A Second Chance to Tackle African Malaria Vector Mosquitoes that Avoid Houses and Don't Take Drugs

View in gallery Figure 2. Estimates of the proportion of human exposure to African vector populations for users (πi,n) and non-users (πi) of long-lasting insecticidal nets (LLINs). All estimates of πi for vector populations in Kenya, Tanzania, Zambia, and Burkina Faso were obtained directly from a recently published analysis.24 For Anopheles gambiae in Equatorial Guinea, an approximate value was derived from published estimates25 of the proportion of mosquitoes caught indoors (Pi) and the proportion caught during the first and last hours that the majority of residents were considered to be asleep indoors (Pfl): πi = Pfl Pi/[Pfl Pi + (1 − Pfl)(1 − Pi)]. Values for πi,n were calculated without explicit calculation of hourly behavior-weighted biting rates, discounted for indoor personal protection (ρ), as originally described for Anopheles funestus and Anopheles quadriannulatus in Zambia.26 Instead πi,n was calculated based on these estimates of πi and a mean of published estimates27 for the personal protection provided by an LLIN (ρ = 0.937): πi,n = πi (1 − ρ)/[πi (1 − ρ) + (1 − πi)]. Note that Figure 3 and the abstract of the original report from Zambia26 mistakenly report a cruder binomial estimate for the proportion of non-user exposure occurring indoors (described by Equation 4 of Seyoum and others and distinguished as πiB in Huho and others) rather than the more refined estimate based on mosquito biting rates weighted according population mean human behavior (described as Equation 1 in Seyoum and others and annotated as πi in both works), which are described in Figure 3 of Huho and others and used to derive the πi,n estimates presented here.