Claudia Pio Ferreira

São Paulo State University | Unesp · Department of Biostatistics

At the beginning of the pandemic, the Brazilian Public Health System (SUS) did not to test all suspects cases of COVID-19, thus, hospitalized individuals, health professionals, and symptomatic contacts were prioritized. Contrary to the criteria adopted by the government, the municipality of Botucatu chose to test all people who manifested flu-like...

A sex-structured mathematical model is proposed to address the interactions among Wolbachia and Aedes mosquitoes. Several features associated with the infection that impacts mosquito phenotype like the cytoplasmic incompatibility, sex ratio biased to females, and maternal inheritance are considered. The analysis of the model shows the presence of t...

Intra- and interspecific competition is considered a fundamental phenomenon in ecology. It acts as one of the most powerful selective forces that drives ecological diversity, the spatiotemporal distribution of organisms, fitness, and evolutionary aspects. Spodoptera frugiperda and Helicoverpa armigera are devastating pests and can co-occur in syste...

In this paper, we investigate the local exact controllability of an age structured problem modelling the ability of malaria vectors to shift their biting time to avoid the stressful environmental conditions generated by the use of indoor residual spraying (IRS) and insecticide-treated nets (ITNs). We establish a new Carleman’s inequality for our ag...

During the coronavirus disease 2019 (COVID-19) pandemic, governments used mobility data to assess the effectiveness of social distancing policies, but is it really possible to measure the effectiveness of epidemic control measures using mobility data? In this work, we found that the relationship between mobility data and epidemic metrics is far fro...

Interrupted time series analyses were conducted to measure the impact of social distancing policies (instituted on March 22, 2020) and of subsequent mandatory masking in the community (instituted on May 4, 2020) on the incidence and effective reproductive number of COVID-19 in São Paulo State, Brazil. Overall, the impact of social distancing both o...

Sequential infections with different dengue serotypes (DENV-1, 4) significantly increase the risk of a severe disease outcome (fever, shock, and hemorrhagic disorders). Two hypotheses have been proposed to explain the severity of the disease: (1) antibody-dependent enhancement (ADE) and (2) original T cell antigenic sin. In this work, we explored t...

In 2020, the world experienced its very first pandemic of the globalized era. A novel coronavirus, SARS-CoV-2, is the causative agent of severe pneumonia and has rapidly spread through many nations, crashing health systems and leading a large number of people to death. In Brazil, the emergence of local epidemics in major metropolitan areas has alwa...

In response to the COVID-19 pandemic, most governments around the world implemented some kind of social distancing policy in an attempt to block the spreading of the virus within a territory. In Brazil, this mitigation strategy was first implemented in March 2020 and mainly monitored by social isolation indicators built from mobile geolocation data...

The spatio-temporal dynamics of insect pests in agricultural landscapes involves the potential of species to move, invade, colonise, and establish in different areas. This study revised the dispersal of the important crop pests Diabrotica speciosa Germar and Spodoptera frugiperda (J.E. Smith) by using computational modelling to represent the moveme...

Transgenic crops expressing Bacillus thuringiensis Berliner (Bt) have been cultivated throughout the world as a great technological tool for developing integrated pest management. We hypothesized that artificial landscapes containing Bt and non‐Bt cotton plants (Gossypium hirsutum L., Malvaceae) at small scales could influence dispersal by ballooni...

Development, mortality, fecundity, and longevity of soybean looper Chrysodeixis includens (Walker) (Lepidoptera: Noctuidae, Plusiinae) were examined at six constant temperatures (18, 22, 25, 28, 32, and 36∘C) under laboratory conditions. This set range comprises temperatures observed at soybean- and cotton-producing regions during the growing seaso...

An agent-based model is proposed to access the impact of vaccination strategies to halt the COVID-19 spread. The model is parameterized using data from S&atildeo Paulo State, Brazil. It was considered the two vaccines that are already approved for emergency use in Brazil, the CoronaVac vaccine developed by the Chinese biopharmaceutical company Sino...

Competition behavior involving agricultural pest species has long been viewed as a powerful selective force that drives ecological and phenotypic diversity. In this context, a Game Theory-based approach may be useful to describe the decision-making dilemma of a competitor with impacts to guarantee its superiority in terms of ecological dominance or...

