ENTOMOLOGY

35~ SANI'rARY ENTOMOLOGYANIMAL ORGANISMS TRANSMITTED BY FLEASProtozoaMastigophora: Binucleata: Trypanosomitla:As stated elsewhere the classification here used was recently proposedby Chalmers. It is especially interesting that all flea-borne diseasesbelong to the genus Trypanozoon Luhe (Lewisonella Chalmers) 2 inwhich the final stage of development in the definitive host (the insect)occurs in the hind gut, and infection is contaminative.Trypanozoon blanchardi (Brumpt), cause of a trypanosomiasis, supposedlynonpathogenic, in rodents of the genera Myoxus and Microtushas been found by Brumpt (1913) to develop in the flea, Ceratophyllusla'lJcrani I.-averan and Pettit. The life cycle is identical with that of T.lewisi and T. nabiasi and is effected entirely in the large intestine of theflea. Metacyclic trypanosomes occur in the rectal ampulla and are foundin the dejections. It is not found in the salivary glands.Trypanozoon duttoni (Thiroux), cause of a trypanosomiasis, supposedlynonpathogenic, in mice of the genus Mus, has been found byBrumpt (1913) to develop in the fica, Ceratophyllus hirundinis Curtis.The evolution of this species occurs in the large intestine of the flea andis comparable to that of 1'. lewisi, T. nabiasi, and T. blanchardi. It isnot found in the salivary glands.Trypanozoon lewis;' (Kent), cause of a trypanosomiasis, rarely pathogenic,in rodents of the genera Epimys, Acanthomys, Mus, Myoxus, andl\feriones, etc., passes its cycle of sporogony in fleas (fig. 62). The lifecycle has been investigated in Ceratophyllus fasciatus (Bose) Curtis,Ctenocephalus canis (Curtis) Baker, and Ctenopsyllus musculi (Duges)Wagner, and it has been shown that Pulex irritans Linnaeus, andXenopsylla cheopis Rothschild may serve as true hosts. In additionCeratophyllus lucifer Rothschild, C. hirundinis Curtis, Ctenophthalmusagyrtes (Heller) Baker, and PUlex brasiliensis Baker. are recorded ascarriers. Fantham, Stephens and Theobald summarize the life cyclein the flea. When infected blood is taken up by the flea, the parasitespass with the ingested blood direct to the mid-gut of the flea. In thestomach they penetrate the cells of the lining epithelium and multiplyby division inside the epithelial cells. They first grow to a large size, thenform large spherical bodies within which nuclear multiplication occurs.Anyone of these large spherical bodies contains at lirst a number of nuclei,kinetonuclei, and developing flagella, the original flagellum still remainingattached for a time. The cytoplasm then divides into daughter"This synonymy is according to Mesnil. Bun'. Inst. Past. vol. 17, p. 190.