| Porocephalus crotali | |
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| specimens infesting a snake Platyceps karelini | |
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| Species: | P. crotali |
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| Porocephalus crotali (Humboldt, 1808) [1] | |
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Porocephalus crotali is a parasitic crustacean from the group Pentastomida, also known as tongue worms.
Porocephalus crotali is cylindrical and annulated (having ring-like segments) with 38–40 body segments, a digestive system, centrally located mouth surrounded by four hooks making it seem like it has five mouths — hence the name “pentastomes” . [3]
Mammals are the intermediate hosts and snakes are the definitive hosts. [4]
Once the larva is released from the egg, it enters the duodenal mucosa of the host. It takes about an hour from the time the egg is swallowed to the time there is complete entrance into the host. After entering the duodenal mucosa, the larvae travel to the abdominal cavity where it takes a week until the larvae molt is encapsulated in the host tissue. During a three-month period, the parasite continues to molt five more times in which the size increases and the body becomes segmented. The sex of the parasite can be determined after the fifth molt. When the sixth molt is complete, the nymphs become encapsulated and dormant. 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. [5]
The larval stages in the nymph may cause visceral pentastomiasis in humans . [3] Visceral pentastomiasis has been reported from Africa, Malaysia and the Middle East.
Ascaris lumbricoides is a large parasitic worm that causes ascariasis in humans. A roundworm of genus Ascaris, it is the most common parasitic worm in humans. An estimated one-sixth of the human population is at some point infected by a roundworm such as A. lumbricoides; people living in tropical and subtropical countries are at greater risk of infection.
Strongyloides stercoralis is a human pathogenic parasitic roundworm causing the disease strongyloidiasis. Its common name in the US is threadworm. In the UK and Australia, however, the term threadworm can also refer to nematodes of the genus Enterobius, otherwise known as pinworms.
Trematoda is a class of flatworms known as flukes or trematodes. They are obligate internal parasites with a complex life cycle requiring at least two hosts. The intermediate host, in which asexual reproduction occurs, is usually a snail. The definitive host, where the flukes sexually reproduce, is a vertebrate. Infection by trematodes can cause disease in all five traditional vertebrate classes: mammals, birds, amphibians, reptiles, and fish.
Toxocariasis is an illness of humans caused by the dog roundworm and, less frequently, the cat roundworm. These are the most common intestinal roundworms of dogs, coyotes, wolves and foxes and domestic cats, respectively. Humans are among the many "accidental" or paratenic hosts of these roundworms.
Taenia saginata, commonly known as the beef tapeworm, is a zoonotic tapeworm belonging to the order Cyclophyllidea and genus Taenia. It is an intestinal parasite in humans causing taeniasis and cysticercosis in cattle. Cattle are the intermediate hosts, where larval development occurs, while humans are definitive hosts harbouring the adult worms. It is found globally and most prevalently where cattle are raised and beef is consumed. It is relatively common in Africa, Europe, Southeast Asia, South Asia, and Latin America. Humans are generally infected as a result of eating raw or undercooked beef which contains the infective larvae, called cysticerci. As hermaphrodites, each body segment called proglottid has complete sets of both male and female reproductive systems. Thus, reproduction is by self-fertilisation. From humans, embryonated eggs, called oncospheres, are released with faeces and are transmitted to cattle through contaminated fodder. Oncospheres develop inside muscle, liver, and lungs of cattle into infective cysticerci.
Ascaris suum, also known as the large roundworm of pig, is a parasitic nematode that causes ascariasis in pigs. While roundworms in pigs and humans are today considered as two species with different hosts, cross-infection between humans and pigs is possible; some researchers have thus argued they are the same species. Ascariasis is associated with contact to pigs and pig manure in Denmark.
Eucestoda, commonly referred to as tapeworms, is the larger of the two subclasses of flatworms in the class Cestoda. Larvae have six posterior hooks on the scolex (head), in contrast to the ten-hooked Cestodaria. All tapeworms are endoparasites of vertebrates, living in the digestive tract or related ducts. Examples are the pork tapeworm with a human definitive host, and pigs as the secondary host, and Moniezia expansa, the definitive hosts of which are ruminants.
Spirometra erinaceieuropaei is a parasitic tapeworm that infects domestic animals and humans. The medical term for this infection in humans and other animals is sparganosis. Morphologically, these worms are similar to other worms in the genus Spirometra. They have a long body consisting of three sections: the scolex, the neck, and the strobilia. They have a complex life cycle that consists of three hosts, and can live in varying environments and bodily tissues. Humans can contract this parasite in three main ways. Historically, humans are considered a paratenic host; however, the first case of an adult S. erinaceieuropaei infection in humans was reported in 2017. Spirometra tapeworms exist worldwide and infection is common in animals, but S. erinaceieuropaei infections are rare in humans. Treatment for infection typically includes surgical removal and anti-worm medication.
