Dioctophymosis in a free-ranging maned wolf (Chrysocyon brachyurus): clinical-therapeutic, ultrasonographic and pathological aspects - case report / [Dioctofimose em um lobo guará (Chrysocyon brachyurus) de vida livre: aspectos clínico-terapêuticos, ultrassonográficos e patológicos - relato de caso]

Dioctophymosis is the disease caused by Dioctophyma renale, a large nematode, popularly known as giant kidney worm, and whose definitive hosts are the domestic dog and many wild mammal species. There are some reports of maned wolf parasitism by D. renale, however, in most cases the reports are restricted to the finding of the parasite during necropsy, without clinical assessment. The present report aimed to describe the clinical-therapeutic, ultrasonographic and pathological aspects of D. renale parasitism in a free-ranging maned wolf, emphasizing the treatment with an association of doramectin, praziquantel, pyrantel pamoate, and febantel that resulted in complete elimination of the parasite.(AU)

A dioctofimose é a doença causada pelo Dioctophyma renale, um nemátodo grande, popularmente chamado de verme gigante do rim e que tem como hospedeiro definitivo o cão doméstico e inúmeras espécies de mamíferos silvestres. Existem alguns relatos do parasitismo do lobo-guará por D. renale, contudo, na maioria das vezes, os relatos se restringem apenas ao achado do parasita durante a necropsia, sem a correlação clínica. O presente relato objetiva descrever os aspectos clínico-terapêuticos, ultrassonográficos e patológicos do parasitismo por D. renale em um lobo-guará de vida livre, enfatizando o tratamento com uma associação de doramectina, praziquantel, pamoato de pirantel e febantel, o que resultou na eliminação completa do parasita.(AU)

Hepatic Capillaria hepatica (Bancroft, 1893) infection in cat (Felis catus)-histopathological findings and first report from Iran.

Capillaria hepatica (syn. Calodium hepaticum) is a globally distributed nematode with a high affinity to the liver of a wide range of mammalian hosts, including humans. Documented reports of the nematode in cats and associated histopathology are rare. Here, we describe a case of C. hepatica infection in a 5-year-old male stray cat from Iran. At post-car accident necropsy, all body parts appeared normal except for the liver, in which a few yellowish-white granulomatous nodules were observed through the capsule and in the organ. Histopathological examination of the tissue revealed a large number of clustered parasite eggs in the parenchyma. The barrel-shaped, un-embryonated eggs (55.19 × 28.37 µm), with inconspicuous caps at both ends, were covered with striated shells. The presence of ova in the liver tissue had resulted in the development of hepatic inflammation with hepatocellular necrosis associated with the development of multifocal granulomas. As predators of small rodents, the cats might have a significant role in the epidemiology of C. hepatica. Infection of hosts through ingestion of embryonated eggs in contaminated water, food, or soil is of major importance in the epidemiology of C. hepatica. Since the rare reports of feline infection have come mainly from accidental detection of the parasite, any hepatic disease presenting difficulties to find an etiological agent may virtually be associated with the infection with this little-known nematode.

Dioctophyme renale (Goeze, 1782) (Nematoda, Dioctophymidae) parasitic in mammals other than humans: A comprehensive review.

A comprehensive review of the infection of mammals with the nematode Dioctophyme renale (Goeze, 1782) (Nematoda, Dioctophymidae) is presented. Mammals, including man, are the definitive hosts for this parasite. Several aspects of the infection with the parasite in mammals other than humans are critically evaluated: geographical distribution, host species recorded so far and the relative importance of the different hosts, location of parasites within the host, prevalence and intensity of the infection, diagnostic methods, pathology induced by the parasites, epidemiology and the methods of control and treatment. The authors provide an updated review about the infection, based on a extensive bibliographic search worldwide, and point out the most relevant aspects of the biology of the parasite as well as several research topics which need to be explored for a better understanding of the biology of this interesting and important parasitic nematode.

