title: The determinant of periodicity in Mycoplasma pneumoniae incidence: an insight from mathematical modelling.
abstract: Until the early 1990 s, incidences of Mycoplasma pneumoniae (MP) infection showed three to five year epidemic cycles in multiple countries, however, the mechanism for the MP epidemic cycle has not been understood. Here, we investigate the determinant of periodicity in MP incidence by employing a mathematical model describing MP transmission dynamics. Three candidates for the determinant of periodicity were evaluated: school-term forcing, minor variance in the duration of immunity, and epidemiological interference between MP serotypes. We find that minor variation in the duration of immunity at the population level must be considered essential for the MP epidemic cycle because the MP cyclic incidence pattern did not replicate without it. Minor variation, in this case, is a less dispersed distribution for the duration of immunity than an exponential distribution. Various lengths of epidemic cycles, including cycles typically found in nature, e.g. three to five year cycles, were also observed when there was minor variance in the duration of immunity. The cyclic incidence pattern is robust even if there is epidemiological interference due to cross-immune protection, which is observed in the epidemiological data as negative correlation between epidemics per MP serotype.
authors.affiliation: Division of Bioinformatics, Research Center for Zoonosis Control, Hokkaido University, Sapporo, 001-0020, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Omori
authors.affiliation: Graduate School of Mathematical Sciences, The University of Tokyo, Tokyo, 153-8914, Japan.
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Nakata
authors.affiliation: Division of Bioinformatics, Research Center for Zoonosis Control, Hokkaido University, Sapporo, 001-0020, Japan.
authors.forename: Heidi L
authors.initials: HL
authors.lastname: Tessmer
authors.affiliation: Department of Bacteriology II, National Institute of Infectious Diseases, Tokyo, 208-0011, Japan.
authors.forename: Satowa
authors.initials: S
authors.lastname: Suzuki
authors.affiliation: Department of Bacteriology II, National Institute of Infectious Diseases, Tokyo, 208-0011, Japan.
authors.forename: Keigo
authors.initials: K
authors.lastname: Shibayama
mesh_terms: D003198:Computer Simulation; D006801:Humans; D007109:Immunity; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008962:Models, Theoretical; D009177:Mycoplasma pneumoniae; D010507:Periodicity; D011019:Pneumonia, Mycoplasma / Q000453:epidemiology* / Q000276:immunology / Q000382:microbiology*