The role of freshwater fish in the life cycle of Dioctophyme renale in Southern Brazil.

Brazil stands out by the diverse records of Dioctopphyme renale in different hosts; however, there is little information about the life cycle of the nematode in the region. This study aims to report on third-stage larvae infections in fish in southern Brazil. In this context, 324 fish of different species belonging to Characiformes, Cyprinodontiformes and Siluriformes were collected in an urban area of Rio Grande do Sul State, where domestic and wild hosts were reported with the nematode. Of the total fish examined, 25(7.7%) were found to be parasitized by third-stage larvae of D. renale which were found encysted in the stomach serous membrane and in the celoma cavity of Hoplosternum littorale (Siluriformes) with a prevalence of 53.2% (25/47) and mean intensity of infection of 4.4 larvae/host (1 to 13 larvae). The occurrence of larvae in H. littorale indicates the presence of parasitosis in the region; however, the contribution of this fish species as a source of infection for dogs in urban areas must be considered with caution given the difficulties these dogs may face in the capture and predation of the fish to the point of effectively maintaining the urban cycle of D. renale. In addition, the low level of larvae registered in the total sample of fish examined indicates that these hosts are unlikely to play an important role in the transmission of D. renale to domestic animals in the region of the study.

Hepatic Capillariasis- Drug Targets.

Zoonotic infections are increasingly becoming public health menaces and are usually transmitted to humans due to unsuitable environmental conditions. One of them is hepatic capillariasis, caused by the parasite Capillaria hepatica, primarily a disease of rodents, with hepatic manifestations in humans. Although its prevalence is very low, it can cause significant morbidity and mortality, with cases reported from all over the world. The main infective form for humans is the embryonated egg of the parasite, which hatches in the intestine and ultimately colonize the liver. The larvae mature and reproduce, and eventually form embryonated eggs, which cause chronic focal inflammation and septal hepatic fibrosis. Clinical presentation mainly consists of fever, abdominal pain, hepatomegaly and eosinophilia. Spurious infection with unembryonated eggs cause gastrointestinal symptoms. Diagnostic modalities include liver biopsy, ultrasonography, CT scan, immunological tests like ELISA and IIFT. The infection can be treated mainly with a combination of benzimidazoles like thiabendazole, mebendazole and albendazole; with corticosteroids. The study emphasizes the need for hepatic capillariasis to be considered as a differential diagnosis in cases of suspected hepatitis, leptospirosis, abdominal lymphadenopathy or other hepatic or parasitic infections prevalent in the region concerned; and meticulously assess the cases to facilitate early diagnosis and prompt treatment, thus reducing the distress faced by patients.

Molecular detection of Capillaria philippinensis: An emerging zoonosis in Egypt.

Human infection with Capillaria philippinensis is accidental; however, it may end fatally if not diagnosed and treated in the proper time. The first case was detected in the Philippines in 1963, but later reported in other countries around the world, including Egypt. In this report, molecular diagnosis using a specific nested PCR for detection of C. philippinensis in faeces is described based on the amplification of small ribosomal subunit. The test showed sensitivity and specificity, as it detected all the positive cases and gave no cross-reaction with human DNA and DNA of other tested parasites. This method can be very useful not only for improvement of diagnosis, but also to understand the different environmental routes of transmission by detection of C. philippinensis DNA-stages in the possible fish intermediate hosts and reservoir animal host, helping to improve strategies for surveillance and prevention of human disease.

Capillaria hepatica infection in black rats (Rattus rattus) on Diego Garcia, British Indian Ocean Territory.

Rats (Rattus spp.) are among the most damaging invasive species worldwide. The accidental introduction of rats has caused significant detriment to native flora and fauna, crops, structures, and human livelihoods. Rats are vectors of disease and carriers of various zoonotic parasites. Capillaria hepatica (syn. Callodium hepaticum) is a parasitic nematode found primarily in rodents but is known to infect over 140 mammal species, including human beings and several species of domestic animals. In this case study, the presence of C. hepatica infection in black rats on Diego Garcia, British Indian Ocean Territory, is reported. Liver samples from 20 black rats (Rattus rattus) were collected during a concurrent population density estimation study. Histology revealed 15 (75%) of the rats sampled had a current or previous infection with C. hepatica. In addition, a larval cestode compatible in size and shape with Cysticercus fasciolaris, the larval stage of Taenia taeniaeformis of cats, was found in 3 (15%) of the rats sampled. The high prevalence of C. hepatica infection in rats on Diego Garcia has implications for human health given the high population density of rats found on the island.

