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1.
High hydrostatic pressure processing (HPP) is an effective non-thermal treatment used to inactivate pathogens from a variety of food and food products. It has been extensively examined using prokaryotic organisms and protozoan's but has had limited study on metazoans. Treatment using HPP has been shown to be effective in inactivating nematode larvae in food and preventing embryonation of Ascaris suum eggs. We conducted experiments using eggs of the canine whipworm Trichuris vulpis collected from naturally infected dogs and A. suum eggs from naturally infected pigs. We observed a delay in development of eggs of T. vulpis in a preliminary experiment and conducted 2 experiments to test the hypothesis that appropriate HPP levels can induce a delay in embryonation of nematode eggs. In experiment 1, nonembryonated T. vulpis eggs in tap water were packaged in sealable bags and exposed to 138-600 megapascals (MPa; 1 MPa=10 atm=147 psi) for 60s in a commercial HPP unit. In a second experiment, nonembryonated eggs of A. suum were exposed to 138-600 MPa and treated for 60s in the same commercial HPP unit. Embyronation of T. vulpis eggs was delayed by 4 and 5 days for eggs treated with 207 and 241 MPa but eventually eggs developed and the numbers of embryonated eggs was similar to controls on day 55. Embryonation of T. vulpis eggs treated with 345 or 350 MPa was delayed by 9 days and never reached more than 5% of eggs embryonated. On day 55 post treatment, 95% of control nontreated T. vulpis eggs were embryonated, 100-65% of eggs treated with 138-276 MPa were embryonated, a maximum of 5% of eggs treated with 345-350 MPa were embryonated, and 0% of eggs treated with ≥ 400 MPa were embryonated. T. vulpis eggs treated with ≥ 400 MPa did not undergo cell division. Embryrnation of A. suum eggs was delayed by 4, 10, and 16 days for eggs treated with 207, 241, and 250MPa, respectively, compared to nontreated control eggs. A. suum eggs treated with 207 MPa eventually embryonated to similar % embryonation values as controls and 138 MPa treated eggs but eggs treated with 241 or 250 MPa were always <5% embryonated. A. suum eggs treated with ≥ 300 MPa did not undergo cell division. On the final day of examination at day 56 after treatment, the % of embryonated eggs was 92% nontreated controls, 94% treated with 138 MPa, 84% treated with 207 MPa, 2% treated with 241 or 250 MPa, and 0% treated with 276, 200, 345, 400, or 414 MPa, respectively. 相似文献
2.
In an experiment it was shown that eggs of Ascaris suum, salmonella and fecal coliform bacteria mixed with sewage sludge and added to soil, will survive the first growing season. Most eggs of Ascaris suum in soil embryonated within a period of 7--15 weeks. In soil without a protective vegetation the concentration of eggs in the top soil layer 0--3 cm decreased faster than in soil with a protective vegetation. At the same time there seemed to be a corresponding increase in the concentration of eggs in the deeper layers of the soil. In the top layer, especially in the top soil without a protective vegetation, there was towards the end of the first growing season a higher per cent of dead eggs than in the deeper layers. The concentration of fecal coliform bacteria and salmonella was in the course of the first growing season reduced to 1/1000 and 1/10000, respectively, of the initial concentration. Infective Ascaris suum eggs and salmonella were found in washing water from vegetables grown in the first season. Infective Ascaris suum eggs were also present in soil in the second and third growing season. 相似文献
3.
4.
