Testosterone and Intestinal Parasite Infetions in Wild Chimpanzees


Am J Phys Anthropol. 2006 Jan 27; [Epub ahead of print]


Intestinal parasite infections and fecal steroid levels in wild
chimpanzees.

Muehlenbein MP.

Department of Anthropology, University of Wisconsin-Milwaukee, Milwaukee,
Wisconsin 53211.

Immune-endocrine interactions have been evaluated much less frequently in
nonhuman primates, and this may be due, in part, to logistical and ethical
concerns regarding trapping and sampling of endangered species, especially
apes. Using noninvasive fecal collection methods, the present study
evaluates possible relationships between fecal steroid levels and
gastrointestinal parasite infections in the Ngogo chimpanzee community in
Kibale National Park, Uganda. Because both testosterone and cortisol
exhibit immunosuppressive effects in vitro and in other animal models, it
was hypothesized that both testosterone and cortisol would be positively
associated with gastrointestinal parasite infections in these animals. When
placed in a mixed model simultaneously, both testosterone (F = 4.98, df =
1, P = 0.033) and cortisol (F = 5.94, df = 1, P = 0.020) were positively
associated with total (helminth and protozoan) parasite richness (the
number of unique intestinal parasite species recovered from hosts' fecal
samples). It is possible that androgens and corticoids alter the ability of
a host to mount an effective immune response against concomitant infection
with multiple parasitic species. The utility of fecal samples for assessing
immune-endocrine interactions is discussed. Am J Phys Anthropol, 2006. (c)
2006 Wiley-Liss, Inc.

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