Some studies on Capillaria philipinensis and its mysterious trip from Philippines to Egypt (review article).

Capillaria philippinensis is a mysterious parasite and intestinal capillariasis is a mysterious disease. It is now more than half a century since the discovery of the first case in Philippines without answering many questions concerning the parasite's taxonomy, morphology, life cycle, diagnosis, pathology, clinical symptoms, mode of transmission as well as how it was transported to Egypt and how it started to spread and progressed in most Egyptian Governorates; particularly those of Middle Egypt. This article is a trial to overview all these aspects of the parasite.

High occurrence of Calodium hepaticum (syn. Capillaria hepatica) spurious infection in a village in the Atlantic Forest of southern Brazil

Calodium hepaticum (syn. Capillaria hepatica) is a nematode of the Capillariidae family that infects rodents and other mammals. In Brazil, human spurious infections of C. hepaticum have been detected in indigenous or rural communities from the Amazon Basin, but not in the southern states of the country. Here, we report the highest occurrence (13.5% of 37 residents) of C. hepaticum human spurious infection detected in Brazil and the first record in a southern region, Guaraqueçaba. The finding is explained by the area being located in the Atlantic Forest of the state of Paraná, surrounded by preserved forests and because the inhabitants consume the meat of wild mammals.

High occurrence of Calodium hepaticum (syn. Capillaria hepatica) spurious infection in a village in the Atlantic Forest of southern Brazil.

Calodium hepaticum (syn. Capillaria hepatica) is a nematode of the Capillariidae family that infects rodents and other mammals. In Brazil, human spurious infections of C. hepaticum have been detected in indigenous or rural communities from the Amazon Basin, but not in the southern states of the country. Here, we report the highest occurrence (13.5% of 37 residents) of C. hepaticum human spurious infection detected in Brazil and the first record in a southern region, Guaraqueçaba. The finding is explained by the area being located in the Atlantic Forest of the state of Paraná, surrounded by preserved forests and because the inhabitants consume the meat of wild mammals.

An overview of the host spectrum and distribution of Calodium hepaticum (syn. Capillaria hepatica): part 2-Mammalia (excluding Muroidea).

Calodium hepaticum (syn. Capillaria hepatica) is a globally distributed zoonotic nematode with low host specificity and a high affinity to the liver. Although murid rodents are the main definite hosts, various other mammals can be affected with hepatic capillariasis: non-murid rodents, Insectivora, Chiroptera, Lagomorpha, Artiodactyla, Perissodactyla, Hyracoidea, Marsupialia, Carnivora, and Primates. Overall, more than 180 mammalian species (including humans) are known as suitable hosts of this pathogen. This review gives an overview of the distribution and host spectrum of C. hepaticum in non-Muroidean mammals in wildlife and zoos as well as in domesticated and laboratory animals. Furthermore, the role of spurious infections in animals and the dissemination of C. hepaticum by mammalian and non-mammalian animals are summarized.

Rattus norvegicus como indicador de la circulación de Capillaria hepatica y Taenia taeniaeformis en la Plaza Minorista de Medellín, Colombia / Rattus norvegicus as an indicator of circulation of Capillaria hepatica and Taenia taeniaeformis on a groceries trade center of Medellín, Colombia

