Chloromyxum reticulatum (Myxozoa, Myxosporea) in the liver of burbot (Lota lota L) and its migration to the final site of infection.

The coelozoic myxosporean Chloromyxum reticulatum Lom, Dyková and Kepr, 1988 forms large sporogonic plasmodia in the gall bladder of burbot (Lota lota). Different, very small stages of the parasite were detected in the liver parenchyma. Their presence between the hepatocytes provoked no pathological changes and induced no host tissue reaction. They were concentrated beneath the epithelial layer of the proximal parts of the bile ducts, were wedged between the bile duct epithelial cells and also in the lumen. These findings indicate that, contrary to earlier assumptions, myxosporea reach the gall bladder via circulating blood, not directly from the intestine through the common bile duct. Thus the haematogenous spread of early myxosporean stages can be presumed in myxosporeans infecting all sites in the fish body.