Sparganosis is a parasitic infection caused by the plerocercoid larvae of the genus Spirometra including S. mansoni, S. ranarum, S. mansonoides and S. erinacei. It was first described by Patrick Manson in 1882, and the first human case was reported by Charles Wardell Stiles from Florida in 1908. The infection is transmitted by ingestion of contaminated water, ingestion of a second intermediate host such as a frog or snake, or contact between a second intermediate host and an open wound or mucous membrane. Humans are the accidental hosts in the life cycle, while dogs, cats, and other mammals are definitive hosts. Copepods are the first intermediate hosts, and various amphibians and reptiles are second intermediate hosts.
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.
Toxocara canis is a worldwide-distributed helminth parasite that primarily infects dogs and other canids, but can also infect other animals including humans. The name is derived from the Greek word "toxon," meaning bow or quiver, and the Latin word "caro," meaning flesh. T. canis live in the small intestine of the definitive host. This parasite is very common in puppies and somewhat less common in adult dogs. In adult dogs, infection is usually asymptomatic but may be characterized by diarrhea. By contrast, untreated infection with Toxocara canis can be fatal in puppies, causing diarrhea, vomiting, pneumonia, enlarged abdomen, flatulence, poor growth rate, and other complications.
Toxascaris leonina is a common parasitic roundworm found in dogs, cats, foxes, and related host species. T. leonina is an ascarid nematode, a worldwide distributed helminth parasite which is in a division of eukaryotic parasites that, unlike external parasites such as lice and fleas, live inside their host. The definitive hosts of T. leonina include canids and felines (cats), while the intermediate hosts are usually rodents, such as mice or rats. Infection occurs in the definitive host when the animal eats an infected rodent. While T. leonina can occur in either dogs or cats, it is far more frequent in cats.
Capillaria hepatica is a parasitic nematode which causes hepatic capillariasis in rodents and numerous other mammal species, including humans. The life cycle of C. hepatica may be completed in a single host species. However, the eggs, which are laid in the liver, must mature outside of the host body prior to infecting a new host. So the death of the host in which the adults reach sexual maturity, either by being eaten or dying and decomposing, is necessary for completion of the life cycle.
Ancylostoma braziliense is a species of hookworm belonging to the genus Ancylostoma. It is an intestinal parasite of domestic cats and dogs. Severe infection is often fatal to these pets, especially in puppies and kittens. The infection is particularly endemic in the southern United States. It is most often confused with the zoonotic hookworm species Ancylostoma ceylanicum because of their uncanny resemblance.
Linguatula serrata is a species of cosmopolitan zoonotic parasite, belonging to the tongueworm order Pentastomida. They are wormlike parasites of the respiratory systems of vertebrates. They live in the nasopharyngeal region of mammals. Cats, dogs, foxes, and other carnivores are normal hosts of this parasite. Apparently, almost any mammal is a potential intermediate host.
Heterophyes heterophyes, or the intestinal fish fluke, was discovered by Theodor Maximaillian Bilharz in 1851. This parasite was found during an autopsy of an Egyptian mummy. H. heterophyes is found in the Middle East, West Europe and Africa. They use different species to complete their complex lifestyle. Humans and other mammals are the definitive host, first intermediate host are snails, and second intermediate are fish. Mammals that come in contact with the parasite are dogs, humans, and cats. Snails that are affected by this parasite are the Cerithideopsilla conica. Fish that come in contact with this parasite are Mugil cephalus, Tilapia milotica, Aphanius fasciatus, and Acanthgobius sp. Humans and mammals will come in contact with this parasite by the consumption of contaminated or raw fish. This parasite is one of the smallest endoparasite to infect humans. It can cause intestinal infection called heterophyiasis.
Gnathostoma hispidum is a nematode (roundworm) that infects many vertebrate animals including humans. Infection of Gnathostoma hispidum, like many species of Gnathostoma causes the disease gnathostomiasis due to the migration of immature worms in the tissues.
Linguatulosis is a condition associated with the organism Linguatula serrata.
Porocephaliasis is a condition associated with species in the closely related genera Porocephalus and Armillifer.
Nematode infection in dogs - the infection of dogs with parasitic nemamotodes - are, along with tapeworm infections and infections with protozoa, frequent parasitoses in veterinary practice. Nematodes, as so-called endoparasites, colonize various internal organs - most of them the digestive tract - and the skin. To date, about 30 different species of nematode have been identified in domestic dogs; they are essentially also found in wild dog species. However, the majority of them often cause no or only minor symptoms of disease in adult animals. The infection therefore does not necessarily have to manifest itself in a worm disease (helminthosis). For most nematodes, an infection can be detected by examining the feces for eggs or larvae. Roundworm infection in dogs and the hookworm in dogs is of particular health significance in Central Europe, as they can also be transmitted to humans (zoonosis). Regular deworming can significantly reduce the frequency of infection and thus the risk of infection for humans and dogs.