**3.1. Land use**

Data on land use for the Cerrado biome was provided by the Federal University of Goiás [23]; the data for the Amazon biome was obtained at the Web site of the Brazilian Institute of Geography and Statistics [21]. The land use maps and municipal boundaries were integrated in ArcGIS, which enabled the calculation of the percentage of land use class in each municipality (**Figure 5**).

Significant positive correlation was identified between the cumulative incidence of human cases (2000–2015) and area with urban influence, ombrophilous forest, and ecological tension areas (**Table 1**). The land use classes that had positive correlation with the yearly incidence were secondary vegetation, urban area, ombrophilous forest, ecological tension areas, pioneer vegetation areas, and agriculture. Savannah had negative correlation with the yearly AVL incidence (**Table 1**).

The presence of *L. (L.) longipalpis* was significantly correlated with secondary vegetation and with ombrophilous forest (**Table 1**). Considering the occurrence of *L. (L.) longipalpis* in all municipalities where there are records of autochthonous human cases of AVL, in addition to the information from the literature [29–37], it is suggested that the vector is present in all classes of land use (**Figure 5**, **Table 1**).

Ecoepidemiology of American Visceral Leishmaniasis in Tocantins State, Brazil: Factors Associated... http://dx.doi.org/10.5772/65852 99

To characterize the municipalities with the presence of the vector *L. (L.) longipalpis*, a literature search was held in the following databases: LILACS [25], MEDLINE [26], and SciELO [27]; using the keywords [28]: *Lutzomyia*, American visceral leishmaniasis, *L. (L.) longipalpis*, and Tocantins. Searches were also performed for conference abstracts, theses, dissertations, and monographs, and unpublished information was provided by the Health Department of

For the municipalities without information on the vector, it was assumed that *L. (L.) longipalpis* occurs where there are human cases of AVL, because so far *L. (L.) longipalpis* is the only vector species associated with the disease in the state of Tocantins and there is no record of *L. (L.) cruzi* in the state [personal communication Health Department of Tocantins State]. While this assumption does introduce a minor uncertainty in the analyses, not considering the presence of the vector in areas where AVL transmission is well-known would compromise the results. From the scarce bibliographic records that were found (9), the vector was recorded in only 22 municipalities of Tocantins [29–37]. In contrast, there are records of human cases in 124 municipalities, which demonstrate the lack of entomological studies in the state (**Figure 5**).

In order to evaluate the association between AVL, *L. (L.) longipalpis*, and different environmental factors (land use and deforestation), nonparametric Spearman correlation tests were applied to the data. Analyses were performed in the software SPSS (version 22) and correla-

Data on land use for the Cerrado biome was provided by the Federal University of Goiás [23]; the data for the Amazon biome was obtained at the Web site of the Brazilian Institute of Geography and Statistics [21]. The land use maps and municipal boundaries were integrated in ArcGIS, which enabled the calculation of the percentage of land use class in each munici-

Significant positive correlation was identified between the cumulative incidence of human cases (2000–2015) and area with urban influence, ombrophilous forest, and ecological tension areas (**Table 1**). The land use classes that had positive correlation with the yearly incidence were secondary vegetation, urban area, ombrophilous forest, ecological tension areas, pioneer vegetation areas, and agriculture. Savannah had negative correlation with the yearly AVL

The presence of *L. (L.) longipalpis* was significantly correlated with secondary vegetation and with ombrophilous forest (**Table 1**). Considering the occurrence of *L. (L.) longipalpis* in all municipalities where there are records of autochthonous human cases of AVL, in addition to the information from the literature [29–37], it is suggested that the vector is present in all

Tocantins State [personal communication].

98 The Epidemiology and Ecology of Leishmaniasis

**3. Environmental factors**

**3.1. Land use**

pality (**Figure 5**).

incidence (**Table 1**).

classes of land use (**Figure 5**, **Table 1**).

tions were considered significant at levels 0.95–0.99.

**Figure 5.** Map of Tocantins State with land use classes in association with the presence of *Lutzomyia (Lutzomyia) longipalpis*. Source: UFG, IBGE. Map design: Núcleo de Geoprocessamento LIS/ICICT/FIOCRUZ.


*(Lutzomyia) longipalpis*, from 2000 to 2015, in Tocantins State.


**Table 1.**

**AVL** 

**Pasture**

**Secondary** 

**Urban area**

**Ombrophilous** 

**Savannah**

**Pioneer** 

**Agriculture** 

**Ecological** 

**Agriculture**

**Seasonal** 

**forest**

**tension areas**

**vegetation** 

**culture**

**areas**

r

r

r

r

r

**forest**

**vegetarian**

**incidence**

r

> 2000

−0.072

0.399

> 2001

> −0.022

0.800

> 2002

> 0.000

0.999

> 2003

> 0.042

0.624

> 2004

−0.136

0.112

> 2005

> −0.045

0.595

> 2006

> −0.018

0.835

> 2007

> 0.117

0.169

> 2008

0.061 0.478

> 2009

> 0.099

0.244

0.647

0.588

0.197

0.006

0.523

0.286

0.001

0.407

0.574

0.039

0.046

0.110

−0.231**\*\***

−0.055

−0.091

0.282**\*\***

0.071

0.048

0.557

0.099

0.067

0.009

0.437

0.455

0.003

0.172

0.622

0.050

0.141

0.156

−0.220**\*\***

−0.067

−0.064

0.251**\*\***

0.117

−0.042

0.942

0.269

0.074

0.002

0.469

0.352

0.006

0.006

0.690

−0.006

0.094

0.152

−0.263**\*\***

−0.062

−0.080

0.232**\*\***

0.232**\*\***

−0.034

0.937

0.320

0.115

0.582

0.379

0.524

0.394

0.703

0.529

−0.007

0.085

0.134

−0.047

−0.075

−0.055

0.073

−0.033

−0.054

0.768

0.126

0.068

0.553

0.625

0.944

0.726

0.655

0.344

0.025

0.130

0.155

−0.051

−0.042

0.006

0.030

−0.038

−0.081

0.610

0.466

0.017

0.899

0.467

0.642

0.968

0.345

0.219

0.044

0.062

0.202**\***

0.011

−0.062

−0.040

−0.003

−0.081

−0.105

0.758

0.003

0.014

0.092

0.461

0.563

0.324

0.690

0.352

0.026

0.247**\*\***

0.209**\***

−0.144

−0.063

−0.049

0.084

−0.034

−0.080

0.538

0.055

0.655

0.426

0.574

0.520

0.269

0.813

0.986

−0.053

0.163

−0.038

0.068

−0.048

−0.055

−0.094

−0.020

−0.001

0.698

0.090

0.348

0.423

0.003

0.775

0.480

0.646

0.824

−0.033

0.144

−0.080

0.068

0.254**\*\***

−0.024

−0.060

−0.039

0.019

0.910

0.431

0.132

0.749

0.570

0.977

0.304

0.544

0.707

100 The Epidemiology and Ecology of Leishmaniasis

−0.010

0.067

0.129

0.027

−0.049

−0.002

−0.088

−0.052

−0.032

r

r

r

r

*(Lutzomyia) longipalpis*, from 2000 to 2015, in Tocantins State.

Correlation between classes of land use and incidence of American visceral leishmaniasis; correlation between classes of land use and the vector, *Lutzomyia* 

**Table 1.** Correlation between classes of land use and incidence of American visceral leishmaniasis; correlation between classes of land use and the vector, *Lutzomyia (Lutzomyia) longipalpis*, from 2000 to 2015, in Tocantins State (Continued).
