The development of ChineseLeishmaniainPhlebotomus majorvar.ChinensisandP. Sergentivar

Abstract

Although it is now more than twenty years since Sergent (1905) suggested the possibility of Phlebotomus being responsible for the transmission of Oriental Sore, it was not until 1921 that any direct evidence was produced in support of this hypothesis. In that year Sergent, Parrott, Donatien and Beguet (1921) collected a large number of P. papatasii from a neighbourhood infected with Oriental Sore and inoculated their contents into human subjects ; subsequently, the characteristic lesions developed at the sites of inoculation, from which typical Leishmania were recovered. Similarly, Aragao (1922) produced in a dog a cutaneous nodule containing Leishmania, by inoculating crushed sandflies (P. intermedius) that had been fed on a case of Brazilian Leishmaniasis 13 days previously. The first demonstration of the development of Leishmania in the sandfly, however, was furnished by Knowles, Napier and Smith (1924), who found flagellates in the gut of Phlebotomus argentipes fed on Kala Azar patients in Calcutta. This discovery has been confirmed and extended by the subsequent investigations of the Indian Kala Azar Commission. Christophers, Shortt and Barraud (1925, A and B), working in Assam, also found that L. donovani developed in the midgut of P. argentipes fed on suitable cases ; the infection was especially well developed on the fifth day, the flagellates being found attached to the wall of the gut up to the hinder end of the pharynx. Finally, Shortt, Barraud and Craighead (1926) carried the development a stage further by demonstrating the presence of flagellates in the buccal cavity, in close proximity to the commencement of the biting parts. These results, combined with the careful epidemiological investigations recorded in Report No. 1 of the Indian Kala Azar Commission (1926), would seem to justify the view held by this Commission that the sandfly is probably the vector of the parasite of Kala Azar. Moreover, the recent observations of Adler and Theodor (1926), who succeeded in producing infection with Oriental Sore by the inoculation of flagellates from the alimentary canal of P. papatasii previously fed on an infected case, shows that in this closely related species of Leishmania, the sandfly is certainly capable of harbouring the organism in an infective form.