Influence of helminth parasite exposure and strategic application of anthelmintics on the development of immunity and growth of swine 总被引：1，自引：0，他引：1
Infection of pigs with the intestinal roundworm parasite Ascaris suum and strategic application of anthelmintic drugs during the growing phase of development were observed for specific effects on 1) development of immunity in feeder pigs and 2) growth rate during the finishing phase. Management treatments included maintenance in a parasite-free concrete environment, maintenance in a concrete environment and inoculation with 1,000 infective A. suum eggs every other day over a 52-d period, and maintenance on a dirtlot contaminated with A. suum and Trichuris suis eggs. Within each management environment, pigs were either untreated, treated with ivermectin or treated with fenbenzadole at strategic times during parasite exposure. Protective immunity, assessed by a challenge inoculation with A. suum eggs following management treatments, was not affected by ivermectin or fenbenzadole treatment during exposure, but adult worm burdens were reduced and the pattern of A. suum larval antigen serum antibody responses were different from those in control pigs not treated with drugs. Exposure to A. suum and treatment with anthelmintics during the growing phase reduced adult worm burdens following the finishing phase of growth. Rate, but not efficiency, of gain was significantly improved by anthelmintic treatment following natural exposure to parasites. Strategic treatment of pigs with anthelmintics following inoculation with A. suum eggs in a concrete management environment had no effect on rate of gain. Results suggest that natural exposure to parasites during the growing phase without therapeutic treatment causes permanent damage to growth potential. 相似文献
5.
Protective immunity to Ascaris suum: analysis of swine peripheral blood cell subsets using monoclonal antibodies and flow cytometry 总被引：1，自引：0，他引：1
Outbred domestic swine or SLA inbred miniature swine were exposed to Ascaris suum either naturally on contaminated lots or by inoculation with UV-irradiated attenuated eggs. Both inbred and outbred swine developed virtually complete protection to a challenge of 10 000 eggs after natural exposure, but inbred swine were less resistant than outbred swine after UV-egg exposure. Flow cytometric analysis of peripheral blood mononuclear cells from these animals, performed to determine changes in cell subsets including helper T-cells, cytotoxic/suppressor T-cells, macrophages, and cells expressing class II major histocompatibility antigens, showed that both outbred and inbred swine had similar responses after parasite exposure. The levels of helper T-cells and cytotoxic/suppressor T-cells did not change after parasite exposure, while there was an appreciable but transient increase in macrophages only in those swine naturally exposed to A. suum. Swine exposed to A. suum, both naturally and by inoculation with UV-eggs, showed an increase in the amount of class II antigens detectable per cell. In a second set of experiments, outbred swine were exposed to A. suum naturally or by repeated experimental inoculation with different doses of normal eggs, and protective immunity and changes in blood cell subsets were determined. The greatest change in blood cell subsets was found at 3 and 5 weeks after initial parasite exposure, when macrophages were elevated moderately in a group of pigs inoculated every other day with 1000 eggs and markedly in a group that was naturally exposed; class II antigen expression was also increased during this period. These increases preceded peak serum antibody responses, which were lower in the naturally-exposed group relative to the experimentally-inoculated group. Both groups had high levels of protective immunity. This suggests than natural exposure to A. suum may activate cells and enhance specific immune responses to give high levels of protection. 相似文献
6.
Commercially reared growers, finishers, and sows of Danish Landrace x Yorkshire crossbred were inoculated orally with Ascaris suum at 50 eggs kg-1 body weight. White spots on the serosal surface of livers and total larval recoveries from lungs were recorded 7 days later. The response in pigs originating from a specific pathogen free and parasite free herd (parasite na?ve) was observed in the three different age groups and compared with age-matched pigs from a herd maintained in a facility contaminated with A. suum (naturally exposed). The pre-inoculation immune status of the various groups was characterized serologically using antigen preparations derived from various stages of A. suum. Inoculation of all age groups of parasite na?ve pigs with A. suum eggs produced relatively high liver white spots and lung larvae, although expression of these counts as a percentage of the inoculum showed a moderate age-related resistance from growers to finishers to sows. In contrast, pigs naturally exposed to A. suum expressed strong immunity to a challenge infection as few or no larvae were detected in the lungs. In addition, growers, finishers, and sows from the naturally exposed herd had significantly higher levels of serum IgG/IgA to several different A. suum antigens compared with pigs from the parasite nave herd. Liver white spots, expressed as a percentage of the inoculum, were highest in growers from the naturally exposed herd but were markedly reduced in finishers and sows from that herd. In fact, few or no white spots were observed in naturally exposed sows, while sows from the parasite-na?ve herd had in excess of 300 liver white spots following challenge. These results indicate that commercially raised pigs that are exposed to A. suum develop a strong protective immunity that ultimately produces a complete pre-hepatic barrier to larval migration, while pigs raised parasite free remain susceptible to infection. 相似文献
7.
