title: Plasmodium genome in blood donors at risk for malaria after several years of residence in Italy.
abstract: BACKGROUND
  At present, the main risk of transfusion-transmitted malaria (TTM) in nonendemic countries is chronic, asymptomatic immigrants from malaria-endemic areas. Semi-immune donors may carry undetected parasitemia. This study examines Plasmodium infection in at-risk blood donors in Northern Italy.
  
  
  METHODS
  Plasma samples from 97 candidate donors and 80 controls were tested for malarial antibodies using a commercial enzyme immunoassay. The conserved 18S rRNA and the mitochondrial genes of Plasmodium were amplified to detect and quantify parasite genomes (copies/mL). Plasmodium species were identified with a species-specific nested polymerase chain reaction. Parasitemic samples were further tested by amplification of polymorphic repetitive regions in MSP-1 Block 2, MSP-2 Block 3, and glutamate-rich protein (GLURP) confirmed by sequencing.
  
  
  RESULTS
  Three of 83 seropositive (3.6%) and one of 14 seronegative at-risk candidate donors carried Plasmodium genome (4 × 10(3) -8.5 × 10(4) copies/mL): two P. falciparum, one P. malariae (seronegative sample), and one coinfection with P. malariae and P. ovale. Alleles of MSP-1 (MAD20 and K1), MSP-2 (3D7 and FC27), and GLURP were amplified from Sample 261. In Sample 282 only one allele in MSP-2 (FC27) and GLURP was amplified. No alleles were detected in Samples 283 and 331.
  
  
  CONCLUSIONS
  Immigrants from endemic countries might carry infectious Plasmodium after 2 to 5 years of continuous residence in Italy. Serologic screening may miss donors carrying P. malariae. Permanent exclusion or screening for both antibodies and genome are needed to prevent TTM.
authors.affiliation: Department of Haematology, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Sonny Michael
authors.initials: SM
authors.lastname: Assennato
authors.forename: Alessandra
authors.initials: A
authors.lastname: Berzuini
authors.forename: Barbara
authors.initials: B
authors.lastname: Foglieni
authors.forename: Marta
authors.initials: M
authors.lastname: Spreafico
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Allain
authors.forename: Daniele
authors.initials: D
authors.lastname: Prati
mesh_terms: D000328:Adult; D000368:Aged; D000913:Antibodies, Protozoan / Q000097:blood; D001782:Blood Donors / Q000706:statistics & numerical data; D001804:Blood Transfusion, Autologous / Q000706:statistics & numerical data; D054242:Emigrants and Immigrants / Q000706:statistics & numerical data; D005260:Female; D014644:Genetic Variation; D018503:Genome, Protozoan; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008288:Malaria / Q000097:blood / Q000235:genetics / Q000469:parasitology* / Q000635:transmission; D008297:Male; D008875:Middle Aged; D010961:Plasmodium / Q000235:genetics* / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D012307:Risk Factors; D017422:Sequence Analysis, DNA; D055815:Young Adult
chemical_list: D000913:Antibodies, Protozoan