Table 4.
Summary results of the bioassays with DDT 4%
| Taxa | N a | % Mortalityb | % KDc | KDT50d | Statuse |
|---|---|---|---|---|---|
| An. scanloni (laboratory strain) | 50 | 84 (74–94) | 42 (28–56) | 63.2 (59.8–69.7) | S |
| An. minimus (s.s.) (laboratory strain) | 50 | 100 (na) | 98 (94–100) | 38.3 (36.9–39.7) | R |
| An. annularis (s.l.) | 0 | na | na | na | na |
| An. barbirostris (s.l.) | 435 | 74 (70–78) | 49 (45–54) | 61 (59.1–63.2) | R |
| An. hyrcanus (s.l.) | 91 | 57 (47–67) | 30 (20–39) | 84.2 (70.9–112.1) | R |
| An. jamesii (s.l.) | 59 | 98 (95–100) | 88 (80–96) | 33.3 (31.3–35.2) | S |
| An. kochi | 0 | na | na | na | na |
| An. maculatus (s.l.) | 239 | 99 (97–100) | 9 (94–99) | 25.5 (23.4–27.4) | S |
| An. minimus (s.l.) | 245 | 100 (na) | 100 (na) | 23.4 (21.8–24.9) | S |
| An. tessellatus | 0 | na | na | na | na |
| An. vagus | 133 | 97 (94–100) | 91 (86–96) | 35.3 (34–36.6) | SR |
a N: number of mosquito phenotyped
b % Mortality: mortality rate (expressed in %) after 1 h of exposure to insecticide, recorded following a 24 h observation period; the values between parentheses indicate the 95% confidence interval of the mean mortality rate
c % KD: rate of mosquitoes “knocked down” (KD, expressed in %) recorded after 1 h of exposure to insecticide; the values between parentheses indicate the 95% confidence interval of the mean KD rate
d TKD50: time (expressed in minutes) necessary to “knock down” 50% of the mosquitoes; the values between parentheses indicate the 95% confidence interval of the TDKD50
e Status: resistance status as defined by WHO [37]. Briefly, a mortality in the range 98–100% indicates susceptibility; a mortality between 90 and 97% indicates suspected resistance; a mortality < 90% indicates confirmed resistance as long as 100 specimens have been phenotyped
Abbreviations: na, not applicable; R, resistant; S, suceptible; SR, suspected resistance