Capillaria hepatica

Last updated

Capillaria hepatica
Trichocephalus hepaticus Bancroft 1893 - Plate VIII.jpg
One of the plates published with the original description of the species, showing the masses of eggs in the liver of the host (above) and free alive eggs (below).
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Nematoda
Class: Enoplea
Order: Enoplida
Family: Capillariidae
Genus: Capillaria
Species:
C. hepatica
Binomial name
Capillaria hepatica
Bancroft, 1893

Capillaria hepatica is a parasitic nematode which causes hepatic capillariasis in rodents and numerous other mammal species, including humans. [1] 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 (in the environment) prior to infecting a new host. [1] Death and decomposition of the host in which the adults reach sexual maturity are necessary for completion of the life cycle.

Contents

Discovery and taxonomy

One of the two plates published with the original description of the species by Thomas L. Bancroft. Trichocephalus hepaticus Bancroft 1893 - Plate VII.jpg
One of the two plates published with the original description of the species by Thomas L. Bancroft.

This species was first described in 1893, from specimens found in the liver of Rattus norvegicus, and named Trichocephalus hepaticus. [2] Various authors have subsequently renamed it Trichosoma hepaticum, Capillaria hepatica, Hepaticola hepatica and Calodium hepaticum. [3] [4] Currently it is usually referred to as either Capillaria hepatica or, less often, Calodium hepaticum.[ citation needed ]

Hosts and distribution

Adults are often found in dozens of rodent species, but also occur in a wide variety of other wild and domestic mammals, and occasionally humans. [5] [6] C. hepatica has been found in temperate and tropical zones on every continent and infestation rates of wild-caught rats of up to 100% have been reported. [1] [7]

Usually, Capillaria hepatica is found in rodents, monkeys and other animals. Capillaria hepatica is rarely found in humans and at least 40 cases have been reported. There are no endemic areas of infection with C. hepatica and human infection primarily results from zoonotic transmission. [8]

Of the human infections, most have been found in children under the age of 5. [9]

Tissue niche and morphology

The tissue niche of this parasite is the liver. The adult females will deposit eggs in the parenchyma of the liver. Occasionally in humans larvae will migrate to the lungs, kidneys and other organs. [1]

Adult worms take the shape of a slender nematode, with the anterior part of the body narrow and the posterior part gradually swelling. [10] The females measure about 53–78mm x 0.11–0.20mm, but the males are approximately 24–37mm x 0.07–0.10mm. [10] The adult worms are rarely seen intact, as they mature and die in the parenchyma of the liver. [11] The adult females lay eggs that are about 48-66μm x 28-36μm. [10] The shell of the eggs is striated with shallow polar prominences at either end. Numerous mini-pores can be seen in the outer shell as well. Unembryonated eggs may be ingested by a carnivore, in which case they are harmless and pass out in the feces. Eggs will embryonate in the environment, where they require air and damp soil to become infective. Under optimal conditions this takes about 30 days. Larvae are juvenile versions of the adult worm. [1]

Life cycle

Hosts ingest C. hepatica eggs (from sources outlined below) which hatch into first stage larvae (L1). The L1 larvae bore through the intestinal wall and are carried to the liver by the hepatic portal vein. Development from the L1 stage to sexually mature adults occurs in the liver within 18–21 days. [1] Eggs are laid in the liver parenchyma of the host throughout the adult worm's life span, which lasts for about 30–40 days. [1] Up to 938,000 eggs have been reported from the liver of a single rodent host. [12]

The eggs in the liver exist in a state of arrested development they are unable to develop into larvae until they spend some time outside of the host, in the environment. Escaping from the liver tissue may be accomplished either by the death and decomposition of the host's body, or by the consumption and digestion of the host by a predator or scavenger. [1] If the host is eaten, the eggs will pass into the environment in the feces of the predator or scavenger. In the environment, eggs require 4–5 weeks to develop, and may remain viable in a dormant state for several more months. [13] Once these "environmentally-conditioned" eggs are eaten by a suitable host, the first stage larvae (L1) hatch in the intestine and continue the life cycle. Humans are usually infected after ingesting embryonated eggs in fecal-contaminated food, water, or soil. [1]

Parasitic cycle, as given by the Centers for Disease Control and Prevention. Calodium hepaticum lifecycle.gif
Parasitic cycle, as given by the Centers for Disease Control and Prevention.

