ABSTRACT
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.
Subject(s)
Capillaria , Liver , Animals , Rats , Argentina/epidemiology , Goats , Microscopy/veterinaryABSTRACT
Sarcocystis spp. are intracellular protozoan parasites with an obligatory heteroxenous life cycle. The objective of this study was to identify Sarcocystis spp. in pig muscles from Argentina, by light and transmission electron microscopy (TEM), and molecular studies. Muscles samples from 561 pigs (Sus scrofa domestica) were classified according to the breeding system in: intensive farming (IF, n = 295; animals kept in confinement during most of their productive cycle), or semi-extensive farming (SEF, n = 266; animals bred outdoors, generally family or backyard production). Results showed that 24.8% (139/561) were positive by light microscopy, with a significantly higher prevalence in the SEF (34.6%; 92/266) than the IF pigs (15.9%; 47/295) (p < 0.05). Of the 202 samples analyzed by PCR, 96 were positive (47.5%) for the 18S rRNA (18S ribosomal RNA) fragment. All samples analyzed by the S. suihominis specific coxI (mitochondrial cytochrome c oxidase subunit I) PCR (n = 235; 96 positives by 18S rRNA PCR and 139 positives by light microscopy) were negative. Fourteen individual cysts were positive for the 18S rRNA PCR and sequenced. Consensus sequences obtained from the 18S rRNA fragment PCR ranged from 613 to 880 bp and showed 100% of identity between them and with previously reported S. miescheriana sequences. In all the pig samples analyzed by TEM, cyst wall ultrastructure was compatible with S. miescheriana. This is the first study that provides infection rates and describes and identifies morphological and molecular features of Sarcocystis spp. cysts in pigs from Argentina.
