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1.
Vet Rec ; 188(5): e73, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33666960

RESUMO

BACKGROUND: Nematodirus battus infection is a major health concern in lambs. Development and hatch of infective larvae on pastures is temperature dependent, making model-based risk forecasting a useful tool for disease control. METHODS: Air and 30 cm soil temperature-based risk models were used to predict hatch dates using meteorological data from 2019 and compared to infection dates, estimated from the first appearance of N. battus eggs, on 18 sheep farms distributed across Great Britain. RESULTS: The air temperature model was more accurate in its predictions than the soil temperature model on 12 of the 18 farms, but tended to predict late hatch dates in the early part of the season. CONCLUSION: Overall, the air temperature model appears the more appropriate choice for predicting N. battus peak hatch in the UK in terms of accuracy and practicality, but some adjustment might be needed to account for microclimatic variations at the soil-air interface.


Assuntos
Modelos Estatísticos , Nematodirus , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/parasitologia , Infecções por Strongylida/veterinária , Ar , Animais , Fazendas , Larva/crescimento & desenvolvimento , Reprodutibilidade dos Testes , Risco , Estações do Ano , Ovinos , Solo , Infecções por Strongylida/epidemiologia , Temperatura , Reino Unido/epidemiologia
2.
Parasit Vectors ; 13(1): 494, 2020 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-32993770

RESUMO

BACKGROUND: Nematodirus battus, unlike most other gastrointestinal nematodes, undergoes maturation to an infective larva within the egg. Historically, eggs were considered to require a period of chilling over winter followed by a period of temperature above 10 °C for synchronous hatching to occur (generally in spring). Anecdotal reports of Nematodirus infection out-with spring in veterinary journals and the farming press suggest that the concentrated pasture abundance of N. battus infective larvae may be changing. In order for control practices to be adapted, and unexpected disease outbreaks to be avoided, it is important to quantify how parasite epidemiology is changing and research the drivers behind it. METHOD: The present study investigated the in vitro hatching response to temperature experiences (with and without a period of chilling) for egg samples of 90 N. battus populations obtained from 73 commercial sheep farms. Six aliquots of larvated eggs were prepared per population, three aliquots were placed at 4 °C for 6  weeks to provide a chill stimulus then incubated at the optimal hatching temperature for the species. The remaining three aliquots of eggs were incubated at the hatching temperature without a prior chill stimulus and the number of hatched larvae was compared between treatments. RESULTS: Median hatch rate across all populations with chilling was 45% (95% CI: 42-48%) and without chilling was 4% (95% CI: 2-6%). Inter-population variation in hatching ranged from 0 to 87% of eggs able to hatch in the absence of a chill stimulus, mean non-chill hatching was 13 ± 2% of eggs (mean ± SE). Non-chill hatching rates were greater than chilled hatching rates in seven of the 90 populations tested. CONCLUSIONS: Clearly, the variation in hatching responses to temperature experience is very large and therefore the seasonality of the parasite may vary not only between regions but also at farm level. In contrast to what previous work has suggested, there was a geographical trend towards higher non-chill hatching in the Northern parts of the UK.


Assuntos
Nematodirus/crescimento & desenvolvimento , Infecções por Strongylida/veterinária , Animais , Feminino , Larva/crescimento & desenvolvimento , Masculino , Óvulo/crescimento & desenvolvimento , Ovinos , Doenças dos Ovinos/parasitologia , Infecções por Strongylida/parasitologia , Temperatura , Reino Unido
3.
Artigo em Inglês | MEDLINE | ID: mdl-32251964

RESUMO

Benzimidazoles (BZ) have been the anthelmintic of choice for controlling Nematodirus battus infections since their release in the 1950s. Despite heavy reliance on this single anthelmintic drug class, resistance was not identified in this nematode until 2010 (Mitchell et al., 2011). The study aimed to explore the prevalence of BZ-resistance mutations in N. battus from UK sheep flocks using deep amplicon sequencing and pyrosequencing platforms. Based on evidence from other gastrointestinal nematodes, resistance in N. battus is likely to be conferred by single nucleotide polymorphisms (SNP) within the ß-tubulin isotype 1 locus at codons 167, 198 and 200. Pyrosequencing and deep amplicon sequencing assays were designed to identify the F167Y (TTC to TAC), E198A (GAA to GCA) and F200Y (TTC to TAC) SNPs. Nematodirus battus populations from 253 independent farms were analysed by pyrosequencing; 174 farm populations were included in deep amplicon sequencing and 170 were analysed using both technologies. F200Y was the most prevalent SNP identified throughout the UK, in 12-27% of the populations tested depending on assay, at a low overall individual frequency of 2.2 ±â€¯0.6% (mean ±â€¯SEM, based on pyrosequencing results). Four out of the five populations with high frequencies (>20%) of the F200Y mutation were located in NW England. The F167Y SNP was identified, for the first time in this species, in four of the populations tested at a low frequency (1.2% ±â€¯0.01), indicating the early emergence of the mutation. E198A or E198L were not identified in any of the isolates. Results obtained were comparable between both techniques for F200Y (Lins' CCC, rc = 0.96) with discrepancies being limited to populations with low frequencies. The recent emergence of resistance in this species will provide a unique opportunity to study the early stages of anthelmintic resistance within a natural setting and track its progress in the future.


