Introduction {#Sec1}
============

*Calodium hepaticum* is a worldwide-distributed zoonotic parasite with a high affinity to the liver. It is the causative agent of hepatic capillariasis and has low host specificity. This parasite is mainly diagnosed during liver biopsies or through necroscopy because the eggs of this nematode are only released into the environment after the host\'s death (after predation, cannibalism, or decay). The main hosts are rodents of the subfamilies Murinae and Arvicolinae. Although murids are the most important hosts, this parasite was documented in more than 70 non-murid species. This review focuses on the mammalian (excluding Muroidea) host spectrum and its geographic distribution in those hosts. Furthermore, the role of spurious infections in animals and the dissemination of *C. hepaticum* are summarized. Information about the pathogenesis, ecology, and host spectrum in Muriodea is given elsewhere (e.g., Fuehrer et al. [@CR45]; Fuehrer [@CR46]; Schmidt [@CR117]).

For data evaluation, the systematic search was based on electronic databases (Scopus, PubMed, Google Scholar) and previous summaries (e.g., Schmidt [@CR117]). The search terms *Capillaria hepatica*, *Calodium hepaticum*, *Hepaticola hepatica*, *Trichocephalus hepaticus*, and hepatic capillariasis were used. An attempt was made to include only those studies where the scientific names of the host and parasite were given clearly. Furthermore, spurious infections (= pseudoparasitism) were differentiated as far as possible from hepatic capillariasis.

Taxonomy, morphology, and biology {#Sec2}
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*C. hepaticum* is a member of the family Capillaridae (Order: Trichocephalida). The parasite is also known under the synonym *Capillaria hepatica*. Although Moravec ([@CR88]) included this nematode in the genus *Calodium*, many scientists still use the synonym *C. hepatica*. Further synonyms are *Hepaticola hepatica* (Hall [@CR54]) and *Trichocephalus hepaticus* (Bancroft, 1893) (Fuehrer et al. [@CR45]).

The taxonomy of the family Capillaridae is pending. All species out of the former genus *Capillaria* are included in the family Capillaridae. A recent study has shown that the family Capillaridae seems to be monophyletic and can be clearly separated from Trichuridae (Guardone et al. [@CR53]). Although most species parasitize in animals, three are known to also infect humans: *Paracapillaria philippinensis* (syn. *Capillaria philippinensis*), *Eucoleus aerophila* (syn. *Capillaria aerophila*), and *C. hepaticum* (syn. *C. hepatica*).

Adult *C. hepaticum* are long slender-shaped nematodes with a narrow anterior body part (0.007--0.01 mm). The posterior body part becomes gradually thicker. Sexual dimorphism is present (females 27--100 mm; males 15--50 mm) (reviewed in Schmidt [@CR117]). The eggs resemble typical trichurid eggs but differ in size (40--67 × 27--35 μM). The eggs are barrel-shaped, striated, and with polar plugs. Numerous minipores are present on the outer shell. The four larval stages differ in size (reviewed in Schmidt [@CR117]).

*C. hepaticum* has a high affinity to the liver and is the causative agent of hepatic capillariasis. The life cycle is a direct one. After the ingestion of embryonated eggs, L1 larvae hatch in the area of the caecum and invade the liver via the portal vein system. Adult *C. hepaticum* nematodes live in the liver parenchyma (life span 18--60 days) where females lay unembryonated eggs into the liver parenchmya. The eggs develop in the liver parenchyma to the eight-cell stage. After the death of the host (cannibalism, predation, decay), the eggs are released into the environment and embryonate (depending on the environmental conditions) to the infective stage. The cycle closes with the ingestion of embryonated eggs by a new host (reviewed in Schmidt [@CR117]). The ingestion of unembryonated eggs leads to spurious infections (= pseudoparasitism) where the non-infective eggs are shed into the environment with the feces.

Host spectrum {#Sec3}
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The main hosts of *C. hepaticum* are several murid rodent species with the highest prevalences in synanthropic Murinae (e.g., Norway rat). The parasite was documented in more than 90 Muroidean rodent species of the subfamilies Murinae, Deomyinae, Arvicolinae, Neotominae, Cricetinae, Sigmodontinae, Gerbillinae, and Cricetomyinae (Führer et al. [@CR44]; Fuehrer [@CR46]).

