Spatial and temporal dynamics of neglected tropical diseases in the Marajó Archipelago, Amazon-PA

Dinâmica espacial e temporal das doenças tropicais negligenciadas no Arquipélago do Marajó, Amazônia-PA

Dinámica espacial y temporal de enfermedades tropicales desatenidas en el Archipiélago de Marajó, Amazonia-PA

Esta obra está bajo una Licencia Creative Commons Atribución 4.0 Internacional.

Neglected tropical diseases (NTDs) are morbidities that affect an economically poor population, lacking basic health services and living in precarious sanitation conditions¹. In Latin America, Brazil represents the highest rates of occurrence of NTDs, with the Amazon being the Brazilian epicenter of important epidemiological findings for a variety of pathogenic agents².

The health and disease situation in the Amazon is conditioned both to changes in the socioeconomic scenario and to the geographic reality, since the difficult access in some municipalities becomes a justification for the lack of investments and the absence of public management policies in the region³. Interest in the Amazon territory comes from a historical context, and from the 1960s onwards, it became more intense, under the argument of providing technological advancement for the place, accelerated population growth, the result of the intense migratory process related to favorable economic prospects in the Amazon⁴.

This in turn presents populous urban centers at the same time that there are small isolated cities with unfavorable living conditions and socioeconomic and health indicators, such as the Marajó Archipelago³. Due to geopolitical aspects, Marajó is not included in the state’s large enterprises because it is far from the road axes that cross the Amazon, making even more economic and infrastructure investments unfeasible⁵. For this, space-time analysis in the peri-urban study in the Amazon is essential to understand the spatial dynamics, as the region brings together unequal and differentiated spatial times⁵.

Formerly called the “Geographical Mesoregion of Marajó”, the Archipelago is a region formed by sixteen municipalities, with a rate equivalent to about 6% of the population of Pará, with growth similar to the rest of the state, although it has one of the lowest demographic densities in the country⁶.

These municipalities are characteristic for presenting precarious socioeconomic conditions, with Municipal Human Development Indexes (MHDI) lower than the national average, since in the ranking of the 100 municipalities with the highest degree of social exclusion, 19 are in the state of Pará, eight of which are in Marajó⁷.

With regard to public policies, the self-styled population of Marajoara are vulnerable due to the neglect of basic services governed by the constitution, such as basic sanitation, health and education⁷. In the context, the search and mapping of epidemiological data are necessary in order to have a real dimension of how certain diseases behave. That said, this study aimed to analyze the space-time distribution of NTDs and their relationship with socio-environmental indicators in the Marajó Archipelago, in the state of Pará, Amazon.

It was possible to verify that, throughout the Marajoara territory, ACL was the second most reported disease, present in 13 of the 16 municipalities, with emphasis on Portel and Bagre. In total, dengue was the most reported with records in 12 municipalities, with a high rate in Breves, Ponta de Pedras, Portel and Soure.

Breves is considered an important Marajoara city, whose economic base for a long time was focused on the extraction of natural resources, such as wood, açaí (fruit) and heart of palm exploitation.¹⁰Currently, the municipality concentrates a consolidated trade and with service offer in the most diverse areas, in addition to hosting various public bodies.¹¹ The municipality has low population growth due, in part, to the evasion of many families to other locations, due to the search for alternatives for better living conditions, a consequence of the closure of many logging companies that impacted the local dynamics and economy.¹¹

In Table 1, Anajás is presented as the municipality with the worst socioeconomic indices, considering that in some years (2007, 2008, 2009 and 2016) data were not available, making a deeper analysis impossible. Breves and Soure are the municipalities with the highest IFDM in this region, however, far from ideal. The IFDM was created with the aim of understanding and monitoring the level of human development of municipalities in socioeconomic aspects over the years.¹² In general, Marajó Archipelago’s IDHM has shown a slight evolution in terms of its classification in most municipalities.

The low IFDM in Breves is related to the decay of logging activities, although the activity may be linked to social segregation in the municipality.¹³ However, the low index both in Breves and the other municipalities may be associated with the absence of public policies and investments in infrastructure.¹⁴

Despite not presenting data for the entire analyzed period, in Table 2, it is possible to observe that Santa Cruz do Arari, Bagre, Curralinho and Muanáhave hydrographic network coverage in more than 40% of households; despite having deficit, it is still one of the largest in the region. Cachoeira do Arari, Melgaço and Chaves do not reach 20% of homes.

In municipalities such as Anajás, Cachoeira do Arari, Salvaterra and Portel, the access network is less than 40%, which highlights worrying rates.¹⁵ Of these, only the capital Soure exceeds the coverage of the service by 60%, however below 85%, foreseen by the country’s basic sanitation companies.

