Rattus norvegicus como indicador de la circulación de Capillaria hepatica y Taenia taeniaeformis en la Plaza Minorista de Medellín, Colombia

Zoonotic nematode in the city of La Plata, Argentina: Report of a case of Calodium hepaticum in Rattus rattus

This study describes a case of Calodium hepaticum (Trichinellida: Capillariidae) infection in an adult rat (Rattus rattus) from the periurban area of the city of La Plata in the province of Buenos Aires, Argentina. The rat was found with neurological signs (ataxia, lethargy, and episodes of unresponsiveness) in the food storage of a goat production facility. The liver was observed with hepatomegaly and diffuse and irregular yellowish-white spots appearing in striae or small nodules on the external surface and inside the liver. Subsequent microscopic and histopathological studies were performed. Eggs were observed by direct microscopy of the impression smear of liver tissue. A multifocal granulomatous tissue reaction with different stages of fibrocellular tissue was observed in the liver parenchyma. The granulomas contained adults and degenerated eggs delimited by an intense infiltrate of mononuclear cells. Macro and microscopic observations and histopathological liver lesions were compatible with C. hepaticum infection. To our knowledge, this is the first confirmation of C. hepaticum infection in R. rattus in Argentina, increasing the host record of this parasite and a new record of distribution in goat production systems in the country.

Variability of Calodium hepaticum eggs from sigmodontine host species through geometric morphometric analysis

Calodium hepaticum is a zoonotic nematode with a worldwide distribution. Although the host range of C. hepaticum includes a wide spectrum of mammals (including humans), this parasite is predominantly associated with the families Muridae and Cricetidae. Several Sigmodontinae species from Argentina were found to be infected by C. hepaticum, with a high prevalence in Akodon azarae. The present study focuses on C. hepaticum eggs from natural infection of three species of sigmodontine rodents from Argentina. Eggs were genetically characterized (intergenic 18S rRNA region). The objectives of this work are: (i) to propose a new analytical methodology; and (ii) to morphologically characterize C. hepaticum eggs, from three Sigmodontinae species (A. azarae, Calomys callidus and Oligoryzomys flavescens). Analyses were made by the Computer Image Analysis System based on the new standardized measurements and geometric morphometric tools. The resulting factor maps clearly illustrate global size differences in the parasite eggs from the three Sigmodontinae species analysed. The degree of similarity between egg populations was assessed through pairwise Mahalanobis distances, showing that the largest distances were detected between parasite eggs from C. callidus and O. flavescens. Herein, the phenotypical plasticity of C. hepaticum eggs is shown. Significant positive correlations were obtained between each egg parasite principal component 1 and rodent corporal characteristics: weight; liver weight; rodent length; and rodent body condition. The usefulness of the geometric morphometric analysis in studies of the relationship between C. hepaticum and its host must be highlighted. The high prevalence observed in A. azarae, associated with the wide size range of the parasite eggs evidenced by principal component analysis, suggests A. azarae to be the Sigmodontinae host species that plays the most important role as reservoir host for C. hepaticum in the New World.

Enzootic Hepatic Capillariasis (Calodium hepaticum) in Street Rats (Rattus norvegicus) from Marseille City, France

Hepatic capillariasis is a rare and neglected zoonosis affecting wild and synanthropic small rodents. It is caused by infection with Calodium hepaticum in liver. Despite the worldwide distribution of the host Rattus norvegicus (brown or street rats) in the urban area, the epidemiological status of this parasitosis remains unknown. In the present study, we examined a total of 27 brown rats from the city centre and a garden (four km from the city centre) of Marseille, France. All rats were autopsied and 52% showed the presence of C. hepaticum eggs in the liver. This result draws general attention to public health risks, since street rats are living near the human population.

Intrinsic and extrinsic factors related to pathogen infection in wild small mammals in intensive milk cattle and swine production systems

BACKGROUND

Understanding the ecological processes that are involved in the transmission of zoonotic pathogens by small mammals may aid adequate and effective management measures. Few attempts have been made to analyze the ecological aspects that influence pathogen infection in small mammals in livestock production systems. We describe the infection of small mammals with Leptospira spp., Brucella spp., Trichinella spp. and Cysticercus fasciolaris and assess the related intrinsic and extrinsic factors in livestock production systems in central Argentina at the small mammal community, population and individual levels.

