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PubMedDate not supplied

Studies on Trichinella spiralis. I. Concerning the time and site of insemination of females of Trichinella spiralis. II. Time of initial recovery of larvae of Trichinella spiralis from blood of experimental animals. III. Effect on the intestinal phase of trichinosis of feeding massive numbers of irradiated trichina larvae. IV. Effect of feeding irradiated Trichinella larvae on production of immunity to re-infection. V. Tests for a strain of trichina larvae resistant to radiation.

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Animals↗
PubMed2003

Molecular identification of natural hybrids between Trichinella nativa and Trichinella T6 provides evidence of gene flow and ongoing genetic divergence.

To date, there are no data available on the population genetics of Trichinella due to the lack of genetic markers and the difficulty of working with such small parasites. In the Arctic region of North America and along the Rocky Mountains, there exist two genotypes of Trichinella, Trichinella nativa and Trichinella T6, respectively, which are well differentiated by biochemical and molecular characters. However, both are resistant to freezing, show other common biological characters (e.g. low or no infectivity to rodents and swine) and produce fertile F1 offspring upon interbreeding. To data, these two genotypes have been considered allopatric. In this study, we detected both genotypes in wolves of the same wolf packs in Alaska, suggesting sympatry. A single GTT trinucleotide present in the ITS-2 sequence of T. nativa but not in Trichinella T6 was used as a genetic marker to study gene flow for this character in both a murine infection model and in larvae from naturally-infected Alaskan wolves. Only F1 larvae originating from a cross between T. nativa male and Trichinella T6 female were able to produce F2 offspring. Larvae (F1) originating from a cross between Trichinella T6 male and T. nativa female were not reproductively viable. As expected, all F1 larvae showed a heterozygote pattern for the GTT character upon heteroduplex analysis; however, within the F2 population, the number of observed heterozygotes (n=52) was substantially higher than expected (n=39.08), as supported by the F(is) index, and was not in the Hardy-Weinberg equilibrium. Larvae from two of the 16 Trichinella positive Alaskan wolves, showed the Trichinella T6 pattern or the T. nativa/Trichinella T6 hybrid pattern. Our data demonstrate that T. nativa and Trichinella T6 live in sympatry at least in Alaskan wolves, where T. nativa occurs more frequently (69%) than Trichinella T6 (31%). One explanation for this phenomenon is that glacial periods may have caused a geographical relocation, colonisation and independent evolution of T. nativa within the Rocky Mountains, resulting in a bifurcation of the freeze-resistant genotype. Additional studies will be required to test this hypothesis.

Alaska↗
PubMed2005

Trichinella infection in a hunting population of Papua New Guinea suggests an ancient relationship between Trichinella and human beings.

A new Trichinella species, Trichinella papuae, was discovered in 11.5% of wild pigs in a remote region of Papua New Guinea. A survey was conducted to determine whether the inhabitants of this region are infected with Trichinella, as wild-pig meat represents their main source of protein. The prevalence of anti-Trichinella antibodies and its determinants were assessed among the inhabitants in 51 of the villages in the Morehead District of Papua New Guinea. We tested and interviewed 1536 people (28.8% of the adult population). Anti-Trichinella IgG were detected in 10.0% (95% Cl 8.5-11.6%) of them. The prevalence of seropositivity was higher in males (12.7%) than in females (7.5%) (P<0.01), and the seroprevalence significantly increased with age. In one area, seroprevalence was highest in villages nearest the hunting area in which wild pigs are infected with Trichinella papuae (P<0.01). Seropositivity was also correlated with the consumption of raw or undercooked meat. Persons reporting pain in the muscle joints and limbs were more likely to be seropositive; no severe clinical manifestations were observed. That infection was never severe suggests that the seropositive people are reinfected relatively often, but with very few larvae. If the epidemiological pattern of Trichinella infection observed among the hunting population of this area is any indication of the pattern of infection in prehistoric hunters, we can speculate that Trichinella infection due to the consumption of meat from wild animals was possibly a common disease among prehistoric populations.

Adolescent↗
PubMed2005

Evaluation of the infectivity of Trichinella papuae and Trichinella zimbabwensis for equatorial freshwater fishes.