As for the sewage service, it was found that only the municipality of Santa Cruz do Arari, between 2014 and 2015, and the municipality of Chaves, in 2014, provided data on coverage. The North region has the worst sanitary percentages in Brazil, as only 14.36% of sewage is treated, with a total service rate of only 7.88%.¹⁶

These data affect the IFDM calculation in the Marajoara region, since not even 50% of the population is contemplated with the provision of these services, and priority must be given to the universalization of sanitation so that IFDM evolution actually occurs. Basic sanitation services are essential to ensure a better quality of life for the population, being essential for health care and maintenance¹⁴

Non-availability of data warns about a worrying reality for the Marajoaras, inferring that the population’s basic rights are being neglected not only due to low supply, but also due to the lack of information or the service itself, an act that violates human dignity. Investments in health in the Amazon region were deficient, resulting in a neglected population, especially rural/riverside populations, a situation that has not improved significantly over time and remains similar in 2019³.

As can be seen in Figures 2 and 3, the spatial distribution of NTDs in the municipalities of Marajó reveals that, from 2007 to 2016, the number of cases of VL, ACL, dengue, TB and CD is not consistent with the region’s socioeconomic data. It was expected that these diseases would present more alarming data, since the region in question does not have adequate sanitary conditions or IFDM, which opens the door to a discussion about underreporting or the lack of medical assistance to the resident population.

Figure 2 a and b shows the distribution of leishmaniasis caused by protozoa of the genus Leishmania. These are endemic diseases in the Amazon, where anthropic actions directly compromise environmental spaces.¹⁷ Researching ATL in Marajó, studies identified that Portel, Anajás and São Sebastião da Boa Vista have high rates of the disease, compatible with those found in the present study.¹⁸

All highlighted diseases are considered serious public health problems compatible with precarious sanitation conditions and difficult access to health services¹. With the exception of TB, the others are of a vector nature, with a direct correlation to environmental impacts, especially deforestation and fires, with loss of habitat for species that until then lived isolated from urban and peri-urban areas.¹⁸

Figure 3a shows the distribution of dengue in Marajoara municipalities. Dengue is a viral infectious disease transmitted by the Aedes aegypti mosquito that spreads rapidly worldwide, with morbidity and mortality.¹⁹ The dengue index is higher in municipalities with low socioeconomic indicators, whose lack of registration in Afuá, Cachoeira do Arari, Curralinho, Gurupá, Melgaço and Santa Cruz do Arari culminated in divergences with exposed data.²⁰

TB in Figure 3b was the only disease reported in all Marajoara municipalities. TB is an infectious and contagious disease of important epidemiology in Amazonian capitals such as Belém and Manaus, with high coefficients associated with socioeconomic vulnerability issues, among other factors.²¹

Despite several municipalities reporting the disease, CD (Figure 3c) had a relatively low number of cases. CD is an anthropozoonosis caused by the parasite Trypanosoma cruzi and transmitted by the vector Triatoma brasiliensis, popularly known as kissing bug. Its contamination can be acquired through blood transfusion, organ transplantation and orally and vertically.²²

The consumption of açaí .Euterpaoleracea. in natura is a cultural factor in the region that is related as a means of contamination for CD, considering that most of the so-called “açaí beaters” do not use the bleaching technique, a practice that prevents contamination, for pulp production.²³ Another preponderant factor would be the material with which many houses are still built in the region, with the use of clay and wood, which facilitates vector installation in these constructions.²⁴

Breves, Portel and Soure were the municipalities that had the most reports regarding at least two of the five identified tropical diseases. Breve stood out for dengue, TB and CD; Portel stood out for ACL, dengue and TB; and Soure stood out for dengue and TB. Breves and Portel are municipalities that have similar socioeconomic aspects, since both had logging as their main economic activity, which, for a long time, was the economic base that led to changes in environmental, socioeconomic and territorial aspects.¹³

This epidemiological reality in the Marajó Archipelago is due, mainly when talking about the rates of ACL, TB and dengue, to the fact that, historically, the diseases considered endemic for the Amazon region are linked to conditions and life behavior of this region.^18,20,21 The anthropization of the environment resulted in these changes, favoring the proliferation of vector agents and, consequently, the incidence of diseases related to inadequate basic sanitation, whose configuration is the result of a disorganized urbanization process and historically exclusive development.²⁵

The Marajó Archipelago is geographically positioned in an area where difficult access to some of its municipalities is used as a justification for the lack of investment, making this damage even more dramatic for the population³. The socioeconomic dynamics in the cities of Marajó has peculiar characteristics. Studying the cities and the way this dynamic take place is essential for understanding the spatial distribution of diseases in the Amazonian context.²⁵

The authors would like to thank the Universidade do Estado do Pará, the coordination of the Graduate Program in Environmental Sciences, the advising professor and everyone who made this work possible.