Posted by: Moges Woldemeskel, DVM, PhD, DACVP (TVDIL)
Sparganosis is an infection of tissues by second stage larvae (spargana or plerocercoid) of pseudophyllidean tapeworms. Sparganosis due to pseudophyllidean cestodes such as Sparganum spp. (e.g. Sparganum proliferum) and Spirometra spp. (e.g. Spirometra mansonoides, Spirometra erinaceieuropaei) can occur in body cavities or in tissues of intermediate and paratenic hosts. Sparganum proliferum is phylogenetically identified as a new species in the order pseudophyllidea. The life cycle and the definitive host of Sparganum proliferum is unknown but believed to be similar to that of Spirometra spp. The definite hosts of Spirometra spp. are carnivores, and the eggs are shed in feces. The eggs embryonate in the environment, hatch in water and release coracidia. Coracidia are ingested by intermediate hosts, copepod crustaceans (Cyclops spp.), and develop into procercoids. Second intermediate hosts including fish, reptiles, and amphibians ingest infected copepods and acquire procercoid larvae. Procercoids develop into plerocercoids in the second intermediate hosts. Predators of the second intermediate hosts are infected by the plerocercoids. Plerocercoidosis/sparganosis develops after ingesting procercoids or plerocercoids with contaminated water or infected intermediate hosts. Humans and other mammals including apes, pigs, dogs, and cats can serve as paratenic or second intermediate hosts and develop sparganosis.
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