Prevalence of Trichinella spp. in red foxes and wild boars in the northwestern part of Poland

The aim of the study was to establish in which degree wild boars and red foxes are reservoir of Trichinella spp. in North-West Poland. Research was carried out between 1997 and 2004 on 505 foxes and 56,462 wild boars in muscle samples. The muscle samples were examined using the digestion method. The average prevalence rate of Trichinella spp. infection of foxes was 4.4 %. Large differences of the infection rate in wild boars were observed. In the years 1999-2001 Trichinella spp. larvae were observed in 58 animals (0.2 %) and between 2002 and 2004 the Trichinella spp. prevalence in 227 wild boars was 0.9 %, demonstrating that the animals were 5.1 times more often infected than in 1999-2001. The growth of red fox population after the oral vaccination against rabies was probably the cause of this phenomenon.     

Survey for Trichinella spp. in red foxes (Vulpes vulpes) in Belgium.

Concurrently with a survey for Echinococcus multilocularis in the red fox (Vulpes vulpes) in Flanders, northern Belgium, serological and parasitological analyses for Trichinella spp. were carried out from 1996 to 1999. Muscle samples from foxes in Wallonia, southern Belgium, were obtained during a survey for rabies and alveolar echinococcosis from 1998 to 2000.In muscle samples from tongue, diaphragm, hindlegs and tail of 179 Flemish foxes no larvae were found by trichinoscopy. Serum and muscle juice of, respectively 176 and 26 animals were examined using an ELISA for the detection of antibodies against excretory-secretory (ES) antigen. There were eight (4.5%) positive sera, but no positive muscle juice samples.All muscle samples from 639 foxes in Wallonia proved to be negative for larvae in artificial digestion. Serum and muscle juice of 130 and 478 foxes, respectively were examined in ES-ELISA. There were 61 (46.9%) positive sera and 90 (18.8%) positive muscle juice samples. A comparison between 88 serum and muscle juice samples of the same foxes showed that only half of the serum-positive animals were detected using muscle juice. However, for establishing the true meaning of these results, a more profound epidemiological study on the vulpine population in Belgium is necessary.     

Spatial distribution of Trichinella britovi, T. spiralis and T. pseudospiralis of domestic pigs and wild boars (Sus scrofa) in Hungary

Trichinellosis is a foodborne disease caused by the consumption of raw meat and raw meat-derived products from swine, horse and some game animals infected with nematode worms of the genus Trichinella. Between June 2006 and February 2011, 16 million domestic pigs and 0.22 million wild boars (Sus scrofa) were tested for Trichinella sp. in Hungary. Trichinella infection was not found in any pigs slaughtered for public consumption. Nevertheless, Trichinella spiralis was detected in four backyard pigs when trace back was done following a family outbreak. Trichinella infection was demonstrated in 17 wild boars (0.0077%). Larvae from wild boars were identified as Trichinella britovi (64.7%), T. spiralis (29.4%) and Trichinella pseudospiralis (5.9%). Although the prevalence of Trichinella sp. infection in wild boars and domestic pigs is very low, the spatial analysis reveals that the level of risk differs by region in Hungary. Most of the T. britovi infected wild boars (63.6%) were shot in the north-eastern mountain area of Hungary; whereas domestic pigs and wild boars infected with T. spiralis were detected only in the southern counties bordering Croatia and Romania. In the north-western and central counties, the prevalence of Trichinella infection seems to be negligible.     

Comparison of two real-time RT-PCR assays for differentiation of C-strain vaccinated from classical swine fever infected pigs and wild boars

Classical swine fever is one of the most important infectious diseases for the pig industry worldwide due to its economic impact. Vaccination is an effective means to control disease, however within the EU its regular use is banned owing to the inability to differentiate infected and vaccinated animals, the so called DIVA principle. This inability complicates monitoring of disease and stops international trade thereby limiting use of the vaccine in many regions. The C-strain vaccine is safe to use and gives good protection. It is licensed for emergency vaccination in the EU in event of an outbreak. Two genetic assays that can distinguish between wild type virus and C-strain vaccines have recently been developed. Here the results from a comparison of these two real-time RT-PCR assays in an interlaboratory exercise are presented. Both assays showed similar performance.     

