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Introduction
Causes of Malaria
The Malaria Cycle
Sign and symptoms
Diagnosis of Malaria
Treatment of Malaria
Prevention and Control of Malaria
Recent outbreak of Malaria in cities
History of Malaria
World Mosquito Day
Dengue and Malaria
References
Introduction:
Malaria is a parasitic disease that involves high fevers, shaking
chills, flu-like symptoms, and anemia.
Malaria is caused by a parasite that is transmitted from one human to
another by the bite of infected Anopheles mosquitoes. Malaria can be easily treated If diagnosed promptly.
The World Health Organization estimates that in 2008, 190 - 311 million
clinical cases of malaria occurred, and 708,000 - 1,003,000 people died
of malaria, most of them children in Africa. 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.
Malaria is a major killer in many countries where resources for prevention, proper diagnosis and drug treatments are lacking.
Causes of Malaria
Malaria is caused by a parasite that is transmitted from one human to
another by the bite of infected "Anopheles" mosquitoes. A mosquito becomes infected when it takes a blood meal from an infected
human. Four kinds of malaria parasites have long been known to infect humans: Plasmodium falciparum, P. vivax, P.ovale, and P.
malariae.. Recently, it has been recognized that P.knowlesi, a type of malaria that naturally infects macaques in
Southeast Asia, also infects humans, causing malaria that is transmitted from animal to human.
P.falciparum is the type of malaria that likely to result in severe infections and if not promptly treated, may lead to death.
Usually, people get malaria by being bitten by an infective female
Anopheles mosquito .When a mosquito bites an infected person, a small amount of blood is
taken in which contains microscopic malaria 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.
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Malaria occurs where the
Anopheles mosquito breeds
Eggs of mosquito
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In humans, the parasites (called sporozoites) migrate to the liver where they mature
and release another form, the merozoites. These enter the bloodstream and infect the red blood cells.
The parasites multiply inside the red blood cells, which then rupture within 48 to 72 hours, infecting more red blood cells. The first
symptoms usually occur 10 days to 4 weeks after infection, though they can appear as early as 8 days or as long as a year later. Then the
symptoms occur in cycles of 48 to 72 hours.
The Malaria Cycle
The life cycle of malaria parasites in the human body.
A mosquito infects a person by taking a blood meal. First, sporozoites enter the
bloodstream, and migrate to the liver. They infect liver cells (hepatocytes), where they multiply into
merozoites, rupture the liver cells, and escape back into the bloodstream. Then, the merozoites infect red blood cells, where they develop into ring forms, trophozoites and
schizonts which in turn produce further merozoites. Sexual forms (gametocytes) are also produced, which, if taken up by a mosquito, will
infect the insect and continue the life cycle.
Sign and symptoms
The main symptom of malaria is a fever that occurs in regular episodes,
with sweating and shivers (known as rigors), and exhaustion.
The common symptoms are
* Chills - including shaking chills
* Fever and flu-like illness
* Sweating
* Headache
* Nausea
* Vomiting
* Muscle pain
* Anemia
* Stools, bloody
* Jaundice (yellow colouring of the skin and eyes)
* Convulsion
* Coma
For most people symptoms begin 10 days to 4 weeks after infection,
Diagnosis of Malaria
Although blood is the sample most frequently used to make a diagnosis,
both saliva and urine have been investigated as alternative. The most preferred, and reliable diagnosis of malaria is
microscopic examination of blood films because each of the four major parasite species has distinguishing characteristics.
Two sorts of blood film are traditionally used. For areas where microscopy is not
available there are commercial antigen detection tests that require only a drop of blood.
Molecular methods are available in some clinical laboratories and rapid
real-time assays based on the polymerase chain reaction (PCR) are being developed with the hope of being able to deploy them in
endemic areas. PCR (and other molecular methods) is more accurate than microscopy.
However, it requires a specialized laboratory.
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Treatment of Malaria
The treatment of malaria depends on the severity of the disease. Uncomplicated malaria is treated with oral drugs.
Severe malaria requires the parenteral administration of antimalarial drugs. The traditional treatment for
severe malaria has been quinine but artemisinins
was found also superior for the treatment of severe malaria.
Modern drugs used include mefloquine and the combination of atovaquone and proguanil hydrochloride
(Malarone). Doxycycline and the atovaquone and proguanil combination
are the best tolerated with mefloquine associated with higher rates of
neurological and psychiatric symptoms. The choice of which drug to use depends on which drugs the parasites in the area are resistant to, as well as side-effects and
other considerations. Before using any drugs first consult your doctor.
