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1.
A series of experiments was carried out to examine the effects of two different isolates of the nematode-trapping fungus Duddingtonia flagrans to reduce the number of free-living larvae of the bovine lungworm, Dictyocaulus viviparus. A laboratory dose-titration assay showed that isolates CI3 and Troll A of D. flagrans significantly reduced (P < 0.05 to P < 0.001) the number of infective D. viviparus larvae in cultures at dose-levels of 6250 and 12,500 chlamydospores/g of faeces. The larval reduction capacity was significantly higher for Troll A compared to CI3 when lungworm larvae were mixed in faecal cultures with eggs of Cooperia oncophora or Ostertagia ostertagi and treated with 6250 chlamydospores/g of faeces. Both fungal isolates showed a stronger effect on gastrointestinal larvae than on lungworm larvae. Two plot trials conducted in 1996 and 1997 involved deposition of artificial faecal pats containing free-living stages of D. viviparus and C. oncophora on grass plots. Herbage around the pats was collected at regular intervals and infective larvae recovered, counted and identified. These experiments showed that both D. flagrans isolates reduced the number of gastrointestinal as well as lungworm larvae in faecal pats. During both plot trials, the transmission of C. oncophora larvae, but not D. viviparus, from faecal pats to the surrounding herbage was clearly affected by climatic conditions. After collection of faecal pats from the grass plots one month after deposition, the wet and dry weight of pats as well as organic matter content were determined. No differences were found between the fungus-treated and non-treated control pats. This indicated that the rate of degradation of faeces was not affected by the addition of the fungus.  相似文献   

2.
The ability of the nematophagous fungus Duddingtonia flagrans to reduce the number of infective nematode larvae in coproculture was investigated in goats using different doses of chlamydospores (0, 1.25 x 10(5), 2.5 x 10(5), 5 x 10(5) chlamydospores/kg BW/day) given by oral administration or by voluntary consumption in feed during natural or experimental infections with nematodes. The kinetics of excretion of D. flagrans chlamydospores in the faeces was also determined using a dose of 5 x 10(5) chlamydospores/kg BW/day for five days. For all the trials, the faecal nematode egg outputs were determined by a modified McMaster method and standard coprocultures were set up (14 days, 25 degrees C) to determine the number of larvae emerging from culture in fungus treated and control faeces. When chlamydospores were orally administered, the number of larvae were reduced by 50 to 97% when compared to control cultures. No difference in the level of larval emergence from the culture was seen for experimental or natural infections at the different chlamydospore dose rates. In contrast, when chlamydospores were distributed in the feed, a dose-dependent relationship was observed 10 days after the start of administration, the larval development being 2.0%, 14.0% and 86.9% for 5 x 10(5), 2.5 x 10(5) and 0 spores/kg BW/day, respectively. In addition, the kinetic study showed that the larval emergence from coproculture in the fungus group was statistically lower than in the control group from the second day of administration of the chlamydospores and remained lower until the second day after the last administration (p < 0.05). The results indicate that, for goats in farm conditions, a minimum daily dose of 5 x 10(5) chlamydospores/kg BW must be used to ensure a high treatment efficacy and that daily administration is preferable for maintenance of efficacy over time.  相似文献   