Introducción. Rattus norvegicus cumple un papel epidemiológico en el mantenimiento y dispersión de agentes zoonóticos bacterianos, virales y parasitarios de interés en salud pública. La presencia de infección por helmintos en especies Rattus cercanas a poblaciones expuestas en condiciones ambientales propicias, puede convertirse en un factor de riesgo de transmisión. Objetivo. Reportar la frecuencia de infección con Capillaria hepatica y formas larvarias de Taenia taeniaeformis en ratas silvestres (R. norvegicus) capturadas en una zona urbana de Medellín. Materiales y métodos. Se capturaron 254 ejemplares de R. norvegicus. Los hígados de 54 ejemplares que presentaron lesión hepática macroscópica durante la necropsia, fueron examinados por histopatología convencional. Resultados. La frecuencia de infección por C. hepatica fue de 20,1 % (51/254). Seis hígados fueron también positivos para larvas de T. taeniaeformis con una frecuencia de 2,4 % (6/254). Los hígados infestados con C. hepatica exhibían parásitos en el estadio adulto o juvenil y huevos ovalados con opérculos bipolares, asociados con hepatitis granulomatosa leve a moderada multifocal y acompañada por infiltrado leucocitario. Se observaron lesiones granulomatosas en resolución y fibrosis residual o calcificada que contenía huevos. Donde se encontraron cisticercos de T. taeniaeformis, el hallazgo más frecuente fueron quistes hepáticos que contenían larvas, y lesiones inflamatorias y fibróticas. Conclusión. Estos resultados indican que helmintos de potencial zoonótico circulan en R. norvegicus de ambientes urbanos. Debe investigarse la verdadera distribución de estos parásitos, para determinar el riesgo potencial que corren las poblaciones animales y humanas expuestas a adquirir este tipo de infecciones.

Introduction. Rattus norvegicus, the Norway rat, plays a pivotal role in the maintenance and spread of several zoonotic bacterial, viral and parasitic pathogens of public health interest. The presence of helminthic infections near susceptible human populations can, under appropriate environmental conditions, become a risk factor for their transmission. Objective. Frequencies of infection were reported for Capillaria hepatica and larval forms of Taenia taeniaeformis in wild rats (R. norvegicus) captured in an urban area. Materials and methods. Two hundred and fifty-four adult specimens of R. norvegicus were collected in an urban zone of Medellín, Colombia. The livers of 54 specimens that showed macroscopic hepatic lesions during necropsy were examined by conventional histopathology. Results. The frequency of infestation with C. hepatica was 20.1% (51/254). Six livers (2.4%) were also positive for larvae of T. taeniaeformis. Livers infested with C. hepatica exhibited adult or juvenile parasites and oval eggs with bipolar opercula, and were associated with mild to moderate multifocal granulomatous hepatitis with leucocyte infiltrate. Granulomatous lesions and calcified residual fibroses were found with eggs but without adult parasites. Those animals with cysticerci of T. taeniaeformis showed a high frequency of hepatic cysts containing larvae as well as inflammed and fibrotic lesions. Conclusion. Zoonotic helminths circulate at high frequency in R. norvegicus that occur in urban environments. Further research about the distribution of these parasites will determine the level of health threat they present for susceptible human and domestic animal populations.

Calodium hepaticum: household clustering transmission and the finding of a source of human spurious infection in a community of the Amazon region.

BACKGROUND: Calodium hepaticum (syn. Capillaria hepatica) is a worldwide helminth parasite of which several aspects of transmission still remain unclear. In the Amazon region, the mechanism of transmission based on the ingestion of eggs present in the liver of wild mammals has been suggested as the cause of the spurious infections described. We performed an epidemiological investigation to determine the incidence, risk of spurious infection and the dynamics of transmission of C. hepaticum in a community of the Brazilian Amazon. METHODOLOGY/PRINCIPAL FINDINGS: Stool samples of 135 individuals, two dog feces and liver tissue from a peccary (captured and eaten by the residents) were analyzed by conventional microscopy. Dog feces were collected from the gardens of households presenting human cases of spurious C. hepaticum infections. Community practices and feeding habits related to the transmission of the parasite were investigated. The individual incidence of spurious infection was 6.7% (95% CI: 2.08-11.24). Cases of spurious infection were observed in 7.5% of the families and the household incidence was from 50% to 83.3%. The risk of spurious infection was 10-fold greater in persons consuming the liver of wild mammals (p = 0.02). The liver tissue of a peccary and one feces sample of a dog presented eggs of C. hepaticum. The consumption of the infected liver was the cause of the spurious infections reported in one household. CONCLUSIONS/SIGNIFICANCE: This is the first identification of a source of spurious infection by C. hepaticum in humans and we describe a high rate of incidence in household clusters related to game liver alimentary habits. The finding of a dog feces contaminating peridomiciliary ground suggests the risk of new infections. We conclude that the mechanism of transmission based on the ingestion of liver is important for the dynamics of transmission of C. hepaticum in the studied area.