Ectopic dioctophymosis in a dog - Clinical, diagnostic and pathological challenges of a silent disease.

A 9-month old, female, stray dog was rescued and conducted to a university veterinary hospital. Moderate anemia was observed and abdominal ultrasound revealed pancreatitis. Right kidney was not visualized due to intestinal gas. Urinalysis was normal. Castration was performed three weeks later. Before discharge, abdominal ultrasound was performed for internal sutures examination. A cyst-like structure was present in the right retroperitoneal space with what appeared to be tubular worms inside it, not observed in previous evaluation. An ectopic dioctophymosis diagnosis was made. Two female Dioctophyme renale were surgically removed from the structure. Right kidney was hyperemic but not removed. No sign of peritonitis was observed. The dog recovered well. Laboratory follow-up showed no abnormalities a year after the episode and Doppler ultrasound revealed a mild right nephropathy. This is the first canine ectopic dioctophymosis case with only an abdominal cyst-like structure containing viable nematodes, successfully treated. It represents the rarity and difficulties in diagnosing ectopic dioctophymosis even in enzootic locations, highlighting the importance of ultrasonographic screening for such silent, potentially zoonotic disease.

First description of parasite load and clinicopathological and anatomopathological changes in a dog naturally coinfected with Dioctophyme renale and Leishmania infantum in Brazil.

This article reports the case of a domestic dog naturally coinfected with the nematode Dioctophyme renale and with the protozoan Leishmania infantum. The dog exhibited no clinical signs but had normocytic hypochromic anemia, hyperproteinemia, hyperglobulinemia, hypoalbuminemia, and hematuria. Necropsy revealed eight D. renale specimens in the abdominal cavity and in right kidney whose parenchyma was atrophied. Histopathological analysis showed glomerular atrophy, fibrosis and a marked diffuse pyogranulomatous inflammatory infiltrate in the right kidney. Moderate multifocal granulomatous peritonitis was observed in the greater omentum. Several Dioctophyme renale eggs were present amidst the inflammatory infiltrate of the right kidney and greater omentum. Leishmania infantum parasites were detected in perirenal adipose tissue of the right kidney, greater omentum, spleen, bone marrow, and popliteal lymph node. The high D. renale load and the severe and uncommon histological alterations associated with the eggs of this parasite may have been influenced by coinfection with L. infantum.

Morphological and Molecular Characterization of Larval and Adult Stages of Eustrongylides excisus (Nematoda: Dioctophymatoidea) with Histopathological Observations.

The genus Eustrongylides includes nematodes known as the etiological agent of the "big red worm disease." The aim of this work was to identify Eustrongylides spp. larvae from fish and adults from great cormorant (Phalacrocorax carbo) sampled at Lake Trasimeno, Italy, by morphological and molecular analysis. Histopathological description of the lesions in birds was also provided. We described adults of Eustrongylides excisus for the first time in Italy, and we also linked larval stages 3 and 4 to adults. The use of molecular tools combined with the traditional taxonomy will help the identification of the species, including species inquirendae. Moreover, molecular analysis can also help to investigate the role of intermediate and paratenic hosts, to deepen the knowledge about geographical distribution of the different Eustrongylides spp. and to define the zoonotic potential of E. excisus, which has not yet been identified as causal agent of human cases.

A Hospital-Based Study of Intestinal Capillariasis in Thailand: Clinical Features, Potential Clues for Diagnosis, and Epidemiological Characteristics of 85 Patients.

