EDUARDO MASSAD
Projetos de Pesquisa
Unidades Organizacionais
Departamento de MedicinaLegal, Ética Médica e Medicina Social e do Trabalho, Faculdade de Medicina - Docente
LIM/01 - Laboratório de Informática Médica, Hospital das Clínicas, Faculdade de Medicina - Líder
LIM/01 - Laboratório de Informática Médica, Hospital das Clínicas, Faculdade de Medicina - Líder
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conferenceObject Madeira's dengue outbreak in 2012: could it happen again in the near future?(2015) QUAM, M. B.; HELMERSSON, J. L.; MASSAD, E.; WILDER-SMITH, A.; ROCKL, J.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.- Equilibrium Analysis of a Yellow Fever Dynamical Model with Vaccination(2015) RAIMUNDO, Silvia Martorano; AMAKU, Marcos; MASSAD, EduardoWe propose an equilibrium analysis of a dynamical model of yellow fever transmission in the presence of a vaccine. The model considers both human and vector populations. We found thresholds parameters that affect the development of the disease and the infectious status of the human population in the presence of a vaccine whose protection may wane over time. In particular, we derived a threshold vaccination rate, above which the disease would be eradicated from the human population. We show that if the mortality rate of the mosquitoes is greater than a given threshold, then the disease is naturally (without intervention) eradicated from the population. In contrast, if the mortality rate of the mosquitoes is less than that threshold, then the disease is eradicated from the populations only when the growing rate of humans is less than another threshold; otherwise, the disease is eradicated only if the reproduction number of the infection after vaccination is less than 1. When this reproduction number is greater than 1, the disease will be eradicated from the human population if the vaccination rate is greater than a given threshold; otherwise, the disease will establish itself among humans, reaching a stable endemic equilibrium. The analysis presented in this paper can be useful, both to the better understanding of the disease dynamics and also for the planning of vaccination strategies.
conferenceObject Seasonality of dengue epidemic potential in Europe - based on vectorial capacity for Aedes mosquitoes(2015) HELMERSSON, J. L.; QUAM, M.; STENLUND, H.; WILDER-SMITH, A.; EBI, K.; MASSAD, E.; ROCKLOV, J.- Interpretations and pitfalls in modelling vector-transmitted infections(2015) AMAKU, M.; AZEVEDO, F.; BURATTINI, M. N.; COUTINHO, F. A. B.; LOPEZ, L. F.; MASSAD, E.In this paper we propose a debate on the role of mathematical models in evaluating control strategies for vector-borne infections. Mathematical models must have their complexity adjusted to their goals, and we have basically two classes of models. At one extreme we have models that are intended to check if our intuition about why a certain phenomenon occurs is correct. At the other extreme, we have models whose goals are to predict future outcomes. These models are necessarily very complex. There are models in between these classes. Here we examine two models, one of each class and study the possible pitfalls that may be incurred. We begin by showing how to simplify the description of a complicated model for a vector-borne infection. Next, we examine one example found in a recent paper that illustrates the dangers of basing control strategies on models without considering their limitations. The model in this paper is of the second class. Following this, we review an interesting paper (a model of the first class) that contains some biological assumptions that are inappropriate for dengue but may apply to other vector-borne infections. In conclusion, we list some misgivings about modelling presented in this paper for debate.
- A public health risk assessment for yellow fever vaccination: a model exemplified by an outbreak in the state of Sao Paulo, Brazil(2015) RIBEIRO, Ana Freitas; TENGAN, Cilea; SATO, Helena Keico; SPINOLA, Roberta; MASCHERETTI, Melissa; FRANCA, Ana Cecilia Costa; PORT-CARVALHO, Marcio; PEREIRA, Mariza; SOUZA, Renato Pereira de; AMAKU, Marcos; BURATTINI, Marcelo Nascimento; COUTINHO, Francisco Antonio Bezerra; LOPEZ, Luis Fernandez; MASSAD, EduardoWe propose a method to analyse the 2009 outbreak in the region of Botucatu in the state of Sao Paulo (SP), Brazil, when 28 yellow fever (YF) cases were confirmed, including 11 deaths. At the time of the outbreak, the Secretary of Health of the State of Sao Paulo vaccinated one million people, causing the death of five individuals, an unprecedented number of YF vaccine-induced fatalities. We apply a mathematical model described previously to optimise the proportion of people who should be vaccinated to minimise the total number of deaths. The model was used to calculate the optimum proportion that should be vaccinated in the remaining, vaccine-free regions of SP, considering the risk of vaccine-induced fatalities and the risk of YF outbreaks in these regions.
