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1.
Vet Parasitol ; 277: 109018, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31896020

RESUMO

Control of sheep gastrointestinal nematode (GIN) infections mostly relies on the use of anthelmintics. Refugia-based control strategies as targeted selective treatments (TST) can delay anthelmintic resistance development, but the optimal decision criteria for selecting individuals to be treated in subclinical infection scenarios remain unclear. The present study aimed to evaluate the suitability of body condition score (BCS) and faecal egg counts (FEC) as treatment indicators and to determine their optimized threshold values for treatment in TST by determining the relationships of BCS, FEC and anthelmintic treatment with several productive parameters in pre-mating and pre-partum periods at an individual level. Deworming in pre-mating period increased BCS gain, but its magnitude was directly associated with strongyle FEC before treatment. Deworming also increased fertility in ewes with BCS < 2.75 and the proportion of lambing ewes that got pregnant during the first ovulation cycle. Nevertheless, treatment did not yield productive benefits in ewes with higher BCS values. On the other hand, deworming in the pre-partum lowered lamb peri-partum mortality and increased lamb weight at birth and the growth of lambs during lactation, especially in lambs born from ewes with strongyle FEC > 400 epg before treatment. These results showed that FEC and especially BCS can be potential decision criteria for the implementation of TST in these types of scenarios. The TST scheme derived from the present results on the control of GIN infections should include anthelmintic treatment of ewes with BCS lower than ≈ 3 approximately five weeks before mating and lambing. In the pre-lambing period, treatment may be unnecessary if flock mean strongyle FEC is lower than ≈ 200 epg, as the proportion of ewes with individual FEC > 400 epg would be very low. The results suggest that implementation of this TST scheme would provide benefits, such as the improvement of productivity, a rational management of parasites in refugia, and preservation of future efficacy of anthelmintics, in comparison to traditional deworming schemes.


Assuntos
Gastroenteropatias/veterinária , Infecções por Nematoides/veterinária , Doenças dos Ovinos/tratamento farmacológico , Doenças dos Ovinos/prevenção & controle , Animais , Infecções Assintomáticas , Feminino , Gastroenteropatias/tratamento farmacológico , Gastroenteropatias/prevenção & controle , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/prevenção & controle , Gravidez , Ovinos
2.
Rev Bras Parasitol Vet ; 28(3): 339-345, 2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-31291435

RESUMO

Gastrointestinal nematode infection is an important cause of high economic losses in livestock production. Nematode control based on a synthetic chemical approach is considered unsustainable due to the increasing incidence of anthelmintic resistance. Control alternatives such as the use of natural products are therefore becoming relevant from an environmental and economic point of view. Proteins are macromolecules with various properties that can be obtained from a wide range of organisms, including plants and fungi. Proteins belonging to different classes have shown great potential for the control of nematodes. The action of proteins can occur at specific stages of the nematode life cycle, depending on the composition of the external layers of the nematode body and the active site of the protein. Advances in biotechnology have resulted in the emergence of numerous protein and peptide therapeutics; however, few have been discussed with a focus on the control of animal nematodes. Here, we discuss the use of exogenous proteins and peptides in the control of gastrointestinal.


Assuntos
Antinematódeos/isolamento & purificação , Proteínas Fúngicas/isolamento & purificação , Gastroenteropatias/veterinária , Infecções por Nematoides/veterinária , Peptídeos/isolamento & purificação , Proteínas de Plantas/isolamento & purificação , Animais , Antinematódeos/administração & dosagem , Biotecnologia , Quitinases/administração & dosagem , Quitinases/isolamento & purificação , Proteínas Fúngicas/administração & dosagem , Gastroenteropatias/parasitologia , Infecções por Nematoides/tratamento farmacológico , Peptídeo Hidrolases/administração & dosagem , Peptídeo Hidrolases/isolamento & purificação , Peptídeos/administração & dosagem , Proteínas de Plantas/administração & dosagem
3.
BMC Vet Res ; 15(1): 216, 2019 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-31248417