Intestinal capillariasis caused by Capillaria philippinensis, a fish-borne nematode, is an important, emerging zoonotic helminthiasis. Cases may be fatal if suitable treatment is not administered in time. We reported a hospital-based study of 85 cases in Thailand, most of which were in the northeast. All patients had a history of eating raw or insufficiently cooked fresh water fish or prawns. The clinical manifestations are characterized by chronic diarrhea, borborygmi, abdominal pain, marked weight loss, muscle weakness, fatigue, dizziness, anorexia, and edema, as well as protein and electrolyte loss. Fecal examination revealed C. philippinensis in all patients. Although 16 of the total of 85 (18.8%) cases were initially found to be negative for C. philippinensis using fecal examination, further examination using an immunoblotting technique found them to be positive for the IgG antibody against Trichinella spiralis larval antigen. One day after administration of 400 mg of albendazole, eggs and/or larvae and/or adult C. philippinensis were found in 16 fecal samples. After treatment with mebendazole (200 mg twice a day for 30 days) or albendazole (200 mg twice a day for 10 days), all 85 patients recovered. The potential clues for diagnosis are clinical manifestations, history of eating raw contaminated food, and positive serological test, and fecal examinations under professional. Administration of anthelminthic drugs stimulates the excretion of larvae, eggs, and/or adult worms and can be used as a supportive method for the diagnosis of intestinal capillariasis in areas where serological test is not available.

Dioctofimatose renal bilateral e disseminada em cão / Bilateral and disseminated renal dioctophimatosis in dog

Este trabalho descreve dioctofimatose renal bilateral e disseminada em canino no município de Pelotas, na região sul do Rio Grande do Sul. Uma cadela sem raça definida, de dois anos de idade e semi-domiciliada foi submetida a exame ultrassonográfico observando-se alterações sugestivas de parasitismo por Dioctophyme renale. O animal veio à morte antes de ser conduzido para nefrectomia e remoção dos parasitas. Foi encaminhado para necropsia no Laboratório Regional de Diagnóstico da Faculdade de Veterinária da UFPel. Macroscopicamente, ao corte do rim direito observou-se atrofia do parênquima com formações císticas e exsudato serosanguinolento com quatro exemplares fêmeas de D. renale. A cápsula renal media 0,4cm de espessura, e apresentava placas multifocais esbranquiçadas, irregulares e de consistência dura, medindo até 2cm de diâmetro. Na pelve do rim esquerdo, havia um parasita macho de 22cm. A bexiga possuía conteúdo escurecido e pastoso. Ainda, livre na cavidade abdominal, próximo ao rim direito havia outro parasita macho de 30cm. No fígado havia região cicatricial no lobo em contato com o parasita. No tórax identificou-se livre na cavidade e formando impressão sob a gordura pericárdica, um parasita macho de D. renale, medindo 20cm. Histologicamente, além de lesões características da enfermidade, observou-se metaplasia óssea na capsula renal direita.(AU)

This paper describes a bilateral and disseminated renal dioctophymiasis in a canine in the municipality of Pelotas, southern region of Rio Grande do Sul, in Brazil. The two-year-old female dog with no defined race was semi-domiciled and was submitted to ultrasound examination presenting alterations suggestive of parasitism by Dioctophyme renale. The patient died before being led for nephrectomy and removal of the parasites. It was referred for necropsy at the Regional Diagnostic Laboratory of the UFPel Veterinary School. Macroscopically, at the cut of the right kidney, atrophy of the parenchyma with cystic formations and serosanguinous exudate with four female specimens of D. renale were observed. The renal capsule was 0.4cm thick and had irregular, hard, multifocal regions measuring up to 2cm in diameter. In the pelvis of the left kidney, there was a 22cm long male parasite. The bladder had darkened and pasty contents. Also, free in the abdominal cavity, near to the right kidney there was another male parasite of 30cm. In the liver there was a cicatricial region in the lobe in contact with the parasite. In the thorax, a male parasite of D. renale measuring 20cm, was identified free in the cavity and forming an impression under the pericardial fat. Histologically, in addition to the characteristic lesions of the disease, bone metaplasia was observed in the right renal capsule.(AU)

Histopathological findings in wild Nutrias (Myocastor coypus) with Capillaria hepatica infection.