3.
Effective alternatives to anthelmintic treatment against nematode parasites of goats are required because of the high prevalence of benzimidazole resistance. Towards this objective, the nematophagous fungus, Duddingtonia flagrans (Df), was used in a plot study against two main parasitic nematode species of goats, Teladorsagia circumcincta (Tcir) and Trichostrongylus colubriformis (Tcol). Worm-free, culled goats were experimentally infected with strains of Tcir and Tcol to constitute donors. Half of the animals were periodically given Df chlamydospores at a daily dose of 2.5 x 10(5) spores/kg BW while the remaining animals were kept as controls. At 5 time periods i.e. March, May, July, September and November 2001, corresponding to the main grazing season in France for goats, faeces were collected from the 6th day of fungus administration for the following 2 days to obtain approximately 1 kg of faeces from each group of animals: Tcir/Control, Tcol/Control, Tcir/Fungus, Tcol/Fungus. For each period and each group, the faeces were deposited on a 1 m2 grass plot and the grass was cut (3 replicates) on weeks 2, 4, 6, 8,12 after deposition, for infective larval recovery. Larvae were counted and the results were expressed as a ratio of larvae/eggs deposited. On the plots with the control faeces deposited in March, July and September, the grass infectivity due to Tcir and Tcol was similar and the maximum number occurred between 2 and 4 weeks post deposition. In May, the maximum numbers of larvae were not recorded until 8 weeks after deposition, due to high daily temperatures and dryness. In November, larval development took place only for Tcir. On the plots with the fungus treated faeces, a significant reduction in grass infectivity occurred for both nematodes and ranged from 50-60% in May, July and November deposits to 80-90% in the September deposit. On the contrary to these findings, no difference was recorded between the fungus and control plots for the March deposit. In conclusion, D. flagrans is suitable for reducing the number of infective larvae in the herbage during the main part of the grazing period for the most important digestive nematodes of goats.  相似文献   

4.
Two anthelmintics, fenbendazole and cambendazole, were used in an attempt to eliminate Muellerius capillaris infections in a group of 44 goats. During the course of this study (508 days), M capillaris larvae were found in at least one fecal specimen from each of 22 of the 44 goats. All 44 goats were dewormed with fenbendazole (30 mg/kg of body weight) at the onset of this study (day 18). Two additional dewormings with fenbendazole at 4- to 8-week intervals were restricted to the goats that continued to shed M capillaris larvae. On the basis of routine fecal examinations, fenbendazole eliminated M capillaris larvae from the feces of 8 (36%) of these 22 goats. On day 253, cambendazole (60 mg/kg) was given orally to 17 of these 22 goats (2 of the 22 had died and 3 were not available for treatment); 13 of these goats were still shedding M capillaris larvae. Cambendazole eliminated M capillaris larvae from the feces of 10 (77%) of these 13 goats chronically infected with M capillaris.  相似文献   

5.
The field efficacy of eprinomectin against a natural infection with Muellerius capillaris was evaluated in adult dairy goats. A total of 13 animals were included in a crossover treatment study. Animals were treated with eprinomectin (0.5 mg/kg) in the spring and again in the autumn of 2006, and monitored by enumeration of the lungworm larvae per gram of faeces (LPG). The reduction in LPG on days 7, 21 and 42 after treatment was used to evaluate the anthelmintic efficacy. Both in the spring and in the autumn a 100% reduction (P<0.01) in LPG was observed on days 21 and 42. These results illustrate that eprinomectin applied as a topical pour-on is a practical alternative to benzimidazole treatment of lungworms in dairy goats. No adverse reactions to the eprinomectin treatment were observed.  相似文献   

6.
Investigations were made into the timing of administration of Duddingtonia flagrans as a biological control agent against ovine parasitic nematodes including stongylid and Nematodirus spp. Faeces from 3-4 months old male lambs were deposited onto pasture plots that had never been grazed by sheep. The trial was conducted over two consecutive years (1998 and 1999). For both years, the following three plot types were involved: Sim plots had faeces containing nematode eggs and Duddingtonia flagrans spores deposited simultaneously; Post plots had faeces containing nematode eggs followed 2 weeks later by faeces containing D. flagrans spores alone; Control plots had faeces containing only nematode eggs; Prior plots (included in 1999) had faeces containing D. flagrans spores alone followed 2 weeks later by faeces containing nematode eggs. In each year, two deposition periods were involved: July and August in 1998 and June and July in 1999. During the first year pasture samples were collected at 2, 4, 6, 8 and 12 weeks after initial deposition. In 1999, additional samples were collected at 10, 16 and 20 weeks. Larvae were extracted from the pasture samples and counts performed to estimate the number and species of infective third-stage (L(3), larvae) present. The number of third-stage strongylid larvae on pasture was significantly lower on Sim plots compared to the remaining plot types for both years at all deposition times (P<0.001). This was also the case for the number of Nematodirus infective larvae in August deposition plots in 1998 (P<0. 02). There was no significant difference between treatments in both deposition times in 1999 and July deposition plots in 1998 for the Nematodirus data. These results suggest that D. flagrans, if deposited at the same time as parasite eggs prevents transmission of third-stage larvae from the faecal deposit onto pasture, including occasionally Nematodirus species, but does not have an effect on third-stage parasitic nematode larvae in the surrounding soil.  相似文献   

