Variation of malaria transmission and morbidity with altitude in Tanzania and with introduction of alphacypermethrin treated nets

Table 3 Data leading to estimates of the personal protection against biting provided by the treated nets.

Lowland hamlets:-	B1, B3, B5, B6, B8 (no nets)	B2, B4, B7, B9, B10 (treated nets)
No. of collections	103	82
All anophelines resting indoors	4.21	0.276
All anophelines in exit traps	1.36	0.578
Total caught	5.57	0.854
Fed & resting indoors	3.44	0.219
Fed & in exit trap	0.71	0.236
Total fed	4.15	0.455
% fed	74.5%	53.3%
Light trap catches per night in rooms with untreated nets in same months	7.76	3.24
Blood fed catch/light trap catch	0.534	0.140
Reduction in biting due to personal protection from treated nets	73.8%

Geometric mean catches of all anophelines, and of those found blood fed, by pyrethrum spraying to collect mosquitoes resting indoors in bedrooms and by window exit traps in/on bedrooms with treated nets in treated lowland hamlets or in rooms without nets in untreated hamlets in January–July 2000. Also included are the light trap catches in rooms with untreated nets over the same months, as a measure of the vector populations of these hamlets, and hence a calculation of the % of the reduction in biting which is attributable to the personal protection due to the treated nets.

ISSN: 1475-2875