Parasitic Lesions of Bovine Liver Attributed to Capillaria Species

Occurrence of Capillaria sp. in the liver of sheep (Ovis aries ) in a slaughterhouse in the state of Acre, Brazil

Although sheep farming has grown in the state of Acre over the past four decades, little is known about occurrences of helminthiases in the herds of this region. The objective of the study was to assess the occurrences of non-intestinal helminthiasis among sheep slaughtered in Rio Branco. A total of 110 sheep livers were inspected from two slaughter batches (july 2014 and march 2015) in a slaughterhouse in Rio Branco. Livers with macroscopic lesions were photographed and were then subjected to histopathological analysis under an optical microscope. The macroscopic lesions showed small nodes with inflammatory characteristics and areas of fibrosis, which appeared to be calcified, thus suggesting a granulomatous reaction. Of the 110 evaluated livers, we noticed 110 nodules in total; these nodules have an average size of 0.5 cm. The histopathological analysis showed alterations to the architecture of the hepatic lobe, with multiple foci of necrosis and polymorphonuclear cells. Two samples revealed the presence of helminths from Nematode class and Capillaria sp. eggs identified by the typical morphology and morphometry. This seems to be the first report of Capillaria sp. in sheep livers in Brazil, and it serves as an important alert regarding animal health surveillance and control and regarding the Capillaria sp. zoonotic role in humans.

Capillaria hepatica (Calodium hepaticum) infection in a horse: a case report

Background

Capillaria hepatica is a zoonotic parasite in humans and animals and has a worldwide distribution. However, infections in mammals apart from rodents, which are natural hosts of the parasite, have rarely been reported. This report describes the first known case of C. hepatica infection in a horse in Japan.

Case presentation

A 3-year-old filly without clinical signs was presented at a slaughterhouse in Japan. Gross examination revealed white to tan nodules 0.5 to 1.5 cm in diameter in the parenchyma of the liver. Histologically, the nodules had mature fibrous capsules and consisted of multifocal to coalescing granulomatous inflammations with numerous nematode eggs. The eggs were barrel shaped with an opercular plug on each end and double-layered shells; these findings are consistent with the features of C. hepatica eggs.

Conclusions

To our knowledge, this is the first case of C. hepatica infection in a horse in Japan. The pathological findings confirmed the presence of this pathogen in this part of the world, and they highlight the importance of this nematode in the differential diagnosis of hepatic granulomatous lesions in horses.

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.

Capillariaisis (Trichurida, Trichinellidae, Capillaria hepatica) in the Brazilian Amazon: low pathogenicity, low infectivity and a novel mode of transmission

Background

Human capillariasis caused by Capillaria hepatica (syn. Calodium hepaticum) is a rare disease with no more than 40 cases registered around the world. Classically, the disease has severe symptoms that mimic acute hepatitis. Natural reservoirs of C. hepatica are urban rodents (Mus musculus and Rattus novergicus) that harbor their eggs in the liver. After examining the feces of 6 riverine inhabitants (Rio Preto area, 8° 03'S and 62° 53' W to 8° 14'S and 62° 52'W) of the State of Rondonia, Brazil, and identifying C. hepatica eggs in their feces, the authors decided to investigate the real dimension of these findings by looking for two positive signals.

Methods

Between June 1^st and 15^th, 2008, 246 out of 304 individuals were clinically examined. Blood samples were collected, kept under -20°C, and test by the indirect immunofluorescence technique.

Results

The first positive signal was the presence of specific antibodies at 1:150 dilution, which indicates that the person is likely to have been exposed to eggs, most likely non-infective eggs, passing through the food chain or via contaminated food (total prevalence of 34.1%). A second more specific signal was the presence of antibodies at higher titers, thus indicating true infection.

Conclusions

The authors concluded that only two subjects were really infected (prevalence of 0.81%); the rest was false-positives that were sensitized after consuming non-embryonated eggs. The present study is the first one carried out in a native Amazonian population and indicates the presence of antibodies against C. hepatica in this population. The results further suggest that the transmission of the parasite occurs by the ingestion of embryonated eggs from human feces and/or carcasses of wild animals. The authors propose a novel mode of transmission, describing the disease as a low pathogenic one, and showing low infectivity.

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.