Chamchod Farida, Cosner Chris, Cantrell R Stephen, Beier John C, Ruan Shigui
Department of Mathematics, Faculty of Science, Mahidol University Bangkok, Thailand.
Department of Mathematics, University of Miami Coral Gables, FL, USA.
Front Microbiol. 2016 Feb 1;6:1568. doi: 10.3389/fmicb.2015.01568. eCollection 2015.
Rift Valley fever virus (RVFV) is an arthropod-borne viral pathogen that causes significant morbidity and mortality in small ruminants throughout Africa and the Middle East. Due to the sporadic and explosive nature of RVF outbreaks, vaccination has proved challenging to reduce RVFV infection in the ruminant population. Currently, there are two available types of vaccines, live and killed, in endemic areas. In this study, two mathematical models have been developed to explore the impact of live and killed vaccines on the transmission dynamics of RVFV. We demonstrate in general that vaccination helps reduce the severity of RVF outbreaks and that less delay in implementation and more vaccination attempts and effective vaccines can reduce the outbreak magnitude and the endemic number of RVFV. However, an introduction of a number of ruminants vaccinated by live vaccines in RVFV-free areas may cause an outbreak and RVFV may become endemic if there is sustained use of live vaccines. Other factors that are the important determinants of RVF outbreaks include: unsustained vaccination programs, recruitment of susceptible ruminants, and the seasonal abundance of mosquitoes.
裂谷热病毒（RVFV）是一种节肢动物传播的病毒病原体，在非洲和中东的小型反刍动物中可导致严重发病和死亡。由于裂谷热疫情具有散发性和爆发性，事实证明，通过疫苗接种来减少反刍动物群体中的RVFV感染具有挑战性。目前，在流行地区有两种可用的疫苗类型，即活疫苗和灭活疫苗。在本研究中，已开发出两种数学模型，以探讨活疫苗和灭活疫苗对RVFV传播动态的影响。我们总体上证明，疫苗接种有助于降低裂谷热疫情的严重程度，并且实施过程中延迟更少、疫苗接种尝试更多以及使用有效的疫苗可以降低疫情规模和RVFV的地方流行数量。然而，在无RVFV地区引入一些接种了活疫苗的反刍动物可能会引发疫情，如果持续使用活疫苗，RVFV可能会成为地方病。其他作为裂谷热疫情重要决定因素的因素包括：非持续性的疫苗接种计划、易感反刍动物的引入以及蚊子的季节性大量繁殖。
