title: Scent recognition of infected status in humans.
abstract: BACKGROUND
  There is a body of experimental evidence that mice and rats use chemical signals to avoid sexual contact with infected conspecifics. In contrast to animals, body scent of sick humans is employed only in medical diagnostics. A modification of human body odor, due to an infection, has not been studied as a potential signal for choice of a sexual partner. It might, however, be especially important for sexually transmitted infections (STI) because many such infections have no obvious external manifestations.
  
  
  OBJECTIVE
  In this study, we have investigated odor pleasantness of young men infected with gonorrhea, Neisseria gonorrhoeae.
  
  
  METHODS
  We collected armpit sweat and saliva from young men (17-25 years old) belonging to three groups: healthy persons (N = 16), young men infected with gonorrhea, Neisseria gonorrhoeae (N = 13), and persons recovered due to specific therapy (N = 5). The sweat samples odor was then assessed by healthy young women (17-20 years old). Concentrations of cortisol, testosterone, immunoglobulin A (IgA), and immunoglobulin G (IgG) were measured in saliva by means of enzyme-linked immunosorbent assay.
  
  
  METHODS
  Subjective rates of odor pleasantness, association of scent of armpit sweat with odor descriptors, stepwise regression of odor pleasantness and salivary cortisol, testosterone, IgA, and IgG.
  
  
  RESULTS
  The odor from infected individuals was reported as less pleasant in comparison with the odor of healthy and recovered young men. The scent of infected men was more frequently associated by raters with the descriptor "putrid." Odor pleasantness of the male sweat correlated negatively with concentration of the nonspecific salivary IgA and IgG, which was measured as an indicator of current immunoenhancement.
  
  
  CONCLUSIONS
  Perhaps, the immune-dependent reduction of the scent pleasantness in the acute phase of STI is part of an evolutionary mechanism ensuring, unconsciously, avoidance of a risky romantic partner.
authors.affiliation: Institute of Cytology and Genetics SB RAS, Novosibirsk, Russia. mmp@bionet.nsc.ru
authors.forename: Mikhail
authors.initials: M
authors.lastname: Moshkin
authors.forename: Nadezhda
authors.initials: N
authors.lastname: Litvinova
authors.forename: Ekaterina A
authors.initials: EA
authors.lastname: Litvinova
authors.forename: Alena
authors.initials: A
authors.lastname: Bedareva
authors.forename: Andrey
authors.initials: A
authors.lastname: Lutsyuk
authors.forename: Ludmila
authors.initials: L
authors.lastname: Gerlinskaya
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D016022:Case-Control Studies; D002443:Ceftriaxone / Q000627:therapeutic use; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006069:Gonorrhea / Q000150:complications* / Q000188:drug therapy; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis; D007070:Immunoglobulin A / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D008297:Male; D009812:Odorants; D012463:Saliva / Q000737:chemistry; D013542:Sweat; D013739:Testosterone / Q000032:analysis; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D013739:Testosterone; D002443:Ceftriaxone; D006854:Hydrocortisone