title: Real-time PCR detection of the HhaI tandem DNA repeat in pre- and post-patent Brugia malayi Infections: a study in Indonesian transmigrants.
abstract: BACKGROUND
  Lymphatic filariasis caused by Wuchereria bancrofti or Brugia spp. is a public health problem in developing countries. To monitor bancroftian filariasis infections, Circulating Filarial Antigen (CFA) test is commonly used, but for brugian infections only microfilariae (Mf) microscopy and indirect IgG4 antibody analyses are available. Improved diagnostics for detecting latent infections are required.
  
  
  METHODS
  An optimized real-time PCR targeting the brugian HhaI repeat was validated with plasma from microfilariae negative Mongolian gerbils (jirds) infected with B. malayi. Plasma samples from microfilaremic patients infected with B. malayi or W. bancrofti were used as positive and negative controls, respectively. PCR results of plasma samples from a transmigrant population in a B. malayi endemic area were compared to those of life-long residents in the same endemic area; and to IgG4 serology results from the same population. To discriminate between active infections and larval exposure a threshold was determined by correlation and Receiver-Operating Characteristics (ROC) curve analyses.
  
  
  RESULTS
  The PCR detected HhaI in pre-patent (56 dpi) B. malayi infected jirds and B. malayi Mf-positive patients from Central Sulawesi, Indonesia. HhaI was also detected in 9/9 elephantiasis patients. In South Sulawesi 87.4% of the transmigrants and life-long residents (94% Mf-negative) were HhaI PCR positive. Based on ROC-curve analysis a threshold for active infections was set to >53 HhaI copies/μl (AUC: 0.854).
  
  
  CONCLUSIONS
  The results demonstrate that the HhaI PCR detects brugian infections with greater sensitivity than the IgG4 test, most notably in Mf-negative patients (i.e. pre-patent or latent infections).
authors.forename: Anna
authors.initials: A
authors.lastname: Albers
authors.forename: Erliyani
authors.initials: E
authors.lastname: Sartono
authors.forename: Sitti
authors.initials: S
authors.lastname: Wahyuni
authors.forename: Maria
authors.initials: M
authors.lastname: Yazdanbakhsh
authors.forename: Rick M
authors.initials: RM
authors.lastname: Maizels
authors.forename: Ute
authors.initials: U
authors.lastname: Klarmann-Schulz
authors.affiliation: Institute of Medical Microbiology, Immunology and Parasitology, University Hospital of Bonn, Sigmund-Freud-Str, 25, D-53105 Bonn, Germany. pfarr@microbiology-bonn.de.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Pfarr
authors.forename: Achim
authors.initials: A
authors.lastname: Hoerauf
mesh_terms: D000818:Animals; D017178:Brugia malayi / Q000235:genetics*; D005368:Filariasis / Q000453:epidemiology / Q000469:parasitology*; D005849:Gerbillinae; D006801:Humans; D007214:Indonesia / Q000453:epidemiology; D008297:Male; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity