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Source of Human Infection:
"Human infection with the sparganum stage of the species of Spirometra results from 1) drinking pond, lake, or stream water containing procercoid-infected Cyclops; 2) eating a raw infected frog, snake, or small mammal, or 3) applying plerocercoid-infected flesh of frogs, snakes, or possible warm -blooded animals as a poultice on an inflamed eye or finger. As spargana are known to develop in pigs, human infection may occasionally be acquired by eating raw pork."
(Beaver, PC, 1985)
Humans are secondary intermediate hosts and develop the following symptoms upon infection:
Clinical Presentation/Diagnosis:
Symptoms of sparganosis depend upon the location of the sparganum within the body described below. In general "more prolonged residence of the parasite provokes an infiltration of eosinophils, epithelioid cells and lymphocytes. As the infection becomes chronic there develops an extremely tender puffy area around the parasite." (Faust, 1975). When the larva dies, its remnants will cause great inflammation in the area and become very painful. Incubation period is unclear, although it is thought that the sparganum worm can live up to 20 years in a human.
subcutaneous tissue
Here the sparganum will cause a nodule under the skin to form and often times it will migrate through the tissue, hence "creeping tumor"
eye region
Inflammation and edema (swelling) around the eye, resulting in great pain.
vaginal region
Inflammation and edema, pain.
Brain
Spirometra proliferum can be lethal for humans. The larva proliferates by breaking itself down by segment, each segment then developing into a new larva plerocercoid within the human which can have profound effects if occurring in many organs at the same time.
Visual diagnosis of sparganosis is the main way to determine the infection. To identify type of larva a primary host (cat or dog) must be infected with the larva after the surgical removal of the larva from the human. The parasite can be identified by the adult worm that hatches.
Treatment:
The main form of treatment of sparganosis is surgical removal of the larva upon visual diagnosis; brain surgery to skin surgery. Praziquatel, can be used, but its effectiveness has not been proven in human, it is effective in vitro however.
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