438 FAMILY: TEYPANOSOMID.E 



LEISHMANIA IN ANIMALS. 



The definition of the genus Leishmania, which has been adopted here, 

 is such that it includes all flagellates which attain the leptomonas form, 

 and which have both a vertebrate and an invertebrate host. The latter 

 feature is in the nature of an assumption, for, as shown above, the actual 

 invertebrate hosts of L. donovani and L. trojnca have not been demon- 

 strated, though the probability of such hosts existing is so great as to 

 amount almost to a certainty. In addition to the two forms already 

 considered as producing diseases in man, there exist certain other lepto- 

 monas forms, which have been described as natural infections of verte- 

 brates, and which must be included in this genus, though here also 

 the invertebrate host has yet to be demonstrated (see p. 398). These 

 naturally occurring infections are not to be compared with the artificial 

 ones which Laveran and Franchini, and Fantham and Porter, claim to 

 have produced in animals by the injection into them of purely insect 

 flagellates. The latter have been considered in the section devoted to 

 the insect flagellates (see p. 392). It seems probable that the naturally 

 occurring infections in lizards result from their feeding on infected insects. 

 Leishmania tarentolse Wenyon, 1921. — Sergent, Ed. and Et., Lemaire, 

 and Senevet (1914), while searching for a host of L. trojnca in North Africa, 

 discovered that cultures of a typical leptomonas could be obtained from 

 the heart blood and organs of the gecko, Tarentola mauritanica. The 

 cultures closely resembled those of L. tropica, and led to the view that 

 the gecko was a possible reservoir host of the human parasite, especially 

 as the sand fly Phlebotomus, the supposed vector of oriental sore, frequently 

 feeds on the lizard. The observation was confirmed by Chatton and 

 Blanc (19186), and by Nicolle, Blanc, and Langeron (1920) at Tamerza. 

 The latter observers studied the cultures carefully, and came to the con- 

 clusion that the flagellates could be distinguished from those in cultures 

 of L. tropica. The organisms must be present in the heart blood of the 

 lizard in very small numbers, for in two positive cases out of twelve geckos 

 examined, flagellates were not to be detected in the cultures till twenty- 

 four to thirty-six days had elapsed. Nicolle and his co-workers believe 

 that the organism is probably of intestinal origin, and is only accidentally 

 present in the blood. Laveran (1915) could obtain no infection in geckos 

 by inoculating them with L. tropica. Chatton and Blanc (19186) inocu- 

 lated geckos with cultures of L. tarentolce, and were able to recover the 

 flagellate from heart blood by culture in 50 per cent, of the cases after 

 one to two months. In nature, 35 per cent, of geckos were found infected. 

 Cultures of trypanosomes (T. platydactyli) were also obtained, but these 

 could be readily distinguished. They also inoculated geckos with cultures 



