title: Evaluation of rapid blood sample collection in the detection of circulating filarial antigens for epidemiological survey by rWbSXP-1 capture assay.
abstract: BACKGROUND
  Lymphatic filariasis is a neglected tropical disease leading to profound disfiguring causing socio economic burden in the tropics. Current diagnosis strategies available during field surveys and epidemics are based on traditional microscopic detections and a few antigen/antibody assays. We have compared different sampling methodologies and standardized the highly sensitive and reliable rWbSXP-1 antigen detection assay to our new sampling methodology.
  
  
  METHODS
  Samples collected as serum, whole blood, whole blood on filter paper and whole blood on microscopic slides from patients belonging to various clinical groups of filariasis [endemic normal(EN), chronic pathology(CP), microfilaraemic(MF) and non-endemic normal(NEN)] were collected and standardized the rWbSXP-1 antigen detection assay using monoclonal antibody raised against rWbSXP-1 protein. The whole blood collected on microscopic slide based sampling method was employed in the field and the presence of circulating filarial antigen (CFA) was assessed using the rWbSXP-1 assay.
  
  
  RESULTS
  The sampling methods were compared and no significant difference was observed for the detection of CFA (MF, P = 0.304, EN, P = 0.675, CP, P = 0.5698, NEN, P = 0.4494). Further the optimized sampling method was utilized to collect the 1106 samples from Polur, Tiruvannamalai. The rWbSXP-1 assay gave 98 antigen positive results whereas the microscopic method gave only 17.
  
  
  CONCLUSIONS
  Four sampling methodologies were analyzed and the new sampling methodology of whole blood collected on microscopic slide was found to be convenient for the detection of CFA using rWbSXP-1 antigen detection assay. The 1106 samples from Polur were collected using the new method. The rWbSXP-1 antigen assay perceived a 7.32% increased result which was read as false negatives on the conventional microscopic staining method. This new sampling methodology coupled with the rWbSXP-1 antigen assay can be used in epidemiological surveys for lymphatic filariasis and the same sampling methodology can be expanded to other antigen based high affinity assays.
authors.affiliation: Centre for Biotechnology, Anna University, Guindy, Chennai, Tamil Nadu, India.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Ansel Vishal
authors.affiliation: Centre for Biotechnology, Anna University, Guindy, Chennai, Tamil Nadu, India.
authors.forename: Y
authors.initials: Y
authors.lastname: Nazeer
authors.affiliation: Centre for Biotechnology, Anna University, Guindy, Chennai, Tamil Nadu, India.
authors.forename: Rajendran
authors.initials: R
authors.lastname: Ravishankaran
authors.affiliation: Centre for Biotechnology, Anna University, Guindy, Chennai, Tamil Nadu, India.
authors.forename: Natarajan
authors.initials: N
authors.lastname: Mahalakshmi
authors.affiliation: Centre for Biotechnology, Anna University, Guindy, Chennai, Tamil Nadu, India.
authors.forename: Perumal
authors.initials: P
authors.lastname: Kaliraj
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000276:immunology; D000947:Antigens, Helminth / Q000097:blood / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D004605:Elephantiasis, Filarial / Q000453:epidemiology* / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000592:standards; D005260:Female; D015801:Helminth Proteins / Q000097:blood / Q000276:immunology*; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D058069:Neglected Diseases / Q000453:epidemiology* / Q000276:immunology*; D011994:Recombinant Proteins / Q000276:immunology; D055815:Young Adult
chemical_list: D000911:Antibodies, Monoclonal; D000947:Antigens, Helminth; D015801:Helminth Proteins; D011994:Recombinant Proteins; C079249:SPX-1 protein, Brugia malayi