Intestinal establishment and reproduction of adult Trichinella spp. in single and mixed species infections in foxes (Vulpes vulpes)
ABSTRACT Intestinal establishment and reproduction of adult Trichinella spiralis, Trichinella nativa, Trichinella britovi and Trichinella pseudospiralis were examined as single species or mixed species infections in foxes. This is the first study of intestinal dynamics of Trichinella spp. in a carnivore model and the results suggest that the intestinal phase is relatively short as only very few worms were recovered 10 days post-inoculation (dpi). In mixed species infection with equal doses of T. nativa and T. spiralis, molecular typing demonstrated that 64% of the intestinal worms and 78% of the muscle larvae were T. nativa. Conversely, T. spiralis dominated in the mixed species infections with T. pseudospiralis, constituting 66% of the intestinal worms and 94% of the muscle larvae. Although, the individual recoveries of intestinal worms were only up to 5.6% on day 1, and up to 1.5% on day 4 post-infection, the muscle larvae establishment was comparable to other fox studies. Infectivity, measured as muscle larvae burden did not differ among the four species of Trichinella, which is in contrast to other models with mice, rats, pigs or herbivores. Although statistically significant differences in intestinal worm burdens were found for some days, no distinct species were recovered in consistently higher numbers than the others.
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ABSTRACT: Because of a lack of comprehensive surveys, the geographic distributions of the North American species of encapsulating Trichinella (T. nativa and its variant T6, T. murrelli, and T. spiralis) are poorly characterized in detail. These species are potentially zoonotic; therefore, biogeographic information is critical to monitoring their status and any distribution changes due to climatic and man-made environmental impacts. The maximum entropy (Maxent) program was used to model predicted ranges for these sylvatic Trichinella spp., using a limited number of available location records with confirmed species identifications collected over 55 yr throughout North America. The resulting prediction models were shown to be robust, and the species maps created are presented. The predicted range of T. nativa is primarily north of the 48 degrees - 52 degrees latitudes, overlapping the Tundra, sub-Arctic, and Warm Continental eco-regions. Its sympatric genotypic variant, T6, has a predicted range covering primarily the sub-Arctic and mountainous Temperate Steppe eco-regions, the latter extending below 48 degrees N latitude. In the east, the T6 range includes the Warm Continental and the mountainous Hot Continental eco-regions; the T6 range is also predicted to extend to the Sierra Madre Mountains of Mexico. The most probable range of T. murrelli is centered in the Midwest within the Hot Continental and Prairie eco-regions, with an extension southward to the Subtropical and Tropical/Subtropical Steppe and Desert eco-regions. In the west, it exists in a restricted range characterized as mountainous Mediterranean. The most probable distribution of sylvatic T. spiralis is along the humid east North American coast (Hot Continental south to Subtropical), and along the coast of northwest North America (Marine) to Alaska (subArctic and Tundra). Its most southerly range extends into central Mexico (Tropical/Subtropical Desert). The difference in relative freeze resistance between T. nativa/T6 and T. murrelli undoubtedly accounts for much of this geographic separation. However, the factors responsible for the absence of a more southerly distribution of T. nativa are not obvious, given the overlap in host range with T. murrelli. The maximum July temperature appears to have a significant effect on this distribution pattern. The results of the model building highlight subjects for future research on the biotic and abiotic factors important in determining Trichinella spp. distributions and directions for model validation research.Journal of Parasitology 08/2009; 95(4):829-37. DOI:10.1645/GE-1952.1 · 1.26 Impact Factor
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ABSTRACT: Blood samples of live-caught polar bears (Ursus maritimus) from Svalbard collected 1991-2000 (Period 1) and 2006-2008 (Period 2) and from the pack ice of the Barents Sea collected in Period 1, were assayed for antibodies against Trichinella spp. by ELISA. Of 54 cubs-of-the-year included in the Period 1 sample, 53 were seronegative, indicating that exposure to Trichinella infected meat is uncommon during the first months of life for polar bears in the Svalbard region. Of 30 mother-offspring pairs, 18 mothers were seropositive with seronegative offspring (n=27), suggesting (1) that maternal antibodies had dropped to levels below detection limit by the time of capture in April (offspring approximately 4 months old), and (2) supporting experimental studies in other animal models showing that vertical transmission of Trichinella spp. is uncommon. Bear 1 year and older had higher prevalence in Svalbard (78%) than in the Barents Sea (51%). There was no temporal change in prevalence for bears from Svalbard during the time between the two periods. The prevalence increased with age in both sexes. A positive correlation was found between anti-Toxoplasma gondii and anti-Trichinella spp. antibodies.Veterinary Parasitology 09/2010; 172(3-4):256-63. DOI:10.1016/j.vetpar.2010.05.018 · 2.55 Impact Factor
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ABSTRACT: This study was conducted to observe the localization and to compare methods for isolation of minute Ascaridia galli larvae in chicken intestine. Firstly, six 7-week-old layer pullets were orally infected with 2,000 embryonated A. galli eggs and necropsied either at 3, 5 or 7 days post infection (dpi). More than 95 % of the recovered larvae were obtained from the anterior half of the jejunoileum, suggesting this part as the initial predilection site for A. galli larvae. Secondly, the intestinal wall of one layer pullet infected with 20,000 A. galli eggs 3 days earlier was digested in pepsin-HCl for 90 min. The initial 10 min of digestion released 51 % of the totally recovered larvae and the last 30 min of continuous digestion yielded only 5 %. This indicates that the majority of larvae were located superficially in the intestinal mucosa. Thirdly, 48 7-week-old layer pullets were infected with 500 A. galli eggs and necropsied at 3 dpi to compare three different larval isolation methods from the intestinal wall, viz., EDTA incubation, agar-gel incubation and pepsin-HCl digestion, resulting in mean percentages of the recovered larvae: 14.4, 18.2 and 20.0 %, respectively (P = 0.15). As conclusion, we recommended Pepsin-HCl digestion as the method of choice for larval recovery from the intestinal wall in future population dynamics study due to high efficiency and quick and simple detection. The agar-gel method was considered to be a prerequisite for molecular and immunological investigations as the larvae were more active and fully intact.Parasitology Research 08/2012; 111(6). DOI:10.1007/s00436-012-3079-3 · 2.33 Impact Factor