Pathogenesis and survival in host

In humans Capillaria hepatica causes hepatic capillariasis, a serious liver disorder. [14] The nematode wanders through the host liver causing loss of liver cells and thereby loss of function. [8] However, as the adult C. hepatica begin to die in the liver tissue, their decomposition accelerates the immune response of the host. [15] This response leads to chronic inflammation and encapsulation of the dead worms in collagen fibers, and eventually to septal fibrosis (abnormal connective tissue growth) and cirrhosis of the liver. [16] The eggs that are left behind can become encased by granulomatous tissue, with large sections of the parenchyma replaced by these egg masses. [14] C. hepatica can also cause hepatomegaly. Infections of C. hepatica can present with several clinical symptoms, including abdominal pain in the liver area, weight loss, decreased appetite, fever and chills, hepatitis (liver inflammation), ascites (excess fluid in the peritoneal cavity) and hepatolithiasis (gallstones in the bile ducts). [14]

This parasite can be fatal in humans, as transmission and survival of the parasite depend on death of the definitive host in order for the eggs to reach soil and water to embryonate. [8]

Diagnosis and treatment

Diagnosis is made by finding eggs or adults of C. hepatica in liver tissue from biopsy or necropsy samples. [1] The encapsulated eggs and adults may appear as white nodules which measure 2–3mm in diameter on the surface and interior of the liver at autopsy. [17] Key identification features of this parasite are a double-layered, [18] :941 striated shell and shallow polar prominences of the egg and a narrowing at anterior end and gradual swelling at posterior end of the adult worm. Identification of C. hepatica eggs in the stool does not result from infection of the human host, but from ingestion by that host of livers from infected animals, the eggs will then pass out harmlessly in the feces. [1] Most cases have been determined after death because clinical symptoms resemble those of numerous liver disorders. [1]

Successful treatment of human cases with thiabendazole [19] or albendazole (with or without corticosteroids) [9] have been reported. Albendazole must be taken with food because a fatty meal will increase the bioavailability of the drug. [1]

Two ways of preventing C. hepatica infections in humans are to institute effective rodent control programs and to prevent dogs and cats from eating rodents. [8]

Paleoparasitology

Capillaria hepatica eggs from the corpse of an adolescent from the late Roman period in France Parasite130094-fig3 Cysts.tif
Capillaria hepatica eggs from the corpse of an adolescent from the late Roman period in France

The first paleoparasitological record of human hepatic capillariasis was published in 2014. [20] Two calcified objects recovered from a 3rd to 4th-century grave of an adolescent in Amiens (Northern France) were identified as probable hydatid cysts. By using thin-section petrographic techniques, probable Capillaria hepatica eggs were identified in the wall of the cysts. The authors claimed that hepatic capillariasis could be expected given the poor level of environmental hygiene prevalent in this period. Identification of tissue-dwelling parasites such as C. hepatica in archaeological remains is particularly dependent on preservation conditions and taphonomic changes and should be interpreted with caution due to morphological similarities with Trichuris sp. eggs.[ citation needed ]

Research uses

The selective liver damage by C. hepatica in rodents has been used in model systems to study the extensive regeneration capabilities of the mammalian liver, [21] and for testing antifibrotic drugs. [22]

C. hepatica has attracted interest for use in Australia as a biocontrol of the house mouse, Mus musculus . [23] It has been moderately successful in Southern Australia. [24]

Related Research Articles

<i>Ascaris lumbricoides</i> One of several species of Ascaris

Ascaris lumbricoides is a large parasitic roundworm of the genus Ascaris. It is the most common parasitic worm in humans. An estimated 807 million–1.2 billion people are infected with A. lumbricoides worldwide. People living in tropical and subtropical countries are at greater risk of infection. Infection by Ascaris lumbricoides infection is known as Ascariasis.

<i>Clonorchis sinensis</i> Species of fluke

Clonorchis sinensis, the Chinese liver fluke, is a liver fluke belonging to the class Trematoda, phylum Platyhelminthes. It infects fish-eating mammals, including humans. In humans, it infects the common bile duct and gall bladder, feeding on bile. It was discovered by British physician James McConnell at the Medical College Hospital in Calcutta (Kolkata) in 1874. The first description was given by Thomas Spencer Cobbold, who named it Distoma sinense. The fluke passes its lifecycle in three different hosts, namely freshwater snail as first intermediate hosts, freshwater fish as second intermediate host, and mammals as definitive hosts.

Alveolar hydatid disease (AHD) is a form of echinococcosis, or a disease that originates from a parasitic flatworm. AHD is caused by an infection of the flatworm species Echinococcus multilocularis. Although alveolar echinococcosis is rarely diagnosed in humans and is not as widespread as cystic echinococcosis, it is also still a serious disease that has a significantly high fatality rate. It is considered one of the most life-threatening helminthic infections humans can have.

