Subsequently, Annecke (1952^ reported that all huts treated 

 with 600 mg. gamma isomer per square foot BH3 remained free of 0. 

 nioubata for at least 27 months. When 300 mg, per square foot " 

 were used, huts remained free of ticks for twelve months. 



The small amounts of BH3 used in malaria control programs, 

 25 to thirty mg. gamma isomer per square foot BHU wettable powder, 

 applied twice three months apart, has little effect on 0. moubata , 

 but Annecke (loc. cit .) believes the cicnulative effect may reduce 

 or destroy the tick. 



The above remark immediately suggests the potentiality of 

 tampan resistence to chemicals. So far as known, none has yet 

 been demonstrated, 



A control program in Fort Jameson township of Northern Rhoda- 

 sia has recently been reported by Holmes (1953 J. Heavy spraying 

 with a five percent BHC solution resulted in general diminution 

 of the tick population but did not result in its elimination. 

 It was foxond that the most economical form for achieving a hundred 

 percent kill was five percent BW powder mixed with 9% (by weight) 

 sawdust diluent, or with chaff left from pounding corn. To obtain 

 a sackful of this mixture, a container holding 65- pounds of forty 

 percent BHD cattle dip wettable powder was mixed with fifty pounds 

 of sawdust. This mixture was then laid as a four inch wide bar- 

 rier, thick enoiogh to insure that ticks must come in contact with 

 it when passing, at the base of all inside walls of the house. 

 The barrier was maintained for three weeks and frequently inspected, 

 especially where it passed door openings, to insure that it was 

 not scattered. This time period shoiild reach all nymphs hatching 

 from eggs laid before the chemical is applied (more or less ex- 

 ceptionally a somewhat longer hatching period may be involved, 

 but for practical purposes this time is probably usually effective - 

 HHJ, Elimination of tampans was obtained by this method, but re- 

 infestation occurred within a year to a year and a half. Fleas, 

 Congo floor maggots, and bedbugs were also killed. In the fol- 

 lowing year, the number of cases of relapsing fever from treated 

 houses was considerably reduced. The cost of this program was so 

 low that other authorities commenced similar control prograjus. 



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