Uniquely, unlike most parasites, the adult worms are relatively harmless, but it is the developing juveniles that cause serious disease called paramphistomiasis (or classically amphistomosis), especially in cattle and sheep.

The most debilitating cases are reported in Europe from Bulgaria, Italy, France, and Poland and also in Asia from Thailand, India, and China.

[3] Adult P. cervi is conical in shape, the anterior end tapering and the posterior being broad, and pink in colour.

The tegumental surface is highly corrugated with transverse folds alternating with grooves and is spineless, which is uncharacteristic of trematodes.

There are two types of bulbous shaped sensory papillae on the surface, each measuring 10–15 μ in diameter at the base with nipple-like tips; one has a short cilia on top.

The sexually mature monoecious adult self-fertilises in the mammalian rumen, and retains the eggs inside its uterus.

Most common intermediate hosts are snails belonging to the genera Bulinus, Planorbis, Physa, Stagnicola and Pseudosuccinea.

Metacercariae are infective larvae but cannot resist desiccation, hence soon die out if suitable host is not found; but under constantly moist conditions, they can survive for up to 1 year and are capable of overwintering.

[10] Excystment is influenced by changing physicochemical conditions (such as temperature, substance concentration, and pH) inside the alimentary tract.

Adults attach to the villi in the rumens of the hosts and sap nutrients from the intestine, although they can wander into the bile and pancreatic ducts, as do other trematodes.

[13] Liver tissue are generally damaged extensively, indicated by swelling, haemorrhage, discolouration, necrosis, bile duct hyperplasia, and fibrosis.

Treatments with reported success (efficacies >90%) are resorantel, oxyclozanide, clorsulon, ivermectin and the combination of bithional and levamisole.