**1. Introduction**

Phlebotomine sandflies (Diptera: Psychodidae) are insects of medical and veterinary impor‐ tance since they are involved in transmission of various pathogens (bacteria, virus and protozoa) that cause diseases such as Bartonellosis, Arboviruses and Leishmaniasis. The latter is caused by trypanosomatids of the genus *Leishmania*, the pathogenic agent of human leishmaniasis. *Leishmania* infection is characterized by a species-specific pathology, varying from cutaneous lesions to the potentially fatal visceral form [1-3]. The distribution of this disease encompasses the tropical, subtropical and Mediterranean regions of the world and its global burden has been estimated to be approximately 500,000 cases of visceral leishmaniasis (VL) and approximately 1.1-1.5 million cases of cutaneous leishmaniasis (CL) per year (4,5]. Despite its widespread distribution, most of the leishmaniasis cases occur in only a few countries: more than 90% of the VL cases occur in Bangladesh, Brazil, Ethiopia, India, South Sudan and Sudan, and most of the CL cases occur in Afghanistan, Algeria, Brazil, Colombia, Iran, Pakistan, Peru, Saudi Arabia and Syria [5].

In the Americas, CL occurs from southern USA to northern Argentina, but its main focus is concentrated in South America, especially in Bolivia, Brazil and Peru, with approximately 90% of the recorded cases of the muco-cutaneous type [5,6]. Yet, in spite of its importance, leish‐ maniasis is one of the most neglected tropical diseases in the world [5].

In Brazil, there has been an expansion of this disease since 1950 [7,8]. Currently, CL has been reported in all Brazilian states, causing outbreaks in several regions of country [9], especially in the Brazilian Amazon. This situation has been correlated to several factors, such as defor‐ estation, the construction of highways and dams, implementation of agricultural poles, migrations of human populations, new mining ventures, the emergence of villages and cities, the use of forest locations for military training, among other factors [6-8,10-16].

*Leishmania* displays two main morphological forms, the amastigote and the promastigote, which are found in close association with vertebrate (mammals) and invertebrate (phleboto‐ mine sandflies) hosts, respectively, comprising the link of several transmission cycles [13,17,18]. The vertebrate hosts include a large variety of mammals, such as rodents, xenar‐ thrans (armadillo, anteater and sloth), marsupials (opossum), canids and primates, including humans [19-21].

There are approximately 30 species of *Leishmania* described in the World and, of these, at least 20 are pathogenic in mammals [22]. In the Neotropical region 22 species were recorded; of these, 12 were reported in Brazil [23] and seven were found infecting humans in the Brazilian Amazon region [24]. The studies conducted in Brazil have found a large number of dermo‐ tropic *Leishmania* species that are proved to infect humans, such as *Leishmania amazonensis*, *Le. braziliensis*, *Le. guyanensis*, *Le. lainsoni*, *Le. naiffi*, *Le. shawi* and *Le. lindenbergi*. There are others species too, but they have been found only in their natural reservoir hosts, as follows: *Le. enriettii*, *Le. forattinii*, *Le. deanei* and *Le. utingensis* [18,20,23,25-27]. With the exception of the two species (*Le. enriettii* and *Le.forattinii*), all those listed above were reported in the Brazilian Amazon, including *Leishmania chagasi* that causes visceral leishmaniasis and whose main vector is *Lutzomyia longipalpis*[23]. Table 1 presents all species of *Leishmania* and their respective proven and suspected sandfly vectors and reservoir hosts reported in Neotropical region.

**1. Introduction**

84 An Overview of Tropical Diseases

humans [19-21].

Iran, Pakistan, Peru, Saudi Arabia and Syria [5].

Phlebotomine sandflies (Diptera: Psychodidae) are insects of medical and veterinary impor‐ tance since they are involved in transmission of various pathogens (bacteria, virus and protozoa) that cause diseases such as Bartonellosis, Arboviruses and Leishmaniasis. The latter is caused by trypanosomatids of the genus *Leishmania*, the pathogenic agent of human leishmaniasis. *Leishmania* infection is characterized by a species-specific pathology, varying from cutaneous lesions to the potentially fatal visceral form [1-3]. The distribution of this disease encompasses the tropical, subtropical and Mediterranean regions of the world and its global burden has been estimated to be approximately 500,000 cases of visceral leishmaniasis (VL) and approximately 1.1-1.5 million cases of cutaneous leishmaniasis (CL) per year (4,5]. Despite its widespread distribution, most of the leishmaniasis cases occur in only a few countries: more than 90% of the VL cases occur in Bangladesh, Brazil, Ethiopia, India, South Sudan and Sudan, and most of the CL cases occur in Afghanistan, Algeria, Brazil, Colombia,

In the Americas, CL occurs from southern USA to northern Argentina, but its main focus is concentrated in South America, especially in Bolivia, Brazil and Peru, with approximately 90% of the recorded cases of the muco-cutaneous type [5,6]. Yet, in spite of its importance, leish‐

