Ximenes Raphael, Amaku Marcos, Lopez Luis Fernandez, Coutinho Francisco Antonio Bezerra, Burattini Marcelo Nascimento, Greenhalgh David, Wilder-Smith Annelies, Struchiner Claudio José, Massad Eduardo
School of Medicine, University of São Paulo and LIM01-HCFMUSP, São Paulo, SP, Brazil.
Center for Internet Augmented Research &Assessment, Florida International University, Miami, FL, USA.
BMC Infect Dis. 2016 Apr 29;16:186. doi: 10.1186/s12879-016-1517-z.
Rio de Janeiro in Brazil will host the Summer Olympic Games in 2016. About 400,000 non-immune foreign tourists are expected to attend the games. As Brazil is the country with the highest number of dengue cases worldwide, concern about the risk of dengue for travelers is justified.
A mathematical model to calculate the risk of developing dengue for foreign tourists attending the Olympic Games in Rio de Janeiro in 2016 is proposed. A system of differential equation models the spread of dengue amongst the resident population and a stochastic approximation is used to assess the risk to tourists. Historical reported dengue time series in Rio de Janeiro for the years 2000-2015 is used to find out the time dependent force of infection, which is then used to estimate the potential risks to a large tourist cohort. The worst outbreak of dengue occurred in 2012 and this and the other years in the history of Dengue in Rio are used to discuss potential risks to tourists amongst visitors to the forthcoming Rio Olympics.
The individual risk to be infected by dengue is very much dependent on the ratio asymptomatic/symptomatic considered but independently of this the worst month of August in the period studied in terms of dengue transmission, occurred in 2007.
If dengue returns in 2016 with the pattern observed in the worst month of August in history (2007), the expected number of symptomatic and asymptomatic dengue cases among tourists will be 23 and 206 cases, respectively. This worst case scenario would have an incidence of 5.75 (symptomatic) and 51.5 (asymptomatic) per 100,000 individuals.
巴西里约热内卢将于2016年举办夏季奥运会。预计约40万无免疫力的外国游客将参加此次奥运会。由于巴西是全球登革热病例数最多的国家，因此对旅行者感染登革热风险的担忧是合理的。
提出了一个数学模型，用于计算2016年参加里约热内卢奥运会的外国游客感染登革热的风险。一个微分方程系统对登革热在当地居民中的传播进行建模，并使用随机近似法来评估游客面临的风险。利用里约热内卢2000 - 2015年报告的登革热历史时间序列，找出随时间变化的感染力，然后用其估计大量游客群体面临的潜在风险。登革热最严重的疫情发生在2012年，利用此次疫情以及里约热内卢登革热历史上的其他年份，讨论即将到来的里约奥运会游客面临的潜在风险。
感染登革热的个体风险在很大程度上取决于所考虑的无症状/有症状比例，但与此无关的是，在所研究期间，从登革热传播角度来看，最糟糕的月份是2007年8月。
如果2016年登革热疫情重现2007年8月（历史上最糟糕的月份）的模式，那么游客中预计出现症状性和无症状性登革热病例数将分别为23例和206例。这种最坏情况的发病率将为每10万人中有5.75例（有症状）和51.5例（无症状）。
