HERPETOMONAS 



103 



\ 



guts of fleas and lice, but are not confined to blood-sucking insects. 

 One example, H. ctenocephali (Fantham, 1912) 1 occurs in the digestive 

 tracts of dog fleas, Ctenocephalns cams, in England, France, Germany, 

 Italy, India, Tunis, etc. It is a natural flagellate of the flea, and might 

 easily be confused with stages of blood parasites in the gut of the dog 

 flea. Dog fleas are stated by Basile to transmit canine kala-azar, which 

 is believed to be the same as human infantile kala-azar. Confusion is 

 further likely to arise since herpetomonads pass through pre-flagellate, 

 flagellate and post-flagellate or encysted stages; pre- and post-flagellate 

 stages being oval or rounded and Leishmania-like. The post-flagellate 

 stages are shed in the faeces, and are the cross-infective stages by 

 means of which new hosts are infected by the mouth. The possible 

 presence of such natural flagellates must always be considered when 

 experimenting with fleas, 

 lice, mosquitoes, etc., as 

 possible vectors of patho- 

 genic flagellates like Leish- 

 mania and Trypanosotna. 

 H. pediculi (Fantham, 

 1912) occurs in human 

 body lice. 2 See further 

 remarks on pp. 107, 112. 



Laveran and Franchini 

 (1913-14) 3 have recently 

 succeeded in inoculating 

 Herpetoinonas ctenocephali^ 

 from the gut of the dog 

 flea, intraperitoneally into 

 white mice, and produc- 

 ing an experimental leish- 

 maniasis in the mice. A 



dog was also infected. They have also succeeded in infecting mice 

 with H. pattoni a natural flagellate of the rat flea by mixing in- 

 fected rat fleas with the food of the mice, and by causing them to 

 ingest infected faeces of rat fleas. Further, they have shown that 

 infection with the herpetomonas occurs naturally by this method, 

 that is, by the rodents eating the fleas and not by the insects inocu- 

 lating the flagellates into the vertebrates when sucking blood. These 

 experiments shed an interesting light on the probable origin of 

 Leishmania and its cultural herpetomonad stage, which were very 

 probably once parasitic flagellates in the gut of an insect. 



1 Bull. Path. Exot. y vi, p. 254. 2 Proc. Roy. Soc., B, Ixxxiv, p. 505. 



3 C. R. Acad. Set., clvii, pp. 423, 744. Ibid., clviii, pp. 450, 770. Bull. Soc. Path. 

 Exot.) vii, 605. 



FIG. 49. a, Herpetomonas ; b y Crithidia ; 

 c, Trypanosoma. (After Porter.) 