Assuntos
Benzimidazóis/farmacologia , Resistência a Medicamentos/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Nematodirus/genética , Doenças dos Ovinos/parasitologia , Infecções por Strongylida/veterinária , Animais , Anti-Helmínticos/farmacologia , Fazendas , Fezes/parasitologia , Frequência do Gene , Genótipo , Mutação , Nematodirus/efeitos dos fármacos , Análise de Sequência de DNA , Ovinos , Doenças dos Ovinos/tratamento farmacológico , Doenças dos Ovinos/epidemiologia , Infecções por Strongylida/tratamento farmacológico , Infecções por Strongylida/epidemiologia , Reino Unido/epidemiologia
4.
Vet Parasitol Reg Stud Reports ; 16: 100277, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-31027604

RESUMO

Reindeer (Rangifer tarandus tarandus) host numerous parasites. Although there is a general knowledge about parasite diversity in reindeer, detailed baseline information about parasitic infections is limited. Detailed knowledge of parasite prevalence and diversity provide a pathway for more targeted parasite control, an increasing need expected in the future. The main aim of our cross-sectional study was to estimate the prevalence of gastrointestinal parasites in semidomesticated reindeer calves. The 480 reindeer calves included in our study were aged 6-7 months, originated from 9 reindeer herding cooperatives in Finland and 1 in Norway, and were slaughtered during September-November 2015 in 10 reindeer slaughterhouses. All the reindeer calves passed meat inspection, and the detected parasitic infections were subclinical. As the reindeer included in this study were young animals intended for slaughter, they had never been administrated any antiparasitic treatment. Assessments of gastrointestinal parasitism among these reindeer calves were based on fecal examination and morphological identification of coccidian oocysts or helminth eggs. Individual fecal samples collected from the rectum of each of the reindeer were examined using a modified McMaster method. Most (78.3%) of the reindeer calves had eggs or oocysts of at least one parasite species in their feces, and more than half (53.5%) had a mixed infection. Strongylid eggs were detected in 75.6%, Eimeria sp. oocysts in 50.6%, Moniezia sp. eggs in 28.1%, Nematodirus sp. eggs in 22.1%, Capillaria sp. eggs in 9.4%, and Trichuris sp. eggs in 0.6% of the samples. The prevalence of gastrointestinal parasites was similar or higher relative to previous estimates from the region; the proportion of reindeer calves shedding strongylid eggs and the proportion of reindeer calves shedding Moniezia sp. eggs had increased. Prevalence varied by geographical region, which may reflect different herding practices or environmental parameters. Higher reindeer density was a risk factor for testing positive for Eimeria sp. oocysts, and the odds of testing positive for Nematodirus sp. eggs were higher if a peroral route was used for antiparasitic treatment in the reindeer herding cooperative. The mean proportion of reindeer estimated to receive antiparasitic treatment in Finland was 86% in 2004-2005 and 91% in 2014-2015. During the historical time frames of current management practices, this routine annual antiparasitic treatment of breeding reindeer has not decreased the prevalence of gastrointestinal parasites in reindeer calves, which can be seen as sentinels or indicators of the infection pressure.


