Oral administration of putrescine inhibits Cryptosporidium parvum infection of neonatal C57BL-6 mice and is independent of nitric oxide synthesis.

We examined the efficacy of oral administration of putrescine (a byproduct of arginine metabolism) in the prevention of Cryptosporidium parvum infection of neonatal C57BL-6 mice. Mice were challenged with the parasite at 7 days of age. Mice receiving putrescine from 3 through 10 days of age had a delayed pattern of infection as compared with control mice. Mice receiving putrescine from 3 through 21 days of age did not become infected, whereas control mice were heavily infected. We also tested the hypothesis that putrescine inhibited C. parvum infection by enhancing nitric oxide (NO) production. Mice receiving the NO inhibitor N omega-L-arginine methyl ester (L-NAME) parenterally and putrescine orally did not become infected. Thus, it appears that putrescine inhibits C. parvum infection in an NO-independent manner.