<i>Fasciola hepatica</i> Species of fluke

Fasciola hepatica, also known as the common liver fluke or sheep liver fluke, is a parasitic trematode of the class Trematoda, phylum Platyhelminthes. It infects the livers of various mammals, including humans, and is transmitted by sheep and cattle to humans all over the world. The disease caused by the fluke is called fasciolosis or fascioliasis, which is a type of helminthiasis and has been classified as a neglected tropical disease. Fasciolosis is currently classified as a plant/food-borne trematode infection, often acquired through eating the parasite's metacercariae encysted on plants. F. hepatica, which is distributed worldwide, has been known as an important parasite of sheep and cattle for decades and causes significant economic losses in these livestock species, up to £23 million in the UK alone. Because of its relatively large size and economic importance, it has been the subject of many scientific investigations and may be the best-known of any trematode species. F. hepatica's closest relative is Fasciola gigantica. These two flukes are sister species; they share many morphological features and can mate with each other.

<i>Taenia saginata</i> Species of flatworm

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.

<span class="mw-page-title-main">Paragonimiasis</span> Medical condition

Paragonimiasis is a food-borne parasitic disease caused by several species of lung flukes belonging to genus Paragonimus. Infection is acquired by eating crustaceans such as crabs and crayfishes which host the infective forms called metacercariae, or by eating raw or undercooked meat of mammals harboring the metacercariae from crustaceans.

<i>Dioctophyme renale</i> Species of roundworm

Dioctophyme renale, commonly referred to as the giant kidney worm, is a parasitic nematode (roundworm) whose mature form is found in the kidneys of mammals. D. renale is distributed worldwide, but is less common in Africa and Oceania. It affects fish-eating mammals, particularly mink and dogs. Human infestation is rare, but results in kidney destruction, usually of one kidney and hence not fatal. A 2019 review listed a total of 37 known human cases of dioctophymiasis in 10 countries with the highest number (22) in China. Upon diagnosis through tissue sampling, the only treatment is surgical excision.

Capillaria philippinensis is a parasitic nematode which causes intestinal capillariasis. This sometimes fatal disease was first discovered in Northern Luzon, Philippines, in 1964. Cases have also been reported from China, Egypt, Indonesia, Iran, Japan, Korea, Lao PDR, Taiwan and Thailand. Cases diagnosed in Italy and Spain were believed to be acquired abroad, with one case possibly contracted in Colombia. The natural life cycle of C. philippinensis is believed to involve fish as intermediate hosts, and fish-eating birds as definitive hosts. Humans acquire C. philippinensis by eating small species of infested fish whole and raw.

<i>Toxocara cati</i> Species of worm

Toxocara cati, also known as the feline roundworm, is a parasite of cats and other felids. It is one of the most common nematodes of cats, infecting both wild and domestic felids worldwide. Adult worms are localised in the gut of the host. In adult cats, the infection – which is called toxocariasis – is usually asymptomatic. However, massive infection in juvenile cats can be fatal.

<i>Toxascaris leonina</i> Species of roundworm

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.

<i>Capillaria aerophila</i> Species of roundworm

Capillaria aerophila is a nematode parasite found in the respiratory tract of foxes, dogs, and various other carnivorous mammals. A few cases of human infestation have also been reported. Though it is sometimes called a "lungworm", this term usually refers to other species of nematodes. Infestation by C. aerophila is referred to as "pulmonary capillariasis", "bronchial capillariasis", or (rarely) "thominxosis". This parasite has a direct life cycle, meaning that the life cycle can be completed in a single host. C. aerophila usually causes only minor clinical symptoms, such as irritation of the respiratory tract and coughing. However, secondary bacterial infections of the respiratory tract, including pneumonia, may develop in heavy infestations. Treatment with anthelmintics, such as levamisole or fenbendazole, is usually sufficient to cure C. aerophila infestations.

<i>Capillaria <span style="font-style:normal;">(nematode)</span></i> Genus of roundworms

Capillaria is a genus of nematodes in the family Capillariidae .

Angiostrongylus costaricensis is a species of parasitic nematode and is the causative agent of abdominal angiostrongyliasis in humans. It occurs in Latin America and the Caribbean.

