A simulation model of the infection cycle of Leishmania mexicana in Neotoma micropus

A simulation model of transmission of Leishmania mexicana among Neotoma micropus by Lutzomyia anthophora was developed to predict the threshold vector density below which L. mexicana would be eliminated from a population of N. micropus within 2 years. Model results supported the hypothesis that N. micropus is a reservoir of L. mexicana. Leishmania mexicana could be maintained in a focus with an initial annual prevalence of 5.7%, which approximated the lowest non-zero prevalence found in field studies, and a peak annual vector density of only 11.4 female sand flies/woodrat. At a peak density of 2.8 female sand flies/woodrat, the prevalence declined below 1% (0.69%) at the end of 2 years. Simulations indicated that if the initial prevalence of infection was 27%, the highest annual prevalence found in the field studies, prevalence would remain > 1% (1.27%) after 2 years even if there was no sand fly activity.