CHAP. XX.] INSECTS AND DISEASE. l8Q 



likely to be dipped up during the dry season when the water-level 

 is low. 



Oriental Sore, otherwise called " Delhi boil " and known under 

 various other local names, is a disease found in North-western 

 India, not South of Cambay nor East of Delhi. Aeeording to 

 Patton's investigations.it is not communicable by species of Musca 

 or bj blood-sucking flies, but is apparently carried only by immature 

 bed-bugs and by them only when the temperature is below 25 C. 

 It is thus only carried in the cold weather, developing two or three 

 months later on. Cases of this disease seen in Madras are usually 

 the result of infection further north but the disease has o< < asionally 

 been introduced and spread in the (older climates ol 1 1 ill Stations in 

 Southern India (e.g.. Bangalore). Tropical Ulcer is also carried 

 similarly by insects and perhaps by leeches. 



Conjunctivitis of the eye, usually caused by a Bacillus, is un- 

 doubtedlj spread toa large extent by means of Eye-flies (Siphonella 

 funicola). 



rhe diseases of domestic animals carried by means of insects 

 are 011 the whole very similar to those found in man and caused by 

 pathogenic organisms which are carried by similar kinds ol insei ts. 

 but usually both organism and carrier arc specifically distinct and 

 peculiar to each particular host. 



I"r\ panosomiases, or diseases caused by infection by minute 

 Protozoa tailed Trvpanosomes, have acquired notoriety by includ- 

 ing the two African diseases. Sleeping Sickness and Nagana 

 or Tsetse-fly disease, the former of which attacks man in West 

 All n ... I ganda and Rhodesia, whilst the latter is fatal to the horse, 

 ass and dog. In some parts of India and Burma " Surra." a disease 

 caused by Trypanosoma evansi, attacks horses, mules, camels and 

 cattle, and is carried by Tabanus and probably other biting flies; 

 later researches, however, seem to show that this Trypanosome may 

 be spread by haematophagous muscid flies which are unable to 

 puncture the skin of an animal by themselves but which suck up the 

 blood exuding from the bite inflicted bj flics such as Philamatotnyia. 

 Trypanosoma theileri is only known to occur in cattle but is apparently 

 non-pathogenic ; it oc< urs in South Africa, Transcaucasia and India 

 and is spread by the bite of the cattle fly ( Hippobosca) . Rats in India 

 and Ceylon arc commonly attacked In Trypanosoma lewisi, another 

 non-pathogenic organism, which is probably carried from one host 

 to another by the rat-lor.se and rat-flea. In Madras the striped palm 

 squirrel (Funambulus palmarum, L.) harbours Trypanosoma indica, 

 which is apparently very closely related to "/'. lewisi of therat. The 

 bandicoot rat (Nesokiabandicotti) is the host of Trypanosoma bandicotti, 



