whereas absence of host reaction by gregarines of the genus Nematopsis in the gut epithelial cells was reported by Winstead et al.
Histological examination showed gregarine protozoan Nematopsis sp.
The oocysts of this gregarine protozoan were pyriform in shape and measured 20 [micro]m (range, 18-22 [micro]m) in length and 15[micro]m (range, 11-16 [micro]m) m in width (n = 30).
gill and digestive tract), as were the gregarines (viz.
Because of the numerical dominance of the gregarines in oyster taxa, a modified total parasite body burden was also calculated as the sum of the quantitative counts of the remaining parasite groups.
Gregarines are widely distributed in oysters along the East and Gulf coasts (Landau & Galtsoff 1951, Otto et al.
Mytilids and oysters were not significantly different from each other, however; thus, the gregarines were primarily responsible for the higher prevalence of parasitism in oysters.
The prevalence of protozoa including ciliates, but excluding gregarines, haplosporidians, and apicomplexans, did not differ significantly between mytilids and oysters (Fig.
As in prevalence, the gregarines strongly influenced these trends.
East-coast oysters had significantly higher infection intensities of gregarines in body tissue than West-coast mytilids; Gulf-coast oysters fell in between (Fig.
This trend was even more evident after discounting the gregarines (Fig.
In a trend opposite to most parasitic taxa, gregarines were not found in East-coast M.
This trend was due solely to the prevalence of gregarines in Gulf-coast oysters, however (Fig.