title: Duration of Loxosceles reclusa venom detection by ELISA from swabs.
abstract: BACKGROUND
  Diagnosis of Loxosceles reclusa envenomations is currently based upon clinical presentation. An enzyme-linked immunosorbent assay (ELISA) can detect surface Loxosceles venom at the envenomation site, allowing diagnostic confirmation. The length of time that venom on the skin is recoverable non-invasively is unknown.
  
  
  METHODS
  To investigate duration of recoverable venom antigen, whole venom and fractionated sphingomyelinase D venom aliquots were injected subcutaneously in New Zealand White rabbits. Cotton and Dacron swabs were compared for venom recovery over a 21-day period using a surface swab technique.
  
  
  RESULTS
  Significant amounts of Loxosceles reclusa antigen were found on the surface of rabbit skin after experimental injection of whole venom and sphingomyelinase D. The duration of recoverable antigen using this experimental model appears to be at least two weeks and as long as 21 days in some cases.
  
  
  CONCLUSIONS
  Because the duration of the recoverable antigen is seen to be at least two weeks, the ELISA venom test appears capable of detecting venom on most patients presenting with Loxosceles envenomations. This detection system will allow the physician more accurate determination of whether the lesion is from a brown recluse spider or some other agent that can cause this type of necrotic ulcer.
authors.affiliation: Wilford Hall Medical Center, Lackland AFB, TX 78236-9908, USA. David.McGlasson@lackland.af.mil
authors.forename: David L
authors.initials: DL
authors.lastname: McGlasson
authors.forename: Jonathon A
authors.initials: JA
authors.lastname: Green
authors.forename: William V
authors.initials: WV
authors.lastname: Stoecker
authors.forename: James L
authors.initials: JL
authors.lastname: Babcock
authors.forename: David A
authors.initials: DA
authors.lastname: Calcara
mesh_terms: D000818:Animals; D000941:Antigens / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006801:Humans; D010727:Phosphoric Diester Hydrolases / Q000032:analysis*; D011817:Rabbits; D012867:Skin / Q000737:chemistry; D001098:Spider Bites / Q000175:diagnosis; D013111:Spider Venoms / Q000032:analysis*; D013997:Time Factors
chemical_list: D000941:Antigens; D013111:Spider Venoms; C055161:loxosceles venom; D010727:Phosphoric Diester Hydrolases