Seasonal dynamics of the faecal excretion of Elaphostrongylus cervi (Nematoda, Metastrongyloidea) first stage larvae in Iberian red deer from South Spain. Parasitol Res

Instituto de Investigación en Recursos Cinegéticos IREC (CSIC-UCLM-JCCM), Ronda de Toledo s/n, 13005, Ciudad Real, Spain.
Parasitology Research (Impact Factor: 2.1). 02/2005; 95(1):60-4. DOI: 10.1007/s00436-004-1255-9
Source: PubMed


Elaphostrongylus cervi (Nematoda, Metastrongyloidea) is an extrapulmonary lungworm of red deer (Cervus elaphus) whose first-stage larvae (L1) require terrestrial gastropods as intermediate hosts. The seasonal pattern of fecal excretion of E. cervi L1 in Iberian red deer (Cervus elaphus hispanicus) was monitored during three annual periods (June 2000-May 2003) on a hunting estate from south-central Spain. The lowest rates of mean intensity of fecal L1 were found in summer, whereas no seasonal variation was found for prevalence. Monthly intensity of excretion was positively associated with early rainfall (the next month) rather than with rainfall of the same month. This seasonal rhythm of E. cervi L1 discharge may be the result of parasite adaptation to the seasonal Mediterranean climate and habitat constraints to improve the chance of parasite transmission. We have standardized the sampling period to compare E. cervi L1 infection rates of Iberian red deer populations in Mediterranean Spain, a natural limit of both the parasite and deer historical ranges, for potential use in the assessment of management strategies.

