Epidemiology of the cutaneous leishmaniasis in Merida, Venezuela: I. Diversity and dispersion of species of phlebotomine sandflies at different altitud and its possible rôle in the transmission of the disease Leia mais sobre Epidemiology of the cutaneous leishmaniasis in Merida, Venezuela: I. Diversity and dispersion of species of phlebotomine sandflies at different altitud and its possible rôle in the transmission of the disease