Studies on vertical transmission of Trichinella spp. in experimentally infected ferrets (Mustela putorius furo), foxes (Vulpes vulpes), pigs, guinea pigs and mice

Vertical transmission of Trichinella spiralis was evaluated in ferrets (n = 21), foxes (n = 11), pigs (n = 12), guinea pigs (n = 16), and mice (n = 41). The placental barrier to be crossed by migratory Trichinella larvae varies structurally in different animal species. Ferrets and foxes have an endotheliochorial placenta structure, guinea pigs and mice a haemochorial, and pigs an epitheliochorial placenta. The non-encapsulating Trichinella pseudospiralis larvae have an extended muscle migration prior to entering a muscle cell. To evaluate if T. pseudospiralis was more likely to be transmitted to offspring, an additional group of foxes (n = 11) infected with T. pseudospiralis was included. Two different dose levels were used for ferrets, pigs, guinea pigs, and mice. In pigs and guinea pigs, infection was given at different times of the gestation period. Vertical transmission, measured as recovery of muscle larvae in the offspring, was demonstrated in both ferrets groups, in all four guinea pig groups, and in the high dose mouse group, but not in any fox or pig groups.     

Comparison of muscle fluid and serum for detection of antibodies against hepatitis E virus in slaughter pigs

Muscle fluid was investigated as an alternative to serum for detecting anti-hepatitis E virus (HEV) antibodies in slaughter pigs. Samples of serum and diaphragmatic muscle juice from 67 pigs were analysed by anti-HEV IgG ELISA. Compared to the serum ELISA, the ELISA on diaphragmatic muscle fluid had a sensitivity of 93%, a specificity of 91.7%, a κ value of 0.84 and a determination coefficient (R(2)) of 0.77; both tests had global agreement of results. Muscle fluid can be used as an alternative to serum for serological detection of HEV antibodies in slaughter pigs.     

Prevalence of Trichinella spp. in North Spain wild fauna and new variety of Trichinella britovi identification

Trichinella spiralis and Trichinella britovi live in apparent sympatry among wild fauna of the Iberian Peninsula. In the present study 105 Trichinella isolates from wild mammals were typed by inter-sequence simple repeat PCR (ISSR-PCR). All isolates identified as T. spiralis were indistinguishable from the ISS48 reference strain. Among those belonging to T. britovi, four variations were clearly distinguishable; two of them, ISS11 C-76 and ISS86 MON, had been previously detected while the ISS2 reference strain and Trichinella Rioja 3, (MVUL/SP/02/R3) had not been reported before. The newly distinguished genotype of T. britovi was analyzed by ISSR-PCR, multiplex-PCR, UARR sequencing, and single larva cross-breeding with the other T. britovi genotypes including Trichinella T8 (ISS49). Among all of them, the ISS11 and ISS2 isolates were found to be the most frequent. The uniformity found within T. spiralis isolates is consistent with its recent introduction in Iberian Peninsula, whereas the presence of four variations within T. britovi suggests that this species is an endemic species. Orographical diversity of the West-End of Eurasian Region could act to preserve population diversity observed within T. britovi.     

Evaluation of ELISA for detection of Trichinella antibodies in muscle juice samples of naturally infected pigs

The performance characteristics of an ELISA test for trichinellosis in pigs applied to muscle juice was assessed using 314 samples collected from pigs located in endemic areas of Croatia. Peptic digestion was used as the reference method. The diagnostic accuracy of the two compared dilutions (1:10 and 1:100) was considered to be high because the area under the curve (AUC) index was 0.922 and 0.920 for each dilution, respectively. In this study the two graph-receiver operating characteristic (TG-ROC) analysis was used as a tool for selecting cut-off points. Sensitivity, specificity, likelihood ratios, efficiency and Youden's index were used as indices of test accuracy. The cut-off values that minimize overall misclassification cost under an assumption of 3% prevalence were calculated. Our results indicate that the ELISA applied to muscle juice is a highly accurate test and can be adapted to process a large number of samples.     

Alaria alata mesocercariae in domestic pigs and wild boars in South Banat,northern Serbia

Alaria alata (Diplostomidae, Trematoda), a potentially zoonotic pathogen, is the only Alaria species in Europe. In recent years, increasing reports of mesocercariae of A. alata in wild boars have been recorded in European countries; however there have been no described cases in domestic pigs over the past decades. Out of 272 diaphragm samples from wild boars (Sus scrofa) and domestic pigs (Sus scrofa), from Serbia, included in the present investigations, mesocercariae of A. alata were found in six (3%) samples from wild boars and in two (2.77%) samples from domestic pigs. Due to the lack of sensitivity of artificial digestion with a magnetic stirrer which was applied in the study, the true prevalence is estimated to be considerably higher in the area of investigation. Confirming the infection in domestic pigs and a wide distribution in wild boars in the area of investigation, the present paper should influence the growing awareness of alariosis as a potential human disease. The meat from free-range domestic pigs and game meat as a potential source of alariosis should always be adequately thermally treated before consumption.     

Intestinal establishment and reproduction of adult Trichinella spp. in single and mixed species infections in foxes (Vulpes vulpes)

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.     

