The role of host mobility in the transmission and spread of Echinococcus granulosus: A Chile-based mathematical modeling approach

This paper explores, as a proof-of-concept, the impact of definitive and intermediate host mobility on the transmission and spread of cystic echinococcosis by characterizing disease dynamics using three classical epidemic models: S-E-I-R for the accidental intermediate host, S-E-I for the habitual intermediate host, and S-I-S for the definitive host. The simulations revealed a significant relationship between the mobility of dogs and the increase in infected sheep. Specifically, for each infected dog, there were twice as many infected sheep as in a situation where mobility was not a factor. The initial conditions took into account that the prevalence of the disease in dogs is higher in rural areas than in peri-urban areas, as has been observed in the Magallanes region of Chile. The results of the simulations suggest that mobility can have a role in the propagation of the disease in humans. Furthermore, the sensitivity index on R0 indicates that a 10% reduction in the average time spent by peri-urban dogs in urban and rural areas could result in a decrease of approximately 1% in R0. In conclusion, including the host mobility factor allows us to observe that, in general, the number of infected in the domestic cycle of the disease increases, i.e., our mathematical model provides valuable information on the impact of host mobility on the transmission and spread of cystic echinococcosis.Author summary: Cystic echinococcosis is a zoonotic disease that has been classified as a neglected tropical disease. In Chile, there are epidemiological situations of high, medium and low endemicity, with an increase in incidence towards the south of the country, where more than 50% of sheep population is concentrated. The disease mainly affects individuals residing in rural settings. The migration of rural human populations, together with small flocks of sheep, to peri-urban areas has led to an expansion in the geographical distribution of the disease. The present study employed mathematical modeling and computer simulations to investigate the impact of dog, sheep and human mobility on the transmission and spread of cystic echinococcosis. Our findings indicate that the number of dogs, sheep and humans infected in the domestic cycle of the disease is higher when considering their mobility between peri-urban, urban, and rural areas. Our model provides insights into the role of host mobility in the transmission and spread of cystic echinococcosis, which could inform strategies for controlling infection in dogs and sheep and reducing human infections.