Meteorological indicators of dengue epidemics in non-endemic Northwest Argentina.

In the last two decades dengue cases increased significantly throughout the world, giving place to more frequent outbreaks in Latin America. In the non-endemic city of San Ramón de la Nueva Orán, located in Northwest Argentina, large dengue outbreaks alternate with several years of smaller ones. This pattern, as well as the understanding of the underlying mechanisms, could be essential to design proper strategies to reduce epidemic size.

Reaction processes among self-propelled particles.

We study a system of self-propelled disks that perform run-and-tumble motion, where particles can adopt more than one internal state. One of those internal states can be transmitted to other particle if the particle carrying this state maintains physical contact with another particle for a finite period of time. We refer to this process as a reaction process and to the different internal states as particle species, making an analogy to chemical reactions.

Who benefits from cellular immune response during the Chagas disease?

We extend our previous model for the dynamical interaction between a mammal's immune response and the Trypanosoma cruzi parasite during the acute phase of Chagas disease. The model here considers both humoral and cellular responses and the different stages of T. cruzi (intracellular and extracellular phases) inside the mammal host.

Effects of rainfall on Culex mosquito population dynamics.

The dynamics of a mosquito population depends heavily on climatic variables such as temperature and precipitation. Since climate change models predict that global warming will impact on the frequency and intensity of rainfall, it is important to understand how these variables affect the mosquito populations. We present a model of the dynamics of a Culex quinquefasciatus mosquito population that incorporates the effect of rainfall and use it to study the influence of the number of rainy days and the mean monthly precipitation on the maximum yearly abundance of mosquitoes M.

Internal-external stimulus competition in a system of interacting moving particles: Persuasion versus propaganda.

We propose a general nonlinear analytical framework to study the effect of an external stimulus in the internal state of a population of moving particles. This novel scheme allows us to study a broad range of excitation transport phenomena. In particular, considering social systems, it gives insight of the spatial dynamics influence in the competition between propaganda (mass media) and convincement.

Can we heal Chagas infection?

We present a model for the parasite-antibody dynamical competition between Trypanosoma rangeli and its antibodies during the acute phase of an infection in a mammal host. The model reproduces experimental data from murine models found in the literature and allows us to demonstrate that a preinfection with T. rangeli induces a temporary protective effect against Chagas disease.

Why does GM1 induce a potent beneficial response to experimental Chagas disease?

Being one of the world's neglected diseases, Chagas has neither a vaccine nor a satisfactory therapy. Inoculation of murine models with the ganglioside GM1 has shown a strikingly nonlinear effect, leading to a strong decrease in parasite load at low doses but reverting to a load increase at high doses. Cardiocyte destruction concomitant with the disease is also significantly reduced by a moderate application of GM1.

Dynamics and steady states in excitable mobile agent systems.

We study the spreading of excitations in 2D systems of mobile agents where the excitation is transmitted when a quiescent agent keeps contact with an excited one during a nonvanishing time. We show that the steady states strongly depend on the spatial agent dynamics. Moreover, the coupling between exposition time (omega) and agent-agent contact rate (CR) becomes crucial to understand the excitation dynamics, which exhibits three regimes with CR: no excitation for low CR, an excited regime in which the number of quiescent agents (S) is inversely proportional to CR, and, for high CR, a novel third regime, model dependent, where S scales with an exponent xi-1, with xi being the scaling exponent of omega with CR.

Evolution of microorganism locomotion induced by starvation.

The search strategies of many organisms play a fundamental role in their competition to survive in a given environment. In this context, the propulsion systems of microorganisms have evolved during life history, to optimize the suitable use of energy they take from nutrients. Starting from a model for the motion of Brownian objects with internal energy depot, we show that the propulsion system of microorganisms has an optimal regimen while searching for new sources of food.

Dynamics of the antibody-T. cruzi competition during Chagas infection: prognostic relevance of intracellular replication.

A recently proposed model for the competitive parasite-antibody interactions in Chagas disease is extended by separately describing the parasitic intracellular and extracellular phases. The model solutions faithfully reproduce available population data and yield predictions for parasite-induced cardiac cell damage.

Dynamic analysis of a parasite population model.

We study the dynamics of a model that describes the competitive interaction between an invading species (a parasite) and its antibodies in an living being. This model was recently used to examine the dynamical competition between Tripanosoma cruzi and its antibodies during the acute phase of Chagas' disease. Depending on the antibody properties, the model yields three types of outcomes, corresponding, respectively, to healing, chronic disease, and host death.

A simple model for the interaction between T. cruzi and its antibodies during Chagas infection.

The evolution of the acute phase of the Chagas infection is analysed from the viewpoint of the dynamic competition between parasite and antibody populations. A simple model for the growth and annihilation of these populations is shown to provide a suitable description of the experimental data. We also find that it is possible to classify antibody response to Trypanosoma cruzi, into three main cases, defined by antibody efficiency, initial number and creation rate.