Insights into the functional biology of schistosomes

Abstract

The need to discover new treatments for human schistosomiasis has been an important driver for molecular research on schistosomes, a major breakthrough being the publication of the Schistosoma mansoni and Schistosoma japonicum genomes in 2009. This 'Primer' considers recent advances in the understanding of schistosome biology by providing a snapshot of selected areas of contemporary functional schistosome research, including that on the genome, the tegument, cell signalling and developmental biology, offering biologists a valuable insight into the life of these fascinating parasites at the basic and molecular level.

Exploring the function of protein kinases in schistosomes: perspectives from the laboratory and from comparative genomics

“…The life cycle of these schistosomes is complex (Walker, 2011). Paired adult male and female worms living in the blood vessels of the human definitive host produce eggs that are excreted and hatch in fresh water releasing a miracidium that infects an aquatic intermediate host snail.…”

“…Each cercaria then transforms into a schistosomule which subsequently enters the circulation and develops into juvenile and then adult worms that pair to stimulate full maturation and egg laying. Considerable morphological and physiological differences exist between these separate schistosome life-cycle stages (Walker, 2011) and thus protein kinase function may be different in each individual life stage, adding a further layer of complexity to role characterization. Also, each life stage will intercept different “input” signals from its environment (Walker, 2011).…”

Bilharzia: Pathology, Diagnosis, Management and Control

“…The parasites lose their tails as they penetrate the skin, and transform into young schistosomes called schistosomula [4,36,37]. After spending at least two days in the skin, the parasites burrow through the dermis, penetrate a blood vessel wall, and gain access into the circulatory system [38]. The parasites migrate to the lungs and remain there for several days before travelling to the liver were they blood-feed on red blood cells, mature and mate within the liver vessels [4,36,37].…”

“…Afterwards, they emerge as male-female worm pairs, and inhabit either the portal or pelvic vessels [36,37]. This habit of the parasite is exemplified by the four schistosome species except S. hematobium which prefers the urinary bladder venous plexus [36,38]. The female begins to lay eggs within the mesenteric or pelvic vessels [36,37].…”

Clinical management of advanced schistosomiasis: a case of portal vein thrombosis-induced splenomegaly requiring surgery

“…Most of the deaths are caused by liver disease induced by the Schistosoma parasite 3. In schistosomiasis, adult worms reside in the mesenteric vasculature where they lay eggs 4. Although these ova are intended to traverse into the bowel lumen to complete the parasite life cycle, many of them are carried upstream to the portal vein where they get trapped in the presinusoidal venules.…”