The discovery of Trichinella species infecting poikilotherm vertebrates has opened new possibilities in the epidemiology of this parasite group. The aim of the present work was to investigate the infectivity of the two non-encapsulated species of Trichinella infecting both mammals and reptiles, Trichinella papuae and Trichinella zimbabwensis, for equatorial freshwater carnivore fishes. To this end, two species of piranhas, four Serrasalmus nattereri and four Serrasalmus rhombeus, were each inoculated per os with the two species of Trichinella larvae. Six days post infection (p.i.), one fish of each species inoculated with one of the two species of Trichinella was sacrificed. The intestines and celomatic cavities were searched for worms using dissection microscopy, and the presence of muscle larvae was evaluated by artificial digestion. The other 4 inoculated fish were sacrificed 60 days p.i. and similarly searched for the presence of worms. No larva or adult worms were detected in any organ or tissue at 6 or 60 days p.i. The lack of infectivity of T. papuae and T. zimbabwensis for fish suggests that the entozoic habitat of this animal does not represent a suitable environment for these two Trichinella species. More importantly, these data indicate that freshwater fishes, one of the food resources for crocodiles, caimans and alligators, are unlikely to play a role in the epidemiology of the known species of the genus Trichinella.

Animals↗
PubMed2000

Molecular investigation of African isolates of Trichinella reveals genetic polymorphism in Trichinella nelsoni.

Molecular genetic studies were carried out on three isolates of Trichinella nelsoni (from Kenya, Tanzania and South Africa) and three isolates of Trichinella T8 (from South Africa and Namibia) from sylvatic carnivores and from a sylvatic swine. A probe (pT7.3) specific for T. nelsoni was obtained by screening a pUC18 genomic library. The pT7.3 sequence was 346 bp in length with an AT content of 70%. The sequence is present approximately 200 times per haploid genome. Southern blot analysis of Hind III digested DNAs of the three isolates of T. nelsoni revealed that the hybridisation patterns of the isolates from Kenya and Tanzania were identical and that they differed from that of the isolate from South Africa, indicating the presence of polymorphism in this species. A pUC18 genomic library of Trichinella T8 was also screened, and one clone (pT8.3) was found to be specific for homologous DNA by dot blot, but Southern blot analysis of DNA samples from eight genotypes showed different hybridisation signals for both Trichinella T8 and Trichinella britovi DNAs. No differences in the nucleotide sequences of the expansion segment V were observed for the T. nelsoni isolates. However, they differed from those of Trichinella T8. The presence of Trichinella T8 in Africa south of the Sahara and its genetic relationship with T. britovi remain unclear and warrant detailed investigations.

Animals↗
PubMed1997

Trichinella spiralis (T1) and Trichinella T5: a comparison using animal infectivity and molecular biology techniques.

We compared Trichinella T5 of bobcat (Lynx rufus) origin with Trichinella spiralis (T1) by using animal infectivity and molecular biology techniques. Swine, SD rats, and CF1 mice were highly resistant to infection with Trichinella T5 but sensitive to T. spiralis, whereas deer mice (peromyscus maniculatus) had similar sensitivity to both parasites. The fecundity of Trichinella T5 in deer mice was 10-35-fold higher in comparison to the fecundity in laboratory rodents (SD rats and CF1 mice). Fecundity of T. spiralis was approximately the same in both groups. A western blot, using excretory-secretory proteins (ESP) from first-stage larvae of T. spiralis as antigen, showed similar banding patterns in the pigs infected with either T. spiralis or Trichinella T5, however, the homologous reaction was stronger than the heterologous reaction. Antibodies were detectable in swine sera commencing 3 or 5 wk postinfection with T. spiralis or Trichinella T5, respectively. Complementary DNAs encoding the 46-, 49/43-, or 53-kDa ESP showed 3.54, 1.94, and 5.91% differences, respectively, between the 2 parasites. Deduced amino acid sequences of the 3 cDNAs were different at 7.20, 5.08, and 8.55%, respectively. All recombinant proteins of the 3 cDNAs from both parasites could detect antibodies in positive sera. The sequences of cDNAs encoding the 46-, 49/43-, or 53-kDa ESP from T. spiralis are also compared to the previously reported sequences, and the differences are discussed.

Amino Acid Sequence↗
PubMed2006

Trichinella nativa and Trichinella T9 in the Hokkaido island, Japan.

