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Distinct Leishmania species infecting wild caviomorph rodents (Rodentia: Hystricognathi) from Brazil.

Cássia-Pires R, Boité MC, D'Andrea PS, Herrera HM, Cupolillo E, Jansen AM, Roque AL - PLoS Negl Trop Dis (2014)

Bottom Line: In 13 caviomorph rodents, DNA sequencing analyses allowed the identification of 4 species of the subgenus L. (Viannia): L. shawi, L. guyanensis, L. naiffi, and L. braziliensis; and 1 species of the subgenus L. (Leishmania): L. infantum.These include the description of parasite species in areas not previously included in their known distribution: L. shawi in Thrichomys inermis from Northeastern Brazil and L. naiffi in T. fosteri from Western Brazil.From the four other positive rodents, two were positive for HSP70 (234) targeting but did not generate sequences that enabled the species identification, and another two were positive only in kDNA targeting.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Trypanosomatid Biology, Oswaldo Cruz Institute, Rio de Janeiro, Rio de Janeiro, Brazil.

ABSTRACT

Background: Caviomorph rodents, some of the oldest Leishmania spp. hosts, are widely dispersed in Brazil. Despite both experimental and field studies having suggested that these rodents are potential reservoirs of Leishmania parasites, not more than 88 specimens were analyzed in the few studies of natural infection. Our hypothesis was that caviomorph rodents are inserted in the transmission cycles of Leishmania in different regions, more so than is currently recognized.

Methodology: We investigated the Leishmania infection in spleen fragments of 373 caviomorph rodents from 20 different species collected in five Brazilian biomes in a period of 13 years. PCR reactions targeting kDNA of Leishmania sp. were used to diagnose infection, while Leishmania species identification was performed by DNA sequencing of the amplified products obtained in the HSP70 (234) targeting. Serology by IFAT was performed on the available serum of these rodents.

Principal findings: In 13 caviomorph rodents, DNA sequencing analyses allowed the identification of 4 species of the subgenus L. (Viannia): L. shawi, L. guyanensis, L. naiffi, and L. braziliensis; and 1 species of the subgenus L. (Leishmania): L. infantum. These include the description of parasite species in areas not previously included in their known distribution: L. shawi in Thrichomys inermis from Northeastern Brazil and L. naiffi in T. fosteri from Western Brazil. From the four other positive rodents, two were positive for HSP70 (234) targeting but did not generate sequences that enabled the species identification, and another two were positive only in kDNA targeting.

Conclusions/significance: The infection rate demonstrated by the serology (51.3%) points out that the natural Leishmania infection in caviomorph rodents is much higher than that observed in the molecular diagnosis (4.6%), highlighting that, in terms of the host species responsible for maintaining Leishmania species in the wild, our current knowledge represents only the "tip of the iceberg."

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Related in: MedlinePlus

Illustrative representation of HSP 70 (234) amplification for Leishmania sp. before and after re-amplification of the PCR products.(A) PCR products of first amplification of HSP 70 (234) targeting analyzed by electrophoresis polyacrylamide gel stained with silver. Lanes: bp. molecular-weight marker (50 bp DNA ladder); 1. Infected Thrichomys laurentius from São Raimundo Nonato/PI; 2. Negative control of PCR reaction. (B) PCR products of re-amplification of the product obtained in the first PCR reaction. Lanes: bp. molecular-weight marker (50 bp DNA ladder); 1. Negative Thrichomys fosteri from Corumbá/MS (Positive only in kDNA); 2–5. Infected T. laurentius from São Raimundo Nonato/PI; 6. Infected T. fosteri from Corumbá/MS; 7. Negative control of PCR after re-amplification.
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pntd-0003389-g001: Illustrative representation of HSP 70 (234) amplification for Leishmania sp. before and after re-amplification of the PCR products.(A) PCR products of first amplification of HSP 70 (234) targeting analyzed by electrophoresis polyacrylamide gel stained with silver. Lanes: bp. molecular-weight marker (50 bp DNA ladder); 1. Infected Thrichomys laurentius from São Raimundo Nonato/PI; 2. Negative control of PCR reaction. (B) PCR products of re-amplification of the product obtained in the first PCR reaction. Lanes: bp. molecular-weight marker (50 bp DNA ladder); 1. Negative Thrichomys fosteri from Corumbá/MS (Positive only in kDNA); 2–5. Infected T. laurentius from São Raimundo Nonato/PI; 6. Infected T. fosteri from Corumbá/MS; 7. Negative control of PCR after re-amplification.

