Modelling entomological-climatic interactions of Plasmodium falciparum malaria transmission in two Colombian endemic-regions: contributions to a National Malaria Early Warning System

Table 4 Endogenous variables considered for human population

Endogenous variable	Used variable		Depending on	Function
Total human population at risk	P_hu	[individual]	HUS, HUI, HUF, HUM	HUS + HUI + HUF + HUM
Primary exo-erythrocytic schizogony	k_in	[days]	Parasite species, SEC	5–13 for P. falciparum; 2 for P. vivax
Erythrocytic schizogony	k_er	[days]	Parasite species, SEC	2 for P. falciparum; 2 for P. vivax
Average infectious period	1/V or P_F	[years]	HUF, ν, VC, P_hu	$\frac{E X P [V C * \frac{H U F}{P_{h u}} * ν] - 1}{V C * \frac{H U F}{P_{h u}}}$ [3]
Average immune period	1/γ or P_M	[years]	HUF, τ, VC, P_hu	$\frac{E X P [V C * \frac{H U F}{P_{h u}} * τ] - 1}{V C * \frac{H U F}{P_{h u}}}$ [3]
Prevalence**	G or Prev	[dec]	HUF, P_hu	$\frac{H U F}{P_{h u}}$

(*) In the system of differential equations, the sum (k_in+k_er) represents the length of the interval between infection (sporozoite inoculation) and the onset of infectivity (gametocyte maturation) in a vertebrate host. It may range from 15 to 19 days (for a mean value commonly used of 17 days), according to good, deteriorating or intermediate social and economic conditions (SEC) prevailing in the community [21]. The average immune and infectious periods (1/V and 1/γ, respectively) were estimated following the Martens assumptions [3]. (**) In simulation results the variable 'Prevalence' considers only the proportion of infectious individuals, expressed by the total number of infectious human hosts at a given time t scaled by the total human population at risk. Some authors define this endogenous variable as the overall malaria prevalence, therefore including both the infected and infectious stages.

ISSN: 1475-2875