Transmission dynamics of Toxoplasma gondii along an urban-rural gradient

Theor Popul Biol. 2010 Jun 2. [Epub ahead of print]

Transmission dynamics of Toxoplasma gondii along an urban-rural gradient

Lélu M, Langlais M, Poulle ML, Gilot-Fromont E.

Université de Lyon, F-69000, Lyon; Université Lyon 1; CNRS, UMR5558, Laboratoire de Biométrie et Biologie Evolutive, F-69622, Villeurbanne, France; 2C2A-CERFE, 5 rue de la Héronniére, F-08240 Boult-aux-Bois, France; Université de Reims Champagne-Ardenne, Laboratoire de Parasitologie-Mycologie, EA 3800, UFR de Médecine, IFR 53, 51 rue Cognacq-Jay, F-51096 Reims, France.

Abstract
Recently, several authors proposed that the availability of intermediate hosts (IH) for definitive hosts (DH) may contribute to determine the dynamics and evolutionary ecology of parasites with facultative complex life cycles. The protozoa Toxoplasma gondii may be transmitted to DH either via predation of infected IH through a complex life cycle (CLC) or directly from contaminated environment through a simple life cycle (SLC). This parasite is also present in contrasting host density environments. We tested the hypothesis that the relative contributions of CLC and SLC along an urban-rural gradient depend on the IH supply. We built and analysed a deterministic model of T. gondii transmission cycle. SLC relative contribution is important only in urban-type environments, i.e., with low predation rate on IH. In contrast, the parasite is predominantly transmitted through CLC in suburban and rural environments. The association of the two cycles enables the parasite to spread in situations of low IH availability and low DH population size for which each cycle alone is insufficient. Copyright © 2010. Published by Elsevier Inc.

PMID: 20685358 [PubMed - as supplied by publisher]