Accuracy of two commercial enzyme-linked immunosorbent assays for the detection of antibodies to Salmonella spp. in slaughter pigs from Canada

Large discrepancies are usually found when different ELISAs for the diagnosis of pig salmonellosis are compared. Thus, our main goal was to estimate the diagnostic accuracy through Bayesian approaches of two commercial assays (Svanovir™ “test A” and HerdCheck™ “test B”) for the detection of antibodies to Salmonella spp. in slaughter pigs. Previously, we estimated the agreement between both tests and their relative sensitivity (Se) and specificity (Sp) with respect to bacteriology on caecal content and ileocaecal lymph nodes. Test A, at a cut-off OD% ≥20%, indicated higher prevalence than test B (OD% ≥10%) (14.6% vs. 8.6%). Relative Se with respect to overall bacteriology was low (≈30%) and similar for both tests, but the relative Sp was significantly lower for test A compared to B (88% vs. 95%). Both tests failed to detect some pigs infected with Salmonella serogroups B and C₁, which they were supposed to identify. In general, tests showed only fair-to-moderate agreement when they were compared (kappa: 0.41). In the Bayesian models, Se of test A varied between 63% and 77%, while Se of test B was 73%. Sp of A was always lower than that of test B (89% vs. 95%). The implications derived from the use of these imperfect serological tests will have to be accounted for in large-scale Salmonella-control programs.     

Prevalence of Toxoplasma gondii and Neospora caninum antibodies in wild boars in the Czech Republic

Sera collected from hunter-killed wild boars (Sus scrofa) during 1999-2005 from seven different regions of the Czech Republic were assayed for antibodies to Toxoplasma gondii by indirect fluorescence antibody test and to Neospora caninum by competitive-inhibition enzyme-linked immunosorbent assay and by indirect fluorescence antibody test. Antibodies to T. gondii were detected in 148 (26.2%) of 565 wild boars with serum dilutions of 1:40 in 40, 1:80 in 40, 1:160 in 27, 1:320 in 19, 1:640 in 18 and 1:1280 in 4 wild boars. Antibodies to N. caninum were detected in 102 (18.1%) of 565 wild boars with 30.1-94.6% inhibition in ELISA; statistical significant differences were observed between sampling regions, ranging from 0% to 31.8%. Sera, positive in ELISA, were examined in IFAT; 58 of 102 (56.9%) were positive with titres 1:40-1:160. Mixed infection (concurrent presence of both T. gondii and N. caninum antibodies) was found in 38 wild boars. It is the first report of antibodies to N. caninum in wild boar. Serological results indicate a common exposure to T. gondii and to N. caninum among wild boars in the Czech Republic.     

Serological survey of antibodies to four pathogens in wild boars in Nagano Prefecture,Japan

Wild boars (Sus scrofa) captured or found dead in Nagano Prefecture were surveyed for antibodies to Aujeszky’s disease virus (ADV), Erysipelothrix rhusiopathiae, porcine reproductive and respiratory syndrome virus (PRRSV), and Toxoplasma gondii. While all 168 samples tested were negative for anti-ADV antibodies and all 140 samples tested were negative for anti-PRRSV antibodies, all 190 samples tested were positive for anti-E. rhusiopathiae antibodies and 12 of 180 samples were positive for anti-toxoplasma antibodies. These results suggest that since E. rhusiopathiae and T. gondii cause zoonotic diseases, in addition to wild boars being a potential source of infection for domestic pigs, caution should be taken when handling wild boars or eating wild boar meat because of the possibility of human infection.     

小鼠实验感染不同种旋毛虫后肉汁抗体水平的研究

为了观察小鼠感染不同种旋毛虫后肉汁抗体水平的变化及其与血清抗体水平的相关性,将200只昆明小鼠随机分成4组（每组50只）,每只分别感染300条乡土旋毛虫（T2）、布氏旋毛虫（T3）、伪旋毛虫（T4）及纳氏旋毛虫（T7）幼虫,感染后2～6周每组每周随机剖杀10只小鼠,收集血清及肉汁,用旋毛虫肌幼虫ES抗原ELISA检测血清及肉汁中抗体水平;另取40只昆明小鼠随机分成4组（每组10只）,每只分别感染500条T2、T3、T4、T7幼虫,感染后6周剖杀,制备肉样,用ELISA检测4℃及-20℃保存不同时间后的肉汁抗旋毛虫抗体动态。T2、T3、T4、T7感染小鼠后的肉汁抗体水平和变化趋势相似,均是在感染后第3周检测出肉汁特异性抗体,抗体阳性率分别为60％、30％、30％、30％,至感染后第4周肉汁抗体阳性率均升至100％。4组小鼠感染后2～6周的肉汁与血清抗体水平均具有相关性。T2、T3、T4、T7感染小鼠肌肉4℃保存7d与1d的肉汁抗体水平相比均无显著性差异;所有的感染小鼠肌肉-20℃保存2个月的肉汁抗体水平与保存1个月的相比均无显著性差异;虽然保存3个月的肉汁抗体水平与保存1个月的相比均已有显著性差异,但抗体阳性率仍均为100％并持续至实验结束时的4个月保存期。结果表明,肉汁中抗旋毛虫抗体的检测可用于新鲜肉、冷藏肉及冷冻肉中乡土旋毛虫、布氏旋毛虫、伪旋毛虫、纳氏旋毛虫捡疫的初筛。     

