NOTES ON TICKS 19 



TREATMENT. 



As for Relapsing fever. 



Immune horse serum, three doses of 10 cc. each in the first twenty- 

 four hours (Inada). 



Destroy all rats, especially those that are apt to foul water or food. 



Much of our knowledge may have to be revised and the above 

 modified as we learn more about the disease. 



NOTES ON TICKS. 



Ticks belong to the Order of the Acarina, of which they are the 

 largest specimens, always visible to the naked eye, and the females 

 invariably larger than the males, some of the latter when engorged 

 with blood being nearly half an inch long. 



They differ from insects by having four pairs of legs and in having 

 the three parts of the body, thorax and head fused into one un- 

 articulated mass. 



After impregnation the female attaches herself to the host, becomes 

 enormously distended with blood, drops off, hides herself, deposits her 

 eggs by thousands within two to ten days after leaving the host. After 

 two to three weeks the eggs are hatched, the forthcoming larvae 

 resembling minute moving grains of sand, with three pairs of legs, but 

 no sexual orifice. The larva attaches itself to its vertebrate host, grows, 

 moults, becomes a nympha with four pairs of legs, and a pair of 

 stigmata behind the hindermost pair of legs. 



It moults thrice more and becomes adult. Then the sexes unite. 



After fertilization the male dies, but the female seeks blood. 



If blood cannot be found the female can fast for weeks, months or 

 years, until blood can be found. 



The two families of ticks are : (i) The Ixodid^e, e.g., Ornithodorus 



moubata. 

 (2) Agarsidse, e.g., Argas persicus. 



The former example transmits the spiroch^etes of African Tick 

 Fever, and the latter of Miana disease, &c. 



Ticks are transmitters of important animal diseases due to Spiro- 

 chastas and Babesise. 



Ornithodorus mouhata. 



It is found throughout Tropical Africa. 



The body is flattened, oval in outline, and greenish-brown in colour. 



The integument is hard, leathery, covered with closely set 

 tubercles lined by grooves. It lives in native huts, hides during the 

 day in cracks of walls, floors, thatched roofs, and is very active during 

 the night. 