7.
The population density and level of infection of terrestrial molluscs, and the output by sheep of first stage protostrongylid larvae, were assessed monthly during a 1-year study. Muellerius capillaris was the predominant protostrongylid (approximately 80% of the larval output); Neostrongylus was also found. Eobania vermiculata, Cernuella virgata and Trochoidea elegans were the most common molluscs. Juveniles were less infected than adults. Banded E. vermiculata had a lower intensity of infection than unbanded ones. Nearly 75% of protostrongylid larvae harboured by molluscs on the studied pasture were found in E. vermiculata. The infectivity of pasture was at its lowest in the dry and hot period (June-September). Infection of snails was primarily related to temperature and the importance and frequency of rains, and secondarily to larval excretion in sheep faeces.  相似文献   

8.
The aim of this study was to test a pellet formulation in a sodium alginate matrix of Duddingtonia flagrans in the biological control of goat gastrointestinal helminths kept in a native pasture in a semi-arid region of Paraíba state, northeastern Brazil. An area of 2.4 ha was divided into three paddocks, where groups of seven goats ware formed. Each group received the following treatments during the months of March to August 2011: D. flagrans group, received 3g of pellets containing D. flagrans (AC001) for each 10 kg/l.w., twice a week; Moxidectin 0.2% group, received 0.2mg/kg of Moxidectin 0.2% orally, every 30 days; Control group, received 3g of pellets without fungi per 10 kg/l.w., twice a week. Each month, a tracer goat was placed in each group for 30 days and then sacrificed and necropsied. The D. flagrans group showed a greater reduction in EPG, increased weight gain, higher rates of packed cell volume and lower parasitic load burden in the tracer goats compared to Moxidectin 0.2% and Control groups. D. flagrans was efficient in controlling goat gastrointestinal helminthiasis in a semi-arid region of northeastern Brazil.  相似文献   

9.
The nematode-trapping fungus Duddingtonia flagrans may be used in biological control of parasitic nematode larvae in faeces of domestic host animals after feeding the hosts with fungal chlamydospores. In this experiment a possible undesirable fungal impact on earthworms, of the species Aporrectodea longa, was investigated. As earthworms eat animal faeces, D. flagrans may come into contact with earthworms both in their alimentary tract and on their body surface. However during the experimental period of 20 days, when earthworms were living in soil and eating cattle faeces that were heavily infested with viable chlamydospores of D. flagrans there were no indications of internal or external mycosis among the earthworms.  相似文献   

10.
The efficacy of netobimin against digestive tract strongyles and the small lungworm Muellerius capillaris was tested in a dairy goat herd. The drenches were given orally at the rate of 20 mg/kg of body weight once, 10 mg/kg on 2 successive days, or 7.5 mg/kg on 3 successive days. Fecal egg counts and larval counts were done 8 days before and on the day of drenching; further counts were performed on postdrenching days 8 and 18. Two goats were necropsied, 1 on postdrenching day 5 and 1 on day 10 in the group treated on 3 successive days. The fecal egg counts were reduced by 44 to 79% depending on dosage on postdrenching day 18; the remaining worms were Trichostrongylus colubriformis. The larval counts of M capillaris were reduced by 72 to 92%, depending on dose. The reduction was significant in all the treated groups, compared with that in the control group. The use of netobimin at the dosage of 10 mg/kg given on 2 successive days or 7.5 mg/kg given on 3 successive days might be recommended to treat goats infected with Muellerius spp and digestive tract strongyles.  相似文献   

