Modelling the Host Immune Response to Primary Dengue Infection

Dengue is a mosquito borne viral infection triggering a series of intracellular events in the host immune system, which sometimes leads to severe dengue infection resulting in serious illness and even in death if the patient is not treated properly. We present stochastic model describing the interplay between dengue virus and host immune response in primary dengue infection. The stochastic model is derived from the deterministic model describing the dynamics of the disease. We analyze the deterministic model to explore the factors influencing the virus persistence in the body for extended periods. The results are then compared with the stochastic model. The stochastic model is shown to provide better insights into the viral dynamics. The stochastic model provides a wide range of results including different size of viral loads and different time of maximum infection occurring in the body. In addition, the stochastic model exhibits positive probability of viral extinction, as opposed to deterministic model, when the virus reproduction number R_0>1. We calculate the extinction probability as a function of R_0 where extinction probability is found to decrease with an increasing R_0, suggesting that at high infection rate the effect of uncertainties in underlying dengue dynamics maybe negligible.