,
headaches, malaise, muscles aches, nausea and vomiting. Malaria can
very rapidly become a severe and life-threatening disease. The
surest way for you and your health-care provider to know whether you
have malaria is to have a diagnostic test where a drop of your blood
is examined under the microscope for the presence of malaria
parasites. If you are sick and there is any suspicion of malaria
(for example, if you have recently traveled in a malaria-risk area)
the test should be performed without delay.
Any traveler who becomes ill with a fever or flu-like illness while
traveling and up to 1 year after returning home should immediately
seek professional medical care. You should tell your health care
provider that you have been traveling in a malaria-risk area.
Treating Malaria
When should malaria be treated?
The disease
should be treated early in its course, before it becomes severe and
poses a risk to the patient's life. Several good antimalarial drugs
are available, and should be administered early on. The most
important step is to think about malaria, so that the disease is
diagnosed and treated in time.
What is the treatment for malaria?
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, whether the patient is
pregnant, and how severely ill the patient is at start of treatment.
If I get malaria, will I have it for the rest of my life?
No, not
necessarily. Malaria can be treated. If the right drugs are used,
people who have malaria can be cured and all the malaria parasites
can be eliminated. However, the disease can persist if it is left
untreated or if it is treated with the wrong drug. Some drugs are
ineffective because the parasite is resistant to them. Some patients
may be treated with the right drug, but at the wrong dose or for too
short a period of time.
Two types (species) of parasites,
Plasmodium vivax
and P. ovale,
have dormant liver stages that can remain silent for years. Left
untreated, these liver stages may reactivate and cause malaria
attacks ("relapses") after months or years without symptoms.
Patients diagnosed with
P. vivax
or P. ovale
are often given a second drug to help prevent these relapses.
Another type (species),
P. malariae,
if left untreated, has been known to persist in the blood of some
persons for several decades.
But in general, if you
are correctly treated for malaria, the parasites are eliminated and
you are no longer infected with malaria.
Malaria Drugs
How do I find out
what is the best drug to take against malaria?
Many
effective antimalarial drugs are available. Please contact your
family physician or nearest hospital/primary health centre or health
care workers.
Can children also take malaria pills?
Yes, but not all types of
malaria pills. Children of any age can get malaria and any child
traveling to a malaria-risk area should be on an antimalarial drug.
However, some antimalarial drugs are not suitable for children.
Doses are based on the child’s weight.
What is the
malaria situation in the country?
Click here to view
the
malaria situation in India.
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