More information about Schistosomiasis

There are three main species of Schistosomiasis, which are Schistosoma haematobium (used in our experiment), Schistosoma japonicum, and Schistosoma mansoni.  The life cycle first starts off with the release of schistosoma eggs through feces or urine of infected host into a source of freshwater.  In optimal conditions, these eggs hatch to release miracidia, which can swim and penetrate the snails living in the water.  The parasites go through two generation of sporocysts within the snail.  When there are disturbances in water, the infected snails release cercariae that can penetrate the human skin.  The cercariae loses its tail when it penetrates a host and becomes schistosomulae.  The schistosomulae travels through circulation in our body and migrate to portal blood in liver and mature into adults.  The adult worms will pair and migrate to specific mesenteric venules of body depending on species.  S. japonicum migrate to venous plexus in small intesitine, S. mansoni to those of large intestine, and S. haematobium to those of bladder.  The worms will lay and accumulate eggs inside the body causing diseases, such as kidney failure and bladder cancer. 

As you can imagine, the process of growing the parasites and testing compound is a lengthy process.  It takes more than six weeks to grow miricidia in snails.  When the time comes to shed cercariae from the snail, we place the snails in dark and in light to stress the snail for few hours.  Afterwards, the collected cercariae has to be transformed through centrifuging, vortexing, and layering to obtain only the head of cercariae.  This whole process can take up a whole day, and the number of shed cercariae for S. haematobium is usually low.  Growing the parasite and testing hundreds of compounds require time and dedication, but we are hopeful we will be able to find effective compounds and help repurpose drug for millions of people suffering worldwide.