RESUMO

BACKGROUND: This study aimed to evaluate the efficacy of anthelmintics in goats raised under mountain farming conditions in northern Italy. On 8 goat farms (n = 143 animals), a faecal egg count reduction (FECR) test was done after farmers conducted their routine anthelmintic treatments. Furthermore, on 5 goat farms (n = 135 animals) a FECR test was done under controlled conditions applying oral formulations of a macrocyclic lactone (ML), benzimidazole (BZ) (partly in combination with salicylanilide (SA)) or a combination of imidazothiazole (IT) and SA on the same farm. AR was assumed if FECR and the upper confidence interval (CI) was < 95% and the lower 95% CI was < 90%. RESULTS: Underdosing was found in 6 of the 8 farms tested after routine treatments. Out of the 6 routinely ML-treated goat flocks, only three were found where ML showed adequate efficacy. FECR in all others ranged between 64 and 93%. In one flock Trichostrongylus spp. and in one Haemonchus spp. larvae were identified after treatment. BZ-treated flocks had an efficacy of 99 and 37%. Larvae identified after treatment were Trichostrongylus spp. in one and Haemonchus spp. in the other flock. Under controlled conditions, ML had an adequate efficacy on 4 farms and a FECR of 88% on another one. BZ was effective on all farms. The combination of BZ and SA had a FECR of 99% on the farm it was tested. IT + SA in combination was effective on 2 farms and had a FECR of 91% on a third farm. Larvae identified after treatment were composed of Haemonchus spp. (ML and BZ), Trichostrongylus spp. (BZ) and Teladorsagia spp. (BZ and SA). CONCLUSIONS: This first report on the prevalence of AR in goats in the mountainous region of South Tyrol reveals a low efficacy of the most commonly used anthelmintics after routine treatments. This might be explained by a high level of underdosing as observed in the farms. However, results from the controlled FECR tests suggest that the observed level of AR was lower but cannot be solely explained by underdosing.


Assuntos
Anti-Helmínticos/uso terapêutico , Doenças das Cabras/tratamento farmacológico , Enteropatias Parasitárias/veterinária , Infecções por Nematoides/veterinária , Animais , Fazendas , Feminino , Doenças das Cabras/parasitologia , Cabras , Enteropatias Parasitárias/tratamento farmacológico , Itália , Masculino , Nematoides/efeitos dos fármacos , Infecções por Nematoides/tratamento farmacológico , Contagem de Ovos de Parasitas/veterinária
4.
Vet Parasitol ; 270 Suppl 1: S38-S44, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31104940

RESUMO

The efficacy and safety of a new topical formulation containing selamectin plus sarolaner (Revolution® Plus / Stronghold® Plus, Zoetis) was evaluated for the prevention of heartworm (Dirofilaria immitis) disease and the treatment of roundworm infection in cats enrolled as veterinary patients in two field studies conducted in Japan. In the heartworm field study, 91 cats negative for D. immitis antigen and anti-D. immitis antibody were enrolled and received 9 monthly topical treatments with selamectin plus sarolaner during the period of April to December 2015. Efficacy was assessed by testing post-treatment blood samples collected 8, 12, and 15 months after initiation of treatment for the presence of D. immitis antigen and anti-D. immitis antibody. Eighty-seven cats completed the entire study and were included in the determination of efficacy. No D. immitis antigen or anti-D. immitis antibody were detected in any of the post-treatment samples. In the roundworm field study, completed in the period from April to November 2015, 64 cats with ≥100 roundworm eggs per gram (EPG) of feces were enrolled and allocated randomly in a 1:1 ratio, to receive either selamectin plus sarolaner or emodepside plus praziquantel (Profender®, Bayer). Treatments were administered topically on Days 0 and 30, and efficacy was assessed by fecal EPG counts conducted on Days 14, 30, and 60. All cats completed the entire study. At enrollment, all cats were infected with Toxocara cati. Compared to pre-treatment, geometric mean T. cati EPG counts on Days 14, 30, and 60 were reduced by >99.9% in both treatment groups. There were no treatment-related adverse events in either study. Monthly topical administration of Revolution® Plus / Stronghold® Plus providing a minimum of 6 mg/kg selamectin and 1 mg/kg sarolaner was safe and effective in the prevention of heartworm disease and the treatment of roundworm infection in cats enrolled as veterinary patients in Japan.