[Rattus norvegicus as an indicator of circulation of Capillaria hepatica and Taenia taeniaeformis on a groceries trade center of Medellín, Colombia]. / Rattus norvegicus como indicador de la circulación de Capillaria hepatica y Taenia taeniaeformis en la Plaza Minorista de Medellín, Colombia.

INTRODUCTION: Rattus norvegicus, the Norway rat, plays a pivotal role in the maintenance and spread of several zoonotic bacterial, viral and parasitic pathogens of public health interest. The presence of helminthic infections near susceptible human populations can, under appropriate environmental conditions, become a risk factor for their transmission. OBJECTIVE: Frequencies of infection were reported for Capillaria hepatica and larval forms of Taenia taeniaeformis in wild rats (R. norvegicus) captured in an urban area. MATERIALS AND METHODS: Two hundred and fifty-four adult specimens of R. norvegicus were collected in an urban zone of Medellín, Colombia. The livers of 54 specimens that showed macroscopic hepatic lesions during necropsy were examined by conventional histopathology. RESULTS: The frequency of infestation with C. hepatica was 20.1% (51/254). Six livers (2.4%) were also positive for larvae of T. taeniaeformis. Livers infested with C. hepatica exhibited adult or juvenile parasites and oval eggs with bipolar opercula, and were associated with mild to moderate multifocal granulomatous hepatitis with leucocyte infiltrate. Granulomatous lesions and calcified residual fibroses were found with eggs but without adult parasites. Those animals with cysticerci of T. taeniaeformis showed a high frequency of hepatic cysts containing larvae as well as inflammed and fibrotic lesions. CONCLUSION: Zoonotic helminths circulate at high frequency in R. norvegicus that occur in urban environments. Further research about the distribution of these parasites will determine the level of health threat they present for susceptible human and domestic animal populations.

Prevalence of Calodium hepaticum (Syn. Capillaria hepatica) in house mice (Mus musculus) in the Azores archipelago.

Calodium hepaticum (Syn. Capillaria hepatica) is a zoonotic liver nematode of mammals distributed worldwide. Rodents are believed to be the main reservoirs of this nematode. In this paper, prevalence of the parasite was analyzed in liver histological sections from 51 house mice (Mus musculus) caught in human-inhabited houses, from two localities (Furnas and Rabo de Peixe) on São Miguel island from the Azores archipelago (Portugal). Mean prevalence of infection was 19.6%, with 33.3% prevalence in Furnas and 4.1% in Rabo de Peixe (P=0.07). No significant differences were found between the prevalence of infection and the age, body weight and the sex of mice. Hepatic lesions found were either acute and/or chronic stage and consisted of moderate to severe multifocal pyogranulomatous hepatitis with encapsulated eggs with typical bipolar plugs and moderate to severe necrotizing hepatitis consistent with larva tracks. Periportal inflammatory infiltration, hepatocyte regeneration and bile duct hyperplasia were also noted. In most cases, hepatic lesions occupied more than 50% of the liver, but despite severe lesions, in some mice, no signs of hepatic failure were noticed. The high rate of infection found in the present study suggests that house mice are an important reservoir for this parasite in the Azores and could have a role in human transmission.

Eucoleus aerophilus respiratory infection in a dog with Addison's disease.

A 4-year-old, standard poodle was presented to the Ontario Veterinary College for a 3-week history of a moist, productive cough that was first noted while boarding at a kennel. Bronchoalveolar lavage revealed numerous ova identified as Eucoleus aerophilus, previously known as Capillaria aerophila. Clinical signs resolved following treatment with fenbendazole.

