H Gil1, W A Qualls2, C Cosner3, D L DeAngelis4, A Hassan5, A M Gad6, S Ruan7, S R Cantrell8, J C Beier9. 1. Department of Public Health Sciences, University of Miami Miller School of Medicine, Miami, FL, USA. Electronic address: hgil@med.miami.edu. 2. Department of Public Health Sciences, University of Miami Miller School of Medicine, Miami, FL, USA. Electronic address: w.qualls@med.miami.edu. 3. Department of Mathematics, University of Miami, Miami, FL, USA. Electronic address: gcc@math.miami.edu. 4. Department of Biology, University of Miami, Miami, FL, USA. Electronic address: ddeangelis@bio.miami.edu. 5. Institute of Environmental Studies and Research, Ain Shams University, Egypt. Electronic address: ali.9973@gmail.com. 6. Department of Entomology, Ain Shams University, Egypt. Electronic address: adelgad2002@yahoo.com. 7. Department of Mathematics, University of Miami, Miami, FL, USA. Electronic address: ruan@math.miami.edu. 8. Department of Mathematics, University of Miami, Miami, FL, USA. Electronic address: rsc@math.miami.edu. 9. Department of Public Health Sciences, University of Miami Miller School of Medicine, Miami, FL, USA. Electronic address: jbeier@med.miami.edu.
Abstract
OBJECTIVES: Rift-Valley Fever (RVF) is a zoonotic mosquito-borne disease in Africa and the Arabian Peninsula. Drivers for this disease vary by region and are not well understood for North African countries such as Egypt. A deeper understanding of RVF risk factors would inform disease management policies. STUDY DESIGN: The present study employs mathematical and computational modeling techniques to ascertain the extent to which the severity of RVF epizootics in Egypt differs depending on the interaction between imported ruminant and environmentally-constrained mosquito populations. METHODS: An ordinary differential system of equations, a numerical model, and an individual-based model (IBM) were constructed to represent RVF disease dynamics between localized mosquitoes and ruminants being imported into Egypt for the Greater Bairam. Four cases, corresponding to the Greater Bairam's occurrence during distinct quarters of the solar year, were set up in both models to assess whether the different season-associated mosquito populations present during the Greater Bairam resulted in RVF epizootics of variable magnitudes. RESULTS: The numerical model and the IBM produced nearly identical results: ruminant and mosquito population plots for both models were similar in shape and magnitude for all four cases. In both models, all four cases differed in the severity of their corresponding simulated RVF epizootics. The four cases, ranked by the severity of the simulated RVF epizootics in descending order, correspond with the occurrence of the Greater Bairam on the following months: July, October, April, and January. The numerical model was assessed for sensitivity with respect to parameter values and exhibited a high degree of robustness. CONCLUSIONS: Limiting the importation of infected ruminants beginning one month prior to the Greater Bairam festival (on years in which the festival falls between the months of July and October: 2014-2022) might be a feasible way of mitigating future RVF epizootics in Egypt.
OBJECTIVES:Rift-Valley Fever (RVF) is a zoonotic mosquito-borne disease in Africa and the Arabian Peninsula. Drivers for this disease vary by region and are not well understood for North African countries such as Egypt. A deeper understanding of RVF risk factors would inform disease management policies. STUDY DESIGN: The present study employs mathematical and computational modeling techniques to ascertain the extent to which the severity of RVF epizootics in Egypt differs depending on the interaction between imported ruminant and environmentally-constrained mosquito populations. METHODS: An ordinary differential system of equations, a numerical model, and an individual-based model (IBM) were constructed to represent RVF disease dynamics between localized mosquitoes and ruminants being imported into Egypt for the Greater Bairam. Four cases, corresponding to the Greater Bairam's occurrence during distinct quarters of the solar year, were set up in both models to assess whether the different season-associated mosquito populations present during the Greater Bairam resulted in RVF epizootics of variable magnitudes. RESULTS: The numerical model and the IBM produced nearly identical results: ruminant and mosquito population plots for both models were similar in shape and magnitude for all four cases. In both models, all four cases differed in the severity of their corresponding simulated RVF epizootics. The four cases, ranked by the severity of the simulated RVF epizootics in descending order, correspond with the occurrence of the Greater Bairam on the following months: July, October, April, and January. The numerical model was assessed for sensitivity with respect to parameter values and exhibited a high degree of robustness. CONCLUSIONS: Limiting the importation of infected ruminants beginning one month prior to the Greater Bairam festival (on years in which the festival falls between the months of July and October: 2014-2022) might be a feasible way of mitigating future RVF epizootics in Egypt.
Authors: Assaf Anyamba; Jean-Paul Chretien; Jennifer Small; Compton J Tucker; Pierre B Formenty; Jason H Richardson; Seth C Britch; David C Schnabel; Ralph L Erickson; Kenneth J Linthicum Journal: Proc Natl Acad Sci U S A Date: 2009-01-14 Impact factor: 11.205
Authors: Assaf Anyamba; Kenneth J Linthicum; Jennifer Small; Seth C Britch; Edwin Pak; Stephane de La Rocque; Pierre Formenty; Allen W Hightower; Robert F Breiman; Jean-Paul Chretien; Compton J Tucker; David Schnabel; Rosemary Sang; Karl Haagsma; Mark Latham; Henry B Lewandowski; Salih Osman Magdi; Mohamed Ally Mohamed; Patrick M Nguku; Jean-Marc Reynes; Robert Swanepoel Journal: Am J Trop Med Hyg Date: 2010-08 Impact factor: 2.345
Authors: R R Arthur; M S el-Sharkawy; S E Cope; B A Botros; S Oun; J C Morrill; R E Shope; R G Hibbs; M A Darwish; I Z Imam Journal: Lancet Date: 1993-11-06 Impact factor: 79.321