Capillaria hepatica is a zoonotic nematode that uses rodents and other mammals as hosts, especially rats and mice, and causes hepatic granuloma and eventually fibrosis/cirrhosis. However, C. hepatica infection in nutria, a large semiaquatic rodent, has rarely been reported, and histopathologic features of the infection have not been described in detail. We conducted necropsy on 36 wild nutrias. Some animals were found to have milky spots, parasitic eggs and worms within hepatic microgranuloma involving central calcification with cell debris, macrophages, eosinophils and multinucleated giant cells (MGCs). Interestingly, the eggs were closely surrounded by MGCs and appeared to be destroyed without inducing further chronic changes. Based on microscopical examination, C. hepatica infection was diagnosed, and we describe its histopathological characteristics in wild nutrias.

Factors affecting carriage and intensity of infection of Calodium hepaticum within Norway rats (Rattus norvegicus) from an urban slum environment in Salvador, Brazil.

Urban slum environments in the tropics are conducive to the proliferation and the spread of rodent-borne zoonotic pathogens to humans. Calodium hepaticum (Brancroft, 1893) is a zoonotic nematode known to infect a variety of mammalian hosts, including humans. Norway rats (Rattus norvegicus) are considered the most important mammalian host of C. hepaticum and are therefore a potentially useful species to inform estimates of the risk to humans living in urban slum environments. There is a lack of studies systematically evaluating the role of demographic and environmental factors that influence both carriage and intensity of infection of C. hepaticum in rodents from urban slum areas within tropical regions. Carriage and the intensity of infection of C. hepaticum were studied in 402 Norway rats over a 2-year period in an urban slum in Salvador, Brazil. Overall, prevalence in Norway rats was 83% (337/402). Independent risk factors for C. hepaticum carriage in R. norvegicus were age and valley of capture. Of those infected the proportion with gross liver involvement (i.e. >75% of the liver affected, a proxy for a high level intensity of infection), was low (8%, 26/337). Sixty soil samples were collected from ten locations to estimate levels of environmental contamination and provide information on the potential risk to humans of contracting C. hepaticum from the environment. Sixty percent (6/10) of the sites were contaminated with C. hepaticum. High carriage levels of C. hepaticum within Norway rats and sub-standard living conditions within slum areas may increase the risk to humans of exposure to the infective eggs of C. hepaticum. This study supports the need for further studies to assess whether humans are becoming infected within this community and whether C. hepaticum is posing a significant risk to human health.

Baruscapillaria obsignata: a serious cause of enteropathy and high mortality in turkeys (meleagris gallopavo).

BACKGROUND: Capillariasis, an important parasitic disease of birds is caused at least by seven different genera of trichurid nematodes with clinical outcome ranging from mild enteritis to high mortality. OBJECTIVE: This study was aimed to investigate the causative agent involved in high mortality associated with severe enteric illness among turkey flocks in an organized commercial poultry farm at Bareilly, India. MATERIALS AND METHODS: Turkey carcasses (n = 119) and fecal samples from the affected deep litter pen constituted as the study materials. The disease was investigated by systematic necropsy, direct microscopy and histopathology. Representative samples were screened for other enteric pathogens. RESULTS: Microscopic examination of mucosal scraping revealed capillarid worms and their eggs in all the samples. The morphological features of adult worms were typically consistent to Baruscapillaria obsignata. Histopathology exhibited thickened muscular and mucosal layers, mononuclear and heterophilic infiltration in the lamina propria, blunting and clubbing of villi, epithelial denudation and sections of capillarid worms. Administration of levamisole at 80 ppm in drinking water reduced the mortality, clinical illness and worm load after three days of therapy. CONCLUSIONS: The capillarid worms in different avian hosts can cause different clinical manifestations and outcomes. From India, this is the first report describing intestinal pathology caused by B. obsignata in turkeys. We conclude that the B. obsignata infection is capable of causing life threatening enteropathy in turkeys and, hence, routine screening, scheduled deworming and good litter management are crucial to control the infection and its associated loss.