Trichinella sp. muscle larvae were isolated from the thigh muscle of two red foxes (Vulpes vulpes) captured in Sapporo and Otofuke, Hokkaido, Japan, in 2003. Multiplex PCR designed for genotyping the genus Trichinella revealed that the Sapporo isolate showed a specific pattern to T. britovi complex (T. britovi, Trichinella T8 and Trichinella T9) and the Otofuke isolate showed that to T. nativa. Nucleotide sequences of a part of the mitochondrial cytochrome oxidase subunit I (COI) gene and internal transcribed spacer 2 (ITS2) of the Sapporo isolate showed the highest similarity to those of Trichinella T9, a species detected in the mainland of Japan. This study shows that both T. nativa and Trichinella T9 are circulating in wildlife of the Hokkaido island.

Animals↗
PubMed1989

Comparative assessment of a double antibody enzyme immunoassay test kit and a triple antibody enzyme immunoassay for the diagnosis of Trichinella spiralis spiralis and Trichinella spiralis nativa infections in swine.

Enzyme immunoassays using the triple antibody enzyme linked immunosorbent assay (ELISA) with both Trichinella spiralis spiralis and T. spiralis nativa excretory-secretory (ES) antigens and a commercial Trichinella spiralis enzyme immunoassay test kit were carried out on sera from pigs that were infected with light, moderate and high doses of infective T. spiralis spiralis and T. spiralis nativa respectively. Seroconversion occurred in all pigs given infective Trichinella larvae although no trichinae were recovered from pigs given T. spiralis nativa larvae and examined between days 92 and 99 postinfection by pepsin digestion. Anti-Trichinella antibodies were detected in pigs infected with T. spiralis spiralis and T. spiralis nativa by ELISA using either the homologous or heterologous ES antigen. The commercial Trichinella spiralis enzyme immunoassay test kit also detected anti-Trichinella antibodies in both the T. spiralis spiralis and T. spiralis nativa infected pigs. The commercial test kit did not appear to be as sensitive as the triple antibody ELISA since it usually took two to three days longer for seroconversion to be detected by the former procedure. Finally seroconversion occurred more rapidly in swine infected with T. spiralis spiralis than with pigs receiving comparable doses of T. spiralis nativa.

Animals↗
PubMed1996

Environmental and human influence on the ecology of Trichinella spiralis and Trichinella britovi in Western Europe.

Surveys on Trichinella parasites in domestic and sylvatic animals collected in France, Italy, and in the Extremadura region of Spain showed that the distribution of Trichinella spiralis and Trichinella britovi is influenced by both environmental and human behaviour factors. In France, both Trichinella species are prevalent in the fox population from mountain areas and natural parks but are infrequent in wild boars (< 0.001%). In Italy, only T. britovi is present in sylvatic animals (foxes, wolves, and mustelids) living 500 m above sea level. This species is rare in wild boars (< 0.001%) in that area. Sylvatic trichinellosis is found in only 24% and 34% of French and Italian territory, respectively, while lowland areas may generally be considered Trichinella-free, because the domestic cycle is absent. The ecology of T. spiralis and T. britovi in the Extremadura shows a different picture from that observed in France and Italy because of the presence of both domestic and sylvatic cycles. The domestic cycle not only allows the maintenance of T. spiralis in the domestic environment, but it also has a great impact on the prevalence in wild boar populations. It does not influence the prevalence in vulpine populations. These data suggest (1) that domestic trichinellosis occurs only in rural areas of Western Europe in association with traditional swine-rearing practices, but not in industrialized pig farms; (2) that sylvatic trichinellosis occurs only in natural habitats which, in Western Europe, are widespread in mountain areas; (3) that the fox is the primary reservoir in the sylvatic cycle, where the parasite is maintained in a closed circuit and (4) that among sylvatic animals T. spiralis is present at lower altitude than is T. britovi.

Animals↗
PubMed2000

Trichinella spiralis and Trichinella pseudospiralis: developmental patterns of enzymes involved in thymidylate biosynthesis and pyrimidine salvage.