- A neurobiologically inspired model of social cognition: Memes spreading in the Internet(2015) ROCHA, Armando Freitas da; MASSAD, Eduardo; SANTOS, Paulo Cesar C. dos; PEREIRA JR., AlfredoThe field of memetics has attracted interdisciplinary attention as a biologically inspired approach to animal communication and sharing of human cultural patterns. Here a formalization of the theory of memes is proposed, making use of a formal language that is adequate to represent neural information processing. This formalization is the basis for our development of a model of social cognition including mathematical tools derived from the field of epidemiology. The model describes processes of communication between individuals of the same biological species, which share the same computational mechanisms of neural information processing. An example of the 'modus operandi' of the model is shown, consisting of a brief study of meme spreading in the Internet. Among the results of this study, we highlight: (1) The operationalization of memetics in a cognitive architecture that is based on biological constraints and possible to be implemented in digital computers; (2) the proposed model of meme spreading in an online social network may be of interest for public organisations, private corporations and people in general; and (3) the limitation of modeling should be considered when interpreting data about any dynamical phenomenon.
- Increasing Dengue Incidence in Singapore over the Past 40 Years: Population Growth, Climate and Mobility(2015) STRUCHINER, Claudio Jose; ROCKLOEV, Joacim; WILDER-SMITH, Annelies; MASSAD, EduardoIn Singapore, the frequency and magnitude of dengue epidemics have increased significantly over the past 40 years. It is important to understand the main drivers for the rapid increase in dengue incidence. We studied the relative contributions of putative drivers for the rise of dengue in Singapore: population growth, climate parameters and international air passenger arrivals from dengue endemic countries, for the time period of 1974 until 2011. We used multivariable Poisson regression models with the following predictors: Annual Population Size; Aedes Premises Index; Mean Annual Temperature; Minimum and Maximum Temperature Recorded in each year; Annual Precipitation and Annual Number of Air Passengers arriving from dengue-endemic South-East Asia to Singapore. The relative risk (RR) of the increase in dengue incidence due to population growth over the study period was 42.7, while the climate variables (mean and minimum temperature) together explained an RR of 7.1 (RR defined as risk at the end of the time period relative to the beginning and goodness of fit associated with the model leading to these estimates assessed by pseudo-R2 equal to 0.83). Estimating the extent of the contribution of these individual factors on the increasing dengue incidence, we found that population growth contributed to 86% while the residual 14% was explained by increase in temperature. We found no correlation with incoming air passenger arrivals into Singapore from dengue endemic countries. Our findings have significant implications for predicting future trends of the dengue epidemics given the rapid urbanization with population growth in many dengue endemic countries. It is time for policy-makers and the scientific community alike to pay more attention to the negative impact of urbanization and urban climate on diseases such as dengue.