However, hepatic *C. hepaticum* infections were also found in Caviidae, Erethizontidae, Castoridae, Myocastoridae, Sciuridae, Geomyidae, Dipodidae, Nesomyidae, and Cuniculidae (Table [1](#Tab1){ref-type="table"}). In wildlife, North American porcupines (USA; 9 % of 53), nutrias (Argentina; 3.6 % of 108), northern pocket gophers (USA; 39 % of 46), Brazilian guinea pigs (Peru; 6.9 % of 143), and lowland pacas (Brazil; 20 % of 5) were evaluated as suitable hosts of this parasite (Dittmar [@CR31]; Hamir and Rupprecht [@CR55]; Martino et al. [@CR79]; Todd et al. [@CR131]).Table 1*Calodium hepaticum* in non-Muroidea rodentsClassificationSpeciesCountry/countriesReferencesCaviidaeDomestic guinea pig (*Cavia porcellus*)Pets: HungaryMeszaros and Varga ([@CR85])PeruOlortegui ([@CR98]); Gonzales ([@CR49])Brazilian guinea pig (*Cavia aperea*)ArgentiniaMorini and Boero ([@CR90])PeruDittmar ([@CR31])PeruOlortegui ([@CR98]); Gonzales ([@CR49])*Cavia* sp.BrazilMentioned in Dittmar ([@CR31])Capybara (*Hydrochoerus hydrochaeris*)Brazil (Nhecolândia)Costa and Catto ([@CR24])ErethizontidaeNorth American porcupine (*Erethizon dorsatum*)USAHamir and Rupprecht ([@CR55])CastoridaeNorth American beaver (*Castor canadensis*)USA (National Zoological Park) District of ColumbiaChitwood BG (Chitwood [@CR21])Eurasian beaver (*Castor fiber*)Hungary (Zoo)Mészáros and Kemenes ([@CR84])Former UDSSRPavlov ([@CR104])Former UDSSR (several cases in a zoological park)Mentioned in Mészáros and Kemenes ([@CR84])RussiaRomašov ([@CR112])MyocastoridaeNutria (*Myocastor coypus*)JapanMatsudate et al. ([@CR81])Germany (Saxony)Seidel ([@CR120])ArgentinaVogelsang and Espin ([@CR135])ArgentinaMartino et al. ([@CR79])SciuridaeBrazilian squirrel (*Sciurus aestuans*)BrazilFreitas and Lent ([@CR42])ArgentinaVogelsang and Espin ([@CR135])Caucasian squirrel (*Sciurus anomalus*)Former UDSSRPavlov ([@CR104])Fox squirrel (*Sciurus niger*)USA (Louisiana)McQuown ([@CR82])Eurasian red squirrel (*Sciurus vulgaris*)UK (north Wales)Stidworthy et al. ([@CR126])American red squirrel (*Tamiasciurus hudsonicus*)Canada (lab infection experiment)Freeman and Wright ([@CR41])Korean squirrel (*Tanias sibericus*)Spain pet shop (imported from China)Carrasco et al. ([@CR19])*Sciurus* sp.TurkeyMerdivenci ([@CR83])Cape ground squirrel (*Xerus inauris*)South Africa (Eastern Free State)Erlwanger et al. ([@CR34])Richardson\'s ground squirrel (*Urocitellus richardsonii*)USA (Montana)Luttermoser ([@CR75])Canada (Alberta)Brown and Roy ([@CR12])Domesticated squirrelsChinaMentioned in Wang et al. ([@CR136])Black-tailed prairie dog (*Cynomys ludovicianus*)USAWeidman ([@CR137])USA (zoo)Landolfi et al. ([@CR66])USA (Pennsylvania)Doran ([@CR32])England (zoo)Redrobe and Patterson-Kane ([@CR109])Alpine marmot (*Marmota marmota*)SpainGortazar et al. ([@CR51])Groundhog (*Marmota monax*)USAReynolds and Gavutis Jr. ([@CR111])USA (Pennsylvania)Doran ([@CR32])Germany (Lab groundhogs imported from the USA)Hilken et al. ([@CR57])FranceGevrey et al. ([@CR48])Red-cheeked flying squirrel (*Hylopetes spadiceus*)MalaysiaLiat et al. ([@CR71])GeomyidaePlains pocket gopher (*Geomys bursarius*)USAUbelaker and Downhower ([@CR134])Northern pocket gopher (*Thomomys talpoides*)Canada (Alberta)Lubinsky ([@CR73]; [@CR74])USA (Wyoming)Law and Kennedy ([@CR67])USA (Wyoming)Todd et al. ([@CR131])USARausch ([@CR108])DipodidaeWoodland jumping mouse (*Napaeozapus insignis*)Canada (Alonquin Park)Freeman and Wright ([@CR41])NesomyidaeMalagasy giant rat (*Hypogeomys antimena*)England (zoo)Redrobe and Patterson-Kane ([@CR109])CuniculidaeLowland paca (*Cuniculus paca*)Brazil (Acre)Almeida et al. ([@CR3])Costa RicaMatamoros et al. ([@CR80])

