122 DISEASES DUE TO PROTOZOA 



That is, only one out of every forty-eight mosquitoes can ever have a 

 chance of carrying malarial parasites (Ross). 



The Mansoni titillans has now been found to be the most numerous 

 of all mosquitoes in the Panama Canal Zone. It has habits which 

 enable it to escape both in the larval and pupal stage all larvicidal 

 efforts, as these stages are passed beneath the water. This is rendered 

 possible by breathing tubes being adapted for piercing the rootlets of 

 the Pistia stratiotes and thus obtaining their supply of oxygen. The 

 roots are sometimes several feet long, and to these the larvas are 

 attached. Xot all plants, however, contain them, other conditions 

 being necessary. 



The adult mosquito has long been known in the Canal Zone, but 

 the larvce and pup^e have not before been found. 



TRYPANOSOMIASIS. 



(i) African Trypanosomiasis. 



(2) South American Trypanosomiasis. 



(3) Notes on Mammalian Trypanosomiasis. 



AFRICAN TRYPANOSOMIASIS. 

 DEFINITION. 



An acute specific infection caused by : — 



(i) Trypanosome gambiense, carried by Glossina palpalis. 



(2) Trypanosome rhodesiense, cari-ied by Glossina morsitans. 



Other species of trypanosomes may cause the disease. 



The morbid manifestations are : irregular chronic fever, fleeting 

 skin eruptions, local oedema, adenitis, physical and mental lethargy, 

 mania, eye lesions, tenderness of muscles and bones. 



HISTORY. 



The '* surra " of India has been ascribed to the bites of certain 

 blood-sucking flies by the natives from time immemorial. 



1724. John Atkins in "The Navy Surgeon " described the sleep- 

 ing distemper common among the negroes of the Guinea Coast, seen 

 by him in 1721, but not published until 1724. 



1803. Winterbottom described it as he saw it on the West Coast 

 near Sierra Leone. Slave dealers would not buy slaves with enlarged 

 cervical glands. 



1846. Trypanosomes first found in fishes. 



1879. Lewis found the rat trypanosome (T. lewisi) in Bombay. 



1880. Evans found the T. evansi in horses of India at Madras. 