11.
A cross-sectional study of lungworm infection was carried out with the aim of determining the prevalence of lungworm infection of small ruminants and identifying the species of the respiratory helminthes circulating in six districts of northeastern Ethiopia: Debresina, Legambo, Habru, Kalu, Chaffa-Dawi and Artumana-Fersejelle. Faecal and postmortem examination were conducted from 1162 and 104 animals, respectively. An overall infection rate of 53.6% and 66.3% was found by faecal and postmortem examinations, respectively. Significant difference (p<0.05) was found between areas of different altitude with an infection rate of 30.4%, 32.5% and 71.3% at low, medium and high altitude areas, respectively. Prevalence on the different months was insignificant (p>0.05). The prevalence of Dictyocaulus filaria and Muellerius capillaris infection showed a significant difference (p<0.05) between young, adult and old age groups. The prevalence of D. filaria decreases and that of M. capillaris increase with increasing age of the animal. Animals under relatively good management system have been found less affected with significant difference (p>0.05) than their counterparts at relatively poor management system. The infection rate between male and female animals showed significant difference (p<0.05) with prevalence rate of 44.4% and 59.3%, respectively. A significant difference between sheep and goats was also noted with infection rate of 24.4% and 50.7%, respectively. Monthly worm burden of D. filaria infection showed significant difference (p>0.05) while it was insignificant in case of M. capillaris. Due to its impact on production, emphasis should be given for the control and prevention of lungworm infection in highland areas.  相似文献   

12.
The aim of this study was to determine the trapping efficacy of Duddingtonia flagrans against Haemonchus contortus at the temperature ranges experienced around lambing in the major sheep producing regions of Australia. Faeces were collected from Merino wethers, maintained in an animal house and which had received either D. flagrans chlamydospores for a 6-day period (DF) or not (NIL). Faeces were incubated at one of four daily temperature regimens which were composed of hourly steps to provide 6-19 degrees C, 9-25 degrees C, 14-34 degrees C and 14-39 degrees C to mimic normal diurnal air temperature variation. Enumeration of the number of preinfective and infective larvae that had migrated from or remained in faecal pellets was used to calculate percentage recovery and trapping efficacy of D. flagrans. Recovery of H. contortus larvae of both stages was significantly lower in DF faeces but the magnitude of the effect was considerably greater for infective larvae. Mean recovery of infective larvae from NIL and DF faeces was 10.6 and 0.4%, respectively, indicating a mean trapping efficacy of 96.4%. The lowest trapping efficacy (80.7%) was observed at 6-19 degrees C but total recovery of infective larvae, from DF faeces, was greatest at the two highest temperature regimens, although still less than 0.9%. The results of this study indicate that typical Australian lambing temperatures should not be a barrier to the use of D. flagrans as an effective biocontrol of H. contortus in Australia.  相似文献   

13.
This study determined the in vitro effects on the viability of internal parasites of grazing undrenched weaner deer on either chicory (Cichorium intybus) or perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) pasture. One experiment investigated the hatching and development of gastrointestinal nematode eggs and larvae, and the development and motility of L1 lungworm (Dictyocaulus eckerti) larvae, and a second experiment used larval migration inhibition assays to test the viability of L1 lungworm larvae extracted from the faeces of weaner deer grazed on either chicory or pasture when they were incubated with rumen and abomasal fluids from fistulated deer also grazing on chicory or pasture. The incubations were undertaken with and without added condensed tannins purified from chicory and with or without polyethylene glycol (PEG) to bind the tannins. Chicory had no effect on the hatching and development of gastrointestinal nematode eggs and larvae. Grazing chicory reduced the number of lungworm larvae developing to the L3 stage, and L1 lungworm larvae from the faeces of chicory-grazed deer were less viable in rumen and abomasal fluid than larvae from pasture-grazed animals. Abomasal fluid was significantly (P < 0.001) less inhibitory to the migration of L1 lungworms than rumen fluid. When the larvae were incubated in rumen and abomasal fluids from chicory-grazed deer, their passage through sieves was significantly (P < 0.001) reduced in comparison with when they were incubated in the fluids from pasture-grazed deer Adding condensed tannins to rumen fluid increased the inhibition of the migration of L1 lungworm larvae but PEG removed this inhibition; this effect was not observed with abomasal fluid.  相似文献   