The potential of the chitin synthesis inhibitor diflubenzuron (DFB) to alter the development of the parasitic nematodes (Ascaris suum and Haemonchus contortus was investigated. DFB given orally (10 mg kg-1 per day for 30 days) to sheep inoculated with H. contortus infective larvae did not prevent the establishment of adults or affect fecal egg output. However, there was a significant (greater than 90%) decrease in the number of infective larvae recovered from fecal cultures derived from lambs harboring H. contortus adults that were treated with DFB. DFB did not affect egg hatching. Oral administration (10 mg kg-1 per day for 20 days) of DFB to swine harboring adult A. suum adults had no effect on the adult worm burden or on egg morphology, but eggs removed from worms obtained from DFB-treated swine contained less chitin than eggs removed from untreated control swine. DFB also inhibited chitin synthesis in vitro in the isolated reproductive tract of A. suum adults. These results indicate that DFB at high doses can inhibit the subsequent development of H. contortus larvae in the feces. Since H. contortus larvae lack chitin, DFB may act on these larvae by a mechanism independent of a direct effect on chitin synthesis. 相似文献
8.
This study investigated the effects of seasonal temperature variations on the rate of development to infectivity of Ascaris suum eggs under western Canadian climatic conditions. Flasks containing a suspension of A. suum eggs were placed inside a pig barn located near Saskatoon, Saskatchewan, Canada, at monthly intervals from July 1997 to July 1998. Eggs from each flask were monitored weekly for development to the infective larval stage. Infectivity of eggs was confirmed using a mouse bioassay. Development to the infective stage took three to four weeks in summer when in-barn temperatures were similar to the external ambient temperature. Fall, winter and early spring egg development took longer as in-barn temperatures were cooler. Mid-winter egg development took as long as 11-12 weeks. The in-barn mean temperature during this period was approximately 17 C, close to the development threshold of A. suum eggs. These data are discussed in relation to similar studies from northern Europe and to potential control measures. 相似文献
9.
川楝素驱猪蛔虫体外杀虫试验研究 总被引：2，自引：0，他引：2
运用超声波技术从苦楝皮中分离提取川楝素（Toosendanin）,并用其对猪蛔虫成虫、第二期幼虫、虫卵作离体毒理试验,同时与临床上常用驱猪蛔虫药进行比较,筛选出驱虫效果较好的药物,为下一步动物试验和新型驱虫药的研究奠定基础。 相似文献
10.
A study was conducted to determine the distribution and transmission rate of Ascaris suum eggs and Oesophagostomum dentatum larvae in a pasture/pig house facility, which during the preceding summer was contaminated with helminth eggs by infected pigs. In May, four groups of 10 helminth na?ve tracer pigs were exposed to fenced sections of the facility for 7 days and necropsied for parasite recovery 9-10 days later (trial 1). The highest rate of A. suum transmission (201 eggs per day) occurred in the pig house (A). On the pasture, egg transmission decreased with the distance from the house: 8 eggs per day in the feeding/dunging area (B); 1 egg per day on the nearest pasture (C); <1 egg per day on the distant pasture (D). Only a few O. dentatum infections were detected, indicating a poor ability of the infective larvae to overwinter. Soil analyses revealed that the highest percentage (5.8%) of embryonated A. suum eggs were in the house (A). Subsequently, the facility was recontaminated with A. suum eggs by infected pigs. A replicate trial 2 was conducted in the following May. A major finding was the complete reversal of egg distribution between the 2 years (trials 1 and 2). In contrast to previous results, the highest rates of transmission (569 and 480 eggs per day) occurred in pasture sections C and D, and the lowest transmission rates (192 and 64 eggs per day) were associated with the feeding/dunging sections and the house (B and A). Soil analyses again supported the tracer pig results, as the pasture sections had the highest concentrations of embryonated eggs. Detailed soil analysis also revealed a non-random, aggregated egg distribution pattern. The different results of the two trials may be due to the seasonal timing of egg deposition and tracer pig exposure. Many eggs deposited during the summer prior to trial 1 may have died rapidly due to high temperatures and dessication, especially when they were not protected by the house, while deposition in the autumn may have favored egg survival through lower temperatures, more moisture, and greater sequestration of eggs in the soil by rain and earthworms. The latter eggs may, however, not have become embryonated until turnout the next year. The results demonstrate that yearly rotations may not be sufficient in the control of parasites with long-lived eggs, such as A. suum, and that a pasture rotation scheme must include all areas, including housing. 相似文献
11.
