Recent Aspect of Drug Used in Treatment of 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.

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Malaria is a leading cause of death and disease worldwide, especially in developing countries. Most deaths occur in young children. Since many countries with malaria are already among the poorer nations, the disease maintains a vicious cycle of disease and poverty. 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.

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 in 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. 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. 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. 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 doctor 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. The World Health Organization estimates that each year 300-500 million cases of malaria occur and more than 1 million people die of malaria.

Malaria is an infectious disease caused by a parasite, Plasmodium, which infects red blood cells. Malaria is characterized by cycles of chills, fever, pain and sweating. Historical records suggest malaria has infected humans since the beginning of mankind. The name "mal 'aria" (meaning "bad air" in Italian) was first used in English in 1740 by H. Walpole when describing the disease. The term was shortened to "malaria" in the 20th century. C. Laveran in 1880 was the first to identify the parasites in human blood. In 1889, R. Ross discovered that mosquitoes transmitted malaria. Of the four species of malaria, the most serious type is Plasmodium falciparum malaria. It can be life-threatening.

 The other three species of malaria (P. vivax, P. malariae, and P. ovale) are generally less serious and are not life-threatening. The life cycle of the parasite is complicated (for life cycle details, see and involves two hosts, humans and Anopheles mosquitoes. The disease is transmitted to humans when an infected Anopheles mosquito bites a person and injects the malaria parasites (sporozoites) into the blood. Sporozoites travel through the bloodstream to the liver, mature, and eventually infect the human red blood cells. While in red blood cells, the parasites again develop until a mosquito takes a blood meal from an infected human and ingests human red blood cells containing the parasites. Then the parasites reach the Anopheles mosquito's stomach and eventually invade the mosquito salivary glands. When an Anopheles mosquito bites a human, these sporozoites complete and repeat the complex Plasmodium life cycle. P. ovale and P. vivax can further complicate the cycle by producing dormant stages (hypnozoites) that may not develop for weeks to years.

Malaria is a particular problem and a major one in areas of Asia, Africa, and Central and South America. Unless precautions are taken, anyone living in or traveling to a country where malaria is present can get the disease. Malaria occurs in about 100 countries; approximately 40% of the world population is at risk for contracting malaria. To get information on countries that have current malaria infection problems, the CDC (Centers for Disease Control) has a constantly updated website that lists the problem areas in detail: Malaria is a particular problem and a major one in areas of Asia, Africa, and Central and South America. Unless precautions are taken, anyone living in or traveling to a country where malaria is present can get the disease. Malaria occurs in about 100 countries; approximately 40% of the world population is at risk for contracting malaria. To get information on countries that have current malaria infection problems, the CDC (Centers for Disease Control) has a constantly updated website that lists the problem areas in detail: The period between the mosquito bite and the onset of the malarial illness is usually one to three weeks (seven to 21 days). This initial time period is highly variable as reports suggest that the range of incubation periods may range from four days to one year. The usual incubation period may be increased when a person has taken an inadequate course of malaria prevention medications. Certain types of malaria (P. vivax and P. ovale) parasites can also take much longer, as long as eight to 10 months, to cause symptoms. These parasites remain dormant (inactive or hibernating) in the liver cells during this time. Unfortunately, some of these dormant parasites can remain even after a patient recovers from malaria, so the patient can get sick again. This situation is termed relapsing malaria.

Malaria may pose a serious threat to a pregnant woman and her pregnancy. Malaria infection in pregnant women may be more severe than in women who are not pregnant. Malaria may also increase the risk of problems with the pregnancy, including prematurity, abortion, and stillbirth. Statistics indicate that in sub-Saharan Africa, between 75,000-200,000 infants die from malaria per year; worldwide estimates indicate over 1 million children die from malaria each year. Therefore, all pregnant women who are living in or traveling to a malaria-risk area should consult a doctor and take prescription drugs (for example, sulfadoxine-pyrimethamine) to avoid contracting malaria. Treatment of malaria in the pregnant female is similar to the usual treatment described above; however, drugs such as primaquine (Primaquine), tetracycline (Achromycin, Sumycin), doxycycline, and halofantrine (Halfan) are not recommended as they may harm the fetus. In addition to monitoring the patient for anemia, an OB-GYN specialist is consulted for further management. All children, including young infants, living in or traveling to malaria-risk areas should take antimalarial drugs (for example, chloroquine and mefloquine [Lariam]). Although the recommendations for most antimalarial drugs are the same as for adults, it is crucial to use the correct dosage for the child. The dosage of drug depends on the age and weight of the child. Since an overdose of an antimalarial drug can be fatal, all antimalarial (and all other) drugs should be stored in childproof containers well out of the child's reach. If you are traveling to an area known to have malaria, find out which medications you need to take, and take them as prescribed. Current CDC recommendations suggest individuals begin taking antimalarial drugs about one to two weeks before traveling to a malaria infested area and for four weeks after leaving the area. Your doctor, travel clinic, or the health department can advise you as to what medicines to take to keep from getting malaria. Currently, there is no vaccine available for malaria, but researchers are trying to develop one. Malaria is a life-threatening parasitic disease transmitted by mosquitoes from person to person. When an infective mosquito bites, she transmits malaria parasites to her victim who falls ill. Other mosquitoes then pick up the parasite from the infected person and continue spreading the disease when biting other people.

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