Public health policies to contain the spread of COVID-19 rely mainly on non-pharmacological measures. Those measures, especially social distancing, are a challenge for developing countries, such as Brazil. In São Paulo, the most populous state in Brazil (45 million inhabitants), most COVID-19 cases up to April 18th were reported in the Capital and...

Two hundred days after the first confirmed case of COVID-19 in Brazil, the epidemic has rapidly spread in metropolitan areas and advanced throughout the countryside. We followed the temporal epidemic pattern at São Paulo State, the most populous of the country, the first to have a confirmed case of COVID-19, and the one with the most significant nu...

Starting from an age structured partial differential model, constructed taking into account the mosquito life cycle and the main features of the Wolbachia -infection, we derived a delay differential model using the method of characteristics, to study the colonization and persistence of the Wolbachia -transinfected Aedes aegypti mosquito in an envir...

The impact of influenza vaccination is largely measured by estimating vaccine effectiveness (VE), which vary in different seasons. Strain mutations and waning immunity present two key mechanisms affecting VE. We sought to quantify the relative effect of these mechanisms by projecting VE and the reduction of illness due to vaccination. We developed...

Interrupted time series analyses (ITSA) were performed to measure the impact of social distancing policies (instituted 22/03/2020) and subsequent mandatory masking in the community (instituted 04/05/2020) on the incidence and effective reproductive number (Rt) of COVID-19 in São Paulo State, Brazil. Overall, the impact of social distancing both on...

Different countries have adopted strategies for the early detection of SARS-CoV-2 since the declaration of community transmission by the World Health Organization (WHO) and timely diagnosis has been considered one of the major obstacles for surveillance and healthcare. Here, we report the increase of the number of laboratories to COVID-19 diagnosis...

Even though the impact of COVID-19 in metropolitan areas has been extensively studied, the geographic spread to smaller cities is also of great concern. We conducted an ecological study aimed at identifying predictors of early introduction, incidence rates of COVID-19 and mortality (up to 8 May 2020) among 604 municipalities in inner São Paulo Stat...

Laboratory and field tests have been highlight the importance of choosing an optimal Wolbachia strain to ensure the success of colonization and persistence of the released Aedes aegypti infected mosquito. Thresholds for vertical infection transmission and male sterilization depend on bacterial density and its distribution in mosquitoes tissue, whic...

Public health policies to contain the spread of COVID-19 rely mainly on non-pharmacological measures. Those measures, especially social distancing, are a challenge for developing countries, such as Brazil. In Sao Paulo, the most populous state in Brazil (45 million inhabitants), most COVID-19 cases up to April 18th were reported in the Capital and...

Early 2020 and the world experiences its very first pandemic of globalized era. A novel coronavirus, SARS-Cov-2, is the causative agent of severe pneumonia and rapidly spread through many nations, crashing health systems. In Brazil, the emergence of local epidemics in major metropolitan areas is a concern. In a huge and heterogeneous country, with...

Objectives: The impact of COVID-19 in metropolitan areas has been extensively studied. The geographic spread to smaller cities is of great concern and may follow hierarchical influence of urban centers. With that in mind, we investigated factors that affect vulnerability of inner municipalities in São Paulo State, Brazil, an area with 24 million in...

Background: The feeding preferences of Diabrotica speciosa(Coleoptera: Chrysomelidae) cause a parent-offspring conflict, as providing the best host for the offspring development is detrimental to adult survival and fecundity. Understanding the implications of this conflict could help entomologists to implement pest-management programs.With this in...

Dengue hemorrhagic fever (DHF) can occur in primary dengue virus infection of infants \(<1\) year of age. To understand the presumed role of maternal dengue-specific antibodies received until birth in the development of this primary DHF in infants, we investigated a mathematical model based on a system of nonlinear ordinary differential equations t...

In this paper, we are concerned with an epidemic model of susceptible, infected and recovered (SIR) population dynamic by considering an age-structured phase of protection with limited duration, for instance due to vaccination or drugs with temporary immunity. The model is reduced to a delay differential-difference system, where the delay is the du...

We present a stochastic model that mimics dengue transmission when two serotypes of the virus are circulating in a human population connected by a Watts–Strogatz complex network that reflects social interactions (human mobility). The influence of the number of connections per vertex and the network topology on the epidemics is analyzed. The first r...

