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1.
Moreno FC Gordon IJ Knox MR Summer PM Skerrat LF Benvenutti MA Saumell CA 《Veterinary parasitology》2012,187(1-2):237-243
The study of the anthelmintic properties of plants rich in plant secondary metabolites can provide ecologically sound methods for the treatment of parasites on grazing animals. The purpose of the present study was to evaluate the anthelmintic effect of five tropical native Australian plant species rich in plant secondary metabolites on adult Haemonchus contortus and Trichostrongylus colubriformis in experimentally infected goats. Thirty young, nematode-free goats were infected with 2500 H. contortus and 5000 T. colubriformis infective larvae thrice weekly for a week (day 1-7 of the experiment). On day 27 after first infection, the goats were allocated into six groups of five animals per group. From day 28 to day 35, fresh leaves from Acacia salicina, Acacia nilotica, Eucalyptus corymbia, Casuarina cunninghamiana and Eucalyptus drepanophylla were included in the goats diet. Five groups were offered leaves from one of these plant species and one group, the untreated control, received only the basal diet formulated with 20% Medicago sativa and 80% Avena sativa. Following plant material administration, the goats were monitored daily until day 40 and then slaughtered on day 41. Total faecal worm egg output, total production of larvae recovered from faecal cultures, total post-mortem worm burdens and the per capita fecundity of female worms were estimated. The toxicity of the plant species for the goats was measured by histopathological analyses of liver and kidney samples. Results showed that goats feeding on the plant material rich in plant secondary metabolites had significantly lower egg output compared to the control goats (P<0.05). A similar response was found for larval production in both H. contortus and T. colubriformis supporting that egg output was affected in both species. Although the total worm burdens were not affected by the plant material (P>0.05), the per capita fecundity was significantly reduced by E. corymbia, A. nilotica and A. salicina (P<0.05). No signs of toxicity were detected in the liver or kidney samples. It is concluded that goats can benefit from the short-term ingestion of plant secondary metabolites, which reduce the total faecal egg output and thus decrease the potential for re-infection from the pasture. 相似文献
2.
The effectiveness of selective anthelmintic treatments and use of nematophagous fungi Duddingtonia flagrans in reducing levels of gastrointestinal nematodes in goats was investigated at Onderstepoort, South Africa. Nineteen (19) naturally infected indigenous male goats, aged 10 months, were separated into four groups and grazed in separate previously ungrazed paddocks for two worm seasons (February 2002-March 2003). Two groups of goats were fed D. flagrans chlamydospores daily and two groups did not receive fungi. The FAMACHA system was used to determine which goats required anthelmintic treatments. Twice as many goats in the no-fungi fed group required treatments as compared with the fungi fed group. Mean FAMACHA scores in the no-fungi fed group were higher during most of the sampling occasions compared to the group fed fungi, but the difference was not significant. The group-mean faecal egg counts and PCV% were comparable between the two treatment groups throughout the study. Haemonchus was the predominant parasite genus in composite group faecal cultures. Group-mean body weights and body condition scores were higher for the no-fungi fed group from May 2002 up to the end of the study, though statistical differences were not significant. Mean worm burdens indicated that the most abundant species infecting animals were Haemonchus contortus and Trichostrongylus spp. and were higher in the fungi fed group. More animals required individual anthelmintic treatments in the no-fungi fed group. The requirement for extra treatments in the no-fungi fed group must, however, be considered against the financial cost of the fungi, the requirement of daily feeding of the fungi, the lower performance and higher worm burdens in the fungi fed group. 相似文献
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Worm egg counts of yearling Angora or Merino wethers grazing in mixed flocks at either 4/ha or 8/ha were observed over a 5 month period. Based on faecal egg counts infection levels in the sheep increased for the first 3 months and then decreased as the animals developed resistance. Egg counts in the goats did not decrease during the experiment. Post mortem worm counts indicated that there was a significant host species--stocking rate interaction on worm burdens of Haemonchus contortus adults and Ostertagia circumcincta adults and larvae. Goats had more H. contortus and O. circumcincta adults than sheep at the 8/ha stocking rate. At 4/ha goats had fewer O. circumcincta fourth stage larvae than sheep. There was no stocking rate effect on the numbers of Trichostrongylus axei or T. colubriformis. Sheep had more T. axei and fewer T. colubriformis than goats. 相似文献
5.
