DEPARTMENT OF MATHEMATICAL SCIENCES

APPLIED AND COMPUTATIONAL MATHEMATICS SEMINAR

**Speaker:**
Simone Bianco, Applied Science, William & Mary

**Title: ***
Epidemics with multistrain interactions: cross immunity and
antibody-dependent enhancement
*

**Abstract:**
The study of multistrain diseases, diseases with several coexisting
strains, is a major challenge for today's science. Example of such
diseases are influenza, AIDS, dengue and ebola. The inclusion of
mechanisms of interactions between the strains represents a further
step in the implementation of a realistic model for this type of
disease, which is paramount towards the assessment of disease control,
as well as the study of vaccination strategies. In this talk I will
present a mathematical model for multistrain disease with nonlinear
interactions among the strains. I will focus my attention on dengue
fever, a 4-strains subtropical disease which is responsible for the
infection of over 50 million people worldwide every year. A prominent
characteristic of dengue fever is the way dengue strains interact with
each other. Once an individual is
infected with one strain, after a period of temporary cross immunity,
his antibodies will increase his infectiousness in the case of
secondary infection with a different strain. This mechanism is called
antibody dependent enhancement (ADE). While the presence of ADE alone
is known to trigger chaotic outbreaks and desynchronization among the
strains, the inclusion of weak cross immunity in the model is proved
to have a stabilizing effect on the dynamics. Strong cross immunity
leads instead to instability and chaos. Finally, I will present new
results about the emergence of chaos and traveling waves in coupled
communities with migration terms. These results may help to give
important insight for new mechanisms of disease control.

**Time:** Friday, Oct. 16, 2009, 1:30-2:30 p.m.

**Place:** Science and Tech I, Room 242

Department of Mathematical Sciences

George Mason University

4400 University Drive, MS 3F2

Fairfax, VA 22030-4444

http://math.gmu.edu/

Tel. 703-993-1460, Fax. 703-993-1491