PThematic project recently started by researchers from Unicamp in collaboration with experts from other institutions aims to develop methods and tools that allow analyzing the behavior of diseases from a spatial point of view. The ultimate objective is to understand how diseases spread in a given region or municipality, which should enable the adoption of more effective measures to control them. The studies are initially considering dengue (Campinas) and work accidents (Piracicaba). “However, we believe that the method could be applied to any type of epidemic phenomenon”, infers the coordinator of the work, epidemiologist Ricardo Cordeiro, professor at the Faculty of Medical Sciences (FCM).

Project brings together scientists from different areas

According to him, although it is still in its infancy, the project has generated preliminary results that allow researchers to better understand the behavior of diseases in relation to space. In the case of dengue, for example, research is currently concentrated in the southern region of Campinas. Scientists were able to demonstrate that severe cases of the disease have a different distribution than those considered mild and moderate. Simply put, it is as if two distinct epidemics were occurring in that area. Ricardo Cordeiro informs that researchers are working with two hypotheses to explain the phenomenon.

The first, which he considers the most likely, points out that the region has recorded other dengue epidemics in the past, which makes people more susceptible to serious cases in the event of new contamination. “In other words, there is evidence that there are more serious cases of the disease in certain parts of the region because people susceptible to these serious cases are concentrated in these places”, he explains. The second conjecture takes into account the possibility of some variation in the type of virus, which would cause different manifestations of the disease. “However, these data are preliminary and still need to be refined so that we have a precise idea of ​​what is happening”, warns the epidemiologist.

Regarding the study of cases of work accidents in Piracicaba, Ricardo Cordeiro highlights that the phenomenon is also of interest to public health scholars. “We chose the city because we have a considerable database on the subject, which has been formed since the year 2000. This has made our work a lot easier. It is important that we study these cases because they have no relationship with the behavior of communicable diseases. They are more related to environmental factors, such as risky locations, traffic characteristics, etc.” According to the epidemiologist, the thematic project arose from the need for experts to improve one of the most important methods of making estimates about the risk of diseases, the so-called case-control study.

By incorporating the spatial dimension into this method, scientists tend to better understand how diseases spread within a given physical limit. Such a task, points out Ricardo Cordeiro, is not trivial. He remembers that people are distributed differently throughout a city. There are more and less populated neighborhoods. “Our challenge is to know if a certain location accumulates more cases of disease because it concentrates more people or if there is something different contributing to the phenomenon. It is, therefore, a very complex task.” To carry out the undertaking, the project brought together five main researchers, from different areas of knowledge.

In addition to Ricardo Cordeiro, a professor from the Institute of Mathematics, Statistics and Scientific Computing (Imecc) at Unicamp and three other scientists are involved in the activities, one from the Federal University of Paraná (UFPR), one from the Oswaldo Cruz Foundation (Fiocruz) and one from an institution in England. “In addition, we have the participation of 15 scientific initiation and postgraduate students, who help to oxygenate the project”, adds the FCM professor. This team works on several fronts simultaneously. Part goes into the field, for example, to collect data from the population. Based on records from basic health units, researchers visit homes occupied by people who have or have had dengue fever and apply a questionnaire. Additionally, they provide other aspects, such as the existence of breeding sites for Aedes aegypti, the mosquito that transmits the disease.

In a complementary way, the researchers randomly select homes among those that have not had cases of dengue fever to carry out the same collection. “By comparing the two situations, we can highlight the differences between the sick population and the sample that represents the population as a whole”, explains Ricardo Cordeiro. But the work of scientists does not stop there. They are also developing computational tools to automate analyses. The idea is to generate a system that, fed with the mass of data being generated, is capable of carrying out simulations on the future behavior of the disease.

In other words, scientists want to anticipate by one or more months how a given disease will behave both in space and time, which would allow for preventive interventions. “If we cannot prevent an epidemic, we want to at least adopt measures that help minimize its effects”, says Ricardo Cordeiro. Another aspect involved in the thematic project, continues the epidemiologist, concerns the development of a method that enables the analysis of diseases based on a classification called multinomial. Traditionally, explains the FCM professor, the case-control study divides people into just two types: sick and non-sick.

What we want, from now on, is to expand this analysis and establish other standards. “There are different types of people within the same population. Patients, for example, present different symptoms of the same illness. By establishing these differences, we will be able to analyze the varied behaviors of a disease from a spatial point of view”, details Ricardo Cordeiro. The ultimate objective of the research as a whole, reinforces the epidemiologist, is to create methods and tools that help guide public policies that prevent or at least minimize the spread of diseases. “The importance of the project lies precisely in this uniqueness. The aim is to extend and generalize the method of analysis, so that it incorporates a large part of the variability and diversity of epidemic manifestations”. Currently, the project is in the first of its eight semesters. The activities are being financed by the São Paulo State Research Support Foundation (Fapesp).