God Ordains and Guides – A Tour of a Parasite in Human Body

Schistosoma is a parasite which has a complex life cycle in both snails and humans. The worm starts its life as an egg in freshwater where it hatches into a larva and finds and infects a host snail. There it passes through several stages to turn into another larva (cercaria) which leaves the snail and returns to water, later to infect a human (such as a swimmer or a farmer). It burrows into the human’s bare skin, enters the bloodstream and hides in the lung for a few days to acquire resistance to the immune system. It returns to the blood and migrates to the venules of the intestine or the urinary bladder, depending on the species of the parasite. Female worms lay eggs which penetrate the blood vessels to be passed out with faeces or urine of the infected persons and hence go back to a freshwater source to begin another life cycle.

Who taught the larva to be attracted to the skin of man? Who taught the larva to hide in the lung from the immune system of humans? Who taught the worm to find its way to the blood vessels of the intestine or bladder? Who guided the worms that they should lay their eggs in the blood vessels of the intestine or bladder, as they are their only way to get back to the fresh water again? Who guides this larva where to go in its tour in the human body, without any previous experience and without eyes or access to a sun map or a magnetic field map? It is God who ordains and guides.

A, Schistosoma Larval stage which penetrates the skin; B, the larval stage of the lung; C, a couple of mature male and female larvae in the blood vessels; D, eggs of different species of Schistosoma.