Use of the FLOTAC technique to diagnosing parasites of the urinary tract of dogs.

Among the nematodes that infect the urinary tract of dogs, the Dioctophyma renale and Capillaria plica are those more frequently reported. For a long time, sedimentation was the only method used to detect eggs of these parasites in urine. The aim of this study was to analyze urine samples (n = 54) of dogs, obtained by bladder catheterization or cystocentesis, by using a modified FLOTAC technique. Animals were divided into two groups, i.e., with (n = 20) and without (n = 34) suspicion of urinary disease. The overall positivity herein observed was 3.8 % (2/54), being all animals (10 %; 2/20) from the group with suspicion of urinary disease. In the first positive sample, a single egg of D. renale was detected, whereas in the second sample two trematode-like eggs were observed. This is the first short survey employed to detect eggs of parasites that inhabit the urinary tract of dogs using a modified FLOTAC technique; in addition, for the first time, eggs of D. renale have been detected using this tool.

Dioctophyma renale em 28 cães: aspectos clinicopatológicos e ultrassonográficos / Dioctophyma renale in 28 dogs: clinicpathological and ultrasonographic findings

A infecção em cães por Dioctophyma renale, relatada em diversas partes do mundo, é considerada incomum, na maioria das vezes. No entanto, em algumas regiões são descritos números crescentes da infecção e muitos dados da epidemiologia e do ciclo biológico do parasito ainda são obscuros. Dessa forma, o trabalho tem como objetivo descrever os aspectos epidemiológicos, clinicopatológicos e ultrassonográficos de casos de infecção por Dioctophyma renale em cães na região da Fronteira Oeste do Rio Grande do Sul. Foram estudados 28 casos de dioctofimose em cães necropsiados ou clinicamente avaliados, submetidos à ultrassonografia e cirurgia para retirada dos parasitos. Os cães errantes foram os mais acometidos e todos com possível acesso às margens do Rio Uruguai. As lesões renais e extrarrenais foram caracterizadas predominantemente por atrofia do parênquima renal com glomerulonefrite esclerosante e peritonite granulomatosa associada a parasitos adultos livres na cavidade abdominal e ovos, bem como migrações erráticas para o tecido subcutâneo. Por fim, os achados ultrassonográficos corresponderam, especialmente, a imagens transversais circulares de até 0,6 cm de diâmetro, com margem hiperecoica e centro hipoecoico. Esses achados foram patognomônicos para infecção por Dioctophyma renale, e o exame ultrassonográfico se mostrou indispensável para o diagnóstico definitivo durante a avaliação clínica. Os achados observados nesse estudo demonstram a importância dessa parasitose na região. Além disso, alertam para a importância do diagnóstico, que vem sendo subestimado, além de apontar a necessidade de mais dados acerca da epidemiologia da doença para que se chegue a métodos efetivos de controle...

Dioctophyma renale infection in dogs is being considered uncommon for most parts of the world. However, some regions show an increase of this infection; but many data of the epidemiology and the biological cycle of the parasite are still unclear. The present study describes the epidemiological, clinicpathological and ultrasonographic aspects of 28 cases of infection by Dioctophyma renale in dogs in the West Frontier region of Rio Grande do Sul, Brazil. Street dogs were the most affected and all of them had access to the banks of the Uruguay River. The renal and extra-renal lesions were predominantly characterized by atrophy of the renal parenchyma, sclerotic glomerulonephritis and granulomatous peritonitis, associated with free adult parasites and eggs in the abdominal cavity and erratic migration into the subcutaneous tissue. The ultrasound findings corresponded especially to the circular cross-sectional images with 0.6cm in diameter at most, with hyperechoic margin and hypoechoic center too. These findings were pathognomonic for Dioctophyma renale infection and this examination was essential for the definitive diagnosis by clinical evaluation. The results of the study demonstrate the importance of this parasitism in the region, alert that the diagnosis has being underestimated, and point out the need to clarify its epidemiology in order to reach effective control measures...

