The Sea as a Source of Novel Antiparasitic Compounds

Primary Author: Rachel Relat

Faculty Sponsor: Roberta O’Connor


Primary College/Unit: College of Veterinary Medicine

Category: Medical and Life Sciences

Campus: Pullman





Cryptosporidium, an intracellular parasite that causes severe diarrhea, is now recognized as a leading cause of waterborne disease worldwide, infecting both humans and valuable livestock.  Cryptosporidium infection is particularly devastating in children as it causes life-threatening diarrhea, along with developmental delays including growth stunting and cognitive impairment. Cryptosporidium is an especially important disease of immunocompromised individuals of all ages, leading to chronic, potentially fatal diarrhea. No effective treatment exists for many human or veterinary patients diagnosed with Cryptosporidium.


To address this medical imperative, we designed a high throughput screen to test thousands of unique compounds, with the goal of discovering new, potent, anti-Cryptosporidium drugs and drug scaffolds. Our collaborators at the Harbor Branch Oceanographic Institute (HBOI) have amassed a library of over 125 natural compounds, and 6500 highly enriched fractions from extracts of marine organisms. We began screening this library as it contains compounds and fractions produced by sessile oceanic animals which frequently use chemical defenses.  We screened greater than 3,600 partially purified extracts from the HBOI library by infecting cells with Cryptosporidium parvum, allowing replication, and then treating with a specific highly enriched fractions or compounds, and then measuring parasite growth after 48 hours.


We identified 10 extracts derived from sessile marine organisms that effectively inhibit (>80% inhibition) Cryptosporidium without damaging the host cells in which these parasites live. This work will significantly contribute to the goal of discovering effective treatments against Cryptosporidium specifically, and further the search for novel anti-parasitic drugs.