**5. Concluding remarks**

In the current scenario, where environmental changes enhance implications on public health, it is critical that the studies of environmental-related diseases are intensified, especially for vector-borne diseases, such as AVL. *Lutzomyia (L.) longipalpis* is the most important link in the transmission chain of AVL and it is undoubtedly a major biological risk factor, essential for the transition between different epidemiological profiles and for the increasing urbanization of the disease. Clearly, the urbanization of the vector has been the main challenge for the surveillance and control of the disease.

The results presented here demonstrate a correlation between deforestation and the possible emergence of outbreaks, since AVL persists in areas with environmental changes. The increase of deforested areas remained constant in the state of Tocantins, and also showed expansion in the record of human cases, especially in the municipality of Araguaína.

The vector *L. (L.) longipalpis* was present in all land use classes, being adapted to all environments, including impacted areas. This information coupled with the correlation between the incidence of the disease and urban areas demonstrate once again the vector's adaptation to anthropic environments.

Brazil faces geographic expansion and urbanization of AVL and the Manual of Control and Surveillance of AVL from the Ministry of Health has as one of its goals to decrease the vector population and/or the minimization of vector contact with man (reducing the risk of transmission); the manual also has as a challenge to evaluate the vector behavior in the urban area and the factors of its adaptation to new habitats and environmental changes in a way to better understand the spatial dynamics of the disease. It is also hypothesized that vector populations are already resistant to insecticides applied against adult sand flies. As a result, recommended control actions for AVL are focused on early diagnosis and treatment of human cases, reduction of the sand fly vector population, elimination of domestic reservoirs, and additionally, health and education activities aimed in particular at patients and populations at risk of contracting the disease. However, despite well-defined guidelines, the actions are not always successful in controlling the vector.

In this context, despite the efforts made by the local Health Department, the state of Tocantins has a persistent scenario of AVL transmission. It is also important to note that the state has suffered over the last few years through major environmental impacts, especially through large enterprises. Such evidence points to a disturbing scenario regarding the transmission of AVL, one of expansion and urbanization; therefore, the determinants of such impacts must be constantly evaluated.

In conclusion, planning and implementation of public policies are necessary to minimize the impacts of anthropogenic environmental change. The results demonstrate the need to incorporate integrated actions, since AVL is expanding as a result of environmental impacts and the adaptation of the vector *L. (L.) longipalpis* to various habitats.
