2 20 Arthropods as Essential Hosts of Pathogenic Protozoa 



Ornithodoros moubata. The evolution proceeds in the first two 

 species of bed-bugs as rapidly as in Conorhinus, or even more rapidly, 

 but they remain infective for a much shorter time and hence Bnunpt 

 considers that they play a much less important r61e in the spread of 

 the disease. 



Conorhinus megistus, like related forms in our Southern States, 

 very commonly frequents houses and attacks man with avidity. 

 Chagas states that the bites are painless and do not leave any traces. 

 They are usually inflicted on the lips, or the cheeks and thus the 

 buccal mucosa of a sleeper may be soiled by the dejections of the 

 insect and the bite serving as a port of entry of the virus, remain 

 unnoticed. 



The possibility of some of our North American Reduviidse play- 

 ing a similar r61e in the transmission of disease should not be over- 

 looked. 



Leishmanioses and Insects — Closely related to the trypanosomes 

 is a group of intracellular parasites which have recently been grouped 

 by Ross under the genus Leishmania. Five species are known to 

 affect man. Three of these produce local skin infestations, but two 

 of them, Leishmania donovani and L. infantum, produce serious and 

 often fatal systemic diseases. 



The first of these, that produced by L. donovani, is an exceedingly 

 virulent disease common in certain regions of India and China. It 

 is commonly known as "Kala-azar," or "dum-dum" fever, and more 

 technically as tropical leishmaniasis. Patton (1907) believes that 

 the parasite is transmitted by the bed-bug Cimex hemipterus, and has 

 described a developmental cycle similar to that which can be found 

 in artificial cultures. Ori the other hand, Donovan was unable to 

 confirm Patton 's work and beheves that the true intermediate host is 

 a Reduviid bug, Conorhinus rubrofasciatus . 



Leishmania infantum is the cause of the so-called infantile splenic 

 leishmaniasis, occurring in northern Africa, Spain, Portugal, Italy, 

 and possibly other parts of Europe. The parasite occtirs habitually 

 in the dog and is only accidentally transferred to children, Alvares 

 and da Silva, in Portvigal (according to Brumpt, 1913) have found 

 that the excrement of a flea from a diseased dog contains flagellates, 

 and they suggest that the infection may be transmitted by the acci- 

 dental inoculation of this excrement by means of the proboscis of the 

 flea, as has been thought to occur in the case of the plague. To this 



