A microsporidian infecting body muscle of Parapenaeopsis stylifera - histological studies.
In the present study, the microsporidian infecting wild shrimp were characterized by histological and histochemical studies. A six months survey to examine the microsporidian infection in feral shrimp revealed that only Parapenaeopsis stylifera was infected with a microsporean, Perezia sp. Other species examined (Metapenaeus brevicornis, Metapenaeus affinis and Solenocera sp.) did not reveal any infection. The prevalence of the microsporean, Perezia infecting P. stylifera was found to be very low (1.76%). The spores were found only in the skeletal musculature and the infected shrimp appeared milky white in colour. The spores measured 1.4-2.8 µm × 0.9-1.9 µm. The histological sections revealed extensive lesions that appeared more homogeneous and muscle fibers found to be completely replaced by spores. The spores were stained with different stains viz, Giemsa, Gram's and hematoxylin & eosin (H&E) stain. The Gram's and H&E stained spores at higher magnification often showed a darkly reddish coloured circular body at the one end. Prussian blue stained histological sections showed bluish tinge near the necrotized area of muscle, due to growth of spores.