Calculation of the extrinsic incubation period (EIP)
The EIP was calculated using mean daily temperature and mean hourly temperature for P. falciparum , P. vivax , P. relictum , Leucocytozoon and Haemoproteus parasites. The mean hourly temperature is used to estimate the effect of diurnal temperature fluctuation on EIP. The diurnal temperature range (DTR) variation across these four sites is the difference between maximum and minimum temperatures on each day of the month at each site. This was done for each day of the month for all four sites. Since all four sites are at different elevations, it is possible that for a few days of a month, the temperature was marginally above the minimum threshold temperature for the development of parasites. The EIP calculated using these temperatures can thus become anomalously high. We thus set the EIP to 90 days whenever the computed EIP exceeded that number. We calculated the mean EIP using both the mean daily temperature as well as mean hourly temperatures for the month with the following procedure: We calculate the EIP using the mean temperature for each day of the month. We then average this EIP over the entire month. We use a similar procedure for the mean hourly temperature. We set the upper threshold temperature to about 5oC above the maximum threshold temperature (Tmax) following Hu and Appel (2004) and Cator et al . (2013). The upper threshold temperature is lethal for parasite development. Once the temperature exceeds this lethal temperature the development of parasites does not occur and no estimate of EIP is possible.