<i>Baylisascaris procyonis</i> Species of roundworm

Baylisascaris procyonis, also known by the common name raccoon roundworm, is a roundworm nematode, found ubiquitously in raccoons, the definitive hosts. It is named after H. A. Baylis, who studied them in the 1920s–30s, and Greek askaris. Baylisascaris larvae in paratenic hosts can migrate, causing larva migrans. Baylisascariasis as the zoonotic infection of humans is rare, though extremely dangerous due to the ability of the parasite's larvae to migrate into brain tissue and cause damage. Concern for human infection has been increasing over the years due to the urbanization of rural areas, resulting in the increase in proximity and potential human interaction with raccoons.

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.

Pterygodermatites peromysci is an intestinal parasitic nematode in the genus Pterygodermatites of the family Rictulariidae.

<i>Contracaecum</i> Genus of roundworms

Contracaecum is a genus of parasitic nematodes from the family Anisakidae. These nematodes are parasites of warm-blooded, fish eating animals, i.e. mammals and birds, as sexually mature adults. The eggs and the successive stages of their larvae use invertebrates and increasing size classes of fishes as intermediate hosts. It is the only genus in the family Anisakidae which can infect terrestrial, marine and freshwater animals.

<span class="mw-page-title-main">Gastropod-borne parasitic disease</span> Medical condition

Gastropod-borne parasitic diseases (GPDs) are a group of infectious diseases that require a gastropod species to serve as an intermediate host for a parasitic organism that can infect humans upon ingesting the parasite or coming into contact with contaminated water sources. These diseases can cause a range of symptoms, from mild discomfort to severe, life-threatening conditions, with them being prevalent in many parts of the world, particularly in developing regions. Preventive measures such as proper sanitation and hygiene practices, avoiding contact with infected gastropods and cooking or boiling food properly can help to reduce the risk of these diseases.

<span class="mw-page-title-main">Cat worm infections</span> Worm infections in cats

Cat worm infections, the infection of cats (Felidae) with parasitic worms, occur frequently. Most worm species occur worldwide in both domestic and other cats, but there are regional, species and lifestyle differences in the frequency of infestation. According to the classification of the corresponding parasites in the zoological system, infections can be divided into those caused by nematode and flatworms - in the case of the latter, mainly cestoda and trematoda - while other strains are of no veterinary significance. While threadworms usually do not require an intermediate host for their reproduction, the development cycle of flatworms always proceeds via alternate hosts.

<span class="mw-page-title-main">Nematode infection in dogs</span> Threadworm infections of dogs are frequent

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.