Weight gain costs due to infection were higher in sheep than goats, 28 and 17.5%, respectively, for Trichostrongylus colubriformis and 48.7 and 32.2%, respectively, for Haemonchus contortus. The extent of bodyweight cost attributed to anorexia in sheep infected with H. contortus was higher (13.5 g/day) than in sheep infected with T. colubriformis (2.3 g/day). On the other hand, bodyweight cost due to the other pathogenic effects in sheep infected with T. colubriformis were higher (35.6 g/day) compared to sheep infected with H. contortus (10.9 g/day). A strong relationship between faecal egg count and worm count (r=0.79, P=0.006) was shown only in sheep infected with T. colubriformis. About half of the infected sheep and goats had low or zero faecal egg counts throughout the study. In about 40% the egg count rose initially but became low by weeks 10-16, whereas in about 10% counts increased progressively throughout the period of observation and these animals also had the highest numbers of worms at slaughter. Packed cell volume was reduced in sheep and goats infected with H. contortus but serum protein and haemoglobin levels were unaffected. Sheep infected with T. colubriformis had a higher level of eosinophilia after 8 weeks (18.4%) than sheep infected with H. contortus (11.4%), whereas this pattern was reversed in goats and levels were also lower (4.1 and 8.9%, respectively). There was no apparent relationship between eosinophilia and resistance to infection with H. contortus or T. colubriformis. 相似文献
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Chiejina SN Musongong GA Fakae BB Behnke JM Ngongeh LA Wakelin D 《Veterinary parasitology》2005,128(1-2):29-40
Although Nigerian West African Dwarf (WAD) goats are relatively resistant to infection with Haemonchus contortus and are also trypanotolerant, natural outbreaks of both infections are known to occur. Despite their relative resistance to H. contortus WAD goats nevertheless show variability in response phenotype and it was of interest to examine the effect of this variability on the outcome of concurrent trypanosome infection. Trypanosoma brucei infections were established in goats that were initially classified as good or poor responders to H. contortus. Thirty-nine goats were exposed to an escalating infection with H. contortus, and on the basis of their mean faecal egg counts (FEC) were allocated to high FEC (poor responders, 18 goats with the highest FEC) or low FEC (good responders, 18 goats with the lowest FEC) classes. Nine uninfected naive control goats were included to provide reference baseline values. Retrospective analysis of parasitological and pathological parameters after allocation into high/low FEC classes showed that FECs differed significantly, in both classes packed cell volume (PCV) values fell relative to naive controls, neither class lost weight and both generated marked IgG responses. All goats received anthelmintic on day 61, half of each group was infected with 50 million trypanosomes and on day 67, excepting the controls, all goats were challenged with 3000 L3 of H. contortus. Trypanosome parasitaemia was generally low, and marginally, but not significantly, higher in the low compared with high FEC class, peaking 12-16 days after exposure in both groups and then falling to below microscopically detectable levels (although still detectable by sub-inoculation into mice) by week 3. At autopsy (days 109/110), worm burdens were significantly higher in the trypanosome-infected goats from the high FEC class, relative to all other groups. Trypanosome infected goats showed a tendency (although not significant) towards higher FEC and, irrespective of their FEC class, had lower PCV values although body weight did not vary significantly. All goats challenged with H. contortus had higher antibody levels than naive controls, but neither trypanosome infection nor FEC class affected the magnitude of responses. These results confirm that WAD goats comprise a range of response phenotypes to initial H. contortus infection and that trypanotolerance is a key trait of this breed. Although immunity to nematode infection develops even in poor responders, these animals harbour higher nematode burdens during concurrent infection with T. brucei. 相似文献
8.
Due to their critical functions in worm physiology, glutathione peroxidases in Haemonchus contortus are potential candidates for vaccine to control haemonchosis. However, information on the protection potential of these molecules is lacking. In this study, recombinant HC29 antigen was tested for protection against experimental H. contortus infections in goats. Fifteen animals were allocated into three trial groups. The animals of HC29 group was vaccinated with a recombinant HC29 DNA vaccine twice at day 0 and day 14, and then challenged with 5000 infective H. contortus L3 (third larval stage) on the 28th day. An unvaccinated positive control group was challenged with L3 at the same time. An unvaccinated negative control group was not challenged with L3. The results indicated HC29 DNA vaccine was transcribed at local injection sites and expressed in vivo post immunizations, respectively. Following L3 challenge, the mean eggs per gram feces and worm burdens of HC29 group were reduced by 36.1% and 35.6% respectively compared to the positive control group. After immunization with the DNA vaccine, significantly high levels of serum IgG, serum IgA, mucosal IgA and CD4(+) T lymphocytes were detected. These results suggest that recombinant H. contortus HC29 glutathione peroxidase DNA vaccine induced a partial immune response and has protective potentials against caprine haemonchosis. 相似文献
9.
