Insects and Human Health 533 



of the Stegomyia mosquito, the sole agency of transfer of the 

 yellow fever parasite (see pages 542-3 ). x 



262. Infantile paralysis. The disease known popularly as 

 infantile paralysis and to medical science as acute anterior 

 poliomyelitis is a current problem of great interest and difficulty. 

 During recent years there have been several widespread epidem- 

 ics with great mortality among young children. Nearly two 

 thirds of those who do not die are permanently crippled in 

 some way. 



Careful investigation has not so far been able to discover the 

 cause of the disease, the agencies of its transmission, or the 

 means of controlling it in the human system. It is supposed 

 that the cause is a microorganism, whether a bacterium or a 

 protozoan is uncertain. It is ultra-microscopic, that is, so 

 small that it cannot be discovered by the aid of the microscope. 

 Its presence is assumed from the effects observed in the course 

 of the disease. 



Search for the agencies of transmission has not met with 

 positive results. Investigations have been made of the house fly, 

 stable fly, bedbug, mosquitoes, and lice as possible carriers, but 

 sufficient evidence has not been found to warrant a final con- 

 clusion as to their agency in transmitting it. It has also been 

 suggested that the disease may be communicated by contact 

 with the infected individual, and that it may be transmitted by 

 food, milk, water, clothing, or dust, or in fact by any medium 

 which has been contaminated by contact with the patient. 



In the treatment of the disease, various means have been em- 

 ployed, but the evidence at present is far from conclusive as 

 to the merits of any particular remedy or method tried. 



The problem is of so great interest to human welfare as to 

 command the efforts of scientific men ; and, like malaria and 

 yellow fever, its cause and ways of transmission will be found 

 and brought under control through the research of scientists. 



1 An excellent account of the conquest of yellow fever and the Stegomyia is 

 presented in the book "Walter Reed and Yellow Fever," by Dr. H. A. Kelly. 