Mentions: We found 17 caviomorph rodents (4.6%) positive in the PCR directed to Leishmania sp. kDNA. From these, 15 samples were also positive when tested for HSP70 (234) primers, two directly after the PCR and 13 only after the re-amplification of the product obtained in the first PCR reaction (Fig. 1). DNA sequencing analyses allowed the identification of −4 species of the subgenus Leishmania (Viannia) and −1 species of the subgenus Leishmania (Leishmania) in samples of 13 caviomorph rodents (Fig. 2, Table 2). In five situations, the DNA sequence analysis revealed identity values above 95% for more than one Leishmania species and we opted not to define one of them as the etiological agent. A single sample (one Thrichomys laurentius from Piauí) displayed different DNA sequences that presented high values of similarity with distinct species of Leishmania in two consecutive reactions. This was considered as result of a hybrid population or mixed infection. Leishmania infection was observed in five caviomorph rodent species captured in two municipalities belonging to Pantanal and in two belonging to Caatinga biomes (Fig. 2). In the Pantanal, 7 animals were positive for Leishmania spp and the identification of the Leishmania species was possible in 4 of them: one T. fosteri captured in Corumbá, was found infected by L. (V). naiffi while L. (L). infantum was found infecting one Dasyprocta azarae and two Clyomys laticeps in Aquidauna and Corumbá, respectively. Also in Corumbá, we were unable to identify the Leishmania species infecting one T. fosteri because the analysis of the parasite DNA sequence revealed similarity with two Leishmania species (L. (V). naiffi and L. (V). braziliensis).


Distinct Leishmania species infecting wild caviomorph rodents (Rodentia: Hystricognathi) from Brazil.

Cássia-Pires R, Boité MC, D'Andrea PS, Herrera HM, Cupolillo E, Jansen AM, Roque AL - PLoS Negl Trop Dis (2014)

Illustrative representation of HSP 70 (234) amplification for Leishmania sp. before and after re-amplification of the PCR products.(A) PCR products of first amplification of HSP 70 (234) targeting analyzed by electrophoresis polyacrylamide gel stained with silver. Lanes: bp. molecular-weight marker (50 bp DNA ladder); 1. Infected Thrichomys laurentius from São Raimundo Nonato/PI; 2. Negative control of PCR reaction. (B) PCR products of re-amplification of the product obtained in the first PCR reaction. Lanes: bp. molecular-weight marker (50 bp DNA ladder); 1. Negative Thrichomys fosteri from Corumbá/MS (Positive only in kDNA); 2–5. Infected T. laurentius from São Raimundo Nonato/PI; 6. Infected T. fosteri from Corumbá/MS; 7. Negative control of PCR after re-amplification.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4263410&req=5