Histopathology and the inflammatory response of European perch, Perca fluviatilis muscle infected with Eustrongylides sp. (Nematoda).

BACKGROUND: The European perch, Perca fluviatilis L. is a common paratenic host of dioctophymatid nematodes belonging to the genus Eustrongylides. In this host, once infected oligochaetes, which serve as the first intermediate host, are ingested, Eustrongylides migrates through the intestine and is frequently encountered within the musculature, free within the body cavity, or encapsulated on the viscera. The current study details the first Italian record of Eustrongylides sp. with larvae reported in the muscle of P. fluviatilis. METHODS: Uninfected and nematode-infected muscle tissues of perch were fixed and prepared for histological evaluation and electron microscopy. Some sections were subjected to an indirect immunohistochemical method using anti-PCNA, anti-piscidin 3 and anti-piscidin 4 antibodies. RESULTS: A total of 510 P. fluviatilis (TL range 15-25 cm) from Lake Trasimeno, Perugia were post-mortemed; 31 individuals had encysted nematode larvae within their musculature (1-2 worms fish(-1)). Histologically, larvae were surrounded by a capsule with an evident acute inflammatory reaction. Muscle degeneration and necrosis extending throughout the sarcoplasm, sarcolemmal basal lamina, endomysial connective tissue cells and capillaries was frequently observed. Within the encapsulating reaction, macrophage aggregates (MAs) were seen. Immunohistochemical staining with the proliferating cell nuclear antigen (PCNA) revealed numerous PCNA-positive cells within the thickness of the capsule and in the immediate vicinity surrounding Eustrongylides sp. larvae (i.e. fibroblasts and satellite cells), suggesting a host response had been initiated to repair the nematode-damaged muscle. Mast cells (MCs) staining positively for piscidin 3, were demonstrated for the first time in response to a muscle-infecting nematode. The piscidin 3 positive MC's were seen principally in the periphery of the capsule surrounding the Eustrongylides sp. larva. CONCLUSIONS: A host tissue response to Eustrongylides sp. larvae infecting the musculature of P. fluviatilis was observed. Numerous fibroblasts, MAs and MCs were seen throughout the thick fibroconnectival layer of the capsule enclosing larvae. PCNA positive cells within the capsule suggest that host repair of nematode damaged muscle does occur, while the presence of the antimicrobial peptide piscidin 3 is shown for the first time. This is first report of Eustrongylides sp. in an Italian population of P. fluviatilis.

Capillaria hepatica infection: a rare differential for peripheral eosinophilia and an imaging dilemma for abdominal lymphadenopathy.

Capillaria hepatica which accidentally infects humans is a zoonotic parasite of mammalian liver, primarily rodents and causes hepatic capillariasis. The diagnosis is difficult because of the non-specific nature of clinical symptoms, leading to misdiagnosis and can be confirmed only through liver biopsy or on autopsy results. This paper is written with an objective to report a new case of hepatic capillariasis as a rare differential for peripheral eosinophilia and an imaging dilemma for abdominal lymphadenopathy.

Third-stage larvae of the enoplid nematode Dioctophyme renale (Goeze, 1782) in the freshwater turtle Trachemys dorbigni from southern Brazil.

The giant kidney worm Dioctophyme renale is normally found in wild carnivores and domestic dogs, with aquatic oligochaetes acting as intermediate hosts. In the present study a prevalence of 50% of third-stage larvae of D. renale was recorded in 60 specimens of the freshwater turtle Trachemys dorbigni from southern Brazil. Larvae were encysted in muscles, the coelomic cavity and mesentery, the serous lining of the stomach and on the surfaces of the lung, heart, liver, pancreas, spleen and intestines. There are no previous records of reptiles being part of the life cycle of D. renale, although fish and amphibians normally act as paratenic hosts. This is the first report of third-stage D. renale larvae in the freshwater turtle, T. dorbigni.

