A core group model for disease transmission

K. P. Hadeler, Carlos Castillo-Chavez

Research output: Contribution to journalArticle

149 Citations (Scopus)

Abstract

Models for sexually transmitted diseases generally assume that the size of the core group is fixed. Publicly available information on disease prevalence may influence the recruitment of new susceptibles into highly sexually active populations. It is assumed that the recruitment rate into the core population is low while disease prevalence is high, core group members mix only with each other, disease levels outside the core are negligible, and some core group members reduce their risk through the use of a partially effective vaccine or prophylactics. A demographic-epidemic model is formulated in which the combined size of the core and non-core population is constant. A simpler version models the epidemic in an isolated core population of constant size under the influence of educational programs and measures that reduce susceptibility. The threshold condition for an endemic infection is determined. Backward bifurcations, multiple infective stationary states, and hysteresis phenomena can be observed even in the simplified version. Abrupt changes in disease prevalence levels may result from small changes in the disease management parameters and do not occur in the absence of such a program. The general conclusion is that partially effective vaccination or education programs may increase the total number of cases while decreasing the relative frequency of cases in the core group. The study throws some new light on the role of the reproduction number in connection with elimination attempts. It shows that although the reproduction number defines the threshold for the spread of the disease in a susceptible population, it is of limited value when elimination of an existing epidemic is planned.

Original languageEnglish (US)
Pages (from-to)41-55
Number of pages15
JournalMathematical Biosciences
Volume128
Issue number1-2
DOIs
StatePublished - 1995
Externally publishedYes

Fingerprint

disease prevalence
disease transmission
education programs
sexually transmitted disease
vaccination
Reproduction number
Population
vaccine
Reproduction
bifurcation
sexually transmitted diseases
hysteresis
at-risk population
Elimination
education
Model
Disease Management
Sexually Transmitted Diseases
disease control
Population Density

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)
  • Applied Mathematics
  • Modeling and Simulation
  • Statistics and Probability
  • Medicine(all)
  • Ecology, Evolution, Behavior and Systematics

Cite this

A core group model for disease transmission. / Hadeler, K. P.; Castillo-Chavez, Carlos.

In: Mathematical Biosciences, Vol. 128, No. 1-2, 1995, p. 41-55.

Research output: Contribution to journalArticle

Hadeler, K. P. ; Castillo-Chavez, Carlos. / A core group model for disease transmission. In: Mathematical Biosciences. 1995 ; Vol. 128, No. 1-2. pp. 41-55.
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