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1.
In a series of five laboratory experiments observations were made on the role of Pilobolus in the translation of infective lungworm larvae from faeces of cattle. The results indicated that a substantial proportion of the lungworm larvae present in the faeces may be translated from the faeces by this fungus within eight days at a temperature of 15 degrees C. No clear relationship was observed between the numbers of Pilobolus and the translation of lungworm larvae. Further a longitudinal study on the occurrence of Pilobolus on faecal pats of grazing calves showed that between the beginning of July and the middle of September peak emergence of sporangia generally occurred within one week and most sporangia emerged within three weeks. From faecal pats which had been deposited at the end of September and the middle of October emergence of sporangia was lower and mainly occurred after two to four weeks. 相似文献
2.
《Preventive veterinary medicine》1987,5(1):43-50
Pilobolus kleinii spores isolated from cattle faeces were administered daily by the oral route to two donor calves excreting Dictyocaulus viviparus larvae in their faeces.Faeces were collected at daily intervals from the donor calves, and on each day a pooled sample of 500 g was placed outside a pen containing two parasite-free experimental calves. A wire screen prevented the experimental calves from coming into contact with the artificially deposited faecal portions.Pilobolus kleinii fruit bodies were observed on the faecal surface in large numbers 5–10 days after deposition.Sporangial discharge was observed to be directed against a window which served as the only light source. Sporangia were found up to 110 cm away from the faeces, and it was estimated that at least 29% of them had been transmitted to a feeding trough placed close to the wire screen. Infective D. viviparus larvae were observed on some of the discharged sporangia.The experimental calves started excreting low numbers of D. viviparus larvae in their faeces 40–49 days after the first portions were deposited. These results indicate that P. kleinii was reponsible for the infection of the experimental calves with D. viviparus, through the discharge of sporangia carrying infective lungworm larvae. 相似文献
3.
A S Fernández M Larsen P Nansen J Gr?nvold S A Henriksen H Bj?rn J Wolstrup 《Veterinary parasitology》1999,85(4):289-304
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
4.
M Eysker 《Research in veterinary science》1991,50(1):29-32
Dispersal of Dictyocaulus viviparus larvae by Pilobolus sporangia was studied on 29 faecal pats deposited between the end of June and late October 1988. Faecal pats were covered daily from day 3 to 4 after deposition with a large petri dish to measure the numbers of sporangia released and the numbers of larvae carried. The yield of both was variable. Dispersal of lungworm larvae was lowest on over-grazed pasture or when Pilobolus growth was very poor. When faecal pats were sheltered by a long sward, 17 per cent or more of larvae present at deposition were transported in this manner. In July and August, peak dispersal of lungworm larvae was on day 5, in September on day 6 and in October on day 7, the increasing time intervals being probably associated with decreasing temperature. 相似文献
5.
6.
R.Jess Jørgensen 《Veterinary parasitology》1980,7(2):153-167
A field experiment was conducted over two grazing seaons with calves on a permanent pasture in order to follow the pattern of infection with Dictyocaulus viviparus. Infective larvae persisted during the first, but not during the second, winter of observation. By means of the agar-bile herbage technique, a moderate first peak of infection was demonstrated in the pasture 2–3 weeks before the appearance of respiratory signs in the calves. Fluctuations in faecal larval output were reflected in the herbage contamination with infective larvae close to faecal pats. This, as well as the horizontal dispersion of larvae in the pasture, took place in less than a week. The proportion of lungworm larvae recovered away from faeces was low during a period of dry and hot weather while herbage sampling at two-hour intervals during two days showed an increase in herbage contamination with lungworm larvae, but not with trichostrongyle larvae between 10 a.m. and 12 noon.The infectivity of the pasture was monitored by tracer calves and compared with the results of the pasture sampling. The general course of the infection in the calves and in the pasture was the results of interaction between them. In addition, the pasture infection was influenced by climate and the infection in the calves by the development of immunity. The course of infection in individuals appeared to have an influence on the general course of the infection through the contamination of the pasture. 相似文献
7.
