An epidemiological focal study was performed in Loncopué, Neuquén, Argentina, in November 2002 to detect the origin of the infection in a human case of fascioliasis confirmed by an indirect-ELISA test, six months before the study. Thirty five individual fecal samples were taken from domestic livestock, and watercress plants and snails were collected from the irrigation ditches connected to a main canal in the surroundings of the patient’s house. A new blood sample was taken from the already recovered patient. The patient was still seropositive to Fasciola hepatica antigens. No metacercariae were found in the 222 watercress leaves checked. All the snails collected (n=130) were identified as Lymnaea viatrix and two out of 101 (2%) were infected with F. hepatica larvae. Coprological analysis showed F. hepatica eggs in 100% of goats (10/10), 82% of sheep (9/11) and 86% of bovines (6/7). The number of eggs per gram shed by positive goats (median=20.7, Q1=6.2, Q3=34.5) and sheep (4, 1.8, 13) was significantly higher than in cows (0.3, 0.3, 1.7) (p<0.01). Local veterinary control programs were apparently not effective in this case. Anthelmintics used and treatment schedule should be revised and small herds raised at households should also be included and treated.

El objetivo del trabajo fue realizar un estudio de foco relacionado con un caso de fasciolosis humana ocurrido en abril de 2002 en Loncopué, Neuquén, Argentina. La confirmación diagnóstica se efectuó en mayo de 2002 por el test de ELISA. En noviembre de 2002 se realizó un muestreo en el área rural donde se ubicaba la vivienda de la paciente, ya restablecida, y se le tomó una nueva muestra de sangre. El suero de la paciente continuó reactivo para antígenos de Fasciola hepatica. Se muestrearon plantas de berro para detectar metacercarias. Se recolectaron caracoles en cuatro canales de riego conectados a un canal principal. Los caracoles fueron trasladados vivos para su identificación, medición y examen de infección. Se recolectaron 35 muestras fecales de ganado de cría. No se observaron metacercarias en las hojas de berro examinadas (n=222). Se recolectaron 130 caracoles identificados como Lymnaea viatrix y 2 de 101 ejemplares (2%) estaban infectados con larvas de F. hepatica. Las prevalencias en el ganado adulto fueron: 100% (10/10) para caprinos, 82% (9/11) para ovinos y 86% (6/7) para bovinos. El número de huevos eliminados por las cabras (mediana = 20.7; Q1=6.2; Q3=34.5) y ovejas (4, 18, 13) infectadas, resultó mayor que el eliminado por vacas (0.3; 0.3; 1.7) (p<0.01). La práctica de control local no tuvo efecto aparente en este caso, por lo que deberían revisarse los calendarios de tratamiento y los antiparasitarios utilizados. Los resultados muestran que el ganado criado a pequeña escala por los pobladores debe incluirse en los programas de control. Se discute la posible importancia de la fasciolosis humana en Argentina.

We report the first finding of Lymnaea viatrix south of parallel 41ºS, in rural and urban areas from Argentina. Ninety snails were collected during year 2000, from a concrete pond at a Public Square in El Bolsón Village, Río Negro province, and 811 snails in November 1999, and during 2000 from waterbodies within a farm at Cholila locality, Chubut province. Fasciola hepatica infection was detected in 0.9% snails from the rural area. We discuss the potential risk of L. viatrix to public health in urban areas and its epidemiological importance in rural areas of the Andean Patagonian region.

The European hare Lepus europaeus was found naturally infected with Fasciola hepatica, but in Argentina no studies have ever been performed on this issue. In this work we evaluated the occurrence of infection in hares from the Andean Patagonian Region of Chubut Province. During 1999, 162328 hares from the northwest of the province were examined for F. hepatica juveniles and adults. In January and March 2001 faecal pellets were collected from waterbodies within a farm in northwestern Chubut province, where cattle and snail infection was already confirmed. Infection prevalence of the examined hares was 0.08% and six out of ten pellets from a temporary pond were positive for F. hepatica (epg median = 2). Despite the low prevalence of infection found, L. europaeus may play a significant role in the parasite transmission cycle, regarding that it shares the same habitats with livestock and snails, its abundance is high, and the density of eggs shed into the environment is higher than that of cattle

La liebre europea (Lepus europaeus) ha sido encontrada naturalmente infectada por Fasciola hepatica en varios países, pero en la Argentina no se han realizado estudios al respecto. Este trabajo tuvo por objetivo la búsqueda de infección en liebres de la zona cordillerana de la provincia del Chubut. Durante 1999 se faenaron 162.328 animales provenientes del noroeste de la provincia y se buscaron juveniles y adultos de F. hepatica. En enero y marzo de 2001 se recolectaron boñigas en cuerpos de agua de un establecimiento ganadero de la localidad de Cholila, al noroeste de la provincia del Chubut, donde estudios previos confirmaron la infección en ganado y caracoles. El 0,08% de las liebres faenadas presentó infección y en el ambiente se encontraron 6/10 boñigas positivas para F. hepatica en un charco (mediana de hpg = 2). A pesar de las bajas prevalencias halladas, el rol de L. europaeus en la transmisión del parásito podría ser importante si se considera que la especie comparte ambientes con el ganado y el caracol, su abundancia es alta, y la densidad de huevos que aporta al medio es mayor que la de bovinos

We report the first evidence of natural infection of Lymnaea columella with Fasciola hepatica in Argentina. A sample of 601 snails was collected in May 2003 in northeastern Corrientes, a province bounded on the north by Paraguay, on the east by Brazil and on the southeast by Uruguay. Among 500 examined snails, 44 (8.8%) were exclusively infected with F. hepatica. Parasite identification was based on morphological features of cercariae from snails, and of eggs and adult flukes from Wistar rats. We discuss the events suggesting that an enzootic transmission cycle of F. hepatica has been recently established in northeastern Corrientes.