HEEEDITAEY TEANSMISSIOff OF THE YELLOW PEVEE PAEASITE Iff 



THE MOSQUITO, 



The question of the herditary transmission of the yellow fever para- 

 site from the Stegomyia fasciata to its progeny is of interest both bio- 

 logically and practically. 



Reasoning by analogy such transmission can not be regarded as 

 impossible, as it is known to occur in some, probably closely allied 

 diseases, namely through the tick in Texas fever and canine piro- 

 plasmosis *. Schaudinn ° has satisfied himself that hereditary transmis- 

 sion of the tertian malarial parasite {Plasmodium vivax) occurs in 

 Anopheles, and recently Dutton and Todd'* have shown that the 

 spirochaete of the tick fever of the Congo is passed from tick to tick 

 through the egg. 



To the sanitarian the question is of interest in its bearing on the 

 problem of the recrudescence of yellow fever. 



The recrudescence of epidemics of yellow fever has heretofore been 

 explained in one of two ways: (1) Either a Stegomyia fasciata that had 

 become directly infected \>y feeding on a case of the disease had sur- 

 vived (as they are experimentally known to be able to do), or (2) the 

 infection had in the interval between the epidemics been continued by 

 unrecognized cases and on the recurrence of favorable conditions the 

 disease would reassume epidemic proportions. 



From time to time a third explanation has been advanced, namely,, 

 the transmission of the infection from the mother mosquito through 

 the eggs to its progeny e which, under favorable circumstances, were. 



" Smith and Kilborne, 1893, IT. S. Department of Agriculture, Bureau of Animal 

 Industry, Bulletin No. 1. 



&Lounsbury, C. P., Transmission of Malignant Jaundice of the Dog by a Species 

 of Tick. Reprint Cape of Good Hope Agricultural Journal, November 21, 1901. 



o Schaudinn, Fritz, Generations und Wirtswechsel bei Trypanosoma und Spiro- 

 chaete. Arbeiten aus dem Kaiserlichen Gesundheitsamte, Berlin, Band XX, Heft 

 3, 1904, p. 428. 



<* Dutton and Todd, Liverpool School of Tropical Medicine, Memoir xvii, 1905. 



«Finlay (Medical Record, N. Y., May 27, 1899, p. 738), inspired by the discovery 

 of Smith and Kilborne of the hereditary transmission of the parasite of Texas fever 

 in the tick, was the first to suggest the hereditary transmission of the yellow fever 

 parasite in the mosquito. In 1901 Reed, Carroll, and Agramonte (American Medi- 

 cine, Phila., July 6, 1901, p. 19) reported the negative results of an inoculation 

 experiment with 14 mosquitoes hatched from the ova of a Stegomyia fasciata that had 

 already shown itself capable of conveying the disease, and Guiteras (American Med- 

 icine, Phila., Nov. 23, 1901, p. 810) reports two experiments. In both the mother 



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