Furthermore, *C. hepaticum* was documented in at least 69 species out of 25 families in non-rodent mammalian including Insectivora, Chiroptera, Lagomorpha, Artiodactyla, Perissodactyla, Hyracoidea, Marsupialia, Carnivora, and Primates (Table [2](#Tab2){ref-type="table"}). In wildlife, hepatic capillariasis was documented in several studies: pronghorn antelopes (Canada; 4/41), red foxes (Italy; 1/75), crab-eating foxes (Brazil; 5.56 %), pampas foxes (Brazil; 13.64 %), and mountain gorillas (Rwanda; 10/19) (Barrett and Chalmers [@CR6]; Graczyk et al. [@CR52]; Macchioni et al. [@CR76]; Ruas [@CR113]). The true burden of this parasite in wildlife is not clear. Numerous documented cases of *C. hepaticum* in non-murid mammals were reported from zoological gardens and laboratories or in domesticated animals.Table 2*Calodium hepaticum* in other mammals other than rodentsClassificationSpeciesCountry/countriesReferencesInsectivora ErinaceidaeEuropean hedgehog (*Erinaceus europaeus*)SwitzerlandBrander et al. ([@CR10], [@CR11])TurkeyMerdivenci ([@CR83]) SoricidaeSmoky shrew (*Sorex fumeus*)USASolomon and Handley ([@CR124])Northern short-tailed shrew (*Blarina brevicauda*)USASolomon and Handley ([@CR124])Laxmann\'s shrew (*Sorex caecutiens*)???Mentioned in Tinnin et al. ([@CR130])Long-tailed shrew (*Sorex dispar*)USASolomon and Handley ([@CR124])Cinereus shrew (*Sorex cinereus*)USASolomon and Handley ([@CR124])Common shrew (*Sorex araneus*)AustriaFrank ([@CR40])Shinto shrew (*Sorex shinto*)JapanIwaki et al. ([@CR60])Long-clawed shrew (*Sorex unguiculatus*)JapanChabaud et al. ([@CR20])Asian house shrew (*Suncus murinus*)IndonesiaBrown et al. ([@CR14]a)Eurasian water shrew (*Neomys fodiens*)England (Gloucestershire)Stidworthy et al. ([@CR126])Greater white-toothed shrew (*Crocidura russula*)France---Mulhouse ZooApéry ([@CR5])France---Lyon ZooApéry ([@CR5])Chiroptera PteropodidaeLesser short-nosed fruit bat (*Cynopterus brachyotis*)IndonesiaBrown et al. ([@CR13])Lagomorpha LeporidaeEuropean hare (*Lepus europaeus*)???Hall ([@CR54])Germany (Saxony-Anhalt)Haupt and Stubbe ([@CR56])Germany (Saxony)Schüppel ([@CR119])AustriaKutzer and Frey ([@CR65])EnglandNicoll ([@CR95])HungarySugár et al. ([@CR129])Former CSSRZajíček ([@CR140])Mountain hare (*Lepus timidus*)GeorgiaKankava et al. ([@CR63])Austria (zoo)Eder [@CR33]European rabbit (*Oryctolagus cuniculus*)SwitzerlandBrander et al. ([@CR11]); Hörning ([@CR58])EnglandMorgan ([@CR89])Domestic rabbit (*Oryctolagus cuniculus forma domestica*)FranceGevrey and Chirol ([@CR47])New Zealand white rabbitsUK (rabbits from commercial distributor)Mowat et al. ([@CR91])Eastern cottontail (*Sylvilagus floridanus*)USALayne ([@CR68]); Layne and Winegarner ([@CR69]) OchotonidaePlateau pika (*Ochotona curzoniae*)China (Gansu)In Wang et al. ([@CR136])Artiodactyla AntilocapridaePronghorn antelope (*Antilocapra americana*)Canada (Alberta)Barrett and Chalmers ([@CR6]) TayassuidaeCollared peccary (*Pecari tajacu*)BrazilMandorino and Rebouças ([@CR77])White-lipped peccary (*Tayassu pecari*)PanamaFoster and Johnson ([@CR39])BrazilSoares et al. ([@CR123])*T. pecari* or *P. tajacu*Brazil (Amazonas)Gonçalves et al. ([@CR50]) BovidaeKirk\'s dik-dik (*Madoqua kirkii*)USA (zoo)Partington and Montali ([@CR103])Cattle (*Bos primigenius*)Japan (Hokkaido)Nakamura ([@CR93]) SuidaeDomestic pig (*Sus scrofa domesticus*)ChinaZhang ([@CR141])Perissodactyla EquidaeHorse (*Equus ferus caballus*)CanadaNation and Dies ([@CR94])EnglandMunroe ([@CR92]) TapiridaeBrazilian tapir (*Tapirus terrestris*)Brazil (Parana)Mangini et al. ([@CR78])Hyracoidea ProcaviidaeSouthern tree hyrax (*Dendrohyrax arboreus*)Democratic Republic of the CongoFain ([@CR35])Marsupialia DidelphidaeBig-eared opossum (*Didelphis aurita*)ParaguayCanese ([@CR16])Common opossum (*Didelphis marsupialis*)ColumbiaCIAT ([@CR22]) MacropodidaeAgile wallaby (*Macropus agilis*)AustraliaCanfield and Hartley ([@CR17])Parma