Assuntos
Coccidiose/veterinária , Gastroenteropatias/veterinária , Helmintíase Animal/epidemiologia , Enteropatias Parasitárias/veterinária , Rena/parasitologia , Matadouros , Criação de Animais Domésticos/métodos , Animais , Capillaria/isolamento & purificação , Coccidiose/epidemiologia , Coccidiose/parasitologia , Estudos Transversais , Eimeria/isolamento & purificação , Infecções por Enoplida/epidemiologia , Infecções por Enoplida/parasitologia , Infecções por Enoplida/veterinária , Fezes/parasitologia , Finlândia/epidemiologia , Inspeção de Alimentos , Gastroenteropatias/epidemiologia , Gastroenteropatias/parasitologia , Helmintíase Animal/parasitologia , Enteropatias Parasitárias/epidemiologia , Enteropatias Parasitárias/parasitologia , Carne/normas , Moniezíase/epidemiologia , Moniezíase/parasitologia , Nematodirus/isolamento & purificação , Noruega/epidemiologia , Densidade Demográfica , Prevalência , Fatores de Risco , Estrongilídios/isolamento & purificação , Infecções por Strongylida/epidemiologia , Infecções por Strongylida/parasitologia , Infecções por Strongylida/veterinária
6.
J Parasitol ; 103(6): 791-794, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28783428

RESUMO

Carnivorous mammals are a trophic guild with an important role in the dissemination of parasite infective stages (larvae, eggs, cysts, and oocysts). In the present study, new samples of coprolites attributed to carnivorous mammals, obtained from 2 archaeological caves, were analyzed for the presence of parasites with the aim to increase the knowledge about parasites in rockshelters that could have spread to humans and other mammals. To this purpose, fragments of 3 coprolites from Cerro Casa de Piedra, cave 5 and cave 7, were examined. Coprolites were rehydrated in aqueous trisodium phosphate and processed by spontaneous sedimentation. High parasite richness was observed and new parasite species for archaeological contexts were found. The parasitological findings in Puma concolor coprolites associated with caves suggest the importance of these carnivores in the dissemination of parasites in areas with high re-use of space and steady conditions of temperature, humidity, and radiation.


Assuntos
Carnívoros/parasitologia , Cavernas/parasitologia , Fezes/parasitologia , Fósseis/parasitologia , Zoonoses/transmissão , Animais , Argentina , Camelídeos Americanos/parasitologia , Dieta Paleolítica , Echinococcus/isolamento & purificação , Eimeria/isolamento & purificação , Fósseis/história , História Antiga , Humanos , Isospora/isolamento & purificação , Nematoides/classificação , Nematoides/isolamento & purificação , Nematodirus/isolamento & purificação , Puma/parasitologia , Espirurídios/isolamento & purificação , Estrongilídios/isolamento & purificação , Taenia/isolamento & purificação , Zoonoses/história , Zoonoses/parasitologia
7.
Br J Nutr ; 117(7): 951-963, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28443527

RESUMO

An experiment was conducted to determine: (1) the effect of excess maternal I supplementation on the thyroid hormone status of the ewe and her progeny; (2) potential mechanisms underpinning the failure of passive transfer associated with excess I and (3) the growing lambs' response to natural gastrointestinal infection. Twin-bearing ewes received one of two treatments (n 32/treatment group): basal diet (C) or C plus 26·6 mg of iodine/ewe per d (I), supplied as calcium iodate. Ewes were individually fed from day 119 of gestation to parturition. Progeny of I ewes had lower (P<0·01) serum IgG concentrations from 24 h to 28 d postpartum but higher serum IgG concentrations at day 70 postpartum (P<0·05). I supplementation increased the relative expression of Fc receptor, IgA, IgM high affinity and polymeric Ig receptor in the ileum of the lamb at 24 h postpartum; however, thyroid hormone receptor-ß (THRB) and ß-2-microglobulin (B2M) expression declined (P<0·05). Progeny of I ewes had higher growth rates to weaning (P<0·05) and lower faecal egg count (FEC) for Nematodirus battus (P<0·05) between weeks 6 and 10 postpartum. In conclusion, excess maternal I supplementation negatively affected the thyroid hormone status, serum IgG concentration, ileal morphology and the gene expression of THRB and B2M in the ileum and ras-related protein (RAB) RAB25 and the mucin gene (MUC) MUC1 in the duodenum of the lamb postpartum. These effects were followed by an enhancement of average daily gain and lower N. battus FEC in the pre-weaning period of I-supplemented lambs.


