CHAPTER XXXIII 



MICROSPORIDIA 



By 



R. R. Kudo 

 The University of Illinois 



INTRODUCTION 



The MICROSPORIDIA (Balbiani, 1882), together with myxospor- 

 IDIA and ACTiNOMYXiDiA, make up the group of protozoa to 

 which Doflein (1901) gave the name cnidosporidia. Consequently 

 the taxonomic status of this group is the same as that of the myxo- 

 sporidia (p. 304). MICROSPORIDIA have been known to science 

 since the middle of the last century when the pebrine disease of 

 the silkworm broke out in several European countries in a severe 

 epidemic form. Because of the economic importance of this disease, 

 numerous investigators directed their attention to the causative 

 organism of the disease, a microsporidian, now known as Nosema 

 homhycis, and this resulted in the appearance of a large number 

 of papers dealing with this and allied forms discovered in various 

 groups of animal belong to phylum arthropoda. For the history 

 of development of our knowledge on microsporidia, the reader is 

 referred to Auerbach (1910). 



As is the case with the members of sporozoa, microsporidia 

 are all parasites. Unlike the myxosporidia which are primarily 

 fish-parasites, the microsporidia have been found in invertebrates 



such as PROTOZOA, PLATYHELMINTHES, BRYOZOA , NEMATHEL- 



MiNTHES, ANNELIDA and ARTHROPODA, and also in vertebrates such 

 as PISCES, AMPHIBIA and reptilia. The great majority of host 

 animals known up to date are arthropods and especially insects 

 (Kudo, 1924). The microsporidia have been reported from 

 various regions of the world, particularly from France, Germany, 