wallaby (*Macropus parma*)AustraliaCanfield and Hartley ([@CR17])Red kangaroo (*Macropus rufus*)AustraliaCanfield and Hartley ([@CR17]) PotoroidaeRufous rat-kangaroo (*Aepyprymnus rufescens*)AustraliaCanfield and Hartley ([@CR17])Woylie (*Bettongia penicillata*)AustraliaCanfield and Hartley ([@CR17])??? ZooMentioned in Redrobe and Patterson ([@CR109])Potoroideae spp.GermanySchmidt ([@CR118])Carnivora MephitidaeEastern spotted skunk (*Spilogale putorius*)USALayne and Winegarner ([@CR69]) CanidaeDomestic dog (*Canis lupus familaris*)New ZealandAnon. ([@CR4])West highland white terrier crossGreat BritainLloyd et al. ([@CR72])ItalyCarta ([@CR18])SwitzerlandBrander et al. ([@CR10], [@CR11])USA (Washington)Wright ([@CR139])IndiaRao et al. ([@CR107])BrazilSaliba et al. ([@CR115]); Santos and Barros ([@CR116]); Silveira et al. ([@CR121])BrazilIlha and Barros (Ilha MR da S, Barros CSL de [@CR59])BrazilPalma et al. ([@CR101])South AfricaSmit ([@CR122])NigeriaAjayi et al. ([@CR2])AustraliaStokes ([@CR127])Gray wolf (*Canis lupus*)RussiaRomašov ([@CR112])Coyote (*Canis latrans*)CanadaWobeser and Rock ([@CR138])USACrowell et al. ([@CR26]); Custer and Pence ([@CR28])Red fox (*Vulpes vulpes*)ItalyMacchioni et al. ([@CR76])Crab-eating fox (*Cerdocyon thous*)BrazilRuas ([@CR113])Pampas fox (*Lycalopex gymnocercus*)BrazilRuas ([@CR113])Maned wolf (*Chrysocyon brachyurus*)BrazilCurial ([@CR27]) FelidaeDomestic cat (*Felis catus*)BrazilSantos and Barros ([@CR116])BrazilIlha and Barros ([@CR59])SlovakiaMituch ([@CR86])NigeriaOkaeme ([@CR96], [@CR97])Cougar (*Puma concolor*)BrazilQuadros et al. ([@CR99])Primates LemuridaeRing-tailed lemur (*Lemur catta*)Chile (zoo)Zordan et al. ([@CR142])??? ZooMentioned in Redrobe and Patterson ([@CR109]) CercopithecidaeVervet monkey (*Chlorocebus pygerythrus*)South AfricaFripp and Kaschula ([@CR43])Grivet (*Chlorocebus aethiops*)South AfricaFripp and Kaschula ([@CR43])Rhesus macaque (*Macaca mulatta*)Brack ([@CR9])Crab-eating macaque (*Macaca fascicularis*)Brack ([@CR9])UK (wild-caught laboratory-maintained primates)Abbott and Majeed ([@CR1])Celebes crested macaque (*Macaca nigra*)England (zoo)Pizzi et al. ([@CR105])England (zoo)Stidworthy et al. ([@CR126])Tibetan macaque (*Macaca thibetana*)China (Huangshan mountain of Anhui)Mentioned in Wang et al. ([@CR136])Northern plains gray langur (*Semnopithecus entellus*)Belgium/Sri LankaKumar et al. ([@CR64])Gelada (*Theropithecus gelada*)USA (zoo)Jensen and Huntress ([@CR61]) AtelidaeMexican spider monkey (*Ateles geoffroyi velerosus*)Mexico (Chiapas)Caballero and Grocott ([@CR15])Geoffroy\'s spider monkey (*Ateles geoffroyi*)PanamaFoster and Johnson ([@CR39])Red-faced spider monkey (*Ateles paniscus*)BrazilSoares et al. ([@CR123])Humboldt\'s woolly monkey (*Lagothrix lagotricha*)Brack ([@CR9]) PitheciidaeWhite-faced saki (*Pithecia pithecia*)England (zoo)Pizzi et al. ([@CR105])Red bald-headed uakari (*Cacajao calvus rubicundus*)Brack ([@CR9]) CebidaeWhite-headed capuchin (*Cebus capucinus*)PanamaFoster and Johnson ([@CR39]) HominidaeHuman (*Homo sapiens*)WorldwideReviewed in Fuehrer et al. ([@CR45])Mountain gorilla (*Gorilla beringei beringei*)Rwanda (Parc National de Volcans)Graczyk et al. ([@CR52])Western gorilla (*Gorilla gorilla*)Poland (spurious infection/zoo)Paciepnik ([@CR100])Common chimpanzee (*Pan troglodytes*)???de Gasperi ([@CR29])Free rangingTroisier et al. ([@CR133])USA (lab animals originated from West Africa)Sadun et al. ([@CR114]) CallitrichidaePied tamarin (*Saguinus bicolor*)UK (zoo)Stidworthy et al. ([@CR126])France---Mulhouse ZooApéry ([@CR5])Portugal---Lisbon ZooCorreia et al. ([@CR23])Red-handed tamarin (*Saguinus midas*)Portugal---Lisbon ZooCorreia et al. ([@CR23])Goeldi\'s monkey (*Callimico goeldii*)Portugal---Lisbon ZooCorreia et al. ([@CR23])White-headed marmoset (*Callithrix geoffroyi*)1 case each in 3 zoos\
UK (zoo)Stidworthy et al. ([@CR126])SpainFernández-Bellon et al. ([@CR37])

