Parasite Protection

Animals’ Native Remedies Offer Insights

We can learn much from animal species that self-medicate naturally. Some have developed the ability to alter their diets and behavior in ways that provide protection from lethal, microscopic parasites.

Chimpanzees held captive often succumb to infection by a parasitic worm, which can lead to lethal intestinal blockages or secondary bacterial infections. But chimps in the wild rarely experience such deadly ailments. More than 30 years ago, Michael Huffman, who studies evolution of social systems at the University of Kyoto, in Japan, noticed that wild chimps treated themselves by ingesting foods with special properties that fight intestinal worm infections.

Scientists recently discovered why monarch butterflies are so picky in choosing the milkweed plants on which to lay their eggs. “The females often taste a plant, reject it and fly away,” explains Jacobus de Roode, Ph.D., of Emory University, in Atlanta, Georgia. His research team found that butterflies infected with a certain protozoan parasite seek out milkweeds containing high levels of cardenolide, a plant steroid that interferes with parasite growth in monarch caterpillars.

Scientists have identified many other species that partake in self-medicating practices, including macaques and sheep. Recognition that various insects such as honey bees and fruit flies share this trait is enabling scientists to rigorously examine the phenomenon in the laboratory, with hopes of finding applications in animal husbandry and even human medicine.

Source: The Scientist magazine