The researchers focused on three primate species, collecting 1,076 fecal samples from the heavily logged area and from an undisturbed, nearby forest from August 1997 to August 2002 as part of a longitudinal study of logging's impact. The samples came from red-tailed guenon, red colobus (Piliocolobus tephrosceles) and black-and-white colobus (Colobus guereza) and were analyzed for the eggs and larvae of worms and protozoan cysts.
The study appears online ahead of publication in the Journal of Applied Ecology.
While the three primate species were subject to a higher risk of infections, only the guenons (pronounced GWINN-ins) suffered from an increased number of parasites, including three parasites not found in undisturbed forest. In the selective-logging area, more than 50 percent of the trees, many of them the food sources for the mostly fruit-eating guenons, had been removed.
"We saw dramatic changes in the prevalence of infection and in the frequency of multiple infections in these logged areas," said lead researcher Thomas R. Gillespie, a postdoctoral fellow in veterinary pathobiology at the University of Illinois at Urbana-Champaign. "When you see infection characteristics like these, they can be associated with very detrimental effects on the host."
Since the logging period of the late 1960s, red-tailed guenons have been appearing in much lower densities, he said.
What once were large groups with multiple males and females are now fragmented, with much smaller groups living isolated and spread out more widely than in undisturbed forest