Zoos {#Sec4}
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Several hepatic cases with *C. hepaticum* had been observed in zoological gardens. Various studies documented single cases of this parasite. In some reports, more than one animal of a single species were infected: black-tailed prairie dogs (USA; 5/21; UK; 45 % of 20) and Kirk\'s dik-diks (USA; 7/18) (Landolfi et al. [@CR66]; Partington and Montali [@CR103]; Redrobe and Patterson-Kane [@CR109]). Most of the cases in primates were found in zoos.

Several studies tried to analyze the relationships of commensal rodents (e.g., Norway rats, house mice) to infections of animals in zoos (e.g., Juncker-Voss et al. [@CR62]). In zoos, high prevalences of free-ranging rats, mice, and shrews were observed: Norway rats (Baltimore Zoo, USA, 75 % of 845; Lisbon Zoo, Portugal 42 % of 50), house mice (Vienna Zoo, Austria, 42.7 % of 166; Lisbon Zoo, Portugal 22 % of 50), and greater white-toothed shrews (France; 10--25 %) (Apéry [@CR5]; Crespo [@CR25]; Farhang-Azad [@CR36]; Juncker-Voss et al. [@CR62]).

Laboratory animals and pet shops {#Sec5}
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*C. hepaticum* was found in various pet shops and laboratories, for example, in one out of four Korean squirrels imported from China to Spain, 3 out of 155 lab groundhogs imported from the USA to Germany, 13 out of 160 New Zealand White rabbits in France from a commercial distributor, two cases in common chimpanzees which were lab animals originating from West Africa, and 0.6 % of 472 wild-caught laboratory-maintained crab-eating macaques (Abbott and Majeed [@CR1]; Carrasco et al. [@CR19]; Hilken et al. [@CR57]; Mowat et al. [@CR91]; Sadun et al. [@CR114]). It can be hypothesized that animals ingested embryonated eggs while living wild and/or with contaminated food.