Assuntos
Antiparasitários/administração & dosagem , Azetidinas/administração & dosagem , Doenças do Gato/prevenção & controle , Dirofilariose/prevenção & controle , Enteropatias Parasitárias/veterinária , Ivermectina/análogos & derivados , Infecções por Nematoides/veterinária , Compostos de Espiro/administração & dosagem , Administração Tópica , Animais , Doenças do Gato/tratamento farmacológico , Doenças do Gato/parasitologia , Gatos , Dirofilaria immitis/efeitos dos fármacos , Dirofilaria immitis/imunologia , Dirofilariose/tratamento farmacológico , Dirofilariose/parasitologia , Composição de Medicamentos/veterinária , Feminino , Helmintíase/tratamento farmacológico , Helmintíase/parasitologia , Helmintíase/prevenção & controle , Enteropatias Parasitárias/tratamento farmacológico , Enteropatias Parasitárias/parasitologia , Enteropatias Parasitárias/prevenção & controle , Ivermectina/administração & dosagem , Masculino , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/parasitologia , Infecções por Nematoides/prevenção & controle , Contagem de Ovos de Parasitas/veterinária , Distribuição Aleatória , Toxocara/efeitos dos fármacos , Resultado do Tratamento
5.
Aust Vet J ; 97(6): 185-190, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31136696

RESUMO

OBJECTIVES: To demonstrate the impact of a single drench with a label dose of injectable doramectin subsequent to weaning on the growth and performance of heifers and steers in central Queensland beef herds. METHODS: Three studies were undertaken on recently-weaned Bos indicus-cross beef calves with ≥ 75% B. indicus content on two farms in central Queensland, just north of the Tropic of Capricorn. Farm 1 was located 50 km north and Farm 2 75 km north-west of Rockhampton. In each study, half of a group of recently-weaned beef calves were treated by random allocation with 0.2 mg/kg of injectable doramectin, and the remainder acting as untreated controls. Study 1 (Farm 1) enrolled 250 heifers, while studies 2 and 3 (Farm 2) both enrolled 200 steers and 200 heifers. The farms involved did not historically use macrocyclic lactone-based drenches on their cattle. There were varying periods of follow-up, with treated and control cattle pastured as one group throughout the study period. Worm burdens were monitored using standard faecal egg counts and larval differentiation procedures. In all studies, the worm genera present were a mix of Cooperia spp., Haemonchus spp. and Oesophagostomum spp. RESULTS: In study 1, conducted on Farm 1 beginning 9 July 2012, doramectin-treated cattle gained an average of 0.27 kg/day while control cattle gained 0.19 kg/day over a monitoring period of 121 days (P < 0.0001). In study 2, conducted on Farm 2 beginning 28 July 2015, doramectin-treated cattle gained an average of 0.15 kg/day versus 0.145 kg/day in the control group (P = 0.44) over a 231-day study period. In study 3, conducted on Farm 2 beginning 4 August 2016, doramectin-treated steers and heifers gained an average of 0.431 and 0.402 kg/day versus 0.342 and 0.311 kg/day in the control group, respectively, over the first 91 days of the study (P < 0.0001 in both cases). The differences in average daily gain (ADG) in subsequent time periods were not statistically significant for steers or heifers. However, overall differences in ADG from day 0 remained statistically significant out to day 258, when the study ended for the heifers. By day 594, when the study ended for the steers, the difference in ADG was no longer significant. CONCLUSION: Treatment with injectable doramectin soon after weaning resulted in improved weight gain in the 3 months after weaning in two of the three studies.