This paper presents an age structured problem modelling mosquito blood-feeding plasticity in a natural environment. We first investigate the analytical asymptotic solution through studying the spectrum of an operator A which is the infinitesimal generator of a C0-semigroup. Indeed, the study of the spectrum of A per se is interesting. Additionally,...

A mathematical model considering female and male individuals is proposed to evaluate vaccination strategies applied to control of HPV transmission in human population. The basic reproductive number of the disease, R 0 is given by the geometric mean of the basic reproductive number of female and male populations. The model has a globally asymptotica...

A mathematical model considering female and male individuals is proposed to evaluate vaccination strategies applied to control of HPV transmission in human population. The basic reproductive number of the disease, $R_0$, is given by the geometric mean of the basic reproductive number of female and male populations. The model has a globally asymptot...

Among lepidopteran insects, the fall armyworm, Spodoptera frugiperda, deserves special attention because of its agricultural importance. Different computational approaches have been proposed to clarify the dynamics of fall armyworm populations, but most of them have not been tested in the field and do not include one of the most important variables...

In this work we formulate a mathematical model to assess the importance of sexual transmission during the Zika virus outbreak that occurred in Rio de Janeiro, Brazil, in 2015. To this end, we deduce from the model an analytical expression of the basic reproduction number of Zika, R0, in terms of the vectorial and sexual transmissions, and we use th...

Background The development of a safe and effective vaccine is considered crucial for dengue transmission control since vetor control has been failed; some potential candidates are currently in test, and in this context theoretical studies are necessary to evaluate vaccination strategies such as the age groups that should be vaccinated, the percenta...

Healthcare-associated infections cause significant patient morbidity and mortality, and contribute to growing healthcare costs, whose effects may be felt most strongly in developing countries. Active surveillance systems, hospital staff compliance, including hand hygiene, and a rational use of antimicrobials are among the important measures to miti...

The evolutionary trend toward increasing complexity and social function is ultimately the result of natural selection's paradoxical tendency to foster cooperation through competition. Cooperating populations ranging from complex societies to somatic tissue are constantly under attack, however, by non-cooperating mutants or transformants, called ‘ch...

In this paper, we study an age-structured model which has strong biological background about mosquito plasticity. Firstly, we prove the existence of solutions and the comparison principle for a generalized system. Then, we prove the existence of the optimal control for the best harvesting. Finally, we establish necessary optimality conditions.

This paper presents an age structured problem modelling mosquito blood-feeding plasticity in a natural environment. We first investigate the analytical asymptotic solution through studying the spectrum of an operator $\mathbb{A}$ which is the infinitesimal generator of a $C_0$-semigroup. Indeed, the study of the spectrum of $\mathbb{A}$ {\it per se...

Background Evidence of changing in biting and resting behaviour of the main malaria vectors has been mounting up in recent years as a result of selective pressure by the widespread and long-term use of insecticide-treated bed nets (ITNs), and indoor residual spraying. The impact of resistance behaviour on malaria intervention efficacy has important...

The selection pressure imposed by the widespread use of transgenic technologies can lead to the evolution of insect resistance, and the availability of refuge areas that allow susceptible homozygous insects to survive is a key factor in delaying the evolution of resistance in agricultural landscapes. Different strategies to exploit refuge areas exi...

A compartmental model was developed to describe the temporal course of an exotic amphipod's population, Talitroides topitotum, in an Atlantic Forest habitat in Brazil. Extensive biological information — including breeding pattern, development and mortality rates, and temperature dependence of the parameters — were considered in the model. A genetic...

This book brings together nine chapters that aim to present the most recent research on the interface between ecological modelling and entomology. The chapters are summaries of research performed in different Brazilian institutions, UK and Ireland universities. The idea of the book is to present different focuses of study by aggregating theoretical...

We report on the use of a spatially explicit model and clustering analysis in order to investigate habitat manipulation as a strategy to regulate natural population densities of the insect-pest Diabrotica speciosa. Habitat manipulation involved four major agricultural plants used as hosts by this herbivore to compose intercropping landscapes. Avail...