pntd-0003389-g001: Illustrative representation of HSP 70 (234) amplification for Leishmania sp. before and after re-amplification of the PCR products.(A) PCR products of first amplification of HSP 70 (234) targeting analyzed by electrophoresis polyacrylamide gel stained with silver. Lanes: bp. molecular-weight marker (50 bp DNA ladder); 1. Infected Thrichomys laurentius from São Raimundo Nonato/PI; 2. Negative control of PCR reaction. (B) PCR products of re-amplification of the product obtained in the first PCR reaction. Lanes: bp. molecular-weight marker (50 bp DNA ladder); 1. Negative Thrichomys fosteri from Corumbá/MS (Positive only in kDNA); 2–5. Infected T. laurentius from São Raimundo Nonato/PI; 6. Infected T. fosteri from Corumbá/MS; 7. Negative control of PCR after re-amplification.
Mentions: We found 17 caviomorph rodents (4.6%) positive in the PCR directed to Leishmania sp. kDNA. From these, 15 samples were also positive when tested for HSP70 (234) primers, two directly after the PCR and 13 only after the re-amplification of the product obtained in the first PCR reaction (Fig. 1). DNA sequencing analyses allowed the identification of −4 species of the subgenus Leishmania (Viannia) and −1 species of the subgenus Leishmania (Leishmania) in samples of 13 caviomorph rodents (Fig. 2, Table 2). In five situations, the DNA sequence analysis revealed identity values above 95% for more than one Leishmania species and we opted not to define one of them as the etiological agent. A single sample (one Thrichomys laurentius from Piauí) displayed different DNA sequences that presented high values of similarity with distinct species of Leishmania in two consecutive reactions. This was considered as result of a hybrid population or mixed infection. Leishmania infection was observed in five caviomorph rodent species captured in two municipalities belonging to Pantanal and in two belonging to Caatinga biomes (Fig. 2). In the Pantanal, 7 animals were positive for Leishmania spp and the identification of the Leishmania species was possible in 4 of them: one T. fosteri captured in Corumbá, was found infected by L. (V). naiffi while L. (L). infantum was found infecting one Dasyprocta azarae and two Clyomys laticeps in Aquidauna and Corumbá, respectively. Also in Corumbá, we were unable to identify the Leishmania species infecting one T. fosteri because the analysis of the parasite DNA sequence revealed similarity with two Leishmania species (L. (V). naiffi and L. (V). braziliensis).

Bottom Line: In 13 caviomorph rodents, DNA sequencing analyses allowed the identification of 4 species of the subgenus L. (Viannia): L. shawi, L. guyanensis, L. naiffi, and L. braziliensis; and 1 species of the subgenus L. (Leishmania): L. infantum.These include the description of parasite species in areas not previously included in their known distribution: L. shawi in Thrichomys inermis from Northeastern Brazil and L. naiffi in T. fosteri from Western Brazil.From the four other positive rodents, two were positive for HSP70 (234) targeting but did not generate sequences that enabled the species identification, and another two were positive only in kDNA targeting.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Trypanosomatid Biology, Oswaldo Cruz Institute, Rio de Janeiro, Rio de Janeiro, Brazil.

ABSTRACT

Background: Caviomorph rodents, some of the oldest Leishmania spp. hosts, are widely dispersed in Brazil. Despite both experimental and field studies having suggested that these rodents are potential reservoirs of Leishmania parasites, not more than 88 specimens were analyzed in the few studies of natural infection. Our hypothesis was that caviomorph rodents are inserted in the transmission cycles of Leishmania in different regions, more so than is currently recognized.

Methodology: We investigated the Leishmania infection in spleen fragments of 373 caviomorph rodents from 20 different species collected in five Brazilian biomes in a period of 13 years. PCR reactions targeting kDNA of Leishmania sp. were used to diagnose infection, while Leishmania species identification was performed by DNA sequencing of the amplified products obtained in the HSP70 (234) targeting. Serology by IFAT was performed on the available serum of these rodents.

Principal findings: In 13 caviomorph rodents, DNA sequencing analyses allowed the identification of 4 species of the subgenus L. (Viannia): L. shawi, L. guyanensis, L. naiffi, and L. braziliensis; and 1 species of the subgenus L. (Leishmania): L. infantum. These include the description of parasite species in areas not previously included in their known distribution: L. shawi in Thrichomys inermis from Northeastern Brazil and L. naiffi in T. fosteri from Western Brazil. From the four other positive rodents, two were positive for HSP70 (234) targeting but did not generate sequences that enabled the species identification, and another two were positive only in kDNA targeting.

Conclusions/significance: The infection rate demonstrated by the serology (51.3%) points out that the natural Leishmania infection in caviomorph rodents is much higher than that observed in the molecular diagnosis (4.6%), highlighting that, in terms of the host species responsible for maintaining Leishmania species in the wild, our current knowledge represents only the "tip of the iceberg."

Show MeSH
Related in: MedlinePlus