Assuntos
Ivermectina/análogos & derivados , Infecções por Nematoides/veterinária , Estrongilídios/isolamento & purificação , Ganho de Peso/efeitos dos fármacos , Animais , Antinematódeos/administração & dosagem , Antinematódeos/uso terapêutico , Bovinos , Doenças dos Bovinos/tratamento farmacológico , Doenças dos Bovinos/parasitologia , Feminino , Ivermectina/administração & dosagem , Ivermectina/uso terapêutico , Masculino , Infecções por Nematoides/tratamento farmacológico , Contagem de Ovos de Parasitas , Queensland , Distribuição Aleatória
6.
Exp Parasitol ; 200: 16-23, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30914262

RESUMO

Gastrointestinal nematodes (GIN) are responsible for enormous economic losses worldwide. The use of anthelmintic drugs reduces the parasitic burden in ruminants. However, the excessive use of these drugs triggers anthelmintic resistance in these parasites, which leads to a worrisome inefficacy of most of the commercially available antiparasitic drugs. Caesalpinia coriaria is an arboreal legume possessing medical properties, although the antiparasitic potential of this plant against animal parasitic nematodes has not yet been studied. The aim of this study was to assess the in vitro ovicidal activity of a hydro-alcoholic extract (HA-E) from C. coriaria fruits against GIN and to identify the compounds responsible for this activity through an egg hatch inhibition (EHI) assay. GIN eggs obtained from cattle faeces were used in bio-guided assays. The HA-E was subjected to a liquid-liquid extraction using water and ethyl acetate to obtain two fractions, an organic fraction (EtOAc-F, 27% yield) and an aqueous (Aq-F, 73% yield) fraction. The chromatographic fractionation of the EtOAc-F (2 gr) was performed on a glass column packed with silica gel and eluted with dichloromethane/methanol with 10% ascending polarity. The bioactive compounds were analysed using high-performance liquid chromatography (HPLC) with UV detection, nuclear magnetic resonance (NMR) spectroscopy and mass spectroscopy (MS). The HA-E extract and the EtOAc-F showed ovicidal activity at a LC50 of 0.92 and 0.16 mg/mL, respectively. A concentration-dependant effect was observed in both treatments. Chromatographic fractionation of the EtOAc-F, allowed for the isolation and characterisation of three important compounds: methyl gallate (1), gallic acid (2) and an unidentified compound (UC). The bioactive molecules (2 and UC) displayed an ovicidal activity close to 100% at 1 mg/mL concentration. The results of this work show that gallic acid (2) isolated from C. coriaria fruits is responsible for its ovicidal activity. The use of Caesalpinia coriaria could be explored in future studies as an environmentally-friendly alternative for the control of GIN in ruminants.


Assuntos
Caesalpinia/química , Doenças dos Bovinos/tratamento farmacológico , Enteropatias Parasitárias/tratamento farmacológico , Infecções por Nematoides/tratamento farmacológico , Extratos Vegetais/farmacologia , Animais , Bovinos , Cromatografia Líquida de Alta Pressão/veterinária , Cromatografia em Camada Delgada/veterinária , Ácido Gálico/química , Ácido Gálico/farmacologia , Ácido Gálico/uso terapêutico , Nematoides/efeitos dos fármacos , Óvulo/efeitos dos fármacos , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/uso terapêutico
7.
Rev Bras Parasitol Vet ; 28(1): 59-67, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30892462

RESUMO

The purpose of this work was to identify, critically assess, and summarize available data from primary research about the anthelmintic resistance of injectable macrocyclic lactones in cattle. Meta-analysis was performed to estimate the pooled Odds Ratio and 95% Confidence Intervals. Of the 1504 abstracts screened for eligibility, 80 were deemed relevant for full publication review. Thirteen publications were included in the qualitative synthesis and assessed for systematic bias. Only five studies were included in the quantitative analysis because they showed a low risk of producing biased results in all the parameters. The forest plot indicated four studies that discuss anthelmintic resistance (P<0.05), while only one study did not discuss anthelmintic resistance (P<0.05). The pooled estimate showed 0.59 (95% Confidence intervals: 0.08, 0.47) times higher odds for studies that report anthelmintic resistance than for studies reporting efficacious anthelmintic treatment, with significant and substantially low heterogeneity (I2=25%). Anthelmintic resistance to injectable macrocyclic lactones is a reality. There are need to improve methodological reporting in studies, which is a problem for investigations that involves systematic review and meta-analysis (SR-MA).


