Fig. 309 The malaria-carrying ?nosquito 

 (Anopheles) sucking blood. It ''stands on its 

 head''' when biting. The common viosquito 

 (Culex) holds its body parallel to the surface of 

 the skin, (science service) 



with rat guards, big metal plates, that 

 make it impossible for a rat to leave the 

 ship by way of the rope. 



The list of insect carriers is a large one. 

 To name but a few: the body louse car- 

 ries typhus germs; some mosquitoes 

 carry yellow fever germs; a species of 

 fly native in Africa (tsetse fly) carries 

 the germs of African sleeping sickness. 

 But the mosquito which transmits malaria 

 does the greatest damage. 



The importance of malaria. Malaria is 

 common in warm climates, especially in 

 swampy regions where mosquitoes breed. 

 In our southern states there are about 

 4,000,000 cases every year. Although 

 few of them result in death, the loss in 

 working time due to the disease is very 

 great. Malaria probably costs the coun- 

 try as much as 500 million dollars a year. 

 Worse than that, it brings misery to mil- 

 lions of persons. In the tropics malaria is 

 often fatal; it probably causes the death 

 of a million people yearly in India and 

 Pakistan alone. The medical department 

 of our army rated it as the most impor- 

 tant of all diseases during World War II. 

 In the early part of the war in the South 

 Pacific about one out of every ten men 

 became ill with malaria. But a well or- 



Stop the Spread of Disease 349 



ganized attack on the disease soon cut 

 down the number of cases to one per five 

 hundred men. Malaria leaves no immunity 

 and each patient becomes a carrier for 

 several years. 



An age-long mystery is solved. Malaria 

 means "bad air," and damp night air was 

 once considered especially "bad." The 

 reason for this is obvious, now that we 

 know that malaria is spread by the mos- 

 quito. Mosquitoes breed in stagnant or 

 slowly flowing water. They are numer- 

 ous where the ground is swampy and the 

 air is damp. Thirty known species of 

 mosquitoes can transmit malaria and 

 most of them live in the tropics or in the 

 South Temperate Zone. Many belong to 

 the genus Anopheles (an-of'el-ees). You 

 learned how to recognize this mosquito. 



The organism carried by the mosquito 

 and causing malaria is a protozoan. It 

 spends part of its life in the red cor- 

 puscles of man, the rest in the body of 

 the mosquito. Many men contributed 

 their share to the story of the cause and 

 transmission of malaria. In 1880 Alphonse 

 Laveran, a French army surgeon in Al- 

 geria, described the parasite which he 

 found in the blood of malaria patients. 

 Italian investigators saw the parasite too. 

 How it got there, no one knew, so this 

 discovery by itself was not of great im- 

 portance. 



About fifteen years later an English- 

 man, Dr. Patrick Manson, suggested that 

 mosquitoes might transmit the parasite 

 to man. He had shown that the mosquito 

 transmits another tropical disease, and it 

 had been known for centuries that ma- 

 laria occurs in regions where mosquitoes 

 breed. Acting on this suggestion, a Brit- 

 ish army surgeon in India, Dr. Ronald 



