Growth Patterns and Scaling Laws Governing AIDS Epidemic in Brazilian Cities

Abstract

Brazil holds approximately 1/3 of population living infected with AIDS (acquired immunodeficiency syndrome) in Central and South Americas, and it was also the first developing country to implement a large-scale control and intervention program against AIDS epidemic. In this scenario, we investigate the temporal evolution and current status of the AIDS epidemic in Brazil. Specifically, we analyze records of annual absolute frequency of cases for more than 5000 cities for the first 33 years of the infection in Brazil. We found that (i) the annual absolute frequencies exhibit a logistic-type growth with an exponential regime in the first few years of the AIDS spreading; (ii) the actual reproduction number decaying as a power law; (iii) the distribution of the annual absolute frequencies among cities decays with a power law behavior; (iv) the annual absolute frequencies and the number of inhabitants have an allometric relationship; (v) the temporal evolution of the annual absolute frequencies have different profile depending on the average annual absolute frequencies in the cities. These findings yield a general quantitative description of the AIDS infection dynamics in Brazil since the beginning. They also provide clues about the effectiveness of treatment and control programs against the infection, that has had a different impact depending on the number of inhabitants of cities. In this framework, our results give insights into the overall dynamics of AIDS epidemic, which may contribute to select empirically accurate models.

City size and the spreading of COVID-19 in Brazil

“…Thus, the persistence of this pattern indicates that large cities are expected to be proportionally more affected at the end of the COVID-19 pandemic. This result is in line with the findings for other infectious diseases [25,27] and probably reflects the existence of a higher degree of interaction between people in large cities [19,28]. Because social distancing is currently the only available measure to mitigate the impact of COVID-19, our results suggest that large cities may require more severe degrees of social distancing policies.…”

“…Urban scaling studies of health-related quantities have shown that the incidence and mortality of diseases are non-linearly related to the city population [24][25][26][27]. Despite the existence of several exceptions [27], noninfectious diseases (such as diabetes) are usually less prevalent in large cities, while infectious diseases (such as AIDS) are relatively more common in large urban areas.…”

Spatial patterns of dengue cases in Brazil

“…A similar result was found to AIDS in Brazil [48]. In the AIDS case, humans are the main carrier of the disease.…”

“…It is notable that, considering the error bars for 99% bootstrapped confidence intervals, the annual γ t exponents remain systematically constant during the whole period. The power law behavior and its γ exponent resemble the values found for AIDS in Brazil γ ≃ 1.87 [48]. This might suggest that the spreading of dengue fever has more influence of human circulation than Aedes , since a new outbreak marks the arrival of a new serotype (infected person or vector) in the region that had previously presented the arthropod vectors [31].…”

The Non-linear Health Consequences of Living in Larger Cities

“…To illustrate a typical scale relation between a variable and the population size of a city, we show a scatter plot of the population size of cities and the number of deaths by heart attack ( For infectious diseases, the exponent α is typically larger than one (Table 1), being strongly super-linear for sexually transmitted infections, 24 meningitis, and the 2009 pandemic influenza in Brazil. Infectious diseases spread mainly through contacts between an infected host and a healthy person.…”