MARCOS AMAKU
Projetos de Pesquisa
Unidades Organizacionais
Departamento de Patologia, Faculdade de Medicina - Docente
LIM/01 - Laboratório de Informática Médica, Hospital das Clínicas, Faculdade de Medicina
LIM/01 - Laboratório de Informática Médica, Hospital das Clínicas, Faculdade de Medicina
6 resultados
Resultados de Busca
Agora exibindo 1 - 6 de 6
- The risk of dengue for non-immune foreign visitors to the 2016 summer olympic games in Rio de Janeiro, Brazil(2016) XIMENES, Raphael; AMAKU, Marcos; LOPEZ, Luis Fernandez; COUTINHO, Francisco Antonio Bezerra; BURATTINI, Marcelo Nascimento; GREENHALGH, David; WILDER-SMITH, Annelies; STRUCHINER, Claudio Jose; MASSAD, EduardoBackground: 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. Methods: 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. Results: 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. Conclusions: 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.
conferenceObject The risk of infectious diseases introduction into non-infected countries by travelers visiting endemic countries(2015) MASSAD, E.; LOPEZ, L. F.; AMAKU, M.; COUTINHO, F. A. B.; QUAM, M.; BURATTINI, M. N.; STRUCHINER, C. J.; WILDER-SMITH, A.- The risk of urban yellow fever resurgence in Aedes-infested American cities(2018) MASSAD, Eduardo; AMAKU, Marcos; COUTINHO, Francisco Antonio Bezerra; STRUCHINER, Claudio Jose; LOPEZ, Luis Fernandez; COELHO, Giovanini; WILDER-SMITH, Annelies; BURATTINI, Marcelo NascimentoAedes aegypti, historically known as yellow fever (YF) mosquito, transmits a great number of other viruses such as Dengue, West Nile, Chikungunya, Zika, Mayaro and perhaps Oropouche, among others. Well established in Africa and Asia, Aedes mosquitoes are now increasingly invading large parts of the American continent, and hence the risk of urban YF resurgence in the American cities should because of great concern to public health authorities. Although no new urban cycle of YF was reported in the Americas since the end of an Aedes eradication programme in the late 1950s, the high number of non-vaccinated individuals that visit endemic areas, that is, South American jungles where the sylvatic cycle of YF is transmitted by canopy mosquitoes, and return to Aedes-infested urban areas, increases the risk of resurgence of the urban cycle of YF. We present a method to estimate the risk of urban YF resurgence in dengue-endemic cities. This method consists in (1) to estimate the number of Aedes mosquitoes that explains a given dengue outbreak in a given region; (2) calculate the force of infection caused by the introduction of one infective individual per unit area in the endemic area under study; (3) using the above estimates, calculate the probability of at least one autochthonous YF case per unit area produced by one single viraemic traveller per unit area arriving from a YF endemic or epidemic sylvatic region at the city studied. We demonstrate that, provided the relative vector competence, here defined as the capacity to being infected and disseminate the virus, of Ae. aegypti is greater than 0.7 (with respect to dengue), one infected traveller can introduce urban YF in a dengue endemic area.
- Estimating the probability of dengue virus introduction and secondary autochthonous cases in Europe(2018) MASSAD, Eduardo; AMAKU, Marcos; COUTINHO, Francisco Antonio Bezerra; STRUCHINER, Claudio Jose; BURATTINI, Marcelo Nascimento; KHAN, Kamran; LIU-HELMERSSON, Jing; ROCKLOV, Joacim; KRAEMER, Moritz U. G.; WILDER-SMITH, AnneliesGiven the speed of air travel, diseases even with a short viremia such as dengue can be easily exported to dengue naive areas within 24 hours. We set out to estimate the risk of dengue virus introductions via travelers into Europe and number of secondary autochthonous cases as a result of the introduction. We applied mathematical modeling to estimate the number of dengue-viremic air passengers from 16 dengue-endemic countries to 27 European countries, taking into account the incidence of dengue in the exporting countries, travel volume and the probability of being viremic at the time of travel. Our models estimate a range from zero to 167 air passengers who are dengue-viremic at the time of travel from dengue endemic countries to each of the 27 receiving countries in one year. Germany receives the highest number of imported dengue-viremic air passengers followed by France and the United Kingdom. Our findings estimate 10 autochthonous secondary asymptomatic and symptomatic dengue infections, caused by the expected 124 infected travelers who arrived in Italy in 2012. The risk of onward transmission in Europe is reassuringly low, except where Aedes aegypti is present.
- Modeling Importations and Exportations of Infectious Diseases via Travelers(2016) LOPEZ, Luis Fernandez; AMAKU, Marcos; COUTINHO, Francisco Antonio Bezerra; QUAM, Mikkel; BURATTINI, Marcelo Nascimento; STRUCHINER, Claudio Jose; WILDER-SMITH, Annelies; MASSAD, EduardoThis paper is an attempt to estimate the risk of infection importation and exportation by travelers. Two countries are considered: one disease-free country and one visited or source country with a running endemic or epidemic infectious disease. Two models are considered. In the first model (disease importation), susceptible individuals travel from their disease-free home country to the endemic country and come back after some weeks. The risk of infection spreading in their home country is then estimated supposing the visitors are submitted to the same force of infection as the local population but do not contribute to it. In the second model (disease exportation), it is calculated the probability that an individual from the endemic (or epidemic) country travels to a disease-free country in the condition of latent infected and eventually introduces the infection there. The input of both models is the force of infection at the visited/source country, assumed known. The models are deterministic, but a preliminary stochastic formulation is presented as an appendix. The models are exemplified with two distinct real situations: the risk of dengue importation from Thailand to Europe and the risk of Ebola exportation from Liberia to the USA.
- Magnitude and frequency variations of vector-borne infection outbreaks using the Ross-Macdonald model: explaining and predicting outbreaks of dengue fever(2016) AMAKU, M.; AZEVEDO, F.; BURATTINI, M. N.; COELHO, G. E.; COUTINHO, F. A. B.; GREENHALGH, D.; LOPEZ, L. F.; MOTITSUKI, R. S.; WILDER-SMITH, A.; MASSAD, E.The classical Ross-Macdonald model is often utilized to model vector-borne infections; however, this model fails on several fronts. First, using measured (or estimated) parameters, which values are accepted from the literature, the model predicts a much greater number of cases than what is usually observed. Second, the model predicts a single large outbreak that is followed by decades of much smaller outbreaks, which is not consistent with what is observed. Usually towns or cities report a number of recurrences for many years, even when environmental changes cannot explain the disappearance of the infection between the peaks. In this paper, we continue to examine the pitfalls in modelling this class of infections, and explain that, if properly used, the Ross-Macdonald model works and can be used to understand the patterns of epidemics and even, to some extent, be used to make predictions. We model several outbreaks of dengue fever and show that the variable pattern of yearly recurrence (or its absence) can be understood and explained by a simple Ross-Macdonald model modified to take into account human movement across a range of neighbourhoods within a city. In addition, we analyse the effect of seasonal variations in the parameters that determine the number, longevity and biting behaviour of mosquitoes. Based on the size of the first outbreak, we show that it is possible to estimate the proportion of the remaining susceptible individuals and to predict the likelihood and magnitude of the eventual subsequent outbreaks. This approach is described based on actual dengue outbreaks with different recurrence patterns from some Brazilian regions.