Humankind’s Greatest Killer

on 20.9.05 with 0 comments

  • Malaria is not only mankind’s biggest killer, it is one of the oldest recorded
  • Appeared in Hippocrates’ 5th century medical journals
  • In the mid-1600s, natives of Lima, Peru were already using the bark from a local tree to treat the disease - quinine
  • Plasmodium vivax, ovale, malariae, and falciparum are organisms capable of causing human malaria
  • At least 2.3 billion people are at risk for the disease worldwide
  • 300-500 million infected causing 120 million cases and at least 1.5-3 million deaths/year
  • 90% of those killed are in Africa; 70% are children under 5
  • Although there are differences seen between species, the life cycles are similar
  • Bite from female Anopheles mosquito leads to injection of the sporozoites
  • Sporozoites rapidly enter parenchymal cells of the liver
  • Numerous asexual progeny (merozoites) leave the liver cells and invade erythrocytes and use the hemoglobin for nutrients
  • Detoxify the heme group in special organelles
  • Multiply in liver cells
  • After entry into red blood cells, differentiate into male or female gametocytes
  • Sexual cycle begins in host but must continue in a female mosquito
  • ‘… Two of them could whip a dog, and … four of them could hold a man down.’
  • Mark Twain
  • On the mosquitoes of Louisiana, from “Life on the Mississippi”
  • Plasmodium falciparum infections are usually the most serious of the four because the sporozoan invades blood cells of all ages and parasitized blood cells produce projections that cause adherence to the lining of blood vessels
  • Symptoms are characteristic shaking chills, then burning fever and sweating
  • Toxin is involved
  • Treatment is with chloroquine
  • Can also be given prophylactically
  • Blocks detoxification of the heme group
  • No effective vaccines for prevention and resistance to chloroquine is widespread and growing
  • Between protozoan and helminthic infections worldwide, parasitic infection in association with malnutrition is the primary cause of morbidity and mortality
  • ~15 million, or one half, of the ~30 million children (<5>
  • ~15 million represents 1/4 of the total ~60 million adult and child deaths from all causes




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