13-04-2012, 11:30 AM
Malaria
48864-MALARIA.pdf (Size: 480.35 KB / Downloads: 36)
WHAT is Malaria?
Malaria is a disease caused by a parasite* that lives part of its life in humans and part in mosquitoes. worldwide, threatening the lives of more than one-third of the world’s It remains one of the major killers of humans
population. Malaria thrives in the tropical areas of Asia, Africa, and South and Central America, where it strikes millions of people. Sadly, as many as 2.7 million of its victims, mostly infants and children, die yearly.
Although malaria has been virtually eradicated in the United States and other regions with temperate climates, it continues to affect hundreds of people in this country every year. In 2000, health care workers reported 1,400 cases of malaria to the U.S. Centers for Disease Control and Prevention (CDC). Malaria in the United States is typically acquired during trips to malaria-endemic areas of the world and therefore is often called travelers’ malaria.
HISTORY of Malaria
Malaria has been around since ancient times. The early Egyptians wrote about it on papyrus, and the famous Greek physician Hippocrates described it in detail. It devastated the invaders of the Roman Empire. In ancient Rome, as in other temperate climates, malaria lurked in marshes and swamps. People blamed the unhealthiness in these areas on rot and decay that wafted out on the foul air, or, as the Italians were to say, “mal aria” or bad air. In 1880, scientists discovered the real cause of malaria, the one-celled Plasmodium parasite, and 18 years later, they attributed the transmission of malaria to the Anopheles mosquito.
LIFE Cycle
The human malaria parasite has a complex life cycle that requires both a human host and an insect host. In Anopheles mosquitoes, Plasmodium reproduces sexually (by merging the parasite’s sex cells). In people, the parasite reproduces asexually (by cell division), first in liver cells and then, repeatedly, in red blood cells. When an infected female Anopheles mosquito bites a human, she takes in blood. At the same time, she injects saliva that contains the infectious form of the parasite, the sporozoite, into a person’s bloodstream.
SPREAD of Malar ia
Many biological and environmental factors shape the character of malaria in a given location. Nearly all the people who live in endemic areas are exposed to infection repeatedly. Those who survive malaria in childhood gradually build up some immunity. They may carry the infection, serving as reservoirs for transmission by mosquitoes without developing severe disease. In other areas, where the infection rate is low, people do not develop immunity because they rarely are exposed to the disease. This makes them more susceptible to the ravages of an epidemic.
Drug Research
New drugs to treat malaria, particularly those infections caused by forms of Plasmodium that are resistant to current medications, are greatly needed. Because the parasite has a complex life cycle, researchers are seeking to understand the molecular biology of the parasite and how it interacts with its human host at each stage in that cycle. Using that information, scientists hope to develop new drugs that block different molecular processes required for parasite survival.
Mosquito Research
Research on mosquito genetics, physiology, and ecology may lead to new ways to treat, prevent, or control malaria. NIAID funds many research projects at institutions in the United States and abroad aimed at developing a comprehensive understanding of the insect’s biology.
48864-MALARIA.pdf (Size: 480.35 KB / Downloads: 36)
WHAT is Malaria?
Malaria is a disease caused by a parasite* that lives part of its life in humans and part in mosquitoes. worldwide, threatening the lives of more than one-third of the world’s It remains one of the major killers of humans
population. Malaria thrives in the tropical areas of Asia, Africa, and South and Central America, where it strikes millions of people. Sadly, as many as 2.7 million of its victims, mostly infants and children, die yearly.
Although malaria has been virtually eradicated in the United States and other regions with temperate climates, it continues to affect hundreds of people in this country every year. In 2000, health care workers reported 1,400 cases of malaria to the U.S. Centers for Disease Control and Prevention (CDC). Malaria in the United States is typically acquired during trips to malaria-endemic areas of the world and therefore is often called travelers’ malaria.
HISTORY of Malaria
Malaria has been around since ancient times. The early Egyptians wrote about it on papyrus, and the famous Greek physician Hippocrates described it in detail. It devastated the invaders of the Roman Empire. In ancient Rome, as in other temperate climates, malaria lurked in marshes and swamps. People blamed the unhealthiness in these areas on rot and decay that wafted out on the foul air, or, as the Italians were to say, “mal aria” or bad air. In 1880, scientists discovered the real cause of malaria, the one-celled Plasmodium parasite, and 18 years later, they attributed the transmission of malaria to the Anopheles mosquito.
LIFE Cycle
The human malaria parasite has a complex life cycle that requires both a human host and an insect host. In Anopheles mosquitoes, Plasmodium reproduces sexually (by merging the parasite’s sex cells). In people, the parasite reproduces asexually (by cell division), first in liver cells and then, repeatedly, in red blood cells. When an infected female Anopheles mosquito bites a human, she takes in blood. At the same time, she injects saliva that contains the infectious form of the parasite, the sporozoite, into a person’s bloodstream.
SPREAD of Malar ia
Many biological and environmental factors shape the character of malaria in a given location. Nearly all the people who live in endemic areas are exposed to infection repeatedly. Those who survive malaria in childhood gradually build up some immunity. They may carry the infection, serving as reservoirs for transmission by mosquitoes without developing severe disease. In other areas, where the infection rate is low, people do not develop immunity because they rarely are exposed to the disease. This makes them more susceptible to the ravages of an epidemic.
Drug Research
New drugs to treat malaria, particularly those infections caused by forms of Plasmodium that are resistant to current medications, are greatly needed. Because the parasite has a complex life cycle, researchers are seeking to understand the molecular biology of the parasite and how it interacts with its human host at each stage in that cycle. Using that information, scientists hope to develop new drugs that block different molecular processes required for parasite survival.
Mosquito Research
Research on mosquito genetics, physiology, and ecology may lead to new ways to treat, prevent, or control malaria. NIAID funds many research projects at institutions in the United States and abroad aimed at developing a comprehensive understanding of the insect’s biology.