title: Preliminary evaluation on the efficiency of the kit Platelia Dengue NS1 Ag-ELISA to detect dengue virus in dried Aedes aegypti: a potential tool to improve dengue surveillance.
abstract: BACKGROUND
  Surveillance is a critical component of any dengue prevention and control programme. Herein, we investigate the efficiency of the commercial kit Platelia Dengue NS1 Ag-ELISA to detect dengue virus (DENV) antigens in Aedes aegypti mosquitoes infected under laboratory conditions.
  
  
  METHODS
  Under insectary conditions, four to five day-old mosquitoes were orally challenged with DENV-2 titer of 3.6 x 10⁵ PFU equivalent/ml, incubated for 14 days and then killed. At ten time-points following mosquito death (0, 6, 12, 24, 72, 96, 120, 144 and 168 h), i.e., during a one-week period, dried mosquitoes were comparatively tested for the detection of the NS1 antigen with other methods of detection, such as qRT-PCR and virus isolation in C6/36 cells.
  
  
  RESULTS
  We first observed that the NS1 antigen was more effective in detecting DENV-2 in Ae. aegypti between 12 and 72 h after mosquito death when compared with qRT-PCR. A second round involved comparing the sensitivity of detection of the NS1 antigen and virus isolation in C6/36 cells. The NS1 antigen was also more effective than virus isolation, detecting DENV-2 at all time-points, i.e., up to 168 h after mosquito death. Meanwhile, virus isolation was successful up to 96 h after Ae. aegypti death, but the number of positive samples per time period presented a tendency to decline progressively over time. From the 43 samples positive by the virus isolation technique, 38 (88.4%) were also positive by the NS1 test.
  
  
  CONCLUSIONS
  Taken together, these results are the first to indicate that the NS1 antigen might be an interesting complementary tool to improve dengue surveillance through DENV detection in dried Ae. aegypti females.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Sylvestre
authors.forename: Mariana
authors.initials: M
authors.lastname: Gandini
authors.forename: Josélio M G
authors.initials: JM
authors.lastname: de Araújo
authors.forename: Claire F
authors.initials: CF
authors.lastname: Kubelka
authors.forename: Ricardo
authors.initials: R
authors.lastname: Lourenço-de-Oliveira
authors.affiliation: Laboratório de Transmissores de Hematozoários, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, RJ, Brazil. freitas@ioc.fiocruz.br.
authors.forename: Rafael
authors.initials: R
authors.lastname: Maciel-de-Freitas
mesh_terms: D000330:Aedes / Q000821:virology*; D000818:Animals; D000956:Antigens, Viral; D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D012367:RNA, Viral / Q000302:isolation & purification; D013048:Specimen Handling; D017361:Viral Nonstructural Proteins / Q000302:isolation & purification*
chemical_list: D000956:Antigens, Viral; C079340:NS1 protein, Dengue virus type 2; D012367:RNA, Viral; D017361:Viral Nonstructural Proteins