A number of immuno-competent Blackface lambs were infected with 10,000 Haemonchus contortus third stage larvae and were later challenged with a second dose of 10,000 H. contortus third stage larvae. One group of lambs was treated with dialysed transfer factor prior to the second challenge dose. Histological changes in the abomasal wall, reductions in abomasal worm burdens at slaughter and faecal egg counts monitored throughout the experiment suggested the presence in some animals of an innate resistance, a "self curing" effect, an enhancement of this "self curing" effect in the transfer factor treated group and a response in one transfer factor treated animal comparable to "classical self cure". 相似文献
10.
The possible existence of breed differences in the response of sheep to primary infection with Haemonchus contortus was examined by comparing worm establishment and pathogenic effects of the parasite in Awassi and Merino sheep of haemoglobin type B infected with 500 third stage H. contortus larvae per kg body weight. The results showed that the Merino sheep had lower faecal egg counts and worm burdens and suffered less severe clinical disturbances than sheep of the Awassi breed. This suggests that genetic resistance operates primarily at the level of worm establishment. 相似文献
11.
A survey of strongyle infections was conducted in sheep and goats reared in a traditional e extensive husbandry system in two ecological zones if Nigeria. One zone had a seasonal pattern of infection. The majority of animals had faecal worm parasite egg counts of below 500 eggs per gram. Kids, and lambs younger than 3 months did not carry strongyle worm burdens, and the highest infection rate was found in the 7–12 month age group. A high proportion of small ruminants shed strongyle eggs during the postparturient period.The helminth species found by the use of larval culture techniques on the faeces were: Haemonchus contortus, Trichostrongylus colubriformis and Oesophagostonum columbianum. Adults of the same species were found in the few animals necropsied. The significance of the findings is discussed. 相似文献
12.
Paolini V Bergeaud JP Grisez C Prevot F Dorchies P Hoste H 《Veterinary parasitology》2003,113(3-4):253-261
Although the use of tanniferous plants or condensed tannins as an alternative to anthelmintics to control gastrointestinal nematodes has been largely documented in sheep, studies remain scarce in goats. The objective of this study was therefore to assess the possible impact of condensed tannins in goats infected with adult Haemonchus contortus. Two groups of cull goats were experimentally infected with 10.000 L3 of H. contortus. After 4 weeks, quebracho extracts, representing 5% of the diet DM, were administered for 8 days to one of the two groups. Goats of the second group remained as controls. One week after the end of quebracho administration, the goats were euthanised. Individual egg excretion and pathophysiological parameters were measured weekly during the study. At the end of the study, worm counts were assessed and histological samples from the abomasa were taken to count the numbers of mucosal mast cells, globule leukocytes and eosinophils. The administration of tannins was associated with a significant decrease in egg excretion, which persisted until the end of experiment. This reduction was not associated with any difference in worm number but with a significant decrease in female fecundity. No significant changes in the mucosal density of the three inflammatory cell types were detected between the two groups. These results indicate that the major consequence of tannin consumption in goats is a reduction in worm fecundity and egg output, which does not seem related to significant changes in the local mucosal response. 相似文献
13.
Joshi BR Kommuru DS Terrill TH Mosjidis JA Burke JM Shakya KP Miller JE 《Veterinary parasitology》2011,178(1-2):192-197
Effect of sericea lespedeza [SL; Lespedeza cuneata (Dum-Cours.) G. Don.] leaf meal feeding was evaluated in two experiments in indoor reared goats with experimental infection of Haemonchus contortus larvae. In the first experiment, ten 8-10 month old male Spanish and Alpine cross kids pair matched for body weight and age were fed SL or bermudagrass [BG; Cynodon dactylon (L.) Pers.] hay one week before infection and were infected with 5000 H. contortus L(3). The animals were maintained on the same diet for the remaining period and were slaughtered 28 days post-infection (DPI) to determine the establishment of incoming infective larvae. Goats fed SL had lower establishment (P<0.05) of H. contortus larvae than that of the control goats fed BG hay. In the second experiment, twenty-five 8-10 months old male Alpine cross, Saanen, Nubian×Saanen and Spanish kids reared in confinement on BG were experimentally infected with 5000 H. contortus L(3). On 35 DPI, the animals were allocated to two groups after blocking by fecal egg count (FEC), and one group was fed SL leaf meal (n=13), and another control group remained on BG (n=12). Four goats/group were slaughtered successively on days 7, 14, and 28 days post SL feeding, except on day 7, when five SL fed goats were slaughtered. Fecal egg counts and blood packed cell volume (PCV) were measured at weekly intervals and worm count, female worm fecundity, worm length and mucosal eosinophils, mast cells and globule leucocytes were measured after slaughter. Goats fed SL had a lower FEC (P<0.05) one week after feeding, as compared to those fed on BG, and the values remained at low level thereafter. Similarly, PCV was also significantly affected by feeding (P<0.01), and feeding and time interaction (P<0.05). However, worm burden, female worm fecundity, parasite length, and mucosal inflammatory cell count were similar between the groups. Feeding SL reduced the establishment of infective larvae and FEC of H. contortus in experimental studies and this plant could be used for biological control of parasite infection under field conditions to limit the harmful effects of the parasites in goats. 相似文献
14.