In Brazil, there has been an expansion of this disease since 1950 [7,8]. Currently, CL has been reported in all Brazilian states, causing outbreaks in several regions of country [9], especially in the Brazilian Amazon. This situation has been correlated to several factors, such as defor‐ estation, the construction of highways and dams, implementation of agricultural poles, migrations of human populations, new mining ventures, the emergence of villages and cities,

*Leishmania* displays two main morphological forms, the amastigote and the promastigote, which are found in close association with vertebrate (mammals) and invertebrate (phleboto‐ mine sandflies) hosts, respectively, comprising the link of several transmission cycles [13,17,18]. The vertebrate hosts include a large variety of mammals, such as rodents, xenar‐ thrans (armadillo, anteater and sloth), marsupials (opossum), canids and primates, including

There are approximately 30 species of *Leishmania* described in the World and, of these, at least 20 are pathogenic in mammals [22]. In the Neotropical region 22 species were recorded; of these, 12 were reported in Brazil [23] and seven were found infecting humans in the Brazilian Amazon region [24]. The studies conducted in Brazil have found a large number of dermo‐ tropic *Leishmania* species that are proved to infect humans, such as *Leishmania amazonensis*, *Le. braziliensis*, *Le. guyanensis*, *Le. lainsoni*, *Le. naiffi*, *Le. shawi* and *Le. lindenbergi*. There are others species too, but they have been found only in their natural reservoir hosts, as follows: *Le. enriettii*, *Le. forattinii*, *Le. deanei* and *Le. utingensis* [18,20,23,25-27]. With the exception of the two species (*Le. enriettii* and *Le.forattinii*), all those listed above were reported in the Brazilian Amazon, including *Leishmania chagasi* that causes visceral leishmaniasis and whose main

maniasis is one of the most neglected tropical diseases in the world [5].

the use of forest locations for military training, among other factors [6-8,10-16].

In addition to those listed in Table 1, other species of sandflies have been observed in the Brazilian Amazon region, harboring *Leishmania* spp. such as *L*. (*Lutzomyia*) *spathotrichia* and *L*. (*Psathyromyia) dendrophyla* [18].

The detection and identification of the *Leishmania* spp. in phlebotomine species are important to predict the risk of the disease spreading in and around endemic areas, once these species are the main determinants of the clinical outcome in humans. Currently, the use of molecular techniques such as polymerase chain reaction (PCR) has increased the sensitivity and specif‐ icity of parasite identification [28]. Based on this technique, *L.* (*Evandromyia*) *georgii* was reported for the first time to be infected with *Leishmania* spp. in the Brazilian Amazon region [29]. Similarly, *L.* (*Trichophoromyia*) *ubiquitalis* and *L.* (*Psychodopygus*) *davisi* were found for the first time to be infected with *Le. lainsoni* in the state of Amazonas, Brazil [30]. These sandflies had already been identified as vectors of *Le*. *lainsoni* [31] and *Le. brazilienesis* [32], respectively, in the state of Pará (Brazil).

Phlebotomine sandflies are amply distributed in all continents, except in Antarctica. Out of the six genera belonging to the subfamily Phlebotominae, only *Lutzomyia* and *Phlebotomus* harbor the main vectors of human leishmaniasis. The former is restricted to the Neotropical and Neartic regions, where approximately 32 out of more than 500 species described [33] are implicated as vectors, whereas the latter is distributed in all the other regions of the world and comprises important vectors such as *Phlebotomus papatasi* in the Old World, which is the main vector of *Leishmania major* [34,35]. Genus *Lutzomyia* includes the subgenera *Nyssomyia* and *Psychodopygus*, which comprise the most important vectors of CL in the Neotropics, in particular in the Brazilian Amazon region (Table 1; Figures 1 and 2).



Speciation in the *Leishmania guyanensis* Vector *Lutzomyia umbratilis* (Diptera: Psychodidae) from Northern Brazil… http://dx.doi.org/10.5772/60921 87

**Parasites Leishmaniasis**

86 An Overview of Tropical Diseases

*Leishmania amazonensis*Br/A

*Leishmania aristidesi*

*Leishmania garnhami*

*Leishmania venezuelensis*

*Leishmania forattinii*Br

*Leishmania deanei*Br/A

*Leishmania braziliensis*Br/A

*Leishmania peruviana*

*Leishmania pifanoi Leishmania* Cutaneous *Lutzomyia*

**in humans**

*Leishmania* Cutaneous *Lutzomyia*

*Leishmania* Not registered *Lutzomyia olmeca*

*Leishmania* Cutaneous *Lutzomyia olmeca*

*Leishmania* Not registered *Lutzomyia ayrozai*<sup>P</sup>

*Viannia* Cutaneous *Lutzomyia intermedia*<sup>P</sup>

*Viannia* Cutaneous *Lutzomyia peruensis*<sup>S</sup>

*Lutzomyia verrucarum*<sup>S</sup>

**Species Subgenus Species Subgenus/Group**

*flaviscutellata*<sup>S</sup>

*flaviscutellata*<sup>P</sup> *Lutzomyia o. olmeca*<sup>P</sup> *Lutzomyia reducta*<sup>P</sup>