Domesticated animals {#Sec6}
====================

*C. hepaticum* was documented in domesticated mammal species like laboratory Norway rats, rabbits, cattle, pigs, horses, dogs, cats, domesticated guinea pigs, and squirrels. In Japan, hepatic capillariasis was observed in 2.25 % of 400 cattle, but the author did not classify the nematode as *C. hepaticum* because the pathogen was not reported in cattle before (Nakamura [@CR93]). Furthermore, Ilha and Barros ([@CR59]) found *C. hepaticum* in the livers of 0.23 % of 3,927 dogs and 1.38 % of 435 cats examined in Brazil.

Dispersal by animals and spurious infections {#Sec7}
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With the death of the animal host (cannibalism, predation, or decay), the eggs of *C. hepaticum* are released into the environment. The dissemination of eggs by ground beetles and rain worms had been reported, but their role in the importance of maintaining the life cycle of this parasite is unclear (Mobedi and Arfaa [@CR87]; Schmidt [@CR117]).

In humans, spurious infections are associated with the consumption of unembryonated eggs in soil or infected game (Fuehrer et al. [@CR45]). The same can be considered for other carnivore and omnivore animals (Reperant and Deplazes [@CR110]). Gonzalves et al. ([@CR50]) described the first case of a spurious infection in a dog in Brazil (Amazonas) after the dog was fed with raw game meat. In the Zoological Garden of Vienna, eggs of *C. hepaticum* were found in the feces of a Pallas\'s cat (*Otocolobus manul*) (Basso et al. [@CR7]). Spurious infections have also been observed in Norway rats (6 %) and black rats (20 %), where cannibalism might be the mode of intake of unembryonated eggs (Firlotte [@CR38]; Promkerd et al. [@CR106]). In Madagascar, eggs from *Capillaria* sp. with the shape of *C. hepaticum* have been found in the feces of gray mouse lemurs (*Microcebus murinus*), greater hedgehog tenrecs (*Setifer setosus*), and black rats (*R. rattus*).

Furthermore, eggs of *C. hepaticum* were found in the feces of non-mammalian animals. In Malaysia, 2.83 % of large-billed crows shed eggs of this parasite with the feces (Lee et al. [@CR70]). Eggs of *C. hepaticum* were also documented in fecal samples from reptiles fed with infected rodents (Pantchev and Tappe [@CR102]). In an analysis of the intestinal content of two timber rattlesnakes (*Crotatus horridus*), eggs of *C. hepaticum* were documented (Solomo [@CR125]).

Although many authors described spurious infections in animals, care should be taken to exclude mix-ups with other Capillaridae or Trichuridae shedding eggs of resembling morphology (e.g., Bork-Mimm and Rinder [@CR8]; Di Cesare et al. [@CR30]; Stuart et al. [@CR128]; Traversa et al. [@CR132]). With the absence of specific molecular diagnostic tools, the classification of *C. hepaticum* in spurious infections is based on the morphology of the eggs only. Consequently, the role of spurious infections for the maintenance of the life cycle of this nematode remains unclear.

Conclusions {#Sec8}
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*C. hepaticum* is a worldwide-distributed zoonotic parasite with a high affinity to the liver and low host specificity. The main definite hosts are Murinae and Arvicolinae, but it has also been found in various other mammals of different families. Eggs are released into the environment after the death of the host only (decay, cannibalism, and predation). It is unclear which method of egg dispersal is the most effective one but it can be hypothesized that:Cannibalism is the most effective method of transmission in the case of rodents with a tendency to cannibalism and egg shedding in the burrow.Dispersal of unembryonated eggs by egg-shedding in feces (after cannibalism, predation by omnivores and carnivores, scavengers, dissemination by insects and earth worms) leads to the most infections in other mammals after the embryonation of the eggs.

Diagnosis is now based on liver biopsy and necroscopy, and it can be suggested that the true burden of this parasite is underrepresented. Novel molecular diagnostic tools are needed to allow species determination in cases of hepatic capillariasis and spurious infections.

I wish to thank all authors who provided personal copies of their manuscripts.

Conflict of interest {#d30e2952}
====================

The author declares that he has no conflict of interest.
