A model of the transmission of dengue fever with an evaluation of the impact of ultra-low volume (ULV) insecticide applications on dengue epidemics
Newton, E.A.; Reiter, P.
American Journal of Tropical Medicine and Hygiene 47(6): 709-720
1992
ISSN/ISBN: 0002-9637 PMID: 1361721 Document Number: 403227
[The authors] have developed a deterministic, susceptible, exposed, infectious, resistant or removed (SEIR) model of dengue fever transmission that enabled the authors to explore the behaviour of an epidemic, and to experiment with vector control practices. Populations of both host and vector [e.g. Aedes aegypti] are divided into compartments representing disease status (susceptible, exposed, infectious and, for humans, resistant), and the flow between compartments is described by differential equations. Examination of the equilibrium points led to a formulation of the basic reproduction rate (z0) of the disease. With a base set of parameters, z0 = 1.9 and the model realistically reproduced epidemic transmission in an immunologically naive population. Control of adult mosquitoes by ultra-low volume (ULV) aerosols was simulated by an abrupt decrease in vector densities, followed by gradual recovery of the vector population. The model indicated that ULV has little impact on disease incidence even when multiple applications are made, although the peak of the epidemic may be delayed. Decreasing the carrying capacity of the environment for mosquitoes, and thus the basic reproduction rate of the disease, by source reduction or other means, is more effective in reducing transmission. AS A deterministic, susceptible, exposed, infectious, resistant or removed (SEIR) model of dengue fever transmission was developed that enabled the authors to explore the behaviour of an epidemic, and to experiment with vector control practices. Populations of both host and vector (e.g. Aedes aegypti) are divided into compartments representing disease status (susceptible, exposed, infectious and, for humans, resistant), and the flow between compartments is described by differential equations. Examination of the equilibrium points led to a formulation of the basic reproduction rate (z0) of the disease. With a base set of parameters, z0 = 1.9 and the model realistically reproduced epidemic transmission in an immunologically naive population. Control of adult mosquitoes by ultra-low volume (ULV) aerosols was simulated by an abrupt decrease in vector densities, followed by gradual recovery of the vector population. The model indicated that ULV has little impact on disease incidence even when multiple applications are made, although the peak of the epidemic may be delayed. Decreasing the carrying capacity of the environment for mosquitoes, and thus the basic reproduction rate of the disease, by source reduction or other means, is more effective in reducing transmission.