es. The parasites also have a significant burden on pregnant women and working adults.”
But despite the huge impact of these parasites on the developing world, few drugs have been developed to effectively combat their infection in human populations. In fact, the drugs available now were mostly developed for use in veterinary medicine. Little effort has been put to directly solve and address the human intestinal roundworm problem.
“For practical reasons, only one drug, albendazole, is now widely used in administering single-dose treatments to large populations,” Aroian added. “But because of the enormous numbers of people that need to be treated repeatedly, the development of resistance to albendazole is a serious threat and is already suspected in two studies in Sri Lanka and Ethiopia. Furthermore, albendazole, as part of mass drug administrations, is a far from ideal drug, having poor impact on whipworms and incomplete impact on hookworms. A recent talk at the Society for Tropical Medicine and Hygiene annual meeting highlighted the inadequacies of albendazole in treating roundworms in South America.”
The latest drug to be developed is tribendimidine, which clinically appears to be similar to albendazole, Aroian said.
But Aroian and his colleagues found in their head-to-head study of tribendimidine against an intestinal parasitic worm in mice that the Cry5B protein is three times better than tribendimidine.
“Comparisons in the literature with the other anti-worm drugs against this same mouse parasite, Heligmosomoides bakeri, indicate that Cry5B is anywhere from 4 times to 10,000 times more effective than various other anti-worm drugs,” said Aroian.
“Furthermore, we found in our study that most of the Cry5B is likely degraded in the stomach, so if we can protect this protein from stomach degradation, it is likely to be an even more powerful drug against parasites than we are currently measuring,” he said.
“The bottom line is that this natural soil bacterium has evolved a way of killing intestinal roundworms that is better than any drug we currently have available,” Aroian said. “Our results pave the way to developing Cry5B as a safe and superior drug against roundworms that can rid a terrible class of parasites from hundreds of millions of children around the world. We are one step closer to finding a more complete treatment. Why this bacterium has evolved such a powerful anti-roundworm protein is because it is likely that roundworms and Bt interact in the wild, engaged in a sort of natural warfare with each other. If so, then the old adage ‘the enemy of my enemy is my friend’ may turn to our advantage here.”
Yan Hu, a postdoctoral fellow in Aroian’s laboratory, and Sophia Georghiou, a graduate student, performed most of the experiments in the study along with Alan Kelleher, a staff scientist in Aroian’s laboratory.
The researchers were supported by grants from the National Institute of Allergy and Infectious Diseases, a part of the National Institutes of Health.
In addition, two patents have been filed by UC San Diego on inventions related to the study. The specific inventions are available for licensing or commercial development through UCSD’s Technology Transfer Office at http://invent.ucsd.edu/technology/biomedical.shtml#infectious
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