Viability and Burden of Leishmania in Extralesional Sites during Human Dermal Leishmaniasis

Autor: Nancy G. Saravia, Yazmín Suárez, Adrian M. Zelazny, Jair Téllez, Roger Adrian Figueroa, Ibeth Romero, Maria Teresa Cardona
Rok vydání: 2010
Předmět:
lcsh:Arctic medicine. Tropical medicine
Cell Survival
lcsh:RC955-962
Palatine Tonsil
030231 tropical medicine
Leishmaniasis
Cutaneous
Polymerase Chain Reaction
Monocytes
Palatine tonsil
law.invention
03 medical and health sciences
0302 clinical medicine
Genes
Reporter
law
RNA
Small Cytoplasmic
parasitic diseases
medicine
Humans
Luciferases
Amastigote
Molecular Biology
Polymerase chain reaction
Skin
Leishmania
0303 health sciences
Microbial Viability
biology
030306 microbiology
lcsh:Public aspects of medicine
Public Health
Environmental and Occupational Health
lcsh:RA1-1270
Leishmaniasis
medicine.disease
biology.organism_classification
Virology
3. Good health
Infectious Diseases
medicine.anatomical_structure
Real-time polymerase chain reaction
Infectious Diseases/Neglected Tropical Diseases
Parasitology
Tonsil
Signal Recognition Particle
RNA
Protozoan
Research Article
Zdroj: PLoS Neglected Tropical Diseases, Vol 4, Iss 9 (2010)
PLoS Neglected Tropical Diseases
ISSN: 1935-2735
Popis: Background The clinical and epidemiological significance of Leishmania DNA in extralesional sites is obscured by uncertainty of whether the DNA derives from viable parasites. To examine dissemination of Leishmania during active disease and the potential participation of human infection in transmission, Leishmania 7SLRNA was exploited to establish viability and estimate parasite burden in extralesional sites of dermal leishmaniasis patients. Methods The feasibility of discriminating parasite viability by PCR of Leishmania 7SLRNA was evaluated in relation with luciferase activity of luc transfected intracellular amastigotes in dose-response assays of Glucantime cytotoxicity. Monocytes, tonsil swabs, aspirates of normal skin and lesions of 28 cutaneous and 2 mucocutaneous leishmaniasis patients were screened by kDNA amplification/Southern blot. Positive samples were analyzed by quantitative PCR of Leishmania 7SLRNA genes and transcripts. Results 7SLRNA amplification coincided with luciferase activity, confirming discrimination of parasite viability. Of 22 patients presenting kDNA in extralesional samples, Leishmania 7SLRNA genes or transcripts were detected in one or more kDNA positive samples in 100% and 73% of patients, respectively. Gene and transcript copy number amplified from extralesional tissues were comparable to lesions. 7SLRNA transcripts were detected in 13/19 (68%) monocyte samples, 5/12 (42%) tonsil swabs, 4/11 (36%) normal skin aspirates, and 22/25 (88%) lesions; genes were quantifiable in 15/19 (79%) monocyte samples, 12/13 (92%) tonsil swabs, 8/11 (73%) normal skin aspirates. Conclusion Viable parasites are present in extralesional sites, including blood monocytes, tonsils and normal skin of dermal leishmaniasis patients. Leishmania 7SLRNA is an informative target for clinical and epidemiologic investigations of human leishmaniasis.
Author Summary Understanding of the dynamics and distribution of Leishmania in the human host is fundamental to the targeting of control measures and their evaluation. Amplification of parasite gene sequences in clinical samples from cutaneous leishmaniasis patients has provided evidence of Leishmania in blood, other tissues and sites distinct from the lesion and of persistence of infection after clinical resolution of disease. However, there is uncertainty about the interpretation of the presence of Leishmania DNA as indicative of viable parasites. Because RNA is short-lived and labile, its presence provides an indicator of viability. We amplified Leishmania 7SLRNA, a molecule involved in intracellular protein translocation, to establish viability and estimate parasite load in blood monocytes, tonsil swab samples, and tissue fluid from healthy skin of patients with dermal leishmaniasis. Results showed that during active dermal leishmaniasis, viable Leishmania are present in blood monocytes, tonsils and normal skin in quantities similar to that in lesions, demonstrating widespread dissemination of infection and subclinical involvement of tissues beyond the lesion site. Leishmania 7SLRNA will be useful in deciphering the role of human infection in transmission.
Databáze: OpenAIRE
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