A model of sub-clinical parasitism in young red deer, using concurrent trickle infections of lungworm (Dictyocaulus sp.) and mixed gastro-intestinal (GI) nematodes of deer-origin was evaluated. 20 parasite-free deer calves were artificially reared indoors from 4 days of age. A further five calves were naturally reared on pasture with their dams, treated with anthelmintic and brought indoors at 3-4 months. At 4-4.5 months of age they were individually housed and allocated to five groups (n=5). Groups were dosed 3 x per week, for 9 weeks with 0, 100 and 500, 200 and 1000 (2 groups), 400 and 2000 infective larvae of lungworm and mixed GI nematodes, respectively, cultured from deer faeces. Liveweight and voluntary feed intake measurements and faecal and blood samples were taken weekly. In the fourth week following cessation of trickle infection, deer were euthanased and lung and GI nematodes recovered. Both lungworm and GI nematode infections became patent at Week 4 of infection. Maximum group arithmetic mean faecal egg counts were 100-190 epg. Maximum group arithmetic mean faecal lungworm larval counts were 58-123 lpg. Group arithmetic mean nematode counts at slaughter ranged from 439-806 for GI nematodes and 31-73 for lungworm, respectively. Despite low nematode counts, reduced liveweight gain, voluntary feed intake and serum albumin concentration, elevated serum pepsinogen, gastrin and globulin concentrations and elevated peripheral eosinophil counts and slight haemoconcentration, but no clinical signs, were observed. The reduction in liveweight gain was related to the reduction in voluntary feed intake (r2=0.83; p<0.088). Naturally-reared deer had similar liveweight gains, voluntary feed intake and nematode counts to artificially-reared deer. Thus, methods of infection to produce concurrent sub-clinical lungworm and GI nematode burdens for study of sub-clinical parasitism in young deer have been defined. 相似文献
8.
In a series of laboratory studies the optimum conditions for the development and survival of the free-living stages of strongyle parasites occurring in horses in tropical north Queensland were determined. No differences in behaviour were noted between the strongyle species. Development to the infective stage occurred only between 10 and 35 degrees C. The rate was affected by temperature, taking 15-24 days and 3 days, respectively, at the lowest and highest temperatures for the developing stages to reach the infective third stage. Yields of infective larvae were very low outside the range 20-33 degrees C, and were highest at 28 degrees C. Survival of infective larvae was good between 20 and 33 degrees C, and large numbers were recovered after 3 months in faeces incubated at 20-28 degrees C. At 33 and 37 degrees C larval survival was affected by the moisture content of the faeces, with infective larvae surviving better in dry than in moist faeces; even a residual moisture level of 40% significantly reduced the number of larvae recovered from faeces incubated at 37 degrees C for 1 month. Moisture also affected larval development, especially at the higher temperatures of 25-39 degrees C. When faecal moisture content fell to less than or equal to 20% by 3 days, larvae which had not yet reached the infective stage were still pre-infective at 7 days, while all larvae in faeces with adequate moisture had reached the infective third stage. It was not possible to determine the critical faecal moisture level below which larval development ceased, however, 28 degrees C (range 25-33 degrees C) was found to be the optimum temperature. Larval development was very rapid and yields of infective larvae highest at this temperature. 相似文献
9.
Ploeger HW Verbeek PC Dekkers CW Strube C Van Engelen E Uiterwijk M Lam TJ Holzhauer M 《Veterinary parasitology》2012,184(2-4):168-179
To test the value of a recently developed bulk-tank milk (BTM) ELISA for diagnosing (sub)clinical Dictyocaulus viviparus infection in lactating dairy herds under field conditions, bulk milk samples were collected from farms with or without clinical symptoms suspected to be caused by lungworm infection. Results of the BTM ELISA were compared against individual examinations for lungworm larvae in faeces and lungworm antibodies in serum from up to 20 heifers (parity 1) and up to 20 cows (parity ≥ 2) on the same farms. This also allowed, for the first time, to examine the value of individual faecal and serological examinations in the diagnosis of (sub)clinical lungworm infections. In total, 33 farms participated. Of these, 16 reported clinical symptoms possibly related to lungworm infection (defined as a suspected positive clinical status or CS(+)) and 17 reported having no such symptoms (CS(-)). In total, 503 heifers and 649 cows were sampled. Of all faeces samples positive for lungworm larvae, 94 were from heifers (18.9% of all heifers) and 75 from cows (11.7% of all cows) (P<0.001). Of all sera positive for lungworm antibodies, 130 were from heifers (26.1% of all heifers) and 113 from cows (17.5% of all cows) (P<0.001). Of the CS(-) farms 41% had at least one heifer or cow shedding larvae and 71% had at least one seropositive heifer or cow. Of the CS(+) farms this was 81% and 94%, respectively. There were only 4 farms, all CS(-), where none of the animals were found shedding larvae and all animals tested seronegative. This implies that on 76% of the CS(-) farms lungworm infection circulated unnoticed. On all CS(+) farms the suspicion that lungworm caused the respiratory symptoms was confirmed by the individual faecal and serological examinations, whereas the