14.
In five trials it was found that the daily administration of fenbendazole in the food for 1 or 2 weeks at dosages of 1.25, 2.5 or 5 mg kg-1 live weight was highly effective against Muellerius capillaris infection in goats. Treated animals had significantly lower numbers of larvae in the faeces for up to 223 days after treatment. There was no obvious difference between the different dose levels. Daily treatment for 2 weeks seemed to be slightly more effective than treatment for 1 week. Treatment for 1 week twice with an intervening period of 1 week seemed to be more effective than treatment for 2 weeks continuously. Goats given a single treatment with fenbendazole at 25 mg kg-1 had a significantly lower number of M. capillaris larvae in their faeces on Days 34 and 69 after treatment than the controls, but on Days 126 and 156 after treatment there was no significant difference between these two groups. Albendazole given daily for 2 weeks at a dose of 1.0 mg kg-1 showed a significant effect for up to 153 days after treatment, which was similar to the result of daily treatment with 1.25 mg kg-1 fenbendazole. Goats treated with albendazole twice at 10 mg kg-1 with a 1 week interval showed a significant reduction in the number of Muellerius larvae in the faeces on Day 41 after treatment, but not on Days 97 and 153 after treatment.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

15.
An experiment was carried out in 1997 to test the efficacy of an isolate of the microfungus Duddingtonia flagrans against free-living stages of horse strongyles under conditions in the field and to assess the eventual effect of the fungus on the normal degradation of faeces. Faecal pats were made from faeces of a naturally strongyle infected horse, which had been fed fungal material at a dose level of 106 fungal unit/kg bwt. Control pats without fungi were made from faeces collected from the same animal just before being fed fungi. Faecal cultures set up for both groups of faeces to monitor the activity of the fungus under laboratory conditions showed that the fungus significantly reduced the number of infective third-stage larvae (L3) by an average of 98.4%. Five faecal pats from each batch of faeces were deposited on pasture plots at 3 times during spring-summer. The herbage around each pat was sampled fortnightly to recover L3 transmitted from faeces. The results showed that the herbage infectivity around fungus-treated pats was reduced by 85.8-99.4%. The remaining faecal material at the end of each sampling period was collected, and the surviving L3 were extracted. Significantly fewer larvae were recovered from the fungus-treated pats. Analysis of wet and dry weight of the collected pats, as well as their organic matter content, were performed to compare the degradation of faeces of both groups. The results indicated that the presence of the fungus did not alter the degradation of the faeces.  相似文献   

16.
2093 Faecal samples from 74 commercial meat ovine flocks were collected and examined by the Baermann-Wetzel method for protostrongylid infection. The risk of being infected by lungworms was evaluated with a data mining classification tree (CHAID), and the intensity of infection with a general linear model (GLM). 242 out of 2093 faecal samples examined were positive for protostrongylid infection (11.6%; 95% CI 10.2-12.9). Only two species were found, Muellerius capillaris (97.9%) and Neostrongylus linearis (5.4%). 50 out of 74 farms presented at least one animal shedding protostrongylid larvae in faeces. All of them held animals infected by M. capillaris and seven presented mixed infections with N. linearis. Average larval output in infected sheep was 11.9 (SD 30.91). This study showed that protostrongylid prevalence in sheep for meat production was determined mainly by a positive interaction with Dictyocaulus filaria infection; other factors that have influenced over protostrongylid infection were age, introducing external animals in the flocks, mixed management with goats and animal density in pastures. Treatment effects on prevalence were only observed in flocks that did not introduce ewes. The lowest protostrongylid prevalence has been reported in flocks without D. filaria infection and without contact with goats.  相似文献   