Thirty-two pigs (average 26.6 kg live weight) were individually housed and fed to study the effect of an infection of Ascaris suum (either 0, 600, 6,000 or 60,000 A. suum eggs/pig) on performance of growing-finishing pigs. Increasing the level of A. suum infection produced linear (P less than .07) and quadratic (P less than .09) effects on final weight, weight gain and average daily gain. Feed to gain ratio and number of A. suum worms recovered from the intestines of pigs at slaughter increased linearly (P less than .01) with increasing doses of A. suum eggs. Pigs receiving 60,000 A. suum eggs were 13% less (P less than .01) efficient than the noninfected controls. In each of two trials, eight crossbred barrows (15.7 kg in trial 1 and 16.1 kg body weight in trial 2) were examined for the effects of two levels of A. suum infection (0 and 20,000 eggs/pig) on digestibility coefficients for dry matter, crude protein and gross energy. The infection did not affect (P greater than .05) digestibility coefficients during the first two collection periods (d 6 through 10 and 19 through 23). However, digestion coefficients for dry matter, crude protein and gross energy obtained from the total collection period on d 33 through 37 postinfection were greater (P less than .01) for control pigs than for pigs given 20,000 A. suum eggs each. Also, N retention was greater (P less than .05) for control pigs than for infected pigs. 相似文献
12.
This study was designed to determine the effect of Ascaris suum infection upon growth of mouse vesicular glands. Mice were infected with varying dosages of A. suum eggs and killed after six weeks. Results indicated a dose dependent increase in seminal vesicle weight, independent of total body weight. 相似文献
13.
Residual infective Ascaris suum eggs in farrowing pens provide the initial source of infection for piglets under Swedish management conditions. In such circumstances there is little evidence to support pre-farrowing treatment of the sow specifically against A. suum. The present study shows, however, that ivermectin-treatment of the sow prevents the early establishment of A. suum and Oesophagostomum spp in her litter. 相似文献
14.
Pigs of 10 days-1 month old were orally infected with eggs of Ascaris suum at different rates and inoculation schedules. Histological sections from various parts of the small intestines were prepared to observe the production and localization of immunoglobulin-bearing cells. Fluorescent antibody and immunoperoxidase staining methods were used to determine the number of IgM-, IgA- and IgG-producing plasma cells in the intestinal lamina propria. Significant increases in immunoglobulin-bearing cells were observed in those pigs which received single inoculations of A. suum eggs. Pigs infected every 2,4,8 and 10 days with 10,000-20,000 embryonated eggs showed numerical increases in IgM-bearing cells. Increases in IgA-bearing cells were noted in pigs which received the higher number of eggs every 8-10 days. Higher concentrations of IgA- and IgM-bearing cells were observed in the jejunal mucosa of infected pigs as compared to those in the duodenum and ileum. 相似文献
15.
