Ecological Analysis of the Helminth Community of Microtus lusitanicus (Gerbe, 1879) (Rodentia) in Asturias (NW Spain).

The Lusitanian pine vole, Microtus lusitanicus, an endemic fossorial rodent of the Iberian Peninsula, has a burrowing behaviour and prefers to live underground. It feeds on bark and roots causing severe damage to trees. In Asturias (NW Spain), where M. lusitanicus is considered a pest in several orchards, a faunistic-ecological study was carried out to describe the helminth community of this species and the main factors that could influence its helminth component species. For this purpose, our own collection of 710 voles from several orchards of various locations in Asturias was used. Eight helminth species, four cestodes and four nematodes, were found. Statistical non-parametric tests were used to analyse the effects of extrinsic and intrinsic factors on the diversity of the helminth community and species prevalence and abundance. The results show the influence of climate variables, the year and season of capture, as well as host age, on the diversity of the helminth community and the infection parameters of some helminth species, underlining the importance of their life cycles. In addition to shedding light on the helminth community of this rodent in Asturias, the results obtained could be used to improve the biological methods applied to fight the M. lusitanicus pest.

First spermatological data on the digenean genus Ityogonimus derived from the description of sperm characters of Ityogonimus ocreatus (Brachylaimidae: Ityogoniminae).

The present study describes the ultrastructural organization of the spermatozoa of the brachylaimid digenean Ityogonimus ocreatus (Ityogoniminae) by means of transmission electron microscopy (TEM). Live digeneans were collected from the digestive tract of an Iberian mole Talpa occidentalis (Eulipotyphla, Talpidae) captured accidentally during a vole pest control campaign in Priesca (Asturias, Spain). The TEM study reveals that the I. ocreatus sperm are filiform, tapered at both extremities, and have two 9+'1' trepaxonematan axonemes, external ornamentation of the plasma membrane associated with cortical microtubules, spine-like bodies, two bundles of parallel cortical microtubules and one mitochondrion overlapping the anterior part of the nucleus. The external ornamentation of the plasma membrane is located in the posterior part of the anterior region. The maximum number of parallel cortical microtubules (45) is located in the anterior part of the sperm cells. Our results are compared with the available data on the family Brachylaimidae, especially on the other Ityogoniminae studied to date (Scaphiostomum palaearcticum).

Mercury, Lead and Cadmium Concentrations in Talpa occidentalis and in Their Digeneans of the Genus Ityogonimus.

INTRODUCTION: Many parasites living in aquatic ecosystems are useful indicators of environmental health. On the other hand, information is scarcer with respect to the use of helminth parasites of vertebrates living in terrestrial ecosystems as monitoring tools for toxic element environmental pollution. The present study evaluates the suitability of the model Talpa occidentalis/Ityogonimus spp. as a bioindicator system for mercury (Hg), lead (Pb) and cadmium (Cd) contamination in agricultural soils from Asturias (Spain). METHODS: Kidney and liver samples collected from T. occidentalis specimens (n = 36) and Ityogonimus spp. samples collected from 14 infected hosts were analyzed by ICP-MS. RESULTS: The highest mean levels of Hg and Pb were found in Ityogonimus individuals (20.9 and 12.4 µg g-1 wet weight, respectively). Considering renal and hepatic concentrations in T. occidentalis, bioaccumulation factors of Ityogonimus for Hg were 83.7 and 58.6, respectively, whereas concerning Pb bioaccumulation factors were 38.2 and 82.9, respectively. No bioaccumulation was detected in Ityogonimus in the case of Cd. CONCLUSIONS: More studies involving digenean parasites of small mammals are needed, especially when biomonitoring environmental toxic element pollution in terrestrial ecosystems. The present results support the above-mentioned model as a suitable biomonitoring system to evaluate environmental Hg and Pb contamination in terrestrial non-urban Iberian habitats. Similar models involving other species (Talpa spp./Ityogonimus spp.) might be used in a much wider geographical range.

First finding of Ityogonimus lorum and I. ocreatus co-infection in the Iberian mole, Talpa occidentalis.

The Ityogonimus lorum-I. ocreatus co-infection is reported for the first time in the Iberian mole Talpa occidentalis in Asturias (NW Spain). Both Ityogonimus species are stenoxenous helminths of insectivores of the genus Talpa and they have often been found parasitizing the Iberian mole and also the European mole T. europaea, but a mixed infection had not been previously reported. The present study also highlights the main differential morphometric characteristics between I. lorum and I. ocreatus such as the body length, the ventral sucker diameter, the ratio between suckers and the distance between suckers.