Assuntos
Colostro/imunologia , Suplementos Nutricionais , Imunidade Materno-Adquirida , Iodo/uso terapêutico , Fenômenos Fisiológicos da Nutrição Materna , Doenças dos Ovinos/prevenção & controle , Infecções por Strongylida/veterinária , Animais , Animais Recém-Nascidos , Colostro/química , Suplementos Nutricionais/efeitos adversos , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Íleo/crescimento & desenvolvimento , Íleo/imunologia , Íleo/metabolismo , Íleo/patologia , Imunoglobulina G/análise , Imunoglobulina G/biossíntese , Mucosa Intestinal/crescimento & desenvolvimento , Mucosa Intestinal/imunologia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Iodo/efeitos adversos , Masculino , Nematodirus/imunologia , Nematodirus/isolamento & purificação , Contagem de Ovos de Parasitas/veterinária , Gravidez , Distribuição Aleatória , Ovinos , Doenças dos Ovinos/imunologia , Doenças dos Ovinos/metabolismo , Doenças dos Ovinos/parasitologia , Carneiro Doméstico , Infecções por Strongylida/imunologia , Infecções por Strongylida/parasitologia , Infecções por Strongylida/prevenção & controle , Receptores beta dos Hormônios Tireóideos/genética , Receptores beta dos Hormônios Tireóideos/metabolismo , Ganho de Peso , Microglobulina beta-2/genética , Microglobulina beta-2/metabolismo
8.
Vet Parasitol ; 226: 17-21, 2016 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-27514876

RESUMO

The eggs of some species of the parasitic nematode Nematodirus require a period of chilling before they can hatch; N. filicollis is one such species. This study investigated this requirement for chilling in a New Zealand strain of this species. Eggs of N. filicollis were extracted from lamb's faeces and incubated at 20°C to allow development to the third stage larvae within the egg. These eggs were then placed into tissue culture plates and incubated at: 2.7°C (±0.99), 3.6°C (±0.90), 4.7°C (±0.35), 6.4°C (±0.37), 8.0°C (±1.54) or 9.9°C (±0.14) for up to 224 days. At 14day intervals until day 84, then every 28 days, one plate was removed from each temperature and placed at 13.1°C (±0.44) for 14 days. Eggs were then assessed for hatching. From this data, chill units were calculated by subtracting the culture temperature from a constant threshold of 11°C and multiplying by the number of days for which the sample was cultured; then the Gompertz model fitted. Even though hatching overall was low, a greater proportion of eggs hatched with chill accumulation. Maximum hatching of eggs required 800-1000 chill units. Consequently in the field, more than one season of chilling would be required before hatching. As such a generation time could take more than one year to complete. This is different to the hatching dynamics of N. spathiger, the other main species found in New Zealand sheep, which does not display this requirement for chilling and hatches immediately once the third stage larvae are developed.


Assuntos
Temperatura Baixa , Nematodirus/crescimento & desenvolvimento , Doenças dos Ovinos/parasitologia , Infecções por Strongylida/veterinária , Animais , DNA de Helmintos/análise , Fezes/parasitologia , Nematodirus/genética , Nova Zelândia , Óvulo/crescimento & desenvolvimento , Reação em Cadeia da Polimerase , Ovinos , Infecções por Strongylida/parasitologia , Fatores de Tempo
9.
Vet Parasitol ; 225: 53-60, 2016 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-27369575

RESUMO

In small ruminants, faecal egg counts (FECs) and reduction in FECs (FECR) are the most common methods for the assessment of intensity of gastrointestinal (GI) nematodes infections and anthelmintic drug efficacy, respectively. The main limitation of these methods is the time and cost to conduct FECs on a representative number of individual animals. A cost-saving alternative would be to examine pooled faecal samples, however little is known regarding whether pooling can give representative results. In the present study, we compared the FECR results obtained by both an individual and a pooled examination strategy across different pool sizes and analytical sensitivity of the FEC techniques. A survey was conducted on 5 sheep farms in Scotland, where anthelmintic resistance is known to be widespread. Lambs were treated with fenbendazole (4 groups), levamisole (3 groups), ivermectin (3 groups) or moxidectin (1 group). For each group, individual faecal samples were collected from 20 animals, at baseline (D0) and 14 days after (D14) anthelmintic administration. Faecal samples were analyzed as pools of 3-5, 6-10, and 14-20 individual samples. Both individual and pooled samples were screened for GI strongyle and Nematodirus eggs using two FEC techniques with three different levels of analytical sensitivity, including Mini-FLOTAC (analytical sensitivity of 10 eggs per gram of faeces (EPG)) and McMaster (analytical sensitivity of 15 or 50 EPG).For both Mini-FLOTAC and McMaster (analytical sensitivity of 15 EPG), there was a perfect agreement in classifying the efficacy of the anthelmintic as 'normal', 'doubtful' or 'reduced' regardless of pool size. When using the McMaster method (analytical sensitivity of 50 EPG) anthelmintic efficacy was often falsely classified as 'normal' or assessment was not possible due to zero FECs at D0, and this became more pronounced when the pool size increased. In conclusion, pooling ovine faecal samples holds promise as a cost-saving and efficient strategy for assessing GI nematode FECR. However, for the assessment FECR one will need to consider the baseline FEC, pool size and analytical sensitivity of the method.


