Comparative infectivity of Fasciola hepatica metacercariae from isolates of the main and secondary reservoir animal host species in the Bolivian Altiplano high human endemic region

Abstract

Abstract. Fascioliasis due to Fasciola hepatica (Linnaeus, 1758) is an endemic disease on the Northern Bolivian Altiplano, where human prevalences and intensities are the highest known, sheep and cattle are the main reservoir hosts, and pigs and donkeys the secondary ones. Investigations were carried out to study the viability of metacercariae experimentally obtained from eggs shed by naturally infected Altiplanic sheep, cattle, pigs and donkeys. A total of 157 Wistar rats were infected with doses of 5, 10, 20 and 150 metacercariae. Metacercariae aged for different number of weeks were used to analyse the influence of age on their viability. The number of worms successfully developed in each rat was established by dissection. Results obtained show that metacercarial infectivity is dependent upon storage time, being lower when metacercariae are older. The maximum longevity is 31 weeks using doses of 20 metacercariae per rat and 48 weeks with 150 metacercariae per rat, although in the latter case only a very low percentage of worms is recovered. Age-related infectivity of metacercariae from Altiplanic F. hepatica does not significantly differ from that of the liver fluke in lowlands of other countries. Concerning the influence of the isolate according to host species, results indicate that metacercarial viabilities of pig and donkey isolates are similar to the viabilities of metacercariae of sheep and cattle isolates. Thus, pig and donkey have a high transmission potential capacity concerning this aspect. This fact is of great importance for the control of human and animal fascioliasis in this highly endemic zone.

CIAS detection of Fasciola hepatica/F. gigantica intermediate forms in bovines from Bangladesh

“…Although metacercarial infectivity does not appear to differ in isolates from different livestock species (Valero and Mas-Coma, 2000), the definitive animal host species is known to pronouncedly influence the phenotype of both adult stage and eggs of the liver fluke, mainly due to the different size of the liver duct microhabitat (Valero et al 2001a(Valero et al , 2002. For this reason, only parasites obtained from bovines were used in the principal component analysis carried out in the present study.…”

Immune Suppression in Advanced Chronic Fascioliasis: An Experimental Study in a Rat Model

“…These snails were, in turn, monomiracidially infected [16]. Six rats were infected with 20 metacercariae/rat, by use of an orogastric syringe [17]. Infection was established by the detection of eggs in feces.…”

Impact of climate change and man-made irrigation systems on the transmission risk, long-term trend and seasonality of human and animal fascioliasis in Pakistan

“…2). It should be considered that metacercariae may be viable for up to 48 weeks (Valero and Mas-Coma, 2000). However, the small risk peak presented by the two altitude stations of Rawalpindi and Jhelum in March should not be neglected.…”

“…Although different livestock species represent similar infection sources (Valero and Mas-Coma, 2000;Valero et al, 2001), animal species susceptibility should be considered. The livestock species influences fluke development and egg production and shedding (Valero et al, 1998(Valero et al, , 2002(Valero et al, , 2009).…”