17.
To evaluate the efficacy of an ivermectin controlled-release capsule (CRC), which delivers 1.6 mg ivermectin per day intraruminally for 100 days to sheep weighing 40-80 kg (IVOMEC Maximizer CR Capsule for adult sheep, Merial), against small lungworms two studies with 48 naturally infected adult female Merino Landrace sheep were conducted. The sheep were allocated by restricted randomization based on bodyweight to untreated controls or received an ivermectin CRC. Eight sheep per group were necropsied 35, 70 or 105 days post-treatment. Lungworms were recovered by dissection or peptic digestion of the lungs. Baermann/Wetzel technique was used for faecal lungworm larval counts at weekly intervals. The efficacy of treatment was 100% against Dictyocaulus filaria and Protostrongylus rufescens (P < 0.05) at each necropsy day. The efficacy against Protostrongylus brevispiculum, Cystocaulus ocreatus and Neostrongylus linearis increased from 35 to 105 days after administration of the CRC and was found to be 100% (P < 0.01), 96.6% (P < 0.01) or 99% (P < 0.01), respectively, at 105 days post-treatment. The reductions of Muellerius capillaris counts varied and were 96.2% (P < 0.05) at 70 days post-treatment and 44.6% (P > 0.1) at 105 days post-treatment. Faecal lungworm larvae disappeared nearly completely from at least 3 weeks after the ivermectin CRC administration for all protostrongylid species including M. capillaris so that pasture infectivity will be subsequently significantly reduced.  相似文献   

18.
The ability of the nematode-killing fungus Duddingtonia flagrans to reduce number of infective larvae of three species of gastro-intestinal parasitic nematodes developing in dung was investigated in both goats and sheep. Groups of lambs and kids (12-20 weeks old) were given mono-specific infections of Haemonchus contortus, Ostertagia (Teladorsagia) circumcincta or Trichostrongylus colubriformis. Following patency of the infections (t1) faecal samples were collected for determination of faecal nematode egg count (FEC) and culture of parasite larvae. Groups of animals were then dosed on 2 consecutive days with one of the two dose rates of the fungus (250,000 or 500,000 spores/kg liveweight). One (t2) and 5 (t3) days after the second dose of fungus samples were again collected for FEC and culture. The number of larvae recovered from the faecal cultures at t1 and t3 were used as controls to assess the efficacy of the experimental treatment at t2. Average efficacy was 78% with group means ranging from 40 to 93%. Dose rate of fungus appeared to influence efficacy against O. circumcincta but not against H. contortus or T. colubriformis. Overall, there were no differences in the efficacy of the fungus against any of the parasite species or in either host animal. The results of this trial indicate the potential use of this fungus as a broad spectrum anti-parasite agent for use in both goats and sheep.  相似文献   

19.
Previous observations showed that Duddingtonia flagrans chlamydospores were visualized in McMaster chambers containing faeces of treated sheep. This trial explored the McMaster technique as a tool to quantify chlamydospores in sheep faeces. A range of individual chlamydospore doses (from 19.5 x 10(6) to 177.5 x 10(6)) were offered orally to nine lambs for 7 consecutive days. A faecal sample (5 g) was daily obtained from the rectum of each animal (from days 1 to 13) to perform the McMaster technique using a sugar flotation fluid with 1.27 g/mL density. Each chlamydospore counted in the McMaster chamber was considered as 50 chlamydospores per g of faeces (CPG). The results confirmed that the estimated CPG was associated with the daily dose offered to the animals (r(2)=0.90; P<0.001). Furthermore, the total chlamydospore dose received by each animal was strongly associated to the total quantity of CPG obtained from the bulk faeces (TCtot) (r(2)=0.96; P<0.0001). Quantification of CPG can be used as a helpful tool to determine the number of chlamydospores reaching the faeces in orally dosed animals. This could be used to evaluate the efficacy of D. flagrans for the control of gastrointestinal nematode larvae in sheep faeces.  相似文献   

20.
A slaughterhouse survey to determine prevalence and larval burden of Oestrus ovis larvae in sheep and goats was performed monthly during one year in Pézenas, South of France, northern mediterranean region. A total of 1303 sheep and goat heads were selected at random. O. ovis larvae were found in 274 sheep out of 631 (43.4%), and the prevalence rate varied from 14.3% in February to 65% in October. The mean number of larvae in infected sheep heads was 10.86 with 9.24 L1, 0.91 L2 and 0.71 L3. One hundred and ninety-one goats out of 672 were infected (28.4%), and the prevalence rate varied from 6.25% in September to 47.1% in April. In infected goat heads, the mean parasitic burden was 5.35 with 4.04 L1, 0.73 L2 and 0.58 L3. These results confirm worldwide observations indicating that the prevalence and the parasitic burdens are less in goats than in sheep.  相似文献   

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