Assuntos
Anti-Helmínticos/farmacologia , Fezes/parasitologia , Gastroenteropatias/veterinária , Nematoides/efeitos dos fármacos , Parasitologia/métodos , Doenças dos Ovinos , Infecções por Strongylida/veterinária , Animais , Anti-Helmínticos/uso terapêutico , Gastroenteropatias/tratamento farmacológico , Gastroenteropatias/parasitologia , Nematodirus/efeitos dos fármacos , Contagem de Ovos de Parasitas , Ovinos , Doenças dos Ovinos/tratamento farmacológico , Doenças dos Ovinos/parasitologia , Infecções por Strongylida/diagnóstico , Infecções por Strongylida/tratamento farmacológico
11.
N Z Vet J ; 64(4): 201-6, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26846152

RESUMO

AIM: To determine the prevalence of benzimidazole resistance in Nematodirus spathiger and N. filicollis from a sample of New Zealand farms. METHODS: The efficacy of albendazole (ABZ) against Nematodirus spp. was assessed by faecal nematode egg count reduction (FECR) tests undertaken in lambs aged 3-8 months old on 27 sheep farms throughout New Zealand. On each farm, groups of 10-16 lambs were either treated with ABZ (4.75 mg/kg) or remained as untreated controls. Faecal samples were collected from all animals at the time of treatment and 7-10 days later. Faecal nematode egg counts (FEC) were performed using a modified McMaster technique. Larvae were cultured from pooled faecal samples, collected 7-10 days after treatment from each group, by incubation at 20°C for 6 weeks, 4°C for 26 weeks then 13°C for 2 weeks. The resulting third stage larvae were identified to species using a multiplex PCR assay, that identified species-specific sequences in the second internal transcribed spacer region of ribosomal DNA. The efficacy of ABZ for N. spathiger and N. filicollis was calculated from the proportion of the two species in culture and the group mean FEC before and after treatment. Only farms with a mean of 10 epg for each species in untreated samples were included for analysis. Resistance was defined as an efficacy <95%. RESULTS: On farms that met the threshold of 10 epg in faecal samples, benzimidazole resistance was found on 20/21 (95%) farms for N. spathiger compared with 4/10 (40%) farms for N. filicollis (p<0.05). In samples collected following treatment, a mean of 83 (min 46, max 100)% of Nematodirus spp. larvae recovered from the untreated groups were N. spathiger, compared with 94 (min 45, max 100)% in the ABZ treated groups (p=0.03). This change in percentage was not influenced by the overall efficacy of treatment based on the FECR test (p=0.324). CONCLUSION: The results confirm the high level of resistance in N. spathiger in New Zealand and that benzimidazole resistance was more common in N. spathiger than N. filicollis. While resistance to benzimidazole anthelmintics has been reported previously in New Zealand, this is the first report of N. filicollis being resistant to benzimidazole anthelmintics.


Assuntos
Albendazol/farmacologia , Resistência a Medicamentos , Nematodirus/efeitos dos fármacos , Doenças dos Ovinos/parasitologia , Infecções por Strongylida/veterinária , Animais , Anti-Helmínticos/farmacologia , Fezes/parasitologia , Nova Zelândia/epidemiologia , Contagem de Ovos de Parasitas , Ovinos , Doenças dos Ovinos/epidemiologia , Infecções por Strongylida/epidemiologia , Infecções por Strongylida/parasitologia
12.
Vet Rec ; 178(4): 84, 2016 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-26795855

RESUMO

Increasing concern about antimicrobial resistance and moves to restrict the use of antibiotics in food-producing animals mean that farmers will need new ways of preventing and controlling disease in their animals. With its focus on addressing the needs of the farming industry, the Moredun Research Institute sees this as an opportunity to be at the forefront of developing new solutions. Kristy Ebanks reports from an event organised to showcase some of the institute's latest research.


