Brauer Fred, Castillo-Chavez Carlos, Mubayi Anuj, Towers Sherry
University of British Columbia, Vancouver, BC, Canada.
Arizona State University, Tempe, AZ, USA.
Infect Dis Model. 2016 Aug 30;1(1):79-87. doi: 10.1016/j.idm.2016.08.001. eCollection 2016 Oct.
Vector-transmitted diseases such as dengue fever and chikungunya have been spreading rapidly in many parts of the world. The Zika virus has been known since 1947 and invaded South America in 2013. It can be transmitted not only by (mosquito) vectors but also directly through sexual contact. Zika has developed into a serious global health problem because, while most cases are asymptomatic or very light, babies born to Zika - infected mothers may develop microcephaly and other very serious birth defects. We formulate and analyze two epidemic models for vector-transmitted diseases, one appropriate for dengue and chikungunya fever outbreaks and one that includes direct transmission appropriate for Zika virus outbreaks. This is especially important because the Zika virus is the first example of a disease that can be spread both indirectly through a vector and directly (through sexual contact). In both cases, we obtain expressions for the basic reproduction number and show how to use the initial exponential growth rate to estimate the basic reproduction number. However, for the model that includes direct transmission some additional data would be needed to identify the fraction of cases transmitted directly. Data for the 2015 Zika virus outbreak in Barranquilla, Colombia has been used to fit parameters to the model developed here and to estimate the basic reproduction number.
登革热和基孔肯雅热等病媒传播疾病在世界许多地区迅速蔓延。寨卡病毒自1947年被发现，2013年侵入南美洲。它不仅可以通过（蚊子）病媒传播，还能通过性接触直接传播。寨卡病毒已发展成为一个严重的全球健康问题，因为虽然大多数病例无症状或症状很轻，但感染寨卡病毒的母亲所生婴儿可能会出现小头畸形和其他非常严重的出生缺陷。我们构建并分析了两种病媒传播疾病的流行模型，一种适用于登革热和基孔肯雅热疫情，另一种包括适用于寨卡病毒疫情的直接传播情况。这一点尤为重要，因为寨卡病毒是首例既能通过病媒间接传播又能直接（通过性接触）传播的疾病。在这两种情况下，我们都得到了基本再生数的表达式，并展示了如何利用初始指数增长率来估计基本再生数。然而，对于包含直接传播的模型，需要一些额外数据来确定直接传播病例的比例。哥伦比亚巴兰基亚2015年寨卡病毒疫情的数据已被用于拟合此处建立的模型参数，并估计基本再生数。
