Haploporids

Haploporids are a family of trematodes, which are parasitic flatworms. These parasites primarily infect the digestive tracts of fish, although some species have been found in other aquatic vertebrates. The life cycle of haploporids typically involves at least two hosts: a mollusk as the first intermediate host and a fish as the second intermediate or definitive host.

The adult haploporid trematodes are characterized by a generally oval or elongate body shape and a simple reproductive system. Their oral sucker is often small and terminal, and the acetabulum, or ventral sucker, can vary in size and position depending on the species. The digestive system consists of a pharynx and two ceca, which are blind-ending pouches. The eggs are usually oval and thin-shelled, and are shed into the host's intestine.

Haploporids are found worldwide in various aquatic environments, including freshwater, brackish, and marine habitats. Their distribution is closely linked to the presence of their specific host species. While many haploporid infections in fish are considered asymptomatic, heavy infestations can potentially lead to reduced growth, organ damage, or other health issues in their hosts. Research on haploporids contributes to our understanding of host-parasite interactions and the ecology of aquatic ecosystems.