ECOLOGICAL AND SOCIAL DETERMINANTS OF LEISHMANIASIS IN THE LEGAL AMAZON , BRAZIL

Leishmaniasis is a reemerging disease of worldwide distribution and has a public health importance. It is an infectious disease, parasitical and clinical severity ranging from a healthy appearance to a severe stage. Features two major forms, such as cutaneous leishmaniasis (cutaneous and mucocutaneous) and visceral leishmaniasis. This form can be deadly for reaching the organs. The four main protozoa that cause such clinical manifestations are Leishmania chagasi, Leishmania braziliensis, Leishmania amazonensis and Leishmania guyanensis. Environment, social and demographic factors are key for the transmission of leishmaniasis, due to its vector being a sand fl y insect with hematophagous habits and its main reservoir are dogs. In Brazil, leishmaniasis is endemic and widely distributed. 80% of reported cases are in children under 10 years. The Legal Amazon region is an area of study of public health, having suffered anthropogenic actions that undermine the ecological balance of the site. In this area, visceral leishmaniasis is increasing in western Pará state due to its economic development, which involves the public health. This study aims to relate environmental and health factors with the incidence of leishmaniasis in the Legal Amazon and this relationship through secondary data from publications in the National Health Information System (DATASUS). Key-Words: public health, visceral leishmaniasis, Amazon, incidence. AS&T Volume 1, Number 2, Dec 2013 visceral form. The severity of clinical manifestations is also related to the low immunity of the patient, in other words, the infection becomes more severe due to the fact that the patients have a reduced immune defense. (Silva et al., 2002). Emphasizing, visceral leishmaniasis is a zooantroponosis with global distribution, having dogs as an important reservoir of the agent (Marzochi et al., 1985); its clinical characteristics show a healthy appearance or even a severe stage of the disease (Marzochi et al., 1985). It can be classifi ed as a reemerging disease due to its ability to rapidly expand into new areas (Oliveira et al., 2001). In Brazil, this illness remains a major public health concern owing to be getting endemic with wide geographic distribution and its relation to hygiene, social class and sanitation. In Brazil, this disease occurs not only by the facts mentioned above, but also by nutrition and the concurrent infections. With increasing urbanization in the last 25 years, it is necessary to analyze the major biological, environmental and social issues that are likely to infl uence spreading this disease (Gontijo & Melo, 2004). Visceral leishmaniasis has a higher risk with urbanization because migration is an important aspect of the disease and, in general, immigrants are low-income people who live in precarious conditions. (Oliveira et al., 2001). In Brazil, visceral leishmaniasis affects people of all ages, but in most endemic areas 80% of reported cases occur in children under 10 years. The fi rst report of visceral leishmaniasis in Brazil was in 1934, when amastigotes of the protozoan were found on a sectional livercut of people who died diagnosed with yellow fever, but only 20 years later was recorded the fi rst outbreak of the disease (Gontijo & Melo, 2004). The disease was initially restricted to northeastern region, but has expanded to other regions reaching even the outskirts of urban centers (Figueiredo et al., 2010). The area of the Legal Amazon covers the states of Amazonas, Acre, Roraima, Rondônia, Pará, Mato Grosso, Amapá, Goiás, and this The area of the Legal Amazon covers the states of Amazonas, Acre, Roraima, Rondônia, Pará, Mato Grosso, Amapá, Goiás (Ferreira et al., 2005). The occupation of this area in the last 50 years has occurred because of the establishment of “axes” and “poles” of development, agricultural projects, mining, production and grains exportation (Alves, 2001). With this accelerated process of occupation, a great part of the forest was cleared for human interests (Alves, 2001). Hot spots can also be considered