Assuntos
Agricultura/métodos , Doenças dos Ovinos/prevenção & controle , Animais , Benzimidazóis/farmacologia , Congressos como Assunto , Resistência a Medicamentos , Humanos , Nanomedicina , Nematodirus/efeitos dos fármacos , Adenomatose Pulmonar Ovina/diagnóstico por imagem , Adenomatose Pulmonar Ovina/prevenção & controle , Ovinos , Tuberculose/terapia , Ultrassonografia , Reino Unido
13.
Parasitology ; 142(10): 1306-17, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26091257

RESUMO

Mismatch in the phenology of trophically linked species as a result of climate warming has been shown to have far-reaching effects on animal communities, but implications for disease have so far received limited attention. This paper presents evidence suggestive of phenological asynchrony in a host-parasite system arising from climate change, with impacts on transmission. Diagnostic laboratory data on outbreaks of infection with the pathogenic nematode Nematodirus battus in sheep flocks in the UK were used to validate region-specific models of the effect of spring temperature on parasite transmission. The hatching of parasite eggs to produce infective larvae is driven by temperature, while the availability of susceptible hosts depends on lambing date, which is relatively insensitive to inter-annual variation in spring temperature. In southern areas and in warmer years, earlier emergence of infective larvae in spring was predicted, with decline through mortality before peak availability of susceptible lambs. Data confirmed model predictions, with fewer outbreaks recorded in those years and regions. Overlap between larval peaks and lamb availability was not reduced in northern areas, which experienced no decreases in the number of reported outbreaks. Results suggest that phenological asynchrony arising from climate warming may affect parasite transmission, with non-linear but predictable impacts on disease burden. Improved understanding of complex responses of host-parasite systems to climate change can contribute to effective adaptation of parasite control strategies.


Assuntos
Mudança Climática , Interações Hospedeiro-Parasita/fisiologia , Nematodirus/fisiologia , Doenças dos Ovinos/transmissão , Infecções por Strongylida/veterinária , Animais , Temperatura Alta , Modelos Biológicos , Ovinos , Doenças dos Ovinos/epidemiologia , Infecções por Strongylida/epidemiologia , Infecções por Strongylida/transmissão , Fatores de Tempo , Reino Unido/epidemiologia
14.
J Helminthol ; 89(3): 259-66, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-24331581

RESUMO

Internal transcribed spacer (ITS) rDNA sequences of three Nematodirus species from naturally infected goats or sheep in two endemic provinces of China were analysed to establish an effective molecular approach to differentiate Nematodirus species in small ruminants. The respective intra-specific genetic variations in ITS1 and ITS2 rDNA regions were 0.3-1.8% and 0-0.4% in N. spathiger, 0-6.5% and 0-5.4% in N. helvetianus, and 0-4.4% and 0-6.1% in N. oiratianus from China. The respective intra-specific variations of ITS1 and ITS2 were 1.8-4.4% and 1.6-6.1% between N. oiratianus isolates from China and Iran, 5.7-7.1% and 6.3-8.3% between N. helvetianus samples from China and America. For N. spathiger, compared with samples from China, sequence differences in ITS1 rDNA were 0.3-2.4% in isolates from America, 0.3-2.9% in New Zealand and 2.1-2.4% in Australia. Genetic variations in ITS2 rDNA of N. spathiger were 0-0.4% between samples from China and America, and 0-0.8% between samples from China and New Zealand. Using mutation sites, polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and specific PCR techniques were developed to differentiate these three Nematodirus species. The specific PCR assay allowed the accurate identification of N. oiratianus from other common nematodes with a sensitivity of 0.69 pg and further examination of Nematodirus samples demonstrated the reliability of these two molecular methods.


Assuntos
Variação Genética , Doenças das Cabras/parasitologia , Técnicas de Diagnóstico Molecular/métodos , Nematodirus/classificação , Nematodirus/genética , Doenças dos Ovinos/parasitologia , Infecções por Strongylida/veterinária , Animais , China , Análise por Conglomerados , Primers do DNA/genética , DNA de Helmintos/química , DNA de Helmintos/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Cabras , Dados de Sequência Molecular , Nematodirus/isolamento & purificação , Filogenia , Reação em Cadeia da Polimerase/métodos , Polimorfismo de Fragmento de Restrição , Sensibilidade e Especificidade , Análise de Sequência de DNA , Ovinos , Infecções por Strongylida/parasitologia
15.
Vet Res ; 45: 116, 2014 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-25487605

