**5. Conclusions**

**4.2. Regional variables**

*domesticus* [39] and the pigs [40] in such areas.

118 Leishmaniasis - Trends in Epidemiology, Diagnosis and Treatment

and therefore, it generates exclusionary urbanization [41].

reservoir hosts of leishmaniasis.

affect Phlebotomine cycle [38, 42-45].

habitation (figure 7).

scarce [15].

In terms of the geographical and the regional variables, the main factor for the scattering leishmaniasis is the presence of Phlebotomine in the specific areas. In fact, since sandflies breed in soil or litter, they are dependent on the availability of water and the dampness. In addition, their small size enables them to live in various different microhabitats [36], however, an indepth analysis detailing the breeding sites of sand flies and their larval development remains

Nevertheless, the peri-urban areas are important risk factors for leishmaniasis transmission since they maintain the niches for Phlebotomine and natural reservoir hosts. Indeed, some studies have demonstrated the increase of known natural reservoir hosts including *Galus*

In relation to the local environment, the urban periphery is frequently inhabited by poor populations, they are forced to live far from downtown and these habitats grow as the people arrive there from the rural areas. This is a common case in the poor and developing countries. Such lesser-developed areas are comprised of the forests or the woodlands and become a favorable place to increase contact of sandflies with the people as well as domestic and wild

At the same time, this population has limited access to basic sanitation and sewage treatment,

In fact, the deforestation linked to unplanned urbanization seems to be the cause of peak incidence of leishmaniasis in some regions [32]. Urbanization parameters associated with the growing cities and the deforestation areas generate ecological changes [41] that could modify the forest flora; this in turn generates trunks of dead trees thereby increasing the amount of decomposed organic material as well as the microorganisms on the ground that positively

These findings justify that in the peri-urban areas there is increase in number of the infected people carrying leishmaniasis and other infectious diseases that are dependent on the vector transmission, the people in those areas get higher exposure to vectors and reservoir hosts.

The reservoir hosts to *Leishmania* are the rodents, the marsupials, the monkeys, wild canines [30], the domestic dogs, chickens, the cattle, the equine, the caprine, the bovine, the swine and

Indeed, the presence of the swine species in the peridomicile is an important risk of the contamination [40], and the contamination has also been found associated with the presence of chickens as wild predators that are potential wild reservoirs hosts of *Leishmania* and *feed* on them, thereby intensifying the parasite cycle to the human and the canine populations [39].

The life cycle of Leishmania is mainly associated with the ecological factors in the rural or the peridomicile areas that harbor the sand fly niches and the reservoir hosts with human

the feline species [11-14, 30], they all inhabit the areas populated with the sand flies.

The aim of this chapter was simply to put together the collected information about the geographical and the environmental variables of leishmaniasis transmission. Leishmaniasis transmission is dependent on the association of contaminated sandflies with the reservoir hosts of *Leishmania* and the humans. In geographical terms association is favored in inter tropical regions, where the environmental factors such as the warm and the wet climate and certain types of the forest vegetation are predominant. In regional terms, the vicinity of the forest remnants or the woodland in the respective local periphery increases the density of sandflies thereby creating favorable conditions for the propagation of *Leishmania* life-cycle and its exposure to the people inhabiting that area.

Accurate and adequate public health policies and the proper dissemination of relevant information to the populations living in the endemic areas along with the severe control and the surveillance would be helpful in eliminating the contamination of humans and reservoir hosts by sandflies.