one of the factors for the deforestation of the Amazon, which characterizes Brazil as a country that emits more CO2 in the world, which causes the greenhouse effect (Oliveira, et al, 2011). The accelerated deforestation due to the factors mentioned causes an expansion of diseases, implying on behavior of public health. Leishmaniasis is found in the group of these diseases because seasonal foci of sand fl y population are associated with cluttered deforestation (Rebelo et al., 1999). Then, a program named “Bolsa Floresta” deploys a series of activities that act on benefi t of environmental conservation, poverty alleviation and climate change (Viana, 2008), allowing control of deforestation and helping the work of public health, meaning, if deforestation helps in expansion of leishmaniasis, controlling it , there will be a disease control too. With the development of public health, the Amazon has become an area of interest for studies because it has relevant characteristics to epidemiological determination and implications for healthcare assistance. This follows up the fact that the region has a great biodiversity and is suffering human actions which can ultimately lead to environmental imbalances and trophic level of the site (Confalonieri, 2005). In the Legal Amazon region, visceral leishmaniasis is expanding in the state of Pará, owing to urbanization trend and some areas of intense transmission occur in the western state. This expansion of the disease is related to the mining enterprise of bauxite where the economic breakthrough of the region has caused environmental changes affecting public health (Garcez et al., 2010). But that does not mean that the illness occurs only 14 Oliveira et al. 2013 in the state of Pará. In the state of Roraima, for example, Indians had an epidemiological profi le of visceral leishmaniasis in cases observed between 1989 and 1993. There was a prevalence of 69.5% for males (Guerra et al., 2004). Deforestation is a huge problem in this area because several factors are infl uencing this situation such as political development in the region, land speculation along highways, growth of cities, the dramatic increase in cattle ranching, timber exploitation and household farming (Ferreira et al., 2005). Public health and the incidence of some diseases have a direct relationship with society and the environment. The environmental issue has been seen with more importance in recent times due to global warming, greenhouse effect, air pollution, the hole in the ozone layer and also by regional environmental problems such as deforestation, soil degradation, water pollution, among other things. One area that discusses these issues is the Environmental Health, which analyzes environmental factors to diseases and gravities on population health, that is exposed to precarious circumstances of survival and certain physical-chemical factors. Through the World Health Organization (WHO), models of Environmental Monitoring were proposed to be used where there are several factors considered that may affect people’s health, such as poverty, population growth, industrialization, urbanization, technological and economic development, soil contamination, water and air; these factors that establish a direct link with environmental hazards and risks to health of the people exposed to such factors, subjecting them to infections, poisoning, morbidity and mortality (Pignatti, 2004). Understanding how environmental factors can infl uence urban and demographic dynamics of pathological leishmaniasis contributes to the understanding of the complexity of the phenomenon of the disease , in this way, the present study aims to determine the main environmental factors related to the incidence of the disease and generate information that foster control programs in the Amazon. MATERIALS AND METHODS Geographical coverage The research comprises the Legal Amazon in a time range of 18 years (1992-2010). Epidemiological design The epidemiological method used is a longitudinal study, time series, which can be understood as the epidemiological study that uses aggregate population as the unit of analysis.


