Giardia lamblia, a protozoan parasite, infects people who drink contaminated water. Researchers have found that infection with parasitic worms decreases a person's odds of being infected with G. lamblia.
Stan Erlandsen/CDC
Giardia lamblia, a protozoan parasite, infects people who drink contaminated water. Researchers have found that infection with parasitic worms decreases a person's odds of being infected with G. lamblia.
Stan Erlandsen/CDC