Asymptomatic infection by Leishmania infantum in blood donors from the Balearic Islands (Spain).
BACKGROUND
Visceral leishmaniasis (VL) caused by Leishmania infantum is a zoonotic disease endemic throughout the Mediterranean basin. The existence of asymptomatic human infection entails the risk of transmission by blood transfusion.


METHODS
The prevalence of Leishmania infection was studied in 1437 blood donors from the Balearic Islands (Majorca, Formentera, and Minorca) using immunologic (Western blot [WB] and delayed-type hypersensitivity [DTH]), parasitologic (culture), and molecular (nested polymerase chain reaction [PCR]) methods. In addition, the efficiency of leukoreduction by filtration to remove the parasite was tested by nested PCR in the red blood cell (RBC) units.


RESULTS
Leishmania antibodies were detected in 44 of the 1437 blood donors tested (3.1%). A sample of 304 donors from Majorca was selected at random. L. infantum DNA was amplified in peripheral blood mononuclear cells (PBMNCs) in 18 of the 304 (5.9%), and cultures were positive in 2 of the 304 (0.6%). DTH was performed on 73 of the 304 donors and was positive for 8 of them (11%). Of the 18 donors with positive L. infantum nested PCR, only 2 were seropositive. All the RBC samples tested (13 of 18) from donors with a positive PBMNC nested PCR yielded negative nested PCR results after leukodepletion.


CONCLUSIONS
Cryptic Leishmania infection is highly prevalent in blood donors from the Balearic Islands. DTH and L. infantum nested PCR appear to be more sensitive to detect asymptomatic infection than the serology. The use of leukodepletion filters appears to remove parasites from RBC units efficiently.
Riera
Cristina
C
The Laboratori de Parasitologia, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Spain. mcriera@ub.edu
Fisa
Roser
R
López-Chejade
Paulo
P
Serra
Teresa
T
Girona
Enrique
E
Jiménez
Mteresa
M
Muncunill
José
J
Sedeño
Matilde
M
Mascaró
Martín
M
Udina
Maria
M
Gállego
Montserrrat
M
Carrió
Jaume
J
Forteza
Alejandro
A
Portús
Montserrat
M
D000818:Animals; D001782:Blood Donors; D004912:Erythrocytes / Q000166:cytology / Q000469:parasitology; D006801:Humans; D018314:Leishmania infantum / Q000235:genetics / Q000302:isolation & purification*; D007898:Leishmaniasis, Visceral / Q000097:blood / Q000453:epidemiology / Q000821:virology*; D016133:Polymerase Chain Reaction; D015995:Prevalence; D013030:Spain / Q000453:epidemiology