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: 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
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ABSTRACT: Rats are selective hosts for Trichinella nativa; infection levels in their muscles remain low when compared to Trichinella spiralis. To identify in which phase of the life cycle the selective responses take place, rats were infected perorally (p.o.) and intravenously (i.v.) with T. spiralis and T. nativa. Six rats were placed in each group; three rats served as uninfected controls. The infection intensities were examined 5 or 6 weeks after the infection. T. spiralis muscle larva burden was 57 times higher compared to that of T. nativa after p.o. inoculation (mean larvae per gram ± SD, 1,243 ± 378.9 vs. 22 ± 21.5). In i.v. inoculation, 12 times more T. spiralis larvae reached the muscle than with T. nativa. Also, in vitro newborn larva (NBL) production at day 6 postinfection was analyzed for parasites originating from both rat and mouse. The mean number of in vitro-produced NBL of rat-origin T. spiralis during 24 h was 70 (95 % CI, 65-75) and of T. nativa, 23 (95 % CI, 21-24). Intriguingly, this difference was less obvious with mouse-origin female Trichinella. NBL production of mouse origin T. spiralis was 57 (95 % CI, 51-62) and T. nativa, 29 (95 % CI, 26-31). Intestine histology at day 40 post p.o. infection, serological response, and weight dynamics were indistinguishable between the Trichinella species but differed from controls. Our results show that the defense against T. nativa is not solely enteral in rats but may partly be explained by different reproduction processes for the two Trichinella species in rat.Parasitology Research 08/2012; DOI:10.1007/s00436-012-3080-x · 2.33 Impact Factor