BTM ELISA confirmed presence of lungworm on half of the CS(+) farms. The latter in particular occurred on farms with the more severe outbreaks. Overall, of 32 available BTM samples 10 tested positive (8 of 15 CS(+) and 2 of 17 CS(-) farms). For diagnosing suspected lungworm disease it was concluded that testing a BTM sample might suffice in case of moderate to severe outbreaks. However, in case of a mild outbreak with just a few animals coughing, examining individual animals has to be preferred over testing a BTM sample. The likelihood to detect lungworm infection is higher if heifers are sampled compared to cows. Sensitivity of the BTM ELISA was 35.7% if the presence of at least one seropositive and/or one larvae shedding animal in the herd was used to define lungworm positive farms. On average, at least 30% of the herd had to be seropositive before the BTM ELISA was found positive for lungworm antibodies. Results indicate that the BTM ELISA in its current form does not appear to be suitable for surveys on the prevalence of lungworm presence on farms. However, this BTM ELISA might be used in large-scale surveys to detect, for instance, annual changes in percentage positive farms, as long as it is recognized that positivity is more closely related to incidence of lungworm disease than to prevalence of lungworm infection. 相似文献
10.
The development of the free-living stages and yields of infective third stage strongyle larvae in faeces from a horse with a mixed natural infection deposited on pasture plots were studied over a 2-year period in a coastal area in tropical north Queensland. Two sets of faecal masses (one exposed to, and the other protected from the action of a natural population of dung beetles) were deposited monthly and after 7 days faecal samples were taken for larval recovery and counts. Hatching and development of the free-living stages occurred in faeces on pasture throughout the year. Development was rapid as infective stages were reached within a week of faecal deposition in all months. Yields of infective larvae were affected by the season and the action of dung beetles on the faecal masses. Highest yields were obtained from both beetle-exposed and protected faeces during winter (June to August) and lowest yields were in spring (September to November). High temperatures in spring and summer resulted in low yields of larvae, however, the dry conditions in spring made this season the most unfavourable period. In autumn and winter the temperatures were never low enough to stop or markedly slow down the rate of development, and allowed the development of large numbers of infective larvae. Dung beetle activity was observed throughout the year, and exposed faeces were usually completely dispersed within 24 h of deposition. This resulted in lower yields of infective larvae from these than from protected faeces. Though larval yields were lower, the actual numbers were still substantial so as to cast doubt on the usefulness of these beetles as biological control agents for equine strongylosis in the dry tropics. 相似文献
11.
The small lungworm Muellerius capillaris is very prevalent in goats and causes production losses. Its control is particularly difficult. The nematophagous fungus Duddingtonia flagrans has been shown to be effective in trapping a large range of gastro-intestinal nematode larvae but its trapping activity against small lungworm remains to be assessed. The purpose of this work was firstly, to evaluate the ability of first-stage larvae of M. capillaris (L1) to induce trap formation in in vitro conditions and secondly, to determine the effect of D. flagrans on the L1 infectivity to snails. In experiments on agar, the presence of L1 failed to induce any D. flagrans traps whereas in the same conditions, gastro-intestinal third-stage larvae induced 44-135 traps/cm(2) depending on the species. Moreover, when the traps were pre-induced by Haemonchus contortus larvae, the L1 of M. capillaris were not trapped. For the in vivo trial, two goats naturally infected with M. capillaris received D. flagrans chlamydospores at the daily dose rate of 5x10(5) spores/kg BW for 8 days. Faeces were collected individually before, during and 11 days after spore administration. On each day of harvest, the initial larval output was determined. The remaining faeces were subjected to coproculture at 21 degrees C for 7 days. At the end of this period, L1 were collected and used to infect snails (30 snails per goat isolate each snail given 40 L1 by direct deposit of the larvae on the foot of the snail). These snails were artificially challenged in contrast to others that were exposed to natural infection by exposure to faeces carrying first-stage M. capillaris larvae. The natural infection used the same number of snails, i.e. 30 snails deposited on the faeces of each goat. After 3 weeks at room temperature, the infective larvae present in the snail foot were counted. There was no difference in the survival of the L1 in faeces after coproculture whether the faeces contained D. flagrans or not. The infectivity of the extracted larvae from the two goats before and after fungal administration was the same. The number of infective larvae per snail obtained after "natural" infection showed variations that were not related to the presence of D. flagrans mycelium in faeces. These trials clearly indicate that D. flagrans was unable to trap or to alter the infectivity of M. capillaris first-stage larvae and thus cannot be considered as a non-chemotherapeutic alternative approach to the control of the small lungworm in goats. 相似文献
12.
