Evidence for leishmania (viannia) parasites in the skin and blood of patients before and after treatment.
BACKGROUND
American cutaneous leishmaniasis is considered to be a zoonotic disease transmitted by sand flies that feed on infected sylvatic mammals. However, the "domestication" of transmission and the increase in treatment failure with antimonial drugs have raised the suspicion of anthroponotic transmission of American cutaneous leishmaniasis.


METHODS
The objective of the present study was to explore the potential of humans as a source of infection for sand flies. Biological (xenodiagnosis and culture) and molecular (polymerase chain reaction/Southern blot) detection methods were used to evaluate peripheral-blood monocytes and tissue fluids from sites accessible to sand flies from 59 adult patients with parasitologically confirmed American cutaneous leishmaniasis.


RESULTS
Overall, 44.1% of patients (26/59) presented biological and/or molecular evidence of Leishmania parasites in normal skin, peripheral-blood monocytes, lesion scars, or lesion border (by xenodiagnosis) before (18/59 [30.5%]) or after (10/27 [37.0%]) treatment. Leishmania parasites were cultured from the unaffected skin of 2 (3.6%) of 55 patients, and xenodiagnosis gave positive results for 5 (8.8%) of 57 patients before treatment.


CONCLUSIONS
The presence of Leishmania parasites in the unaffected skin and peripheral-blood monocytes of a high proportion of patients even after treatment and the acquisition of infection by sand flies support the plausibility of anthroponotic transmission of American cutaneous leishmaniasis.
Vergel
Carolina
C
Centro Internacional de Entrenamiento e Investigaciones Medicas, Cali, Valle, Colombia.
Palacios
Ricardo
R
Cadena
Horacio
H
Posso
Claudia Jimena
CJ
Valderrama
Liliana
L
Perez
Mauricio
M
Walker
John
J
Travi
Bruno Luis
BL
Saravia
Nancy Gore
NG
D000293:Adolescent; D000328:Adult; D000818:Animals; D000981:Antiprotozoal Agents / Q000627:therapeutic use; D002921:Cicatrix / Q000469:parasitology; D016054:DNA, Protozoan / Q000032:analysis; D004197:Disease Reservoirs; D005260:Female; D006801:Humans; D007303:Insect Vectors / Q000469:parasitology; D007891:Leishmania / Q000302:isolation & purification*; D016773:Leishmaniasis, Cutaneous / Q000188:drug therapy / Q000469:parasitology* / Q000635:transmission*; D007963:Leukocytes, Mononuclear / Q000469:parasitology; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011576:Psychodidae / Q000469:parasitology; D012867:Skin / Q000469:parasitology
D000981:Antiprotozoal Agents; D016054:DNA, Protozoan