Thymidylate synthase, dihydrofolate reductase and dUTPase specific activities were found to remain at a high and constant level in crude extracts from adult worms of Trichinella spiralis, as well as from muscle larvae of both Trichinella spiralis (isolated 1-24 months after infection) and Trichinella pseudospiralis (isolated 5.5-13 months after infection). The results obtained with Trichinella pseudospiralis muscle larvae isolated with the use of pepsin did not differ from those obtained when pepsin was not used. No thymidine kinase activity could be detected in muscle larvae of either species and thymidine phosphorylase could be found only in T. pseudospiralis larvae isolated without the use of pepsin. Muscle larvae of both species contained orotidylate phosphoribosyl transferase activity, pointing to a possibility of 5-fluorouracil activation. Uridine phosphorylase, another enzyme involved in 5-fluorouracil anabolism, was also present in T. pseudospiralis muscle larvae. Results of comparative studies on inhibition of purified T. spiralis and rat thymidylate synthases by substrate (4-thio-5-fluoro-dUMP, 2-thio-5-fluoro-dCMP and N4-hydroxy-dCMP) and cofactor (ZD 9331) analogues indicated only dUMP analogues to show feeble selectivity towards the parasite enzyme. A hypothesis is discussed, assuming high expression of thymidylate synthase in muscle larvae to be connected with their cells being arrested in the cell cycle.

Animals↗
PubMed1998

[Genetic variability of Trichinella spiralis Oven, 1835, and Trichinella pseudospiralis Garkavi, 1972, detected by polymerase chain reaction with random primers].

DNA polymorphisms in two parasitic nematode species, Trichinella spiralis Oven, 1835, and Trichinella pseudospiralis Garkavi, 1972, were revealed via random amplification of polymorphic DNA by the polymerase chain reaction (RAPD PCR). The diagnostic value of seven 10-bp oligonucleotide primers was evaluated, and the extent of the homology between the genomes of the two species was estimated. The intraspecific variation of RAPD markers was revealed in larvae of both species isolated from experimentally infected white rats. The variation was higher in larvae from nonlinear rats than in larvae from linear rats. When animals were infected with both Trichinella species simultaneously, "hybrid" progeny were obtained that had capsule that somewhat differed in shape from one characteristic of the parental species, T. spiralis. In RAPD spectra, the hybrids showed higher similarity of T. spiralis than to T. pseudospiralis. Intra- and interspecific differentiation, genome divergence, and factors inducing the intraspecific variation in Trichinella species are discussed.

Animals↗
PubMed1988

Trichinella spiralis infections of inbred mice: immunologically specific responses induced by different Trichinella isolates.

The immune response of inbred mice was studied following infection with Trichinella spiralis var. pseudospiralis (TP) or with isolates of T. spiralis derived from a pig or from an arctic fox. Animals given a primary infection with 1 isolate of Trichinella and challenged 21 days later with the same or different isolates responded more quickly by expelling worms from the homologous challenge. In addition, although mesenteric lymph node cells from mice infected with each isolate of Trichinella would proliferate in vitro when cultured with antigen derived from each of the others, the strongest proliferation response always occurred when cells were cultured in the presence of antigen prepared from the specific isolate used to infect the mouse from which the cells were derived. In addition, it was possible to prepare monoclonal antibodies that recognized an antigen expressed by TP which was not shared by T. spiralis isolates and vice versa. Collectively, these data support the conclusion that the differences observed in the kinetics of immune responsiveness to different Trichinella isolates are referable, at least in part, to differences among the isolates in the expression of functionally relevant antigens.

Animals↗
PubMed1993

[Comparison of numbers of active lymphocytes B in spleen of mice infected with Trichinella pseudospiralis or Trichinella spiralis].

The experiments were performed on BALB/c mice (male, 20 g body weight). The mice were infected 23 days before the experiment by peroral application of about 100 Trichinella larves. Control group consisted of not infected mice. The number of lymphocytes B producing antibodies was determined according to Cunningham and Szenberg. Five days before performance of the test, all mice were immunized by peritoneal application of sheep erythrocyte suspension. After that the mice were sacrificed, spleen was isolated and cellular suspension was prepared which was then introduced to the chamber in presence of sheep erythrocytes and guinea pig complement. After one hour incubation clearance appearing around active lymphocytes B was counted. Results were expressed in percentages, accepting as 100% number of clearances in not infected mice. It was found that number of clearances was reduced to 40% in mice infected with Trichinella pseudospiralis and to 46% in animals infected with Trichinella spiralis. Similar results were obtained in mice to whom lipid fraction of Trichinella extract containing prostaglandins was applied. These results indicate immunosuppressive influence of invasion on mice organism and also on the role of prostaglandins in evoking this immunosuppression.