INTRODUCTION
Leishmaniasis is a zoonosis of public health importance.It is an infectious and parasitic disease, which etiology in Brazil is given by four species of protozoa: Leishmania chagasi (causes visceral leishmaniasis), Leishmania braziliensis (causes mucocutaneous form), Leishmania amazonensis and Leishmania guyanensis (causes cutaneous leishmaniasis).
The transmission occurs through the bite of a sand fl y, an hematophagus insect belonging to the order Diptera.The blood is required for maturation of the eggs, that's why only female can perform the transmission.
The protozoa of the genus Leishmania causes a range of clinical syndromes through mucocutaneous lesions and can be lethal in its visceral form.The severity of clinical manifestations is also related to the low immunity of the patient, in other words, the infection becomes more severe due to the fact that the patients have a reduced immune defense.(Silva et al., 2002).Emphasizing, visceral leishmaniasis is a zooantroponosis with global distribution, having dogs as an important reservoir of the agent (Marzochi et al., 1985); its clinical characteristics show a healthy appearance or even a severe stage of the disease (Marzochi et al., 1985).It can be classifi ed as a reemerging disease due to its ability to rapidly expand into new areas (Oliveira et al., 2001).In Brazil, this illness remains a major public health concern owing to be getting endemic with wide geographic distribution and its relation to hygiene, social class and sanitation.
In Brazil, this disease occurs not only by the facts mentioned above, but also by nutrition and the concurrent infections.With increasing urbanization in the last 25 years, it is necessary to analyze the major biological, environmental and social issues that are likely to infl uence spreading this disease (Gontijo & Melo, 2004).Visceral leishmaniasis has a higher risk with urbanization because migration is an important aspect of the disease and, in general, immigrants are low-income people who live in precarious conditions.(Oliveira et al., 2001).
In Brazil, visceral leishmaniasis affects people of all ages, but in most endemic areas 80% of reported cases occur in children under 10 years.The fi rst report of visceral leishmaniasis in Brazil was in 1934, when amastigotes of the protozoan were found on a sectional livercut of people who died diagnosed with yellow fever, but only 20 years later was recorded the fi rst outbreak of the disease (Gontijo & Melo, 2004).
The disease was initially restricted to northeastern region, but has expanded to other regions reaching even the outskirts of urban centers (Figueiredo et al., 2010).
The area of the Legal Amazon covers the states of Amazonas, Acre, Roraima, Rondônia, Pará, Mato Grosso, Amapá, Goiás, and this The area of the Legal Amazon covers the states of Amazonas, Acre, Roraima, Rondônia, Pará, Mato Grosso, Amapá, Goiás (Ferreira et al., 2005).The occupation of this area in the last 50 years has occurred because of the establishment of "axes" and "poles" of development, agricultural projects, mining, production and grains exportation (Alves, 2001).With this accelerated process of occupation, a great part of the forest was cleared for human interests (Alves, 2001).Hot spots can also be considered one of the factors for the deforestation of the Amazon, which characterizes Brazil as a country that emits more CO2 in the world, which causes the greenhouse effect (Oliveira, et al, 2011).
The accelerated deforestation due to the factors mentioned causes an expansion of diseases, implying on behavior of public health.Leishmaniasis is found in the group of these diseases because seasonal foci of sand fl y population are associated with cluttered deforestation (Rebelo et al., 1999).Then, a program named "Bolsa Floresta" deploys a series of activities that act on benefi t of environmental conservation, poverty alleviation and climate change (Viana, 2008), allowing control of deforestation and helping the work of public health, meaning, if deforestation helps in expansion of leishmaniasis, controlling it , there will be a disease control too.
With the development of public health, the Amazon has become an area of interest for studies because it has relevant characteristics to epidemiological determination and implications for healthcare assistance.This follows up the fact that the region has a great biodiversity and is suffering human actions which can ultimately lead to environmental imbalances and trophic level of the site (Confalonieri, 2005).In the Legal Amazon region, visceral leishmaniasis is expanding in the state of Pará, owing to urbanization trend and some areas of intense transmission occur in the western state.This expansion of the disease is related to the mining enterprise of bauxite where the economic breakthrough of the region has caused environmental changes affecting public health (Garcez et al., 2010).But that does not mean that the illness occurs only in the state of Pará.In the state of Roraima, for example, Indians had an epidemiological profi le of visceral leishmaniasis in cases observed between 1989 and 1993.There was a prevalence of 69.5% for males (Guerra et al., 2004).
Deforestation is a huge problem in this area because several factors are infl uencing this situation such as political development in the region, land speculation along highways, growth of cities, the dramatic increase in cattle ranching, timber exploitation and household farming (Ferreira et al., 2005).
Public health and the incidence of some diseases have a direct relationship with society and the environment.The environmental issue has been seen with more importance in recent times due to global warming, greenhouse effect, air pollution, the hole in the ozone layer and also by regional environmental problems such as deforestation, soil degradation, water pollution, among other things.One area that discusses these issues is the Environmental Health, which analyzes environmental factors to diseases and gravities on population health, that is exposed to precarious circumstances of survival and certain physical-chemical factors.
Through the World Health Organization (WHO), models of Environmental Monitoring were proposed to be used where there are several factors considered that may affect people's health, such as poverty, population growth, industrialization, urbanization, technological and economic development, soil contamination, water and air; these factors that establish a direct link with environmental hazards and risks to health of the people exposed to such factors, subjecting them to infections, poisoning, morbidity and mortality (Pignatti, 2004).
Understanding how environmental factors can infl uence urban and demographic dynamics of pathological leishmaniasis contributes to the understanding of the complexity of the phenomenon of the disease , in this way, the present study aims to determine the main environmental factors related to the incidence of the disease and generate information that foster control programs in the Amazon.

