Table 1.

Description of the subpopulations

Class symbols	Description
$S_H$	Susceptible individuals in home country
	that never travelled to the endemic country
$I_H$	Infectious individuals in home country
	that acquired the infection locally in their home country
	(autochthonous infections from the $S_H$ class)
$R_H$	Recovered individuals in home country, from the
	autochthonous infections $I_H$ class
$S_T$	Susceptible travelers that returned susceptible
	to their home country
$I_T$	Infectious travelers, infected locally in home country
	after returning (autochthonous infections from the $S_T$ class)
$R_T$	Recovered individuals from the autochthonous
	infections $I_T$ class
${\stackrel{\ast }{S}}_T$	Susceptible travelers visiting an endemic country
${\stackrel{\ast }{I}}_T$	Infectious travelers, that acquired the infection at the
	visited country and return infectious
${\stackrel{\ast }{R}}_T$	Recovered travelers, that were infected and recovered in
	the visited country before returning home
${\stackrel{\ast \ast \ast }{R}}_T$	Individuals ${\stackrel{\ast }{R}}_T$ that returned to their home country
${\stackrel{\ast \ast }{I}}_T$	Individuals ${\stackrel{\ast }{I}}_T$ that returned to their home country
${\stackrel{\ast \ast }{R}}_T$	Recovered travelers, that were infected in the visited
	country, returned home infected, and recovered there
$S_M$	Susceptible mosquitoes (disease vectors in the home country)
$L_M$	Latent mosquitoes, disease vectors which have been infected
	locally by $I_H$, $I_T$ and ${\stackrel{\ast }{I}}_T$ but are not yet infectious
$I_M$	Infectious mosquitoes, disease vectors which have survived
	to the incubation period and can transmit the disease