METHODOLOGY/PRINCIPAL FINDINGS

Ten pig farms and eight dairy farms were studied by removal trapping of small mammals from 2008 to 2011. Each farm was sampled seasonally over the course of one year with cage and Sherman live traps. The 505 small mammals captured (14,359 trap-nights) included three introduced murine rodents, four native rodents and two opossums. Leptospira spp., anti-Brucella spp. antibodies and Trichinella spp. were found in the three murine rodents and both opossums. Rattus norvegicus was also infected with C. fasciolaris; Akodon azarae and Oligoryzomys flavescens with Leptospira spp.; anti-Brucella spp. antibodies were found in A. azarae. Two or more pathogens occurred simultaneously on 89% of the farms, and each pathogen was found on at least 50% of the farms. Pathogen infections increased with host abundance. Infection by Leptospira spp. also increased with precipitation and during warm seasons. The occurrence of anti-Brucella spp. antibodies was higher on dairy farms and during the winter and summer. The host abundances limit values, from which farms are expected to be free of the studied pathogens, are reported.

CONCLUSIONS/SIGNIFICANCE

Murine rodents maintain pathogens within farms, whereas other native species are likely dispersing pathogens among farms. Hence, we recommend preventing and controlling murines in farm dwellings and isolating farms from their surroundings to avoid contact with other wild mammals.

Reappraisal of Hydatigera taeniaeformis (Batsch, 1786) (Cestoda: Taeniidae) sensu lato with description of Hydatigera kamiyai n. sp

The common cat tapeworm Hydatigera taeniaeformis is a complex of three morphologically cryptic entities, which can be differentiated genetically. To clarify the biogeography and the host spectrum of the cryptic lineages, 150 specimens of H. taeniaeformis in various definitive and intermediate hosts from Eurasia, Africa and Australia were identified with DNA barcoding using partial mitochondrial cytochrome c oxidase subunit 1 gene sequences and compared with previously published data. Additional phylogenetic analyses of selected isolates were performed using nuclear DNA and mitochondrial genome sequences. Based on molecular data and morphological analysis, Hydatigera kamiyai n. sp. Iwaki is proposed for a cryptic lineage, which is predominantly northern Eurasian and uses mainly arvicoline rodents (voles) and mice of the genus Apodemus as intermediate hosts. Hydatigera taeniaeformis sensu stricto (s.s.) is restricted to murine rodents (rats and mice) as intermediate hosts. It probably originates from Asia but has spread worldwide. Despite remarkable genetic divergence between H. taeniaeformis s.s. and H. kamiyai, interspecific morphological differences are evident only in dimensions of rostellar hooks. The third cryptic lineage is closely related to H. kamiyai, but its taxonomic status remains unresolved due to limited morphological, molecular, biogeographical and ecological data. This Hydatigera sp. is confined to the Mediterranean and its intermediate hosts are unknown. Further studies are needed to classify Hydatigera sp. either as a distinct species or a variant of H. kamiyai. According to previously published limited data, all three entities occur in the Americas, probably due to human-mediated introductions.

OCCURRENCE OF Calodium hepaticum (BANCROFT, 1893) MORAVEC, 1982 EGGS IN FECES OF DOGS AND CATS IN LAGES, SANTA CATARINA, BRAZIL

This study aims to report the incidence of Calodium hepaticum among dogs and cats, pets or stray animals, captured by the Zoonosis Control Center (CCZ) in Lages, Santa Catarina, Brazil. Fecal samples from 108 pet dogs and eight pet cats, and from 357 stray dogs and 97 stray cats, captured by CCZ, were analyzed within the period from July 2010 to November 2012. Coproparasitological exams were performed by techniques of sedimentation, centrifuge-flotation, and simple flotation. Among 465 fecal samples from dogs and 105 from cats, the overall spurious infections for C. hepaticum eggs were 1.05%. For dogs, this positivity was 0.43% and for cats it was 3.81%. The two positive dogs were stray and out of the four cats, three were stray and one was a pet. Although the occurrence of C. hepaticum eggs was low, these data reveal the existence of infected rodents, especially in public places, since, out of the six infected animals, five (83.33%) were stray. These results are discussed and analyzed with an emphasis on the risk to public health.