J L Duncan J Armour K Bairden G M Urquhart R J J?rgensen 《The Veterinary record》1979,104(13):274-278
In the West of Scotland the epidemiology of parasitic bronchitis in grazing calves was studied over a two year period with the aid of tracer calves and herbage examinations for Dictyocaulus viviparus larvae. The observations of both years emphasised the importance of overwintered lungworm larvae as a source of disease. In the first year it was shown that the ingestion and development of these overwintered larvae were, by themselves, directly responsible for severe morbidity, high faecal larval counts and deaths. In the second year it was shown that pasture ungrazed during the winter and spring and from which a hay crop was removed in mid-summer was still capable of producing clinical parasitic bronchitis in susceptible calves within three to four weeks of their introduction in later summer. In both years there was some evidence that the outbreaks appeared to be associated with the sudden availability of infective larvae on the herbage. The possibility that such larvae may have survived for many months in the soil is discussed. Despite the heavy challenge with lungworm larvae experienced by the grazing calves in the first year those vaccinated with lungworm vaccine survived, their clinical signs were mild and of short duration and their faecal larval output was greatly reduced. 相似文献
13.
G A Oakley 《Research in veterinary science》1982,32(2):163-169
A five year ley pasture was used as a source of natural infection with Dictyocaulus viviparus for cattle in anthelmintic trials. Pasture larval counts, faecal larval counts of permanently grazing calves and lungworm burdens harboured by tracer calves were monitored in three grazing seasons to assess the pattern of infection. Carrier calves were introduced at the beginning of the grazing season in the first two years of the study but not in the third. In the fourth year the pasture was subdivided into two paddocks where overwintered infection with and without carrier infection were compared. A control paddock exposed to carrier infection but no overwintered infection was also monitored. Pasture larvae survived the winter but carrier infection appeared to make a larger contribution to pasture larval counts and the onset of parasitic bronchitis in susceptible calves. In the absence of grazing cattle at the end of the grazing season the concentration of D viviparus larvae on the herbage fell rapidly to undetectable levels. Discrepancies between contamination of herbage by infective D viviparus larvae and infectivity of pasture for susceptible cattle occurred in all years but were particularly marked on the third year when natural immunity appeared to influence the number of lungworms accumulating in tracer calves. Failure to recover lung worms from tracer calves cannot be regarded as an accurate indication of lungworm free pasture. In the first three years the proportion of the lungworm population which was inhibited in tracer calves was higher early and late in the grazing season and negligible in mid season. This suggests that a predisposition to inhibition in larvae which have overwintered on pasture may influence the time of onset of parasitic bronchitis in the next grazing season, but results from the fourth year did not support this hypothesis. 相似文献
14.
On the basis of routine diagnostic examinations of 12424 bovine faeces samples for larvae of Dictyocaulus viviparus, performed during the period 1963 through 1977, some calculations and reflections have been made on the incidence and epidemiology of lungworm infection in cattle in Denmark. It seems justified to conclude that dictyocaulosis is an important disease in heifers and cows as well as in calves. A distinct seasonal variation in the incidence of lungworm infection is apparent, in that more than 85% of the faeces samples were submitted within the period July through October. Lungworm larvae could be demonstrated in faeces samples from cattle during the winter and spring- This is considered to be of great importance with a view to re-establishment of the infection in the following grazing season. Overwintering of larvae on pastures seems possible. too, since patent infections among calves were demonstrated already in May and June. A comparison of meteorological data with totals of samples submitted and with relative numbers of positive samples seems to confirm, that both the level and the spread of lungworm infections are influenced by the amount of rainfall during the period June through August. 相似文献
15.