We studied the effects of landscape structure on species with resource nutritional partition between the immature and adult stages by investigating how food quality and spatial structure of a landscape may affect the invasion and colonization of the insect pest, Diabrotica speciosa. To this end, we formulated two bidimensional stochastic cellular a...

In this paper we show how to obtain efficient designs of experiments for fitting Michaelis-Menten and Hill equations useful in chemical studies. The search of exact D-optimal designs by using local and pseudo-Bayesian approaches is considered. Optimal designs were compared to those commonly used in practice using an efficiency measure and theore...

This book provides a synopsis of the major topics currently studied in entomology combining population theory with experimentation. The chapters address different ecological aspects important for agricultural and medical entomology, emphasising pest management and conservation.

The population dynamics of blowflies (Diptera: Calliphoridae) has been investigated in studies combining different mathematical formalisms, with estimates of demographic parameters and spatial models. However, these applications are limited to laboratory data only. In this study, we investigated the population dynamics of three species of blowflies...

In this study, a mathematical model with temporal dependence for dengue transmission was developed, considering coupling between human population and the vector mosquito, and a sorotype circulating on population. This model was analysed with the goal to explain disease's periodicity. Finally, a genetic algorithm was set up to study model's sensibil...

This study focused on representing spatio-temporal patterns of fungal dispersal using cellular automata. Square lattices were used, with each site representing a host for a hypothetical fungus population. Four possible host states were allowed: resistant, permissive, latent or infectious. In this model, the probability of infection for each of the...

Since 1997, the Lethargic Crab Disease (LCD) has decimated native populations of the mangrove land crab Ucides cordatus (Decapoda: Ocypodidae) along the Brazilian coast, spreading preferentially in the North–South direction and showing a periodic epidemic behavior. To study the spatial dissemination of LCD between estuaries, we propose a mathematic...

Este trabalho visou modelar o padrão de dispersão espaço-temporal de fungos em superfícies planas via o formalismo de Autômatos Celulares. Os autômatos foram aloca-dos em um reticulado bidimensional, em analogia à disposição espacial de uma população hipotética de hospedeiros. A cada autômato foi atribuído um dentre um conjunto de quatro estados po...

This paper presents a mathematical model for cholera epidemics which comprises seasonality, loss of host immunity, and control mechanisms acting to reduce cholera transmission. A collection of data related to cholera disease allows us to show that outbreaks in endemic areas are subject to a resonant behavior, since the intrinsic oscillation period...

In this work, we use a mathematical model for dengue transmission with the aim of analysing and comparing two dengue epidemics that occurred in Salvador, Brazil, in 1995-1996 and 2002. Using real data, we obtain the force of infection, Λ, and the basic reproductive number, R(0), for both epidemics. We also obtain the time evolution of the effective...

Neste trabalho apresenta-se um modelo de mapas acoplados para o estudoda dispersao da Doenca do Caranguejo Letargico (DCL) entre dois estuarios, em que mediu-se a influencia da coleta de caranguejos e da existencia de caranguejos resistentes sobre a dinâmica da doenca. Observou-se que a coleta de caranguejos afeta tanto a intensidade quanto a perio...

Neste trabalho foi abordada a constru»c~ao de delineamentos experimentais ¶otimos exatos quando resposta de interesse pode ser modelada pela equa»c~ao de Michaelis-Menten. Foi suposta a situa»c~ao em que o pesquisador deseja maximizar a informa»c~ao obtida sobre os par^ametros do modelo e, portanto, foi utilizado o crit¶erio de D-otimalidade. Para...

Ecological modeling is an important tool for investigating dynamic behavior patterns in populations, trophic interactions, and behavioral ecology. However, the ecological patterns that reflect population oscillation trends are often not clearly visible without analytical instruments such as ecological models. Thus, ecological modeling plays a funda...

The lethargic crab disease (LCD) is an emergent infirmity that has decimated native populations of the mangrove land crab (Ucides cordatus, Decapoda: Ocypodidae) along the Brazilian coast. Several potential etiological agents have been linked with LCD, but only in 2005 was it proved that it is caused by an ascomycete fungus. This is the first attem...

We performed a computational analysis employing a cellular automata model to investigate the larval dispersal behavior of blowflies. The spatially discrete model developed here, incorporates simple behavioral rules in local interactions to produce the large-scale patterns observed in the larval dispersal process. We were able to find parameter rang...