Transmission reduction is a key component of global efforts to control and
eliminate malaria; yet, it is unclear how the density of transmission
stages (gametocytes) influences infection (proportion of mosquitoes
infected). Human to mosquito transmission was assessed using 171 direct
mosquito feeding assays conducted in Burkina Faso and Kenya. Plasmodium
falciparum infects Anopheles gambiae efficiently at low densities (4%
mosquitoes at 1/μl blood), although substantially more (>200/μl)
are required to increase infection further. In a site in Burkina Faso,
children harbour more gametocytes than adults though the non-linear
relationship between gametocyte density and mosquito infection means that
(per person) they only contribute slightly more to transmission. This
method can be used to determine the reservoir of infection in different
endemic settings. Interventions reducing gametocyte density need to be
highly effective in order to halt human–mosquito transmission, although
their use can be optimised by targeting those contributing the most to
transmission. Characteristics of
membrane feeding assay blood donors and mosquito
infectionsModel takes raw QT-NASBA
data from Schneider et al. 2007 (doi:10.5061/dryad.589ft) and Ouédraogo et
al. 2009 (doi:10.5061/dryad.hv01f) and fits a mathematical model to
estimate the gametocyte density (gam.median) and 95% Bayesian Credible
Intervals (gam.lower, gam.upper). These are combined with blood donor and
mosquito characteristics from the membrane feeding assays. Column “Host”
denotes host id, “Experiment” gives country (0=Burkina, 1=Kenya), age
(0=<7 or 1=>=7 years old) and “asexual.cat” is the asexual parasite
density category as measured by microscopy (0=none,1=low,2=high). The
point estimate for prevalence of oocysts is given from the model outputs
“prev.median” together with 95% Bayesian Credible Intervals (prev.lower,
prev.upper). Full details are given in the manuscript.data_eLife.xlsx