Chronic social stress, social status, and susceptibility to upper respiratory infections in nonhuman primates.
OBJECTIVE
The objective of the study was to assess the roles of social stress and social status in susceptibility to upper respiratory infection.


METHODS
Sixty male cynomolgus monkeys were randomly assigned to stable or unstable social conditions for 15 months. Two markers of social status, social rank and percent of behaviors that were submissive, were assessed at independent observation periods. Endocrine, immune, and behavioral responses were each assessed (at 3-month intervals) during the 9th through 14th months of the study. At the beginning of the 15th month, all animals were exposed to a virus (adenovirus) that causes a common-cold-like illness. The primary outcome was whether or not an animal developed an infection (shed virus) after viral exposure.


RESULTS
Although the social instability manipulation was associated with increased agonistic behavior as indicated by minor injuries and elevated norepinephrine responses to social reorganizations, the manipulation did not influence the probability of being infected by the virus. However, low social status (as assessed by either marker) was associated with a substantially greater probability of being infected. It was also associated with less body weight, greater elevated cortisol responses to social reorganizations, and less aggressive behavior. However, none of these characteristics could account for the relation between social status and infection.


CONCLUSIONS
Social stress was not associated with susceptibility to infection. However, animals with lower social status were at higher risk than high social status animals.
Cohen
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S
Department of Psychology, Carnegie Mellon University, Pittsburg, PA 15213 USA. SCOHEN@cmu.edu
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Manuck
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Rabin
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Heise
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Kaplan
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JR
D000261:Adenoviruses, Simian / Q000276:immunology; D000374:Aggression / Q000502:physiology; D000818:Animals; D001143:Arousal / Q000502:physiology; D003139:Common Cold / Q000276:immunology / Q000523:psychology / Q000662:veterinary*; D004198:Disease Susceptibility / Q000276:immunology / Q000523:psychology; D004837:Epinephrine / Q000097:blood; D006608:Hierarchy, Social; D006854:Hydrocortisone / Q000097:blood; D007108:Immune Tolerance / Q000276:immunology; D008252:Macaca fascicularis / Q000276:immunology / Q000523:psychology*; D008297:Male; D008992:Monkey Diseases / Q000276:immunology / Q000523:psychology*; D009638:Norepinephrine / Q000097:blood; D012307:Risk Factors; D012919:Social Behavior; D013315:Stress, Psychological / Q000150:complications*; D017201:Virus Shedding / Q000276:immunology
D006854:Hydrocortisone; D009638:Norepinephrine; D004837:Epinephrine