*bicolor*<sup>S</sup>

*bicolor*<sup>S</sup>

*Leishmania hertigi Leishmania* Not registered Unknown Rondent(*Coendou*

*Lutzomyia rangeliana*<sup>S</sup>

*Lutzomyia yuilli*<sup>P</sup>

*Leishmania* Cutaneous *Lutzomyia youngi*<sup>S</sup> Group *Verrucarum* Marsupials (*Didelphis*

*Leishmania* Not registered Unknown Rondent (*Coendou p.*

*Lutzomyia whitmani*<sup>P</sup> *Lutzomyia wellcomei*<sup>P</sup> *Lutzomyia davisi*<sup>P</sup> *Lutzomyia complexa*<sup>S</sup>

**Sandfly vectors Reservoir host**

*Nyssomyia Nyssomyia Nyssomyia*

*Nyssomyia* Ungrouped

*Psychodopygus Nyssomyia*

*Nyssomyia Nyssomyia Psychodopygus Psychodopygus Psychodopygus*

*Helcocyrtomyia* Group *Verrucarum*

*Nyssomyia* Unknown

Rodents (*Proechimys*

fox (*Cerdocyon thous*)

*robinsoni*), rodents (*Poechmys semispinosus, Dasyprocta punctata*)

*Oryzomys* spp., *Nectomys, Neacomys*, *Dasyprocta*) Marsupials (*Marmosa*, *Metachirus*, *Didelphis,*

spp.,

*Philander*),

*marsupialis*)

Domestic cat

*rothschildi*)

*prehensilis*)

*concolor*,

Rodents (*Oryzomys*

*O. capito*, *O. nigripes*, *Akodon arviculoides*, *Proechimys* spp., *Rattus rattus*, *Rhipidomys leucodactylus, Sigmodon hispidus, Bolomys lasiurus*)*,* marsupials (*Didelphis marsupialis*)

Rodent (*Phyllotis andinum*), marsupials (*Didelphis marsupialis*) and domestic dog

Rodents (*Proechimys inheringi*), marsupials (*Didelphis marsupialis*)

*Nyssomyia* Marsupials (*Marmosa*


Br/A=Brazil, including Amazon; Br=Brazil, except Amazon; P=proven vector; S=suspect vector. \*In Costa Rica, the infection occurs mostly as non-ulcerative skin lesions; Honduras and Nicaragua, the infection is much visceral as skin. Information compiled from Lainson (2010) [23].

**Table 1.** *Leishmania* species with their respective proven and suspect vectors (phlebotomine sandflies) and natural reservoirs (mammals) reported for the Neotropical region.

**Figure 1.** Distribution of the sandfly vectors of *Leishmania amazonensis* (A), *Leishmania braziliensis* (B) and *Leishmania guyanensis* (C and D). Highlight in green color corresponding to the Brazilian Amazon region. Map modified from Young and Duncan (1994) [2].

Speciation in the *Leishmania guyanensis* Vector *Lutzomyia umbratilis* (Diptera: Psychodidae) from Northern Brazil… http://dx.doi.org/10.5772/60921 89

**Figure 2.** Distribution of the sandfly vectors of *Leishmania lainsoni* (A), *Leishmania naiffi* (B), *Leishmania shawi* (C) and *Leishmania chagasi* (D). Highlight in green color corresponding to the Brazilian Amazon region. Map modified from Young and Duncan (1994) [2].

**Figure 1.** Distribution of the sandfly vectors of *Leishmania amazonensis* (A), *Leishmania braziliensis* (B) and *Leishmania guyanensis* (C and D). Highlight in green color corresponding to the Brazilian Amazon region. Map modified from

Young and Duncan (1994) [2].

88 An Overview of Tropical Diseases

Similar to other insect groups, the Brazilian Amazon hosts a large diversity of sandfly species likely because of the great variety of ecological niches available [36] which are favorable for survival and reproduction. For example, in a single hectare of forest 50 sandfly species were captured [37]. This high level of diversity of insect vectors and also of reservoirs permits the simultaneous circulation of several species of *Leishmania* and is particularly interesting for the dynamic transmission studies of CL in this region [38,39].

In northern South America, in particular in the Brazilian Amazon region, the transmission of CL is associated to *Lutzomyia umbratilis* Ward and Fraiha and *Lutzomyia anduzei* Rozeboom, implicated as principal and secondary vectors of *Le. guyanensis*, respectively*.* The *Le. guyanen‐ sis* cycle is completed in several species of mammals, especially in xenarthrans, the two-toed sloth (*Choloepus didactylus*), considered the main reservoir, and marsupials such as the opossum (*Didelphis marsupialis*) (*Didelphis marsupialis*) [40-43].
