A cellular automaton model for the transmission of Chagas disease in heterogeneous landscape and host community

Abstract

International audienceChagas disease is a vector-borne disease and a major public health concern in Latin America. To understand the disease dynamics, we investigated the influence of landscape heterogeneity and host diversity on pathogen transmission. We developed an epidemiological model based on the cellular automata approach to simulate the spread of Chagas disease in homogeneous and heterogeneous environments with competent and noncompetent hosts species. We show at first that weak levels of dispersal are associated with a reduction in infection as vectors infected in habitats of high transmission tend to spread into habitats with fewer hosts. A second important conclusion is that larger levels of dispersal can have very contrasted effects depending on the composition of the host community in the area of lower intrinsic transmission

Clustered Breeding Sites: Shelters for Vector-Borne Diseases

“…The influence of spatiotemporal heterogeneities of vectors on the propagation of vector-borne diseases has been experimentally [ 24 , 25 ] and theoretically [ 8 , 26 ] analyzed. Here, our simplistic epidemic model reveals that the more the vectors are clustered in a given region, the lower is the prevalence; however, the greater must be the effort to eradicate the disease from such a region.…”

“…Reducing the vector population is one of the key methods employed to control the transmission of vector-borne diseases [ 7 , 8 , 11 – 13 , 20 ]. Our simulations suggest that vector-control programmes should take into consideration the spatial distribution of vectors and not only the disease prevalence and/or the vector population size.…”

The Basic Reproduction Number for Chagas Disease Transmission Using Cellular Automata

“…Vectors are assumed not to have an immune class. This compartmental approach of CA have been successfully used to describe disease spreading [6,15]. The model is defined as follows:…”

“…The host and vector species adaptation are modelled by setting each species death rate (d s ) for the susceptibles s where s = H, h, V and d H + α p H with p = I, R at different levels in the two habitats [6]. These demographic parameters are given 'good' values in the habitat that species is adapted to, and 'bad' values in the other habitat: For the simulations, the landscape was set up by randomly distributing 'good' and 'bad' cells that occurs in equal frequency with E + s = 1.5 and E − s = 0.5.…”

“…Several works dealing with epidemic CA models have been developped [2,4,11,20]. In [6], a deterministic CA model involving host and vector populations has been developed. In this paper, we use the basic reproduction number R 0 computed with the next generation method, in order to investigate the impact of some environmental factors on the transmission dynamics.…”