Multiple Endemic Solutions in an Epidemic Hepatitis B Model without Vertical Transmission

Nelson Owuor Onyango

School of Mathematics, CBPS, University of Nairobi, Nairobi, Kenya.

DOI: 10.4236/am.2014.516242                

Abstract

This paper examines the dynamics of Hepatitis B via a Susceptible Exposed Infectious Recovered (SEIR) type epidemic model. Previous studies have shown that Hepatitis B is characterized by multiple endemic solutions, a matter which may be of concern in developing control strategies. We identify the possible causes of multiple endemic solutions in a Hepatitis B model and conclude that the dependance of the probability of carriage development  (q(Λ)) on the force of infection (Λ) is the main reason for multiple endemicity. Other factors such as a large proportion of infants that are not vaccinated (ω) may also enhance the possibility of multiple endemicity. The role of carriers may also play a key role in the possibility of such complex dynamics, i.e., when infectiousness of carriers-(α) is high, the probability of existence of multiple endemic equilibrium solutions is increased. In our arguments, the traditional reproduction number R₀< 1 which we define here by a function G(0) < 1 does not imply stability of disease-free equilibrium.

Keywords

SEIR Epidemic Models, Endemic Equilibriums, Hepatitis B

Conflicts of Interest

The authors declare no conflicts of interest.

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