Intestinal capillariasis in the 21st century: clinical presentations and role of endoscopy and imaging.

BACKGROUND: Intestinal capillariasis is one of the common causes of malabsorption in the East. Reports emphasizing the roles of clinical, endoscopic and radiologic findings of intestinal capillariasis are limited. METHODS: Retrospective review of medical records of 26 patients diagnosed with intestinal capillariasis at Siriraj Hospital, Bangkok, Thailand between 2001- 2013. RESULTS: Clinical manifestations were chronic watery diarrhea (93%), chronic abdominal pain (70%), significant weight loss (92%), hypoalbuminemia (100%; 85% lower than 2.0 g/dL), and anemia (50%). The median duration of symptoms was 5.5 months (1-60 months). Parasites were found in stool in 15 patients (57%). In patients whose stool tests were initially negative, parasites were discovered in tissue biopsy from endoscopy in 1 from 10 esophagogastroduodenoscopies (EGD), 0 from 7 colonoscopies, 3 from 5 push enteroscopies, and 3 from 5 balloon-assisted enteroscopies (BAE). Endoscopic findings included scalloping appearance, mucosal cracking, and redness of mucosa. These endoscopic findings affected mostly at jejunum and proximal ileum. They were similar to celiac disease except duodenal involvement which is uncommon in capillariasis. Three patients underwent video capsule endoscopy (VCE) and typical abnormal findings were observed in all patients. Small bowel barium study showed fold thickening, fold effacement, and increased luminal fluid in 80% of patients, mainly seen at distal jejunum and ileum. CT findings were long segment wall thickening, enhanced wall, and fold effacement. Treatment with either albendazole or ivermectin cured all patients with most responding within 2 months. CONCLUSIONS: In endemic area, intestinal capillariasis should be considered if patients develop chronic watery diarrhea accompanied by significant weight loss and severe hypoalbuminemia. Stool examination had quite low sensitivities in making diagnosis in our study. Deep enteroscopy with biopsy guided by imaging or VCE may improve diagnostic yield. Empirical therapy may also be justifiable due to the very good response rate and less side effects.

Factors associated with the prevalence and pathology of Calodium hepaticum and C. splenaecum in periurban micromammals.

Calodium hepaticum (syn. Capillaria hepatica) and Calodium splenaecum (syn. Capillaria splenaecum) are nematodes that infect the liver and spleen, respectively, of mammals. While the host range, distribution, pathology and zoonotic potential of C. hepaticum are well known, very little is known about C. splenaecum. The observed prevalence of these two parasites, the factors associated with prevalence, and the lesions resulting in the different host species were studied in 408 micromammals captured in two periurban areas of Barcelona (NE Spain) from 2011 to 2013. C. hepaticum was found in 4% of 322 wood mice (Apodemus sylvaticus) (with local prevalence up to 16%) and 1 of 2 Norwegian rats (Rattus norvegicus). C. splenaecum was found in 10 % of 38 greater white-toothed shrew (Crocidura russula) (local prevalence up to 30%). Neither parasite was detected in 29 Algerian mice (Mus spretus) and 17 black rats (Rattus rattus). Prevalence of C. hepaticum was significantly higher in wood mice captured in natural areas (6.4%) than those from residential areas (0%), and infected mice were in better body condition. No differences in prevalence were found among age and sex groups, years and seasons. Lesions of hepatic capillariasis in wood mice consisted mainly of mild to moderate multifocal granulomas around degenerating adult parasites and/or eggs, while lesions seen in a rat consisted of multifocal granulomatous hepatitis and bridging fibrosis extending from the necrotic areas caused by the parasites. Splenic lesions found in shrews due to C. splenaecum, representing the first histological description of this parasite, were single nodules that corresponded to finely encapsulated clusters of eggs with adult parasites.