All you need to know about Schistosomiasis: Life Cycle
The adult female eyes are released in to the environment from the infect individuals, hatching on contact with fresh waters to release the free swimming miracidium. The miracidium come close to a suitable snails usually the Bulinus species, they become excited and make a dash for it, burrowing into the tentacles other parts much to the irritation of the snail. Many miracidia become mired in the tongue tissues of the foot or head. After infection close to the site of penetration, the miracidium transforms into a primary (mother) sporocyst, (cdc 2000).
Germ cells within the primary sporocyst will then begin to divide to produce secondary (daughter) sporoctsis which migrate to the snails hepatopancrease germ cell within the secondary sporocysts begin to divide again, this time producing thousand of new parasites known as cercaria which are the larva capable of infecting mammals (CDC 2000). The cercaria emerge daily from the snail host and is then shed into water in a circadian rhythm dependent on ambient between vigorous upward movement and sinking to maintain their position in the water.
Cercaria activity in particularly stimulated by water turbulence, by shadows, movement and sinking to maintain their position in the water. Cercaria activity is particularly stimulated by water turbulence, by shadows, chemicals found on human skin. The cercaria swims about in water with its tail first, penetration of skin occurs after cercaria have attracted to and explored the skin.
The parasite secretes enzymes that break down the skins protein to enable penetration of the cercaria head through the skin. As cercaria penetrates the skin it loses its tail and becomes a schistosomule after penetration of the intact skin, it enters the blood stream, carried to the blood vessels of the lungs, migrates to the liver and develops to maturity in the venues blood vessels of the mesenteries or the bladder and finally, they develop into adult, mating takes place immediately or later.
The female deposits the eggs in the veins of the plexus. The eggs escape from the veinules into the tissues, mainly into the walls of the bladder and occasionally into the intestine. Many eggs pass through the mucosa to the excreted in urine (CDC 2000)