HEREDITARY INFECTION 



363 



resembles that described by Porter for Crithidia melophagia in the 

 fly Melophagus ovinus. 



Pathogenicity. — In an able paper published in 1916 Fantham 

 and Porter have shown that by feeding and by inoculation of various 

 forms of herpetomonads and crithidias acute and chronic attacks 

 of herpetomoniasis can be induced in vertebrates. Thus Herpeto- 

 monas jaculum, from Nepa cinerea, by feeding, produced the disease 

 in mice, birds, a snake, frogs, newts, and fish; H. stratiomyicB from 

 Stratiomyia chameleon in a mouse; H. pediculi froifi Pediculus 

 corporis in mice; H. culicis from Culex pipiens in birds; 

 H. ctenocephali from a flea in a dog; Crithidia gerridis from Gerris 

 paludum in dogs, lizards, mice, and frogs. In the infected animals 

 both flagellate and Leishmaniform parasites were present. 



These experiments are of great importance, and support the views 

 expressed by Archibald that the method of infection of kala-azar 

 in man is from aquatic insects and per os. Experimental herpeto- 

 moniasis is characterized by insidious onset followed by rapid illness, 

 splenic and often hepatic enlargement, attacks of fever, emaciation, 

 and often death . 



Evolution of Herpetomoniasis. — As a result of the above-mentioned 

 experimental work, Fantham and Porter have deduced the view 

 that, in the case of the herpetomonads, disease is in the making to- 

 day, and that as the result of change of habitat (brought about by 

 ingestion or insect-faecal contamination of a bite), a herpetomonas 

 may find itself in a vertebrate host, and there, taking on its Leish- 

 maniform stage, becomes pathogenic, producing the disease herpeto- 

 moniasis, which may be acute or chronic. In the acute disease the 

 flagellate forms abound, while in the chronic there are many more 

 Leishmania-like forms. 



Vertebrate Reservoir. — As a variety of the chronic infection may 

 be mentioned the vertebrate reservoir. 



In 1914 Sergent, Lemaire, and Sanevet found herpetomonad 

 flagellates in the blood and organs of a gecko in areas in Algeria in 

 which Oriental sore was endemic, and suggested that the possible 

 carrier was a phlebotomus. In the same year Chatton and Le 

 Blanc found Leishmania-like forms in the red blood-cells of geckos 

 in Tunis. 



In 1915 Bayon found herpetomonas in the alimentary canal of 

 Chameleon pumilus at Robbin Island, and also in a fly, Scatophaga 

 hottentota, and suggested the possibility of infection of the verte-' 

 brate by swallowing a fly. 



In 1914 Lindsey suggested that the oral Leishmaniasis of Paraguay 

 might have its reservoir in rattlesnakes and its carrier in ticks or 

 Simulium flies. 



On the other hand, the very careful work carried out by Archibald 

 in the Sudan has apparently excluded domestic animals as possible 

 reservoirs of kala-azar in that region, where dogs are not readily 

 susceptible to the virus, a fact which rather tends to differentiate 

 the parasites of Sudan kala-azar from those of the Mediterranean. 



