Blood flukes include species of the genus Schistosoma.Lung flukes: there are eight species of lung flukes that infect humans: Paragonimus westermani, P. heterotremus, P. skryabini, P. miyazakii, P. africanus, P. uterobilateralis, P. kellicotti, and P. mexicanus. Paragonimus westermani needs three different hosts in order to survive, reproduce, and complete its life cycle. The completion of a lung flukes life cycle follows the cycle of first, second, and final hosts. The first intermediate host of the lung fluke is a snail, the second intermediate host is a crab or crayfish, and the final host for lung flukes is an animal or human host.Liver flukes: include Clonorchis, Opisthorchis, and Fasciola. Clonorchis and Opisthorchis are considered the most important human pathogens because they are classified as class 1 carcinogens. Liver flukes are commonly found within bile ducts, liver, and gallbladder in mammalian and avian species. There are high numbers of human infection with all three of these liver flukes.Blood flukes: include five species of Schistosoma: Schistosoma japonicum, S. mekongi, S. mansoni, S. haematobium, and S. intercalatum. Humans get infected by the cercariae, which are the larval forms of trematodes. Any contact with water can cause potential human infection. Adult blood flukes can live indefinitely in human or animal reservoir hosts. Anatomy
Trematodes are flattened oval or worm-like animals, usually no more than a few centimeters in length, although species as small as 1 millimetre (0.039 in) are known.
Trematoda is a class within the phylum Platyhelminthes. It includes two groups of parasitic flatworms, known as flukes. They are internal parasites of molluscs and vertebrates. Most trematodes have a complex life cycle with at least two hosts. The primary host, where the flukes sexually reproduce, is a vertebrate. The intermediate host, in which asexual reproduction occurs, is usually a snail. Taxonomy and biodiversity
The trematodes or flukes include 18,000 to 24,000 species, divided into two subclasses. Nearly all trematodes are parasites of mollusks and vertebrates. The smaller Aspidogastrea, comprising about 100 species, are obligate parasites of mollusks and may also infect turtles and fish, including cartilaginous fish. The Digenea, the majority of trematodes, are obligate parasites of both mollusks and vertebrates, but rarely occur in cartilaginous fish. Two other parasitic classes, the Monogenea and Cestoda, are sister classes in the Neodermata, a group of Rhabditophoran Platyhelminthes.Flukes can be classified into two groups based on, the system in which they infect their vertebrate host. They may also be classified according to the environment in which they are found. For instance, pond flukes infect fish in ponds. Tissue flukes infect the bile ducts, lungs, or other biological tissues. This group includes the lung fluke, Paragonimus westermani, and the liver flukes, Clonorchis sinensis and Fasciola hepatica. Blood flukes inhabit the blood in some stages of their life cycle.