Eustrongylides sp. (Nematoda: Dioctophymatoidea) from the stomach of a Nile crocodile, Crocodylus niloticus Laurenti, 1768, in Botswana.

During a study conducted between 2003 and 2005 on the diet of Nile crocodiles in Botswana, two young adult nematodes, one male and one female, belonging to the genus Eustrongylides Jägerskiöld, 1909 were recovered from the stomach contents of one of these animals. The caudal bursa of the male is present and the ejaculatory duct could be identified, but the spicule could not be seen. The vulva of the female has opened and the anus is situated on a terminal protruberance. Measurements and drawings of these specimens are provided, together with some data on the occurrence and life-cycles of members of the genus Eustrongylides in crocodilians world-wide and in African hosts in particular. Piscivorous birds are the usual final hosts of these nematodes. It is probable that the specimens described herein had developed in a paratenic fish host, and that the latter had been eaten by the crocodile.

Epizootiology of Eustrongylides ignotus in Florida: transmission and development of larvae in intermediate hosts.

Under laboratory conditions, 2 modes of transmission of Eustrongylides ignotus (Nematoda: Dioctophymatoidea) to fish were identified. Eastern mosquitofish (Gambusia holbrooki) became infected after ingestion of either eggs of E. ignotus containing first-stage larvae or aquatic oligochaetes (Limnodrilus hoffmeisteri) containing third-stage larvae of E. ignotus. After removal from the uterus of gravid E. ignotus females and incubation for 17-28 days, depending on temperature, it was found that parasite eggs contained first-stage larvae that were infective to fish and oligochaetes. Larvae developed to the third stage in oligochaetes and were infective to fish 35-77 days postinfection (PI) and when fed to fish, developed to the fourth stage between 127 and 184 days PI. Eggs containing first-stage larvae fed directly to fish developed to the fourth stage between 84 and 105 days PI. The amount of time for development from the undifferentiated egg to the fourth-stage larva was 78-156 days shorter when fish ingested eggs containing first-stage larvae than when fish ingested oligochaetes containing third-stage larvae. Three species of large piscivorous fish, including black crappie (Pomoxis nigromaculatus), largemouth bass (Micropterus salmoides), and warmouth (Lepomis gulosus), were fed mosquitofish containing fourth-stage larvae. At necropsy, live E. ignotus larvae were recovered from all 3 species. Several fish had multiple infections after ingesting > 1 larva, indicating that bioaccumulation of the parasite in the food chain may occur.

Hepatic calodium hepaticum (Nematoda) infection in a zoo colony of black-tailed prairie dogs (Cynomys ludovicianus).

Calodium hepaticum (syn. Capillaria hepatica), a nematode parasite commonly found in the liver of wild rodents, infects a wide variety of mammals, including humans. A retrospective study of black-tailed prairie dogs (Cynomys ludovicianus) at the Baltimore Zoo showed that 5 of 21 (24%) of the prairie dogs submitted for postmortem examination between 1981 and 2001 had hepatic capillariasis, with all the infections diagnosed during or after 1997. Affected livers contained multifocal granulomas containing numerous eggs and occasional adult nematodes. Asymptomatic wild rats in the zoo with a high prevalence of infection may have served as a reservoir for the disease. Wild rodent control is essential to minimize exposure of susceptible exhibition animals as well as humans to C. hepaticum.

Altered predation susceptibility of mosquitofish infected with Eustrongylides ignotus.

