Fish-borne parasitic zoonoses transmission dynamics: The case of anisakiasis

Abstract

Anisakiasis is a fish-borne parasitic disease that poses threat to human health and food safety, affecting peoples’ livelihood and the economy of countries. In this paper, a mathematical model for transmission dynamics of anisakiasis is formulated and analyzed. The analysis shows that both the disease free and endemic equilibria exist. To study the dynamics of anisakiasis, the basic reproduction number R0 is derived using the next generation matrix method. Lyapunov functions are used to assess the global stability of model equilibria. The disease free equilibrium is globally asymptotically stable whenever R0<1 and unstable otherwise whereas the endemic equilibrium is globally asymptotically stable whenever R0>1. The normalized forward sensitivity index is adopted to determine sensitivity indices of model parameters. The rate at which marine mammals release anisakid eggs η, recruitment rates for fish and crustaceans Λf and Λc, and their infection rates βf and βc respectively, and the rates at which marine mammals are recruited Λm and the rate at which susceptible marine mammals become carriers βm are the most positive sensitive parameters. The natural death rate for marine mammals μm is the most negative sensitive parameter suggesting that marine mammals drive anisakiasis. Control measures implemented to control anisakiasis using improved fish treatment reveal that the number of infected humans declines significantly with improved fish treatment giving sufficient anisakiasis control. Therefore, to control anisakiasis, more efforts should be directed towards improving fish treatment which involves the use of microwaving, heating, salting, freezing and use of anthelmintic drugs.