Faizal AC Rajapaksha WR Rajapakse RP 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2002,49(3):115-119
The benefit of gastrointestinal nematode control in cross-bred goats in the dry area of Sri Lanka was studied throughout 1 year by comparing the performances of three groups: group 1 animals (n = 11) were left untreated against gastrointestinal nematodes; group 2 animals (n = 11) were given monthly anthelmintic treatment. doramectin, at the dose rate of 300 microg/kg bodyweight during the entire study period; group 3 animals (n = 11) were also given monthly doramectin treatment at the dose rate of 300 microg/kg bodyweight but only during the rainy months, October to January and again once in April. All three groups were turned out together on to communal pasture. Tracers were used for the monthly estimation of gastrointestinal nematode burdens. Four untreated animals and a group 3 animal suffered from parasitic gastroenteritis during the study period. When compared with the controls, the treated groups had significantly lower gastrointestinal nematode infection as indicated by faecal egg counts (P<0.01). Faecal egg counts in group 3 were significantly higher than those in group 2 (P < 0.01). When compared with the controls, the treated groups had significantly greater weight gains (P< 0.05). Haemonchus contortus and Trichostrongylus colubriformis were the predominant gastrointestinal nematodes identified from tracers. The worm burden varied according to the rainfall pattern, with very minimal transmission during the dry period which extends from May to August. Under the conditions of this study, the monthly anthelmintic treatments increased weight gains and prevented parasitic gastroenteritis of goats in the dry zone of Sri Lanka. 相似文献
15.
Multiple resistance to albendazole, thiophanate, levamisole and orally administered ivermectin was detected in an isolate of Haemonchus contortus in sheep on a farm where benzimidazole resistance had already been identified. Following a faecal egg count reduction test, this was confirmed by both critical and controlled anthelmintic tests. Different groups of sheep infected naturally or given an experimental infection with the benzimidazole-resistant isolate were treated with the recommended doses of various anthelmintics. Compared to the control group, the percentage reductions in the faecal egg counts of sheep treated with albendazole, thiophanate, levamisole and ivermectin varied between 38.2% and 79.1% and the residual worm counts between 27.3% and 57.5%. The results indicate the presence of multiple anthelmintic resistance in this isolate of H. contortus. Sheep treated with closantel showed 100% reductions in faecal egg and worm counts, indicating that this drug was very effective against the population of H. contortus on the farm. 相似文献
16.
Bambou JC de la Chevrotière C Varo H Arquet R Kooyman FN Mandonnet N 《Veterinary parasitology》2008,158(4):311-318
The objective of this study was to evaluate the relationship of parasite-specific serum antibodies with the resistance status of Creole kids. The average breeding values on egg output predicted in a context of natural infection at 11 months of age were distant of 1.07 genetic standard deviation between resistant and susceptible animals. After drenching the animals were maintained worm-free during 1 month until experimental infection with 10,000 Haemonchus contortus infective larvae (L3). Enzyme-linked immunosorbent assay was carried out in serum samples to determine the level of IgG, IgA and IgE anti-H. contortus L3 crude extracts and adult excretion/secretion products (ESP). Parasitological and blood immunological parameters were measured on the 2 extreme groups. Despite the absence of any typical signs of haemonchosis, susceptible kids had more than 11 times higher faecal egg counts (FEC) at 35 days post-infection (d.p.i.) than resistant kids had. Levels of immunoglobulin against H. contortus L3 and ESP increased significantly after infection in both groups. However, no difference in the host immune response mediated by immunoglobulin against H. contortus was evidenced between groups. This finding suggests that, in goats previously infected by H. contortus, a degree of protection occurred and the phenotypic and genetic segregation in resistant and susceptible animals were not related to the humoral immune response. The correlation coefficients between FEC and IgE anti-ESP (r=0.593; P<0.05 was significant in both resistant and susceptible animals. Such correlation suggesting a hypersensitivity reaction dependent on worm prolificacy has never been described. This result needs further studies to understand the mechanisms underlying this observation. 相似文献
17.