- Potential for international spread of wild poliovirus via travelers(2015) WILDER-SMITH, Annelies; LEONG, Wei-Yee; LOPEZ, Luis Fernandez; AMAKU, Marcos; QUAM, Mikkel; KHAN, Kamran; MASSAD, EduardoBackground: The endgame of polio eradication is hampered by the international spread of poliovirus via travelers. In response to ongoing importations of poliovirus into polio-free countries, on 5 May 2014, WHO's Director-General declared the international spread of wild poliovirus a public health emergency of international concern. Our objective was to develop a mathematical model to estimate the international spread of polio infections. Methods: Our model took into account polio endemicity in polio-infected countries, population size, polio immunization coverage rates, infectious period, the asymptomatic-to-symptomatic ratio, and also the probability of a traveler being infectious at the time of travel. We applied our model to three scenarios: (1) number of exportations of both symptomatic and asymptomatic polio infections out of currently polio-infected countries, (2) the risk of spread of poliovirus to Saudi Arabia via Hajj pilgrims, and (3) the importation risk of poliovirus into India. Results: Our model estimated 665 polio exportations (>99 % of which were asymptomatic) from nine polio-infected countries in 2014, of which 78.3 % originated from Pakistan. Our model also estimated 21 importations of poliovirus into Saudi Arabia via Hajj pilgrims and 20 poliovirus infections imported to India in the same year. Conclusion: The extent of importations of asymptomatic and symptomatic polio infections is substantial. For countries that are vulnerable to polio outbreaks due to poor national polio immunization coverage rates, our newly developed model may help guide policy-makers to decide whether imposing an entry requirement in terms of proof of vaccination against polio would be justified.
- Plasmodium falciparum in the southeastern Atlantic forest: a challenge to the bromeliad-malaria paradigm?(2015) LAPORTA, Gabriel Zorello; BURATTINI, Marcelo Nascimento; LEVY, Debora; FUKUYA, Linah Akemi; OLIVEIRA, Tatiane Marques Porangaba de; MASELLI, Luciana Morganti Ferreira; CONN, Jan Evelyn; MASSAD, Eduardo; BYDLOWSKI, Sergio Paulo; SALLUM, Maria Anice MurebBackground: Recently an unexpectedly high prevalence of Plasmodium falciparum was found in asymptomatic blood donors living in the southeastern Brazilian Atlantic forest. The bromeliad-malaria paradigm assumes that transmission of Plasmodium vivax and Plasmodium malariae involves species of the subgenus Kerteszia of Anopheles and only a few cases of Plasmodium vivax malaria are reported annually in this region. The expectations of this paradigm are a low prevalence of Plasmodium vivax and a null prevalence of Plasmodium falciparum. Therefore, the aim of this study was to verify if Plasmodium falciparum is actively circulating in the southeastern Brazilian Atlantic forest remains. Methods: In this study, anophelines were collected with Shannon and CDC-light traps in seven distinct Atlantic forest landscapes over a 4-month period. Field-collected Anopheles mosquitoes were tested by real-time PCR assay in pools of ten, and then each mosquito from every positive pool, separately for Plasmodium falciparum and Plasmodium vivax. Genomic DNA of Plasmodium falciparum or Plasmodium vivax from positive anophelines was then amplified by traditional PCR for sequencing of the 18S ribosomal DNA to confirm Plasmodium species. Binomial probabilities were calculated to identify non-random results of the Plasmodium falciparum-infected anopheline findings. Results: The overall proportion of anophelines naturally infected with Plasmodium falciparum was 4.4% (21/480) and only 0.8% (4/480) with Plasmodium vivax. All of the infected mosquitoes were found in intermixed natural and human-modified environments and most were Anopheles cruzii (22/25 = 88%, 18 Plasmodium falciparum plus 4 Plasmodium vivax). Plasmodium falciparum was confirmed by sequencing in 76% (16/21) of positive mosquitoes, whereas Plasmodium vivax was confirmed in only 25% (1/4). Binomial probabilities suggest that Plasmodium falciparum actively circulates throughout the region and that there may be a threshold of the forested over human-modified environment ratio upon which the proportion of Plasmodium falciparum-infected anophelines increases significantly. Conclusions: These results show that Plasmodium falciparum actively circulates, in higher proportion than Plasmodium vivax, among Anopheles mosquitoes of fragments of the southeastern Brazilian Atlantic forest. This finding challenges the classical bromeliad-malaria paradigm, which considers Plasmodium vivax circulation as the driver for the dynamics of residual malaria transmission in this region.