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November 29, 2014


What are Microsporidians?


If you’re a shrimp farmer and have not yet read the Network of Aquaculture Centres in Asia-Pacific’s (NACA) report on Enterocytozoon hepatopenaei (EHP), a disease caused by a microsporidian parasite, I recommend that you read it before you read this item.  One farm manager told me that EHP might turn out to be more devastating than early mortality syndrome (EMS)!  The Thai shrimp farming industry’s slow recovery from EMS is probably associated with the presence of EHP.


According to Wikipedia, microsporidia constitute a phylum of spore-forming unicellular parasites.  They were once thought to be protists, but are now known to be fungi.  Loosely 1,500 of the probably more than one million microsporidia have been named.  They are restricted to animal hosts, and all major groups of animals host microsporidia.  Most infect insects, but they are also responsible for common diseases of crustaceans and fish.


Microsporidia lack motile structures, such as flagella, and produce highly resistant spores capable of surviving outside their host for up to several years.  Spore morphology is useful in distinguishing between different species.  Spores of most species are oval or shaped like a flame or pear, but rod-shaped or spherical spores are not unusual.


Sources: 1. Wikipedia.  Microsporidia.  Website visit on November 28, 2014.  2. Bob Rosenberry, Shrimp News International, November 29, 2014.

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