The patterns of gastrointestinal and lung helminth infections in grazing calves were studied in two small grazing experiments carried out between May and October in 1985 and 1986, respectively, at Utrecht State University. For lungworm a very rapid translation of infective larvae was seen in both experiments, resulting in a rapid build-up of the worm burdens, and in July the second generation of Dictyocaulus caused husk. After the end of patency for lungworm, in the beginning of August, a rapid decrease in pasture infectivity, measured by pasture larval counts and worm counts of tracer calves, was observed. For the gastrointestinal nematodes the translation of infective larvae was much slower as a distinct 'midsummer increase' of pasture infectivity was not seen before the end of July. The worm counts of the tracer calves and the pasture larval counts showed that these larvae remained on pasture much longer than the lungworm larvae. As in Dictyocaulus, patency stopped in August-September in Nematodirus but not in Ostertagia and Cooperia, indicating a slower rate of development of immunity in both latter genera. In contrast to lungworm, the results indicate a clear and predictable seasonal pattern for gastrointestinal helminth infections. 相似文献
16.
Michael Larsen Peter Nansen Svend Aage Henriksen Jens Wolstrup Jrn Grnvold Anders Zorn Erik Wed 《Veterinary parasitology》1995,60(3-4):315-320
This study was undertaken to examine the potential of the nematode-trapping microfungus Duddingtonia flagrans to survive passage through the gastrointestinal tract of horses and subsequently to destroy free-living stages of cyathostomes in faecal cultures. Three different oral dose levels were tested, two horses being used for each level. Faeces were collected twice daily and the number of parasite eggs per gram of faeces were determined. The numbers of infective third stage larvae which developed in faecal cultures were determined after the cultures had been incubated for 2 weeks at 24°C. Results showed a positive relationship between dose level and reduction in the number of infective larvae. Fungi were recovered in faeces at times which corresponded to high larval reduction. 相似文献
17.
In the lungworm-endemic areas of Kashmir, 6-10 week old lambs of Karnah and Kashmir Merino breeds were vaccinated with two doses of 50 kR gamma-irradiated larvae of Dictyocaulus filaria, given a month apart. Assessed on the basis of reduced prevalence and significantly lower faecal larval output over an eight-month observation period, vaccinated lambs showed a high degree of resistance to naturally acquired D. filaria infection. The results also show that vaccination against D. filaria provided some degree of protection against infection with other lungworm species. 相似文献
18.
The effects of varying single doses of Dictyocaulus filaria larvae on the course of infection in lambs were studied. Four 6-months-old male lambs received an infection of 100 (Group I), 150 (Group II), 200 (Group III) and 300 (Group IV) infective larvae per kg body weight per lamb. No significant differences were observed in the lenght of prepatent period or in the onset of “useful patency” in animals receiving different quanta of infections. The percentage establishment of worms in lambs decreased as infection levels increased. The mortality and the severity of the disease produced in lambs was directly related to the level of infection given. Infected lambs vioded less quantity of faeces than their uninfected healthy controls. The number of larvae per gram of faeces (LPG) was highest in animals receiving infections of 300 larvae oer kg body weight. Allowing for the greater number of abnormalities associated with higher levels of infection, a dose of 150 larvae per kg was found to be the most suitable for establishment of infection in lambs for vaccine production. 相似文献
19.
Rhodes AP 《New Zealand veterinary journal》1993,41(3):131-133
One hundred and fifteen young red deer (Cervus elaphus), heavily infected with lungworm (Dictyocaulus viviparus) and lightly infected with gastro-intestinal nematodes, were divided into three groups. One group of 50 animals was treated with one adult sheep dose of a slow-release albendazole capsule, another group of 50 was dosed orally five times with liquid albendazole and 15 were left as untreated controls. The capsule eliminated faecal lungworm larvae during the 103-day trial period. There was a highly significant difference in faecal larval counts between the capsule-treated and control group. Over the trial period, the mean body weight gain of the untreated, liquid albendazole and capsule-treated animals was 0.1 kg, 4.5 kg and 7.8 kg respectively. 相似文献
20.
Three groups of eight Friesian calves, reared parasite-free, were experimentally infected with 1000 infective larvae of Dictyocaulus viviparus. Two groups were injected subcutaneously with 1% doramectin at 0.2 mg/kg body weight, one group 5 days after infection and the other 25 days after infection. A third group served as untreated controls. Faecal samples were examined for lungworm larvae on days 28, 32, 33, 34 and 35 after infection; the calves were killed and necropsied 39 or 40 days after infection and any lungworms present recovered and counted. Doramectin proved 100% effective against both 5-day-old and mature D. viviparus infections. 相似文献