Animals↗
PubMed2006

Trichinella spiralis and Trichinella pseudospiralis mixed infection in a wild boar (Sus scrofa) of Germany.

A wild boar (Sus scrofa) from the island Usedom in Mecklenburg-Western Pomerania (north-east Germany) was detected as Trichinella-positive during routine meat inspection. Encapsulated and non-encapsulated larvae were detected in the muscle tissue by trichinoscopy. In the diaphragm, 922 larvae per g were detected by artificial digestion. Muscle larvae displayed two different sizes of about 700 and 1100 microm. By a multiplex PCR analysis, larvae with a large size were identified as Trichinella spiralis, whereas those of a smaller size were identified as Trichinella pseudospiralis. This is the first finding of a mixed infection of T. spiralis and T. pseudospiralis in a naturally infected animal and it supports the tendency of more frequent detection of the non-encapsulated species T. pseudospiralis in Europe.

Abattoirs↗
PubMed1994

The effect of Trichinella spiralis and Trichinella pseudospiralis on the mechanical properties of mammalian diaphragm muscle.

The isometric mechanical properties of diaphragm muscle were studied in mice infected with either Trichinella spiralis or Trichinella pseudospiralis. Measurements of muscle stress were taken at 15, 20, 30 and 40 days post-infection. Infected diaphragm muscle showed a significant (P < 0.001) reduction in muscle stress during both twitch and tetanic contractions when compared with muscle from control animals. T. spiralis caused a significant reduction in resistance to muscle fatigue. The consequences of these changes in muscle function to host pathology are discussed, and related to previous work on the effects of Trichinella on host biochemistry and the immune response.

Animals↗
PubMed1997

Evidence of potential gene flow in Trichinella spiralis and in Trichinella britovi in nature.

During a study on the epidemiology of trichinellosis in Spain, 91 animals and 9 samples of sausages homemade with pork were found positive for Trichinella. Parasite identification at the species level was carried out by the polymerase chain reaction with a random primer on single muscle larvae. Seventy-one animals harbored Trichinella spiralis (17 domestic pigs, 53 wild boars, 1 fox), and 17 were infected with Trichinella britovi (1 domestic pig, 13 wild boars, 3 foxes). Sausages were infected with T. spiralis. Three wild boars (3.3% of infected animals) harbored both species. The presence of both T. spiralis and T. britovi in the same host suggests that infections with 2 isolates of the same species can also occur, permitting the gene flow within the species.

Animals↗
PubMed2006

Comparative analysis of the excretory-secretory proteome of the muscle larva of Trichinella pseudospiralis and Trichinella spiralis.

The nematodes Trichinella spiralis and Trichinella pseudospiralis are both intracellular parasites of skeletal muscle cells and induce profound alterations in the host cell resulting in a re-alignment of muscle-specific gene expression. While T. spiralis induces the production of a collagen capsule surrounding the host-parasite complex, T. pseudospiralis exists in a non-encapsulated form and is also characterised by suppression of the host inflammatory response in the muscle. These observed differences between the two species are thought to be due to variation in the proteins excreted or secreted (ES proteins) by the muscle larva. In this study, we use a global proteomics approach to compare the ES protein profiles from both species and to identify individual T. pseudospiralis proteins that complement earlier studies with T. spiralis. Following two-dimensional gel electrophoresis, tandem mass spectrometry was used to identify the peptide spots. In many cases identification was aided by the determination of partial peptide sequence from selected mass ions. The T. pseudospiralis spots identified included the major secreted glycoproteins and the secreted 5'-nucleotidase. Furthermore, two major groups of T. spiralis-specific proteins and several T. pseudospiralis-specific proteins were identified. Our results demonstrate the value of proteomics as a tool for the identification of ES proteins that are differentially expressed between Trichinella species and as an aid to identifying key parasite proteins that are involved in the host-parasite interaction. The value of this approach will be further enhanced by data arising out the current T. spiralis genome sequencing project.

Animals↗