These lesions within these organs are characterized by well-circumscribed focal fibrosis, accumulation of eosinophils and histiocytes, hemorrhage or hemosiderosis with the loss of normal architecture.

These appear as raised, grayish-white to translucent foci with a central accumulation of fluid.

Multiple, depressed areas of fibrosis with calcification representing healed lesions may also be found.

Microscopically the liver cysts have an irregular central space filled with faintly eosinophilic, acellular, flocculent material.

Surrounding this is a peripheral rim of myriad, round, lightly basophilic merozoites which measure ~1.0–2.0 mm in diameter.

Having reached maturity, they gradually decline in number and normally disappear after a month.

The early gametocytes consist of minute dense spots of chromatin with a tiny loop of cytoplasm.

Mature gametocytes are larger than a normal erythrocyte stain poorly compared to other protozoa.

The nucleus has a pale pink area with dense chromatin in the middle and is much smaller than that of the microgametocyte.

The nucleus is a large, oval, pale pink area occupying one-third to one-half of the parasite.

Some versions of the Duffy antigen have been associated with protection from Hepatocytis infection in yellow baboons (Papio cynocephalus).