RESUMO

Benzimidazole resistance is common amongst many ovine trichostrongylid nematodes species globally. Although anthelmintics have been used for over half a century in some areas of the world for the control of Nematodirus battus, resistance has never been detected. Veterinary investigations conducted in 2010 demonstrated reduced efficacy in a flock that had been treated previously with fenbendazole (FBZ), suggesting probable resistance in N. battus. Infective larvae (L3; designated MNba2) were generated from the original material to conduct a controlled efficacy test (CET). Faecal egg counts showed an average of 37% reduction in the FBZ treated group 7 days post treatment compared to the untreated lambs. Average worm burden results showed no reduction after FBZ treatment compared to the untreated group (3850 and 3850 worms respectively). A molecular assay to assess the frequency of the commonly associated single nucleotide polymorphisms (SNP) in the ß-tubulin isotype 1 gene, F200Y and E198A, was developed. Larval genotypes were predominantly homozygous resistant at codon 200 SNP, ranging from 56%-83% and remained stable at 70% for adult worm populations taken from treated and control lambs in the CET. Only susceptible genotypes were found at codon 198. The allele frequency for F200Y ranged between 80-83% in adult worms taken from the CET from treated and control lambs. The results confirmed initial findings and demonstrated the first report of FBZ resistance in N. battus whilst providing evidence that the P200 point mutation in the ß-tubulin isotype 1 gene is a potential mechanism of resistance in the species.


Assuntos
Benzimidazóis/farmacologia , Resistência a Medicamentos/genética , Proteínas de Helminto/genética , Nematodirus/efeitos dos fármacos , Nematodirus/genética , Contagem de Ovos de Parasitas/veterinária , Tubulina (Proteína)/genética , Animais , Anti-Helmínticos/farmacologia , Fezes/parasitologia , Genótipo , Proteínas de Helminto/metabolismo , Larva/efeitos dos fármacos , Reação em Cadeia da Polimerase/veterinária , Polimorfismo de Nucleotídeo Único , Ovinos , Doenças dos Ovinos/parasitologia , Doenças dos Ovinos/prevenção & controle , Infecções por Strongylida/parasitologia , Infecções por Strongylida/prevenção & controle , Infecções por Strongylida/veterinária , Tubulina (Proteína)/metabolismo
16.
Parasit Vectors ; 7: 319, 2014 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-25015379

RESUMO

BACKGROUND: Nematodirus spp. are among the most common nematodes of ruminants worldwide. N. oiratianus and N. spathiger are distributed worldwide as highly prevalent gastrointestinal nematodes, which cause emerging health problems and economic losses. Accurate identification of Nematodirus species is essential to develop effective control strategies for Nematodirus infection in ruminants. Mitochondrial DNA (mtDNA) could provide powerful genetic markers for identifying these closely related species and resolving phylogenetic relationships at different taxonomic levels. METHODS: In the present study, the complete mitochondrial (mt) genomes of N. oiratianus and N. spathiger from small ruminants in China were obtained using Long-range PCR and sequencing. RESULTS: The complete mt genomes of N. oiratianus and N. spathiger were 13,765 bp and 13,519 bp in length, respectively. Both mt genomes were circular and consisted of 36 genes, including 12 genes encoding proteins, 2 genes encoding rRNA, and 22 genes encoding tRNA. Phylogenetic analyses based on the concatenated amino acid sequence data of all 12 protein-coding genes by Bayesian inference (BI), Maximum likelihood (ML) and Maximum parsimony (MP) showed that the two Nematodirus species (Molineidae) were closely related to Dictyocaulidae. CONCLUSIONS: The availability of the complete mtDNA sequences of N. oiratianus and N. spathiger not only provides new mtDNA sources for a better understanding of nematode mt genomics and phylogeny, but also provides novel and useful genetic markers for studying diagnosis, population genetics and molecular epidemiology of Nematodirus spp. in small ruminants.


Assuntos
Genoma Mitocondrial , Doenças das Cabras/parasitologia , Nematodirus/genética , Doenças dos Ovinos/parasitologia , Infecções por Strongylida/veterinária , Animais , China/epidemiologia , Cabras , Filogenia , Ovinos , Infecções por Strongylida/parasitologia
17.
N Z Vet J ; 62(5): 286-9, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24916540

