''Porocephalus crotali'' is a parasitic

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

from the group

Pentastomida The Pentastomida are an enigmatic group of parasitic arthropods commonly known as tongue worms due to the resemblance of the species of the genus ''Linguatula'' to a vertebrate tongue; molecular studies point to them being degenerate crustaceans. ...

, also known as tongue worms.

Morphology

''Porocephalus crotali'' is cylindrical and annulated (having ring-like segments) with 38–40 body segments, a

digestive system The human digestive system consists of the gastrointestinal tract plus the accessory organs of digestion (the tongue, salivary glands, pancreas, liver, and gallbladder). Digestion involves the breakdown of food into smaller and smaller compone ...

, centrally located mouth surrounded by four hooks making it seem like it has five mouths — hence the name “pentastomes” .

Life cycle

Mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

s are the

intermediate host In biology and medicine, a host is a larger organism that harbours a smaller organism; whether a parasitic, a mutualistic, or a commensalist ''guest'' (symbiont). The guest is typically provided with nourishment and shelter. Examples include a ...

s and

snake Snakes are elongated, Limbless vertebrate, limbless, carnivore, carnivorous reptiles of the suborder Serpentes . Like all other Squamata, squamates, snakes are ectothermic, amniote vertebrates covered in overlapping Scale (zoology), scales. Ma ...

s are the definitive hosts. Once the larva hatches from the egg, it penetrates the duodenal mucosa of the host. The process from swallowing the egg to complete entry into the host takes about an hour. After reaching the duodenal mucosa, the larvae migrate to the abdominal cavity, where they spend about a week until they are encapsulated in the host tissue. Over a three-month period, the parasite molts five additional times, increasing in size and developing segmentation. The sex of the parasite becomes identifiable after the fifth molt. Upon completing the sixth molt, the nymphs become encapsulated and enter a dormant state. If a snake eats the nymph, the nymph loses its dormancy and quickly enters the intestinal wall of the snake where it travels to the lungs. They then feed on the blood and tissue fluids in the lungs until they reach maturity.

Disease

The larval stages in the nymph may cause visceral pentastomiasis in humans . Visceral pentastomiasis has been reported from

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Malaysia Malaysia ( ; ) is a country in Southeast Asia. The federation, federal constitutional monarchy consists of States and federal territories of Malaysia, thirteen states and three federal territories, separated by the South China Sea into two r ...

and the

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References

{{DEFAULTSORT:Porocephalus crotali Parasitic crustaceans Maxillopoda Crustaceans described in 1808