title: Asymptomatic infection by Leishmania infantum in blood donors from the Balearic Islands (Spain).
abstract: 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.
authors.affiliation: The Laboratori de Parasitologia, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Spain. mcriera@ub.edu
authors.forename: Cristina
authors.initials: C
authors.lastname: Riera
authors.forename: Roser
authors.initials: R
authors.lastname: Fisa
authors.forename: Paulo
authors.initials: P
authors.lastname: López-Chejade
authors.forename: Teresa
authors.initials: T
authors.lastname: Serra
authors.forename: Enrique
authors.initials: E
authors.lastname: Girona
authors.forename: Mteresa
authors.initials: M
authors.lastname: Jiménez
authors.forename: José
authors.initials: J
authors.lastname: Muncunill
authors.forename: Matilde
authors.initials: M
authors.lastname: Sedeño
authors.forename: Martín
authors.initials: M
authors.lastname: Mascaró
authors.forename: Maria
authors.initials: M
authors.lastname: Udina
authors.forename: Montserrrat
authors.initials: M
authors.lastname: Gállego
authors.forename: Jaume
authors.initials: J
authors.lastname: Carrió
authors.forename: Alejandro
authors.initials: A
authors.lastname: Forteza
authors.forename: Montserrat
authors.initials: M
authors.lastname: Portús
mesh_terms: 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