References

  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 "Parasites and Health: Capillariasis". Center for Disease Control. Retrieved September 14, 2011.
  2. Bancroft TL (1893). "On the whip worm of the rat's liver". Journal and Proceedings of the Royal Society of New South Wales. 27: 86–90. doi: 10.5962/p.359144 . S2CID   259695802.
  3. Hall MC (1916). "Nematode parasites of mammals of the orders Rodentia, Lagomorpha, and Hyracoidea". Proceedings of the United States National Museum. 50 (2131): 1–258 (p. 31). doi:10.5479/si.00963801.50-2131.1.
  4. Moravec F (1982). "Proposal of a new systematic arrangement of nematodes of the family Capillariidae". Folia Parasitologica. 29 (2): 119–32. PMID   7106653.
  5. Spratt DM, Singleton GR (2001). "Hepatic capillariasis". In William M. Samuel, A. Alan Kocan, Margo J. Pybus, John William Davis (eds.). Parasitic Diseases of Wild Mammals (2nd ed.). Ames, Iowa: Iowa State University Press. pp. 365–379. ISBN   978-0-8138-2978-4.[ permanent dead link ]
  6. Nabi F, Palaha HK, Sekhsaria D, Chiatale A (2007). "Capillaria hepatica infestation" (PDF). Indian Pediatrics. 44 (10): 781–2. PMID   17998580.
  7. Claveria FG, Causapin J, De Guzman MA, Toledo MG, Salibay C (2005). "Parasite biodiversity in Rattus spp caught in wet markets". The Southeast Asian Journal of Tropical Medicine and Public Health. 36 (Suppl 4): 146–8. PMID   16438200.
  8. 1 2 3 4 Roberts LS (2009). Foundations of Parasitology. McGraw Hill Higher Education.
  9. 1 2 Sawamura R, Fernandes MI, Peres LC, Galvão LC, Goldani HA, Jorge SM, de Melo Rocha G, de Souza NM (1999). "Hepatic capillariasis in children: report of 3 cases in Brazil" (Free full text). The American Journal of Tropical Medicine and Hygiene. 61 (4): 642–7. doi:10.4269/ajtmh.1999.61.642. PMID   10548302. S2CID   39515343.
  10. 1 2 3 Li CD, Yang HL, Wang Y (2010). "Capillaria hepaticain China". World Journal of Gastroenterology. 16 (6): 698–702. doi: 10.3748/wjg.v16.i6.698 . ISSN   1007-9327. PMC   2817057 . PMID   20135717.
  11. Klenzak J, Anthony Mattia, August Valenti, John Goldberg (2005). "Hepatic Capillariasis in Maine presenting as a Hepatic mass". The American Journal of Tropical Medicine and Hygiene. 72 (5): 651–653. doi: 10.4269/ajtmh.2005.72.651 . PMID   15891145.
  12. Reperant LA, Deplazes P (2005). "Cluster of Capillaria hepatica infections in non-commensal rodents from the canton of Geneva, Switzerland" (PDF). Parasitology Research. 96 (5): 340–2. doi:10.1007/s00436-005-1358-y. PMID   15924224. S2CID   23226752.
  13. Olsen OW (1986). "Capillaria hepatica". Animal Parasites: Their Life Cycles and Ecology (3rd ed.). New York City: Dover Publications. pp.  503–504. ISBN   978-0-486-65126-2.
  14. 1 2 3 Ferreira LA, Zilton A. Andrade (1993). "Capillaria hepatica: a cause of septal fibrosis of the liver". Mem. Inst. Oswaldo Cruz. 88 (3): 441–7. doi: 10.1590/S0074-02761993000300015 . PMID   8107607.
  15. Kim DK, Joo KH, Chung MS (2007). "Changes of cytokine mRNA expression and IgG responses in rats infected with Capillaria hepatica". The Korean Journal of Parasitology. 45 (2): 95–102. doi:10.3347/kjp.2007.45.2.95. PMC   2526303 . PMID   17570971.
  16. Gomes AT, Cunha LM, Bastos CG, Medrado BF, Assis BC, Andrade ZA (2006). "Capillaria hepatica in rats: focal parasitic hepatic lesions and septal fibrosis run independent courses" (PDF). Memórias do Instituto Oswaldo Cruz. 101 (8): 895–8. doi: 10.1590/S0074-02762006000800012 . PMID   17293985.
  17. Jeong WI, Do SH, Hong IH, Ji AR, Park JK, Ki MR, Park SC, Jeong KS (2008). "Macrophages, myofibroblasts and mast cells in a rat liver infected with Capillaria hepatica" (PDF). Journal of Veterinary Science. 9 (2): 211–3. doi:10.4142/jvs.2008.9.2.211. PMC   2839101 . PMID   18487945. Archived from the original (PDF) on July 28, 2011.
  18. Quaglia A, Burt AD, Ferrell LD, Portmann BC (2012). "Chapter 16: Systemic disease". In Burt A, Portmann B, Ferrell L (eds.). MacSween's Pathology of the Liver (Sixth ed.). Churchill Livingstone Elsevier. pp. 935–986. ISBN   978-0-7020-3398-8.
  19. Klenzak J, Mattia A, Valenti A, Goldberg J (2005). "Hepatic capillariasis in Maine presenting as a hepatic mass" (Free full text). The American Journal of Tropical Medicine and Hygiene. 72 (5): 651–3. doi: 10.4269/ajtmh.2005.72.651 . PMID   15891145.
  20. Mowlavi G, Kacki S, Dupouy-Camet J, Mobedi I, Makki M, Harandi M, Naddaf S (2014). "Probable hepatic capillariosis and hydatidosis in an adolescent from the late Roman period buried in Amiens (France)". Parasite. 21: 9. doi:10.1051/parasite/2014010. PMC   3936287 . PMID   24572211.
  21. Santos CC, Onofre-Nunes Z, Andrade ZA (2007). "Role of partial hepatectomy on Capillaria hepatica-induced hepatic fibrosis in rats" (PDF). Revista da Sociedade Brasileira de Medicina Tropical. 40 (5): 495–8. doi: 10.1590/S0037-86822007000500001 . PMID   17992401.
  22. de Souza MM, Silva LM, Barbosa AA J, de Oliveira IR, Paraná R, Andrade ZA (2000). "Hepatic capillariasis in rats: a new model for testing antifibrotic drugs" (PDF). Brazilian Journal of Medical and Biological Research. 33 (11): 1329–34. doi: 10.1590/S0100-879X2000001100011 . PMID   11050664.

Further reading