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    • "An isolated population of Iberian red deer managed for hunting purposes in south-central Spain was selected to evaluate the potential effect of hunting management schemes on the genetic diversity of a relatively recent founded population. This reference deer population has been studied by our group over the last 16 years and the population dynamics are well known (Landete-Castillejos et al., 2004; Vicente, Fierro & Gortazar, 2005). The MHC-II DRB-2 locus was selected for genetic analysis because it composes part of the functional important peptide binding groove, which has been shown to be the most polymorphic part in MHC-II genes (Klein, 1986) and its polymorphisms have been related to variation in parasite burdens in deer (Ditchkoff et al., 2005). "
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    ABSTRACT: The major histocompatibility complex (MHC) contains the most variable functional genes described in vertebrates. Individuals from natural populations deal constantly with a diverse range of pathogens and the polymorphism at MHC loci is what determines the diversity of foreign antigens that the host immune system can recognize. Polymorphism at individual loci may result in variable MHC class II (MHC-II) haplotypes. We characterized for the first time, the allelic diversity at the second DRB locus of the MHC-II in the Iberian red deer Cervus elaphus hispanicus. The studied population was sampled from a fenced estate that has been managed for hunting purposes and may provide information of the effect of game management on the genetic diversity of this species. Deer presented high levels of variation at MHC-II DRB-2 with 18 different alleles detected in 94 individuals. However, a significant heterozygous deficiency was found for MHC-II DRB-2 locus (92.5% of individuals only amplified one allele), whereas genotype frequencies at three neutral microsatellite loci were according to Hardy–Weinberg equilibrium, with heterozygosity over 50%. The analysis of control Iberian red deer from different geographic locations identified two expressed DRB-2 loci with a high degree of heterozygosis. The annual diversity index of MHC-II DRB-2 alleles significantly decreased along the 16-year study period, which was confirmed with losses in microsatellite markers. Although we cannot exclude positive non-assortative mating and/or substructured breeding (Wahlund effect) within our reference population, such unexpected apparent homozygosity at MHC DRB-2 loci is suggestive of null alleles occurring at our population. The observed pattern could be the result of a founder effect in this recently established population. Nonetheless, the loss of MHC-II DRB-2 allele diversity could reflect the effects of inbreeding in this fenced population managed for hunting. These findings support the importance of immunogenetic studies to assess management decisions, especially in isolated ungulate populations.
    Full-text · Article · Jan 2009 · Journal of Zoology
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    • "Current preventive measures applied before the release of farm-reared game birds (if they exist) are based on (1) a coprological analysis performed in feces collected in the aviary soil and (2) antiparasite treatment following the same protocol that is used in the case of poultry (Villanúa et al. 2007b). The first point of this protocol has the problem that there are a lot of factors such as host reproductive status (Ruíz de Ybañez et al. 2004), weather (Vicente et al. 2005), season (Kumba et al. 2003), random day-to-day variations (Giver et al. 2000), phase of the parasitic infection (Giver et al. 2000), or hour of sampling (Villanúa et al. 2006b) that can modify propagule excretion and are not always considered. In addition, the effectiveness of antiparasite protocols in game species is insufficient to prevent introducing parasites into the field as recently shown in the case of Albendazole treatment against A. caudinflata and H. gallinarum in redlegged partridges (Villanúa et al. 2007b). "
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    ABSTRACT: We studied the helminth community and body condition of 99 hunter-harvested red-legged partridges (Alectoris rufa) from Ciudad Real (Central Spain). Forty-six were sampled in two game estates where an important number of farm-reared red-legged partridges are released yearly. The remaining 53 were obtained from natural wild populations adjacent to one of the estates with releases. Four nematode species (Heterakis gallinarum, Aonchoteca caudinflata, Eucoleus contortus and Cheilospirura gruveli) and two cestode species (Raillietina (R.) tetragona and Skryabinia bolivari) were identified. The managed areas showed higher parasite diversity, with higher prevalences and intensities for all helminths found. Three of these species were typical of farm-bred partridges and two of these, A. caundinflata and S. bolivari, were found parasitizing adult partridges. This suggests introduction of these helminths into the breeding population of managed states. The birds sampled in the nonmanaged estates showed a better body condition, but no relation with parasite infection was found. Our results suggest that the release of farm-reared red-legged partridges, a strategy that is becoming a common practice in Spanish hunting areas, poses risk to wild populations because of introducing parasites. However, these results also suggest that simply stopping releases may be a good way to remove locally those parasites from populations, as the establishment of the introduced parasites seems limited.
    Full-text · Article · Apr 2008 · European Journal of Wildlife Research
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    • "Fresh faecal samples were collected from the rectum of the shot deer; L1 were extracted, identified and expressed as number of larvae per gram of faeces (Forrester & Lankester, 1997). The sampling period was limited to winter in order to avoid seasonal variations in parasite excretion (Vicente, Fierro & Gortazar, 2005). Spleen tissue samples were fixed in 10% neutral buffered formalin, dehydrated, embedded in paraffin wax and sectioned at 4 mm then were stained with haematoxylin-eosin and examined by light microscope (Bacha, William & Wood, 1990). "
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    ABSTRACT: ABSTRACT • In studies of birds and their pathogens, spleen size has frequently been used to make inferences about immune system strength. However, the use of spleen size in mammals is more complicated because, in addition to having an immune function, the mammalian spleen is also a reservoir for red blood cells. • To assess the reliability of mammalian spleen mass as an indicator of immune activity, we quantified the white and red pulp mass by histology of spleens from shot red deer Cervus elaphus. We then analysed the relationships among spleen mass, the amounts of white and red pulp, and the deer's body condition relative to faecal counts of the nematode parasite Elaphostrongylus cervi. • White and red pulp mass were positively correlated so that an increase in spleen mass was a positive function of both components of the spleen. In male deer, which had significantly lower body condition and higher parasite loads than females, parasite counts were negatively correlated with spleen mass, white pulp mass, and red pulp mass. • Our findings suggest that (i) spleen mass in shot red deer is a reliable measure of white and red pulp content; and (ii) when looking at the red deer life history, which is greatly influenced by sex of the deer, splenic mass and white pulp mass could be used as reflections of immune system strength. • Future studies of mammalian spleens can contribute to the understanding of evolved strategies of immune response investment in mammals. However, determination of the white and red pulp spleen components using various sampling methods must be made prior to their application.
    Full-text · Article · Oct 2007 · Mammal Review
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