Deposition rates and accretion patterns of intramuscular fat, loin muscle area, and backfat of Duroc pigs sired by boars from two time periods

A study was conducted to evaluate differences in performance and in carcass composition and tissue deposition rates between purebred Duroc pigs sired by boars currently available and those sired by boars from the mid-1980s. Two lines were developed by randomly allocating littermate and half-sib pairs of females to matings by current time period (CTP) or old time period (OTP) boars. Pigs from 2 replications were placed on test at a group mean BW of 63.5 kg. Serial ultrasonic measurements of the 10th-rib LM area (LMA), off-midline backfat (BF10), and intramuscular fat percentage (IMF) were collected every 2 wk in the first replication and used to assess deposition rate differences. Off-test ultrasonic LMA, BF10, and IMF measurements from a total of 557 pigs from 23 CTP sires and 232 pigs from 15 OTP sires across 2 replications and at a mean BW of 109 kg were evaluated. All available barrows and randomly selected gilts (n = 277) were sent to a commercial abattoir, and carcass measurements of 10th-rib backfat, last-rib backfat, last lumbar backfat, and LMA were collected. Analysis of serial backfat measurements revealed a linear relationship between back-fat and BW between 73 and 118 kg for pigs from both time periods. Pigs sired by OTP boars deposited more backfat (P < 0.05) at a faster rate than pigs sired by CTP boars over the entire test period. A curvilinear cumulative tissue deposition pattern was revealed for ultrasonically estimated LMA and IMF within both time periods. Significant linear and quadratic regression coefficient differences between lines indicated that pigs sired by CTP boars deposited more LMA and less IMF per kilogram of BW gain than pigs sired by OTP boars. Pigs sired by CTP boars had more LMA and less BF10 (P < 0.05), whereas pigs sired by OTP boars had more IMF (P = 0.04). Carcass evaluation revealed more (P < 0.01) carcass measurements of LMA and less (P < 0.05) carcass measurements of 10th-rib backfat, carcass measurements of last-rib backfat, and carcass measurements of last lumbar backfat for pigs sired by CTP boars. No difference (P > 0.05) between the time periods was found for ADG over the entire test period. Results from this study illustrate that significant progress in carcass composition has been realized within the Duroc breed since the mid-1980s. The long-term selection response in carcass leanness has also resulted in changes in deposition rates of correlated traits such as LMA and IMF.     

The prevalence of Sarcocystis spp in dogs and red foxes.

Protozoan parasites of the genus Sarcocystis have been recognised for many years as intramuscular cysts of numerous vertebrates. It is only comparatively recently that the two-host nature of the life cycle has been recognised and that the intramuscular cysts are a stage in the developmental cycle of coccidian parasites of flesh eating mammals (Fayer 1974, Fayer and Johnson 1973, 1974, Rommel and others 1972, Dubey 1976). Carnivores ingest the intramuscular cysts from herbivores and presumably from other animals too and eventually shed sporulated tetrazoic sporocysts in their faeces. The cystic stages which occur in the flesh of herbivores are probably non-pathogenic but the earlier stages in which schizonts develop in vascular endothelium may be severely pathogenic. Sarcocystis cruzi, S ovicanis and S porcifelis are known to be severely pathogenic in cattle, sheep and pigs respectively (Dubey 1976). Observations on the prevalence of Sarcocystis spp in the faeces of working farm dogs, greyhounds and foxes (Vulpes vulpes) are recorded.     

两种片形吸虫感染山羊的对比试验

片形吸虫病是在全球范围广泛流行，并对人有一定危害的寄生虫病。在大部分地区该病病原为肝片形吸虫（Fasciola hepatica），非洲、亚洲的热带地区是大片形吸虫（F．gigantica）。据本地的资料和以往的研究显示，广西主要是大片形吸虫。由于国内外对肝片形吸虫的研究较多，对大片形吸虫的研究较少，使得国内一些研究未能注意到这两个种的虫在对动物的致病性及其所引起的免疫反应等方面的差别。