Lead concentrations in Hymenolepis diminuta adults and Taenia taeniaeformis larvae compared to their rat hosts (Rattus norvegicus) sampled from the city of Cairo, Egypt

Abstract

Concentrations of lead, determined by electrothermal atomic absorption spectrometry, were compared between the cestodes Hymenolepis diminuta and Taenia taeniaeformis and its host rat (Rattus norvegicus). Rats were sampled at 2 sites, which differed in respect to lead pollution as quantified from road dust, adjacent to the city of Cairo, Egypt. Comparing lead levels among host tissues and the parasites the significantly highest accumulation was found in H. diminuta, followed by rat kidney and larvae of T. taeniaeformis. Calculation of bioconcentration factors showed that H. diminuta contained 36-, 29-, 6- and 6-fold higher lead levels than intestinal wall, liver, kidney and larvae of T. taeniaeformis, at the more polluted site. At the less contaminated site lead bioconcentration factors for H. diminuta were found to be 87, 87 and 11 referred to intestine, liver and kidney of the host. Due to a high variability of the lead concentrations in H. diminuta it was not possible to indicate differences in metal pollution between both sampling sites. This variability may be influenced by different age structures of cestode infrapopulations. It is likely that younger worms contain lower metal levels than older worms due to a shorter exposure period. Thus, it is necessary to standardize the sampling of worms which should be used for indication purposes. Due to a lack of adequate sentinel species in terrestrial habitats more studies are required to validate and standardize the use of helminths as accumulation bioindicators in order to obtain mean values with low standard deviations. The host-parasite system rat-H. diminuta appears to be a useful and promising bioindication system at least for lead in urban ecosystems as rats as well as the tapeworm are globally distributed and easily accessible.

Cadmium and lead concentrations in Gallegoides arfaai (Cestoda: Anoplocephalidae) and Apodemus sylvaticus (Rodentia: Muridae) from Spain

“…According to our results, G. arfaai presented 6, 20 and 24 times more lead than that detected in the kidney, liver and muscle of A. sylvaticus from not especially polluted areas of Catalonia. These values are comparable with those (6 and 29-fold higher lead levels in H. diminuta as compared with kidney and liver of R. rattus) reported by Sures et al (2003) in Helban, a highly polluted area of Cairo, Egypt. Thus, according these and the present results, it seems that cestodes of rodents may be considered suitable sentinel organisms of environmental lead pollution.…”

“…Thus, according these and the present results, it seems that cestodes of rodents may be considered suitable sentinel organisms of environmental lead pollution. Sures et al (2003) reported a particularly high variability in lead concentrations in H. diminuta with relative standard deviations ranging between 112% and 135%. These authors also emphasised the need to standardise the sampling procedures for cestodes used as sentinel species, and proposed the use of worms of approximately the same length, thus reflecting a measure of age.…”

Cadmium and lead concentrations in Moniliformis moniliformis (Acanthocephala) and Rodentolepis microstoma (Cestoda), and in their definitive hosts, Rattus rattus and Mus domesticus in El Hierro (Canary Archipelago, Spain)

“…Also considering the terrestrial compartment, the system Rattus norvegicus/Hymenolepis diminuta was the first host/cestode system to be evaluated for its possible capacity of Pb accumulation both under experimental conditions (Sures et al 2002) and in the field (Sures et al 2003). The latter was performed in the city of Cairo (Egypt) and the evaluated host-parasite model was confirmed as a promising bioindicator system for Pb in urban ecosystems (Sures et al 2003).…”

“…The latter was performed in the city of Cairo (Egypt) and the evaluated host-parasite model was confirmed as a promising bioindicator system for Pb in urban ecosystems (Sures et al 2003). Other subsequent field studies included cestode parasites of rodents (Apodemus sylvaticus; Torres et al 2004Torres et al , 2006, lagomorphs (Oryctolagus cuniculus; Eira et al 2005) and terrestrial urban birds (Columba livia; Torres et al 2010).…”

“…Therefore, the available information about systems involving rodents and some of their helminth parasites is scarce. In fact, few experimental (Scheef et al 2000;Sures et al 2000aSures et al , 2002 and field studies (Sures et al 2003;Torres et al 2004Torres et al , 2006 have been performed using cestode and acanthocephalan parasites of rodents. This general lack of information motivates the need for further studies on organisms or models that may reflect small-scale differences in heavy metal pollution in terrestrial ecosystems.…”