Eustrongylides ignotus is a parasitic nematode whose definitive hosts are often piscivorous wading birds (Ciconiiformes). Several species of small fishes are intermediate hosts, while larger predatory fish may be paratenic (transport) hosts. We examined predation susceptibility of infected mosquitofish (Gambusia holbrooki) to three species of predatory fishes, including juvenile largemouth bass (Micropterus salminoides), warmouth (Lepomis gulosus), and bluegill (Lepomis macrochirus). A 250 L aquarium with removable plexiglass divider and remote observation windows was constructed. Aquatic macrophytes were placed in the tank to provide refuge for the fishes. Predatory fish were allowed to acclimate to one half of the tank, while one infected and one uninfected mosquitofish were placed in the other. The divider was removed and an observer recorded the number of capture attempts and time required for capture. Predators were observed for behavioral alterations for 4 days after ingestion of infected mosquitofish, then examined at necropsy. Infected prey were selected preferentially in 31 of 38 (82%) trials. The number of capture attempts was 2.7+/-0.2 (x +/- SE) for infected fish and 3.9+/-0.4 for uninfected fish. Mean time of capture was 12.4+/-1.6 min for infected fish and 21.7+/-2.9 for uninfected fish. Because of these differences, infected mosquitofish were more susceptible to predation (P < 0.01) than uninfected fish. Aberrant behavior including lethargy, convulsions, and buoyancy abnormalities was observed in eight (67%) predatory fish. At necropsy, larvae of E. ignotus were found in the coelomic cavity, viscera, and swim bladders of predators. Parasite-induced behavior modification of intermediate hosts may predispose them to predation by wading birds and thereby facilitate the transmission of this nematode in natural populations.

Capillaria hepatica, a parasite of zoonotic importance--a brief overview.

This review briefly elucidates the biology and mode of transmission of the parasite capillaria hepatica, an cuimial parasite. Occasional transmitted to man.

[Pathogenic effect of the nematode parasite Romanomermis iyengari(Nematoda: Mermithidae) in Aedes aegypti mosquito larvae (Diptera: Culicidae) under laboratory conditions in the state of Oaxaca, Mexico]. / Efecto patogénico del nematodo parásito Romanomermis iyengari (Nematoda: Mermithidae) en larvas del mosquito aedes aegypti (Diptera: Culicidae) en condiciones de laboratorio en el Estado de Oaxaca, México.

Laboratory tests with waters from Aedes aegypti Linneaus (1762) breeding places were made to determine the pathogenic effect of the mermithid nematode Romanomermis iyengari Welch 1964 in mosquito larvae of this species. According to the results obtained, the administration of a dosage of 10:1 (10 preparasitics per mosquito larvae) showed levels of parasitism of 90, 93, 91, and 85% in mosquito larvae in the I, II, III, and IV stage, respectively. With the highest dosage of 20:1 (20 preparasitics per mosquito larvae) there were obtained levels of parasitism with values of 98, 97, 93 and 89% among larvae in the I, II, III, and IV stage, respectively. Generally, the values of the physical and chemical parameters such as pH, conductivity, oxygen, and chlorides calculated in these waters did not affect apparently the infective capacity of the preparasitics of R. iyengari.

[The fate of parasites of animal origin transmitted to humans]. / Devenir des parasites d'origine animale transmis à l'homme.

The fate of a parasite transmitted from an animal to man depends on the ability of the contaminating agent to reach a place where it can thrive, to find necessary nutrients, and to resist host defense mechanisms. The purpose of this study was to evaluate the incidence of transmission of parasites from animals to man and to determine to what extent transmission is followed by development. Stenoxenic parasites whose life cycle requires transmission from animals to man obviously develop in man and then return to animals. These parasites cause holozoonoses of the cyclozoonosis type. Some euryxenic parasites can develop as well in man as in animals. These parasites can cause holozoonoses of the amphixenoses type. Other presumably euryxenic parasites can be transmitted from animals to man but not vice versa. These parasites are hemizoonoses agents. Non-transmission back from man to animals can be observed under several circumstances: incomplete development in man with failure to reach the stage at which transmission back to animals is possible; full development but with immaturity or sterility of the elements of dissemination necessary for transmission back to animals; full development but no way of evacuating elements of dissemination; full development and evacuation but with failure of elements of dissemination to survive. In these four cases man constitutes a dead-end for the parasite. A fifth possibility is that the parasite reaches full development but transmission back to animals cannot occur because man is not preyed upon by a carnivorous animal. In this case parasites are potential agents of holozoonoses and man is a cul-de-sac for the involved parasites.