The life cycle of Haplorchis pumilio (Trematoda: Heterophyidae) from the Indian region

The life cycle of the heterophyid fluke, Haplorchis pumilio is elucidated for the first time from the Indian region. Various stages in the life cycle were established based on observations made on natural infections found in snails and fish in a freshwater stream at Visakhapatnam, India and experimental infections carried out in the laboratory. The thiarid snail, Thiara tuberculata served as the first intermediate host and a wide range of freshwater fish as second intermediate hosts. Natural infections with adult flukes were found in the piscivorous birds Ardeola grayii and Bubulcus ibis. Adults were raised experimentally in day-old chicks. Distinguishing features of the cercaria of H. pumilio are: a large body size (200–224×92–96 μm), body–tail ratio of 1:2.1 and densely distributed pigment granules in the parenchyma imparting a brownish tinge to the body. Natural infections with metacercariae were found in the freshwater fish Channa punctatus, C. orientalis, Puntius sophore, Gambusia affinis and fingerlings of Cyprinus carpio and Liza macrolepis. Additionally, experimental infections were established in Therapon jarbua, Esomus danricus and Oreochromis mossambica. Metacercariae were embedded in the caudal muscles of fish and heavy infections induced mortality. Metacercariae were infective at about 15 days of age.

Observations on the life cycle of Grysoma indica n.sp. (Trematoda: Psilostomidae)

The life history of Grysoma indica n.sp., a psilostome trematode, obtained experimentally in ducklings, after feeding with metacercariae occurring in the snail Thiara tuberculata, is elucidated. Natural infections with cercariae were found in T. tuberculata, collected from a freshwater stream at Visakhapatnam, India. Metacercarial cysts were found in the same and other species of snails in the locality. The new species differs from other species of the genus in the sucker proportions, position of the testes and distribution of the vitelline follicles.

Prevalence of larval helminths in freshwater snails of the Kinmen Islands

A survey of larval helminths in freshwater snails of Kinmen was conducted from 1986 to 1987. Parasitological examinations of a total of 726 live snails collected from 25 loci revealed that 20 of 80 Bithynia fuchsiana were infected with metacercariae of Echinostoma gotoi and 36 with metacercariae of other echinostomes. Among 57 Radix auricularia swinhoei snails, 27 were infected with echinostomes and with metacercariae of other flukes. Of 20 Cipangopaludina chinensis, 18 were found with larvae of echinostomes. Larval trematodes were also found in three of 37 Austropeplea ollula and two of 87 Gyraulus spirillus. Third-stage larvae of Parastrongylus cantonensis were found in Ampullarius canaliculatus (5/103), Sinotaia quadrata (20/141), Hippeutis umbilicalis cantori (1/70) and Gyraulus spirillus (2/87). Segmentina hemisphaerula were not infected. Cercariae of Centrocestus formosanus, Haplorchis pumilio and xiphidiocercaria were found in three, two and two specimens, respectively, of 37 Thiara tuberculata.

Fasciola hepatica en ganado bovino de carne en Siquirres y lesiones anatomo-histopatológicas de hígados bovinos decomisados en mataderos de Costa Rica

El presente estudio fue realizado con el objetivo de determinar la infección por Fasciola hepatica (F. hepatica) en una finca dedicada al ganado de carne en el cantón de Siquirres, provincia de Limón para caracterizar las lesiones más comunes de hígados parasitados, en 3 plantas de sacrificio de bovinos del país. De agosto del 2005 a agosto del 2006, fueron recolectadas muestras fecales de 577 bovinos de razas cebuinas con edades entre 6 meses y 2,5 años. Cada muestra fue sometida a la técnica coprológica de sedimentación; también se buscaron y recolectaron moluscos con el objetivo de identificar la(s) especie(s) involucrada(s) en la transmisión del parásito en la finca. Asimismo, se recolectaron muestras de hígados bovinos infectados con el parásito en 3 mataderos del Valle Central, para el análisis histopatológico. F. hepatica fue diagnosticada en 67 (11,3%) de los 577 bovinos evaluados, y el porcentaje de infección fue mayor en agosto del 2005 (31,6%) y agosto del 2006 (26,2%). Además, los animales con edades entre 18 y 24 meses mostraron mayor frecuencia de infección (19,4%), mientras que los animales de 12 a menos de 18 meses mostraron la menor frecuencia de infección (2,4%). Los caracoles identificados fueron de la especie Thiara tuberculata, que no fue identificada como vector de F. hepatica. Las principales lesiones en los hígados decomisados fueron atrofia moderada de lóbulos hepáticos, aumento de consistencia, engrosamiento de ductos hepáticos con presencia de calcificación, material mucoso y formas adultas del parásito. Histológicamente corresponden a colangiohepatitis necrótica con formación de depósitos cálcicos distróficos e hiperplasia de ductos biliares. Con base en los resultados obtenidos se pudo determinar la presencia de F. hepatica en los bovinos de la finca y de la zona, con marcado incremento de la infección en la época lluviosa, además del hallazgo colateral de Paramphistomum spp.