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As of May 27, 2018, 6 suspected, 13 probable and 35 confirmed cases of Ebola virus disease (EVD) had been reported in Équateur Province, Democratic Republic of Congo. We used reported case counts and time series from prior outbreaks to estimate the total outbreak size and duration with and without vaccine use. We modeled Ebola virus transmission using a stochastic branching process model that included reproduction numbers from past Ebola outbreaks and a particle filtering method to generate a probabilistic projection of the outbreak size and duration conditioned on its reported trajectory to date; modeled using high (62%), low (44%), and zero (0%) estimates of vaccination coverage (after deployment). Additionally, we used the time series for 18 prior Ebola outbreaks from 1976 to 2016 to parameterize the Thiel-Sen regression model predicting the outbreak size from the number of observed cases from April 4 to May 27. We used these techniques on probable and confirmed case counts with and without inclusion of suspected cases. Probabilistic projections were scored against the actual outbreak size of 54 EVD cases, using a log-likelihood score. With the stochastic model, using high, low, and zero estimates of vaccination coverage, the median outbreak sizes for probable and confirmed cases were 82 cases (95% prediction interval [PI]: 55, 156), 104 cases (95% PI: 58, 271), and 213 cases (95% PI: 64, 1450), respectively. With the Thiel-Sen regression model, the median outbreak size was estimated to be 65.0 probable and confirmed cases (95% PI: 48.8, 119.7). Among our three mathematical models, the stochastic model with suspected cases and high vaccine coverage predicted total outbreak sizes closest to the true outcome. Relatively simple mathematical models updated in real time may inform outbreak response teams with projections of total outbreak size and duration.

Travel frequency of people varies widely with occupation, age, gender, ethnicity, income, climate and other factors. Meanwhile, the distribution of the numbers of times people in different regions or with different travel behaviors bitten by mosquitoes may be nonuniform. To reflect these two heterogeneities, we develop a multipatch model to study the impact of travel frequency and human biting rate on the spatial spread of mosquito-borne diseases. The human population in each patch is divided into four classes: susceptible unfrequent, infectious unfrequent, susceptible frequent, and infectious frequent. The basic reproduction number R0 is defined. It is shown that the disease-free equilibrium is globally asymptotically stable if R0 ≤ 1, and there is a unique endemic equilibrium that is globally asymptotically stable if R0 > 1. A more detailed study is conducted on the single patch model. We use analytical and numerical methods to demonstrate that the model without considering the difference of humans in travel frequency mostly underestimates the risk of infection. Numerical simulations suggest that the greater the difference in travel frequency, the larger the underestimate of the transmission potential. In addition, the basic reproduction number R0 may decreasingly, or increasingly, or nonmonotonically vary when more people travel frequently. [ABSTRACT FROM AUTHOR]

Dong, D.; Zhu, D.; Ya, H.; Chen, X., and Chen, B., 2019. Typhoon-driven storm jet generation and water level fluctuations near the coast of Guangxi. In: Guido-Aldana, P.A. and Mulahasan, S. (eds.), Advances in Water Resources and Exploration. Journal of Coastal Research, Special Issue No. 93, pp. 427–435. Coconut Creek (Florida), ISSN 0749-0208. Using acoustic Doppler current profiler data from a single station for one year in duration, as well as associated tide level and wind field observational data, the corresponding relationship between westward storm jets and water level fluctuation near the coast of Guangxi during Typhoon Nesat in 2011 is studied. The primary causes of the formation of the westward storm jets near the coast of Guangxi during the typhoon are analyzed. The results show that during the landfall of the typhoon, the surface and bottom current velocities were more than doubled compared to conditions without the typhoon. The maximum residual current speed was more than tripled compared to the normal situation. It is very rare to observe such strong westward storm jets less than 1 km offshore. The generation of strong westward storm jets and water level fluctuation were closely related to the typhoon. Systematic study on the theories of deformation, intensification, and decay of storm jets after the jets entered the coastal bay of Guangxi during the typhoon is of theoretical and practical significance for revealing the characteristics of Guangxi nearshore pollutant transport. [ABSTRACT FROM AUTHOR]

Chen, B.; Dong, D.; Qin, X.; Xu, M.; Chen, X., and Shi, M., 2019. Relationship between the occurrence of red tides and the dynamic response mechanisms in the northern Beibu Gulf. In: Guido-Aldana, P.A. and Mulahasan, S. (eds.), Advances in Water Resources and Exploration. Journal of Coastal Research, Special Issue No. 93, pp. 185–193. Coconut Creek (Florida), ISSN 0749-0208. Unlike the common outbreak mechanism of red tides, the northern Beibu Gulf in the Guangxi Zhuang Autonomous Region of China experiences frequent red tides with distinct characteristics, such as large distances from the mainland and the presence of industrial pollution. By tracing the sources and transport of the high concentrations of nitrogen and phosphorus, the relationship between pollutant transport and the dynamic response mechanisms was explored. The results showed that the concentrations of nitrogen and phosphorus nutrients in the areas of red tide outbreaks near Weizhou Island and in the Qinzhou Gulf in the northern Beibu Gulf were higher than those in the surrounding areas. However, the high concentrations of nitrogen and phosphorus nutrients in the northern Beibu Gulf did not originate from terrestrial pollution from Guangxi Province; rather, these pollutants originated on the east coast of China and were transported through the Qiongzhou Strait. The primary sources were the Pearl River Estuary and the coastal waters of eastern Guangdong. In addition, the differences in the concentration distributions of nitrogen and phosphorus nutrients between the east and west coasts of the Qinzhou Gulf in the northern Beibu Gulf were clearly related to dynamic response mechanisms. [ABSTRACT FROM AUTHOR]