Scent Recognition of Infected Status in Humans

Abstract

Introduction 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. Aim 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. Main Outcome Measures 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. Conclusion 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.

Attractiveness Is Multimodal: Beauty Is Also in the Nose and Ear of the Beholder

“…For example, humans can use olfactory cues present in body odor to assess sex (Schleidt et al, 1981), personality (Sorokowska, 2013a) including dominance (Havlíček et al, 2005), actual fertility (Gildersleeve et al, 2012), diet (Fialová et al, 2013), genetic compatibility (Havlíček and Roberts, 2009), health status (Moshkin et al, 2012), and age (Mitro et al, 2012). Humans also have the capacity to recognize kin via body odor (Weisfeld et al, 2003; Ferdenzi et al, 2010), which may be important in mate choice in order to avoid inbreeding.…”

Coevolution of parasite virulence and host mating strategies

“…Identifying the means by which hosts detect infected individuals is especially difficult in the absence of visual cues (e.g., in asymptomatic infections). Behavioral cues are likely to be important indicators of host condition, and some evidence points toward olfactory mechanisms as a means of detecting disease (50,53). Many parasites are capable of remaining asymptomatic for long periods of time, but are still highly transmissible (e.g., Chlamydia, HIV).…”

Behavioral and neural correlates to multisensory detection of sick humans

“…Similarly, different patient groups are associated with characteristic body odors (9,10). However, none of these studies has manipulated acute health status, and therefore they have not been able to establish any evidence for causality between sickness and detectable cues, nor have they investigated these cues soon after the induction of a systemic sickness response.…”