CHAPTEK VII 



MODES OF INFECTION OF ANIMALS WITH PLAGUE 1 



The manner in which plague is or can be transmitted, 

 whether to man or to the rat, has long been the subject 

 of much discussion, observation, and experiment ; so that 

 our knowledge in these matters is by no means restricted 

 in character. Nevertheless, some observers seem to regard 

 the chief method of transmission of plague as likely to 

 be parallel with that observed in regard of diseases like 

 malaria and yellow fever. 



Malaria is accepted as solely transmitted by the bite 

 of an Anopheles mosquito, and the like is probably 

 true of yellow fever (Stegomyia). But in malaria the 

 Anopheles, having sucked, along with blood from a human 

 being, the malarial parasite in a certain phase of this 

 parasite's life, becomes the host of such parasite in further 

 phases of its development ; until, that is, the parasite is 

 ripe again for infection of the human subject by means 

 of the bite of the mosquito which has harboured it. 

 There is no other way of transmission of malaria at 

 present proved. 



As an agent in the transmission of plague, the flea has 



1 Report of the Medical Officer of the Local Government Board, 1904-1905. 



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