Epidemiological design
The epidemiological method used is a longitudinal study, time series, which can be understood as the epidemiological study that uses aggregate population as the unit of analysis.

Information base
The information base is composed of secondary data from the publication of the National Health Information System (DATASUS) from 2000 to 2010 and the Brazilian Institute of Geography and Statistics (IBGE) -Synopsis Sector.

Statistical design
The secondary data collected through the DA-TASUS were arranged on a spreadsheet in Bioestat 5.3 © software and analyzed for adherence to a normal distribution by the Shapiro-Wilk test.The variables considered potentially related to the incidence of leishmaniasis were used in curve fi tting as independent variables, and regressions were performed with better adjustment after a debris analysis that excluded outliers data.

RESULTS AND DISCUSSION
Deforestation of the Legal Amazon is a threat to the biodiversity of the site and this can be the occurrence of certain factors such as agricultural expansion, accelerated industrialization since the 50s and an adaptation to economic globalization (Vieira et al., 2008).The table and fi gure below (Table I, Figure 1) show a relationship between the rate of deforestation in the Legal Amazon and the incidence of leishmaniasis in the region:  It can be observed that deforestation has meant an increase in the occurrence of the disease.This pattern may be due to the human being increasingly overlapping with their habitat of the sand fl y, thus being more prone to infection and stings.Since the ancient cultures, sanitation is associated with precarious health.Sanitation is a determining and conditioning factor for health, so, both must have an important connection (Teixeira, 2011).Table II and Figure 3 below show a linear relationship between households without sanitation and the incidence of leishmaniasis:  The regression indicates a positive relationship between sanitation and the incidence of leishmaniasis.This pattern is possibly also related to the precariousness of hospital care and the highest population density in these areas.
The relationship between the absence of schooling and the incidence of leishmaniasis is also positive (Table 3, Figure 3), indicating that the lack of education can be a social factor favoring the incidence of disease due to this portion of the population has little or no knowledge about the disease, its prevention and prophylaxis.The infectious and parasitic diseases in Brazil reached an expressive underprivileged population, low income, low education level and has no conditions for sanitation and primary health care (Paes et al., 1999), however the analyzes of this study have shown no signifi cant (Table IV, Figure 4), which may suggest that these factors are not correlated in the study area.From these results, it is possible to observe that many factors are related to the incidence of leishmaniasis in the Legal Amazon region.Deforestation, sanitation and absence of schooling were positive index rate of leishmaniasis.Deforestation may infl uence the spread of the disease due to the fact of being a human action, refl ecting the expansion of the spatial distribution of man, which increasingly overlaps with the habitat of the sand fl y, forcing insects that once had their habitat in the forest to encroach homes or start to colonize urban environments.
The absence of schooling, in turn, may be related to lack of knowledge about the disease, its transmission, diagnosis and cure, thus increasing the risk, while on the other hand the family income apparently has no direct implications on risk.
Thus, this study reinforces the importance of fi ghting deforestation of Legal Amazon, because among the various climatic consequences and threat to biodiversity degradation of this ecosystem features, there are also signifi cant epidemiological implications regarding leishmaniasis.

Figure 1 :
Figure 1: Geometrical regression linking the incidence of leishmaniasis and the Legal Amazon (relative) deforestation in the years 1992-2010.R 2 = 48.14% and p-value <0.01

Figure 2 :
Figure 2: Linear regression linking the incidence of leishmaniasis in the Legal Amazon with the number of households without sanitation in the years 2001-2009.R 2 = 85.03% and p-value <0.01

Figure 3 :
Figure 3: Linear regression linking the incidence of leishmaniasis in the Legal Amazon with people who have no educational level in the years 2001-2009.R 2 = 94.46%

Figure 4 :
Figure 4: Logarithmic regression linking the incidence of leishmaniasis in the Legal Amazon with people who have incomes less than one minimum wage in the years 2001-2008.R2 = 38.408%and p-value = 0.103

Table I :
Relative deforestation data and relative incidence of leishmaniasis in the Legal Amazon basin in the period 1992-2010 Source: Brazilian Institute of Geography and Statistics (IBGE)

Table II :
Index of households without sanitation and inci- Source: Brazilian Institute of Geography and Statistics (IBGE)

Table III :
Test of relationship between absence of school education and incidence of leishmaniasis Source: Brazilian Institute of Geography and Statistics (IBGE)

Table IV :
Test of relationship between incomes less than one minimum wage and incidence of leishmaniasis Source: Brazilian Institute of Geography and Statistics (IBGE)