Prevention and Control of Malaria
To prevent the spread of Malaria, or to protect individuals
in areas where malaria is endemic, include prophylactic drugs, mosquito
eradication, and the prevention of mosquito bites. Mosquito nets help keep mosquitoes away from people and greatly reduce
the infection and transmission of malaria. The nets are often treated with an insecticide designed to kill
the mosquito before it has time to search for a way past the net. Insecticide-treated nets
(ITNs) are estimated to be twice as effective as untreated nets and offer greater than 70% protection compared with no
net.
Recognizing the disease in the early stages can also stop the disease
from becoming a killer. Education can also inform people to cover over areas of stagnant, still water e.g. Water Tanks which are ideal breeding
grounds for the parasite and mosquito, thus cutting down the risk of the transmission between people. This is most put in practice in urban areas
where there are large centers of population in a confined space and transmission would be most likely in these areas.
Vaccines for malaria are under development, with no completely effective vaccine yet available.
Indoor residual spraying (IRS) is the practice of spraying insecticides
on the interior walls of homes in malaria affected areas. The first pesticide used for IRS was DDT.
Although DDT has never been banned for use in malaria control and there
are several other insecticides suitable for IRS. The World Health Organization
(WHO) currently advises the use of 12 different insecticides in IRS operations.
The most important step
for you is to avoid being bitten by mosquitoes are-
* Using effective insect repellent
* Wearing long sleeves and full-length trousers
* Rooms with screen doors and closing windows and use of mosquito nets.
Recent outbreak of Malaria in cities
The big Metros Delhi, Mumbai, Kolkata etc. are most affected by the
outbreaks of Malaria in the rainy seasons. There is battling record levels of malaria infection in
Mumbai, .Since August 1, 2010 just over 3,800 people have tested positive -- mostly
for the non-lethal vivax strain -- and there have been 28 deaths, according to figures released Friday by the Brihanmumbai Municipal Corporation.
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History of Malaria
The term malaria originates from Medieval Italian "mala aria" — bad air ; the disease was formerly called
ague or marsh fever due to its association with swamps and
marshland. Malaria was once common in most of Europe and North America.
Malaria was the most important health hazard encountered by U.S. troops in the South Pacific during World War II , where about 500,000 men were infected. Sixty thousand American soldiers died of malaria during
the North African and South Pacific campaigns.
Scientific studies on malaria made their first significant advance in
1880, when a French army doctor working in the military hospital of Constantine in Algeria
named Charles Louis Alphonse Laveran observed parasites for the first time, inside the red blood cells of people suffering from malaria. He, therefore,
proposed that malaria is caused by this organism, the first time a protist was identified as causing
disease. For this and later discoveries, he was awarded the 1907 Nobel Prize for Physiology or Medicine
The malarial parasite was called Plasmodium by the Italian scientists Ettore Marchiafava and Angelo Celli.
A year later, Carlos Finlay , a Cuban doctor treating patients with yellow fever
in Havana , provided strong evidence that mosquitoes were transmitting disease to and from
humans. It was Britain's Sir Ronald Ross , working in the Presidency General Hospital
in Calcutta (Kolkata), who finally proved in 1898 that malaria is transmitted by mosquitoes.For this work, Ross received the 1902 Nobel Prize in
Medicine..
The first effective treatment for malaria came from the bark of cinchona
tree, which contains quinine. The first successful continuous malaria culture
was established in 1976 by William Trager and James B.Jensen research into the molecular biology of the parasite and the development of new drugs.
World Mosquito Day
World Mosquito Day observed always on August 20, 2010. On this day tribute
paid to the memory of Sir Ronald Ross, the Nobel laureate who made the epoch-making discovery of malarial transmission by the female anopheles
mosquito. He also proclaimed his mosquito theory which states that in order to
eradicate the disease, the vector must be eliminated. This theory was tested successfully in the Malong straits, the British
empire's key commercial outpost for rubber and tin. After it was implemented by Dr
Malcolm Watson, mortality rates among plantation workers and tin labour fell dramatically. In Cuba, Colonel W C Gorgus applied the Ross method
to solve the problem of malarial deaths in US barracks.
Dengue and Malaria
Malaria, Dengu
and Chikungunya a new threat are all caused by a parasite that is transmitted from one human to
another by the bite of infected mosquitoes.. |
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