738 THE ANIMAL PARASITES OF MAN 



being fed on insects containing the protozoa. Fantham and Porter 1 

 (June, 1915) published the following results. Flagellates from 

 sanguivorous and non-sanguivorous insects were used, and cold- 

 blooded as well as warm-blooded vertebrates as hosts. The intro- 

 duced protozoa were pathogenic to the mammals, but not markedly 

 so to the cold-blooded vertebrates. Herpetomonas janiliiiu, H. stratio- 

 myice, H. pediculi, and Crithidia gerridis (parasitic in certain water- 

 bugs) proved pathogenic to mice. A puppy was infected by way 

 of the digestive tract with H. ctenocephali. Frogs became infected 

 with H. jaculum and with C. gerridis, toads and grass snakes with 

 H. jaculum, lizards with C. gerridis, and sticklebacks with H. jaculum. 

 Second and third passages of some of the parasites were obtained. 

 The protozoa, whether Herpetomonas or Crithidia, were present in 

 the vertebrate hosts in either the non-flagellate or the flagellate form, 

 or usually both. They were more abundant in the internal organs 

 of the hosts, more particularly in the liver, spleen and bone-marrow. 

 In all experiments in which C. gerridis was used the parasite 

 invariably retained the crithidial facies in the vertebrate host. No 

 transition to a trypanosome was ever seen. Infections in adult 

 animals were not so heavy as in the young ones, and the parasites 

 were more virulent in young hosts, as is the case with Mediterranean 

 kala-azar in children. 



The mode of infection of the vertebrate in Nature seems to be 

 contaminative, either by its food or through an already existing 

 abrasion or puncture on the surface of its body. Cases in which the 

 flagellate-infected insects have been allowed to suck the blood of 

 vertebrates have proved negative up to the present. In areas where 

 leishmaniases are endemic, an examination should be made of all 

 insects and other invertebrates likely to come into contact with men 

 or dogs, or rats and mice (see below), in order to ascertain if these 

 invertebrates harbour herpetomonads. Preventive measures should 

 be directed against such invertebrates, especially arthropods. Further, 

 it is likely that certain vertebrates, such as reptiles and amphibia 

 (especially those that are insectivorous), may serve as reservoirs 

 of leishmaniases, or, as they should preferably be termed, herpeto- 

 moniases. From such reservoirs the herpetomonads may reach 

 man by the agency of ectoparasites or flies, especially such as are 

 sanguivorous. 



That vertebrates in Nature can harbour herpetomonads in their 

 blood has been shown by the work of Button and Todd (1903) on 

 the herpetomonads of Gambian mice, while the recently published 



1 Proc. Camb. Philosoph. Soc., xviii, p. 137 ; and Annals Trap. Med. and Parasitol.. ix, 

 P- 335- 



