Sự phổ biến của A. lumbricoides và T. trichiura nói chung thấp tại các địa điểm nơi có nhiệt độ giảm xuống dưới ngưỡng nhiệt ít hơn 35-40 ngày, và tăng với số lượng ngày càng tăng của ngày. Giun móc, tuy nhiên, yêu cầu một cửa sổ (8 ngày) nhỏ hơn nhiều của nhiệt phù hợp để truyền và vì vậy đã có thể tồn tại ngay cả khi thời gian có sẵn để phát triển được thứ tự của 10 ngày. | 230 S. BROOKER ET AL. days in the year that below the thermal threshold Figure 4 . The prevalence of A. lumbricoides and T. trichiura was generally low in locations where temperatures fall below the thermal threshold for less than 35-40 days and increased with increasing number of days. Hookworms however required a much smaller 8 day window of thermal suitability for transmission and so were able to persist even when the period available for development was of the order of 10 days. Finally a potentially very important factor is the longevity of the adult worm since the location inside the host is essentially a refuge Days below thermal threshold Figure 4 Relationship between the proportion of humans infected with worms and the number of days during which temperature was less than 40 C which is suitable for survival of free-living STH infective stages based on observed data for 601 locations from nationwide surveys in Cameroon Ratard et al. 1991 1992 Chad Brooker et al. 2002a and Uganda Brooker et al. 2004b . Data were collected in cross-sectional school surveys using similar diagnostic technique Kato-Katz method and sampling designs stratified random and encompass a broad range of infection rates. Insert Relationship between mean LST and number of weeks temperature falls below 40 C y r p . Estimates were derived for each survey location and locations with the same number of days under the thermal threshold were averaged for presentation. Table 2 Prevalence of STH infections among schoolchildren in urban and rural communities in developing countries. Included studies sought to restrict investigation to areas of similar socio-economic characteristics Setting Sample size A lumbrỉcoỉdes T. trỉchỉura Hookworm Reicrcncc Urban Ruilii 1 Urban Rulii Urban Rulii Biantyre. Malawi 553 cliidlnm U I4 years old Ihnri et al. 2000 Pemba Tanzania 256 L liidlirni U I4 years old 100 100 Albonico et al. 1997 Buea Cameroon .