The aim of this experiment was to investigate the effect of Haemonchus contortus infection on rumen function and digestion of Merino sheep from lines divergently selected for genetic resistance to H. contortus. Rumen function and whole-tract digestibility were determined in 29 Merino weaner wethers from the CSIRO Haemonchus selection flock, increased resistance to Haemonchus (IRH), decreased resistance to Haemonchus (DRH) and random bred control (C) selection lines. Wethers were fed a restricted low quality roughage diet (5.9 MJ ME/kg DM, 29 g MP/kg DM) to maintain weight and were either uninfected (NIL) or infected with H. contortus (INF). Measurements were taken at week 7 of infection, while animals were housed in metabolic crates. Animals were then euthanased to determine abomasal worm counts. IRH had significantly lower worm egg count than DRH and C lines however, adult worm and larval counts, though lower in IRH animals, did not differ significantly. DM and OM digestibility and in sacco degradability of IRH and DRH selection lines were greater than C animals. Rumen function of animals from the IRH line was altered in response to H. contortus infection with an increase in fluid outflow and turnover rate and a decrease in propionic acid concentration. These changes may be a component of a greater host resistance and begin to explain the failure of IRH animals to translate lower worm egg count into greater bodyweight gain. 相似文献
18.
The prevalence of anthelmintic resistant nematodes among 52 commercial flocks in south-east England was investigated by comparing the faecal egg counts of groups of lambs before, and seven days after, treatment with thiabendazole and levamisole. Evidence of thiabendazole resistance was found on seven farms. in each case Haemonchus contortus was the only species of nematode involved. In vitro egg hatch assays carried out for isolates from these farms gave ED50 estimates of 0.065 to 0.332 micrograms thiabendazole/ml compared with estimates of 0.027 to 0.031 micrograms thiabendazole/ml for a known susceptible strain of H contortus assayed at the same time. In a series of slaughter trials, there was a 17 to 85 per cent reduction, as compared with controls, in the mean worm burdens of groups of lambs infected with these isolates and killed seven days after treatment with thiabendazole, confirming their resistance to this anthelmintic. 相似文献
19.
Efficacy of three broad-spectrum anthelmintics against gastrointestinal nematode infections of goats
Groups of 10 goats, harbouring both naturally acquired and experimental infections of gastrointestinal nematodes, were drenched with either levamisole (5 mg kg-1), albendazole (3.8 mg kg-1) or parbendazole (15 mg kg-1), or remained untreated. Haemonchus contortus was the numerically dominant infection, with Strongyloides papillosus, Trichostrongylus colubriformis and Oesophagostomum columbianum also present. At 5-6 days post-treatment, goats were killed and necropsied. Post-mortem worm counts showed that the reduction in mean total worm burdens was 57.4% in levamisole-treated animals, 71.1% in the albendazole group and 85.1% in the parbendazole group. Reductions for H. contortus were 80.2, 87.9 and 83.9% in the levamisole-, albendazole- and parbendazole-treated groups, respectively. These data indicate that the anthelmintics in question are not being applied at an adequate dose rate for goats, and/or resistance to anthelmintics is occurring in the field in Pernambuco State, northeast Brazil. 相似文献
20.
Following evidence of reduced efficacy of ivermectin in a field population of Haemonchus contortus in Brazil, this strain of the parasite was submitted to a controlled anthelmintic test. Eighty worm-free lambs were randomly split into two groups of 40. Each lamb in the first group was infected with 5000 third stage larvae (L3) of the ivermectin-resistant strain; the remaining 40 lambs were each infected with 5000 L3 of a H. contortus strain of known susceptibility to the major groups of anthelmintic compounds used in sheep. On Day 28 post-infection, each group was subdivided according to egg counts and at random into four sub-groups of ten lambs, each of which was treated with albendazole (ABZ) at 3.8 mg kg-1, levamisole (LEV) at 7.5 mg kg-1 or ivermectin (IVM) at 0.2 mg kg-1, or was left as untreated control. At slaughter, 7 days later, all the anthelmintics reduced worm burdens in animals infected with the susceptible strain (ABZ 98.9%, LEV and IVM 100%). By contrast, in the lambs infected with the ivermectin-resistant strain, LEV was 99.8% effective, but ABZ reduced worm counts by only 14.7% and IVM by only 10.4%. Interestingly at necropsy on Day 7 post-treatment, the egg counts in the resistant strain treated with ABZ had been reduced by 92.5%, although worm counts were reduced by only 14.7%.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献