Frontera E Roepstorff A Gázquez A Reina D Serrano FJ Navarrete I 《Veterinary parasitology》2003,111(1):9-18
In the present work, we carry out an immunopathological study of the swine ascariosis, under different conditions (control, infection and immunization). Twenty-one Iberian pigs were used and divided in seven groups. Groups 1 and 2 were the uninfected and challenged controls, respectively. Groups 3 and 4 were weakly infected with increasing doses of Ascaris suum eggs and treated with pyrantel (Group 4). Groups 5-7 were immunized with 14, 42 and 97 kDa proteins from the parasite, respectively. Groups 2-7 were challenged with 10,000 infective eggs 7 days before the sacrifice. The focal parasitic granulomata with eosinophils and lymphocytes were the main histopathological lesions in the liver of reinfected pigs, while more marked cellular infiltrate and abundant connective tissue were seen in the livers of immunized animals. There were important deposits of antigens in the livers of immunized and infected pigs. Antigens were mainly located in the connective tissue, with positive staining detection of the somatic larvae antigen, the body wall from the adult worms and the 14-, 42- and 97-kDa proteins. However, cholangiols, biliary ducts and macrophages presented an immunohistochemical positive stain against excretory-secretory and somatic antigens from the larvae and the body fluid antigen from the adult parasite. The detection of A. suum antigens in the liver of infected pigs improves the diagnosis of swine ascariosis. It may be possible to apply these procedures for diagnosis of human ascariosis in liver biopsies since A. suum from swine have been previously used as a substitute for the study of the human parasite Ascaris lumbricoides. 相似文献
16.
感染性猪蛔虫卵以每头份3000个卵的量感染断奶仔猪，于第3天开始肌肉注射不同剂量苏云金芽胞杆菌晶体蛋白（insecticidal crystal proteins，ICPs），每天1次，连续4d。同时测定猪血液生理生化指标，饲喂2个月后收集猪粪便计算虫卵数。结果显示，感染猪出现咳嗽、发热等临床症状，GOT、GPT、ALP、LDH等指标明显升高，经ICPs治疗后又恢复正常。粪便检查，ICPs高剂量组（16．08mg）的EPG（每克粪便虫卵数）为0，而ICPs低剂量组（9．45mg）的EPG为394，未经ICPs作用对照组EPG为2113，差异极显著（P〈0．01），证明ICPs对猪体内猪蛔虫具有较好的杀灭作用。 相似文献
17.
Five growing pigs experimentally infected with low doses of Oesophagostomum dentatum, Ascaris suum, and Trichuris suis were turned out with 5 helminth-na?ve pigs on each of 3 pastures in June 1996 (Group 1). On one pasture all pigs received nose-rings. After slaughter of Group 1 in October, pasture infectivity was monitored using helminth-na?ve, unringed tracer pigs. In 1997, helminth-na?ve young pigs were turned out on the contaminated pastures in May (Group 2) and again in August (Group 3). Again all pigs on one pasture received nose-rings. All pigs and pastures were followed parasitologically and reduction in grass cover was monitored. Based on the acquisition of infection by the na?ve pigs in Group 1, the estimated minimal embryonation times for eggs deposited on pasture were 23-25 days for O. dentatum, 5-6 weeks for A. suum and 9-10 weeks for T. suis. Results from tracer pigs and grass/soil samples indicated that pasture infectivity was light both years. Free-living stages of O. dentatum did not survive the winter. The nose-rings reduced rooting considerably, resulting in three-fold more grass cover on the nose-ring pasture compared to the control pastures by the end of the experiment. Nevertheless, the nose-rings did not significantly influence parasite transmission. 相似文献
18.