RESUMO

AIM: To compare the prevalence of Nematodirus spathiger and N. filicollis on a sample of farms in the lower South Island with the lower and central North Island of New Zealand by way of a presence/absence survey. METHODS: A presence/absence non-random survey was conducted in which pooled faeces from lambs from 50 farms in the lower and central North Island (n=22) and lower South Island (n=28) were cultured, with and without a post-culture period of chilling, to produce third-stage parasitic nematode larvae (L3). After recovery using the Baermann technique, individual L3 were identified to Nematodirus spp. using a PCR assay. This identified the species that were present on each farm that were then used to compare the regions. RESULTS: Nematodirus filicollis was present in 38/50 (76%) samples from which Nematodirus spp. larvae were cultured, compared with 50/50 (100%) in the case of N. spathiger. No regional differences were observed in the prevalence of either species (p=0.74). Of the Nematodirus spp. L3 recovered from the unchilled samples, 415/428 (97%) were N. spathiger and 13/428 (3%) N. filicollis. After chilling 594/695 (85%) of the Nematodirus spp. L3 were N. spathiger and 101/695 (15%) were N. filicollis. CONCLUSION: Despite the non-random nature of the study, the evidence suggests that both these species are likely to occur sympatrically on most sheep farms throughout New Zealand. In general N. filicollis eggs did not hatch without a period of chilling and this has implications for the identification of these larvae using conventional culture methods.


Assuntos
Nematodirus/classificação , Doenças dos Ovinos/parasitologia , Infecções por Strongylida/veterinária , Animais , Fezes/parasitologia , Nematodirus/fisiologia , Nova Zelândia/epidemiologia , Prevalência , Ovinos , Doenças dos Ovinos/epidemiologia , Infecções por Strongylida/epidemiologia , Infecções por Strongylida/parasitologia
19.
Vet Rec ; 173(6): 135-8, 2013 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-23934294

RESUMO

Nematodirosis in lambs Jejunal haemorrhagic syndrome in a heifer Epitheliogenesis imperfecta in a bovine fetus Plant poisoning in cattle and sheep Abomasal emptying defect in a ewe Cholangiocellular carcinoma in a duck These are among matters discussed in the Northern Ireland animal disease surveillance quarterly report for April to June 2013.


Assuntos
Doenças dos Animais/epidemiologia , Surtos de Doenças/veterinária , Animais , Bovinos , Surtos de Doenças/estatística & dados numéricos , Patos , Cavalos , Nematodirus , Irlanda do Norte/epidemiologia , Estações do Ano , Vigilância de Evento Sentinela/veterinária , Ovinos , Doenças dos Ovinos/epidemiologia , Infecções por Strongylida/epidemiologia , Infecções por Strongylida/veterinária
20.
Heredity (Edinb) ; 110(5): 420-9, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23512009

RESUMO

The genetic architecture underlying nematode resistance and body weight in Blackface lambs was evaluated comparing genome-wide association (GWA) and regional heritability mapping (RHM) approaches. The traits analysed were faecal egg count (FEC) and immunoglobulin A activity against third-stage larvae from Teladorsagia circumcincta, as indicators of nematode resistance, and body weight in a population of 752 Scottish Blackface lambs, genotyped with the 50k single-nucleotide polymorphism (SNP) chip. FEC for both Nematodirus and Strongyles nematodes (excluding Nematodirus), as well as body weight were collected at approximately 16, 20 and 24 weeks of age. In addition, a weighted average animal effect was estimated for both FEC and body weight traits. After quality control, 44 388 SNPs were available for the GWA analysis and 42 841 for the RHM, which utilises only mapped SNPs. The same fixed effects were used in both analyses: sex, year, management group, litter size and age of dam, with day of birth as covariate. Some genomic regions of interest for both nematode resistance and body weight traits were identified, using both GWA and RHM approaches. For both methods, strong evidence for association was found on chromosome 14 for Nematodirus average animal effect, chromosome 6 for Strongyles FEC at 16 weeks and chromosome 6 for body weight at 16 weeks. Across the entire data set, RHM identified more regions reaching the suggestive level than GWA, suggesting that RHM is capable of capturing some of the variation not detected by GWA analyses.


Assuntos
Peso Corporal/genética , Resistência à Doença/genética , Infecções por Nematoides/veterinária , Doenças dos Ovinos/genética , Carneiro Doméstico/genética , Animais , Feminino , Estudo de Associação Genômica Ampla , Imunoglobulina A/genética , Masculino , Infecções por Nematoides/genética , Nematodirus/isolamento & purificação , Nematodirus/patogenicidade , Ostertagia/patogenicidade , Contagem de Ovos de Parasitas , Polimorfismo de Nucleotídeo Único , Ovinos , Doenças dos Ovinos/parasitologia , Carneiro Doméstico/parasitologia
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