Impacts of Seasonal and Spatial Variations on the Transmission of Typhoid Fever
Huei-Li Lin,
Kuang-Hui Lin,
Yu-Chiau Shyu,
Feng-Bin Wang
Issue:
Volume 12, Issue 2, April 2023
Pages:
26-41
Received:
13 March 2023
Accepted:
3 April 2023
Published:
11 April 2023
Abstract: Typhoid fever is a disease caused by the bacteria Salmonella Typhi through the ingestion of contaminated food or water, and it is still serious in developing countries. The infection routes include both human-to-human transmission and environment-to-human transmission. It was observed that higher incidence of typhoid fever occur during the rainy season and people living near water bodies may have a higher rate of typhoid infection. On the other hand, asymptomatically infected individuals also play a central role in the transmission of typhoid since they are not experiencing any symptoms but they are able to shed S. Typhi into the environment for years. Thus, a well-described model of the Typhoid transmission should include the asymptomatical compartment and the factors of spatial homogeneity and seasonality. This motivates us to develop a periodic two-patch system to investigate the spatial and seasonal effects on the transmission of Typhoid fever, in which the bacteria in the environment is included, and the population of human is divided into five classes, namely, susceptible individuals, infected individuals, carrier individuals, individuals under treatment and recovered individuals. We first introduce the basic reproduction number for the model, then we show that the extinction/persistence of Typhoid can be determined by R0. Our numerical results indicate that an outbreak of Typhoid fever in a two-patch environment could be eliminated if migration between patches is prohibited. Finally, we also numerically observe that the infection risks of Typhoid may be underestimated if seasonal effects are ignored.
Abstract: Typhoid fever is a disease caused by the bacteria Salmonella Typhi through the ingestion of contaminated food or water, and it is still serious in developing countries. The infection routes include both human-to-human transmission and environment-to-human transmission. It was observed that higher incidence of typhoid fever occur during the rainy se...
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network. We also determine the domination number of the networks, such as the twig network Tm, double fan network F2,n, bistar network Bn,n and linear kc4 – snake network.