Vlaminck J Nejsum P Vangroenweghe F Thamsborg SM Vercruysse J Geldhof P 《Veterinary parasitology》2012,189(2-4):267-273
The significant economical consequences of infections with Ascaris suum in pigs are already well documented. However, due to the subclinical nature of the disease and the lack of practical diagnostic means, ascariasis often remains undiagnosed. Here we describe the development and evaluation of a novel indirect ELISA using the purified A. suum haemoglobin (AsHb) molecule as an antigen. Initial validation using sera from 190 pigs experimentally infected twice a week with A. suum and Trichuris suis (25 and 5eggskg(-1)day(-1) respectively) demonstrated that the AsHb ELISA is able to detect long-term exposure to A. suum with a high sensitivity and specificity (99.5% and 100.0% respectively). Furthermore, this serological technique proved to be more sensitive than faecal examination on week 7 and 14 of the experiment (99.5% and 100% compared to 59.5% and 68.4% respectively). Cross-reactivity caused by T. suis infection was shown to be limited after analysing sera from pigs with an experimental T. suis mono-infection. Seroconversion was shown to occur from week 6 onwards in pigs receiving 100 A. suum eggs 5 times a week. Preliminary testing of the ELISA on six randomly selected farms confirmed the results obtained in the artificial infection trials, showing a higher sensitivity of the serologic method compared to faecal examination. Finally, the ELISA was used to investigate Ascaris infection rates on 101 conventional Flemish pig farms. The results showed that on 38.6% of the farms less than 20% of the tested samples were seropositive, while in 19.8% of the farms 80-100% of all pigs were seropositive. The results of this study suggest that the AsHb ELISA could provide pig farmers and veterinarians with an easier and more sensitive way to estimate the overall prevalence of A. suum on their farm. 相似文献
19.
A Roepstorff 《Veterinary parasitology》1991,39(1-2):149-160
Faecal samples from sows and their litters, all untreated with anthelmintics, were examined in eight sow herds, ranging from very intensive to very traditional management. Four helminth genera were recorded, namely Oesophagostomum sp., Ascaris suum, Trichuris suis and Strongyloides ransomi. The herds with the most intensive management were only infected with A. suum, while the more traditionally managed herds were infected with three or four species. In one herd, the sows showed a small relative increase in the excretion of Oesophagostomum eggs during lactation, but in general there was no consistently observable peri-parturient increase in faecal egg output. Furthermore, faecal examination of 5-12-week-old pigs indicated that sow-to-piglet transmission was important in the traditionally managed herds, while it was negligible in the intensive herds. A seasonal variation in the excretion of Oesophagostomum sp. and A. suum eggs was observed in the youngest pigs in the traditional herds, with the highest faecal egg counts occurring in the summer and autumn. However, this pattern became indistinct during the fattening period and did not exist in the sows, except for A. suum infections in the heavily infected traditional herds. The helminths egg excretion in the intensive herds did not show any seasonal variation. 相似文献
20.
Eriksen L Bøgh HO Loftager M Lind P 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2004,51(4):185-190
This experimental study was designed to compare the acquired resistance in pigs to Ascaris suum eggs following 4-weekly oral immunizations with either 200 A. suum infective eggs or 50 A. suum third stage larvae (L3). The two immunized groups (n = 7) together with an unimmunized control group (n = 7) of pigs were challenged orally with 50 infective A. suum eggs per kilogram bodyweight on day 19 after the last immunization. Seven days post-challenge the group immunized with eggs showed signs of resistance as evidenced by reduced lung larval counts compared with the challenge control group. Such significant resistance was not observed in the L3-immunized group. However, a markedly increased inflammatory liver reaction and white spot formation was demonstrated in the L3-immunized pigs after challenge compared with both control animals and egg-immunized pigs. On the day of challenge only the egg-immunized pigs mounted an anti-Ascaris antibody response both in serum and in lung lavage fluid. Ascaris-antigen induced increased histamine release from peripheral leucocytes following both immunization and challenge could only be demonstrated in the egg-immunized pigs. On day 7 post-challenge local IgA-anti-Ascaris antibodies were further demonstrated in bile of the egg-immunized group and in the small intestine of both immunized groups. In conclusion, oral A. suum egg immunization of pigs induced a significant reduction in lung larval counts upon challenge. In contrast, oral L3 immunization seemed to prime the pigs as observed by the presence of stunted lung larval growth and increased liver reaction post-challenge with A. suum eggs. 相似文献