DISEASES TRANSMITTED BY MOSQUITOES 259 



cians, intermedium, viediopunctatus, pseudomacuUpes, punctipermis, and 

 quadrimacidatus, three of which species occur in the United States. 



AVIAN MALARIA. — Several forms of avian malaria are known. 



Plasmodium danilewsky Grassi and Feletti (1890), a malaria of spar- 

 rows, partridges, finches, and crows is carried by Culex quinquefasciatus 

 (fatigans), C. pipiens, Aedes nemorosus Meigen, and A. argentevis 

 {calopus) according to various textbooks. 



Plasmodium relicttim, a malaria of the canary, was proven by Sergent 

 and Sergent (1918) to be carried by Culex pipiens. 



Mastigophora: Spirochaetacea: Spirochaetidae 



Spiroschaudimnia ctdicis JaflFe (1907) was found by JafFe in the 

 gut and malpighian tubules of Culex pipiens and Anopheles maculi- 

 peTvnis. 



Leptospira icteroides Noguchi (1919) has been proven to be the 

 causative organism of YELLOW FEVER in investigations made in 

 Ecuador. Noguchi obtained pure cultures by inoculation of guinea pigs 

 with blood of yellow fever patients. He isolated the organisms from 

 three patients and also from mosquitoes and inoculated them into guinea 

 pigs, dogs, and marmosets {Midas oedipus and M. geoffroyi). The 

 organism is filterable. 



This dread disease of the tropics has been studied for years and 

 many other investigators have sought the organism without success. Sei- 

 delin, in 1909, described a parasite belonging to the Babesiidae in the 

 blood and organs of yellow fever patients, as Paraplasma flavigenum, 

 which he considered to be the cause of yellow fever, but this organism 

 was not generally accepted as the causative organism. The incubation 

 period in man is three days and the mosquito to become infected must bite 

 a patient during the first three days of his illness, and then twelve days 

 must elapse before the infected mosquito can transmit the disease to man. 



The organism of yellow fever may pass through the pores of a Pasteur 

 Chamberlain B. filter. The disease can be conveyed by subcutaneous in- 

 jection of the blood taken from the general circulation of a person sick 

 with the disease during the first three days of the disease, but can be 

 carried naturally only by the bite of a mosquito {Aedes argent eus, usually 

 called Stegomyia fasciata), that at least 12 days before has fed on the 

 blood of a person sick with this disease, during the first three days of his 

 illness. But Noguchi transmitted it by the bite of a mosquito from a 

 diseased to a healthy guinea pig in 8 days and 8-12 days, and from man 

 to guinea pig, 23 days after biting'man. Prophylaxis therefore consists 

 in prevention of biting by mosquitoes, and mosquito extermination. 



There is no definite proof that the virus can be transmitted heredita- 