Assuntos
Anti-Helmínticos/administração & dosagem , Resistência a Medicamentos , Gastroenteropatias/veterinária , Lactamas Macrocíclicas/administração & dosagem , Infecções por Nematoides/veterinária , Animais , Bovinos , Doenças dos Bovinos/parasitologia , Gastroenteropatias/tratamento farmacológico , Gastroenteropatias/parasitologia , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/parasitologia
8.
Onderstepoort J Vet Res ; 86(1): e1-e3, 2019 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-30843409

RESUMO

Clinical indicators such as diarrhoea (DISCO) or anaemia (FAMACHA©) are used as a measure for targeted selective treatments against gastrointestinal nematodes (GIN). Enteric cestodes such as Moniezia may interfere directly with DISCO or indirectly with the FAMACHA© score. We investigated 821 Ouled Djellal rams naturally infected in a steppe environment (GIN alone, cestodes alone, GIN and cestodes) or not. The rams were treated with ivermectin 2 months before being slaughtered to reduce the impact of nematodes on the clinical scores; however, persistent or newly acquired GINs were not related to both scores. Of the non-infected rams (n = 296), 26% identified as needing treatment against GIN using the FAMACHA score, and 34.5% using DISCO would have been thus selected. This implies that the clinical indicators used for the targeted selective treatment of gastrointestinal nematodes are not fully reliable when a low infection is recorded and may well be influenced by confounding factors. As expected, only DISCO was affected by cestode infection, and we suggest that the presence of Moniezia should also be taken into consideration.


Assuntos
Anti-Helmínticos/uso terapêutico , Infecções por Cestoides/veterinária , Ivermectina/uso terapêutico , Infecções por Nematoides/veterinária , Doenças dos Ovinos/tratamento farmacológico , Doenças dos Ovinos/epidemiologia , Argélia/epidemiologia , Animais , Cestoides/efeitos dos fármacos , Infecções por Cestoides/tratamento farmacológico , Infecções por Cestoides/epidemiologia , Infecções por Cestoides/parasitologia , Enteropatias Parasitárias/tratamento farmacológico , Enteropatias Parasitárias/epidemiologia , Enteropatias Parasitárias/parasitologia , Enteropatias Parasitárias/veterinária , Masculino , Nematoides/efeitos dos fármacos , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/epidemiologia , Infecções por Nematoides/parasitologia , Prevalência , Ovinos , Doenças dos Ovinos/parasitologia
9.
Behav Processes ; 162: 7-13, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30685411

RESUMO

The aim of this study was to identify modifications in the feeding behaviour of goats browsing a tropical deciduous forest (TDF) when natural gastrointestinal nematode (GIN) infection was suppressed. Continuous bite monitoring through direct observation was implemented in 12 Criollo goats (adults, non-pregnant) foraging for 4 h per day during the rainy season. In the first Period (P1, one observation point) all goats were maintained with natural GIN infection. In the second Period (P2, three observation points), goats were equally distributed into 2 groups: i) moxidectin treated group (TG) used in a suppressive scheme; and ii) naturally infected group (IG). For each observation point, goats were monitored at three timepoints per day (80 min each), for three consecutive days, to estimate their intake of dry matter (DM), condensed tannins (CT), crude protein, metabolizable energy and digestible DM. Live weight (LW), faecal samples and blood samples were obtained every 28 days to determine LW change, faecal egg counts (FEC) and packed cell volume (PCV). During P1 and P2, the TG and IG had similar LW change and PCV. During both periods, the intake of DM, CT and all macronutrients were similar for TG and IG. The suppression of GIN infection did not modify the feeding behaviour of goats. Therefore, a therapeutic self-medicative behaviour was not identified in Criollo goats browsing a TDF.


Assuntos
Comportamento Alimentar , Doenças das Cabras/psicologia , Infecções por Nematoides/psicologia , Animais , Fezes/parasitologia , Feminino , Doenças das Cabras/parasitologia , Cabras , Macrolídeos/uso terapêutico , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/veterinária , Contagem de Ovos de Parasitas/estatística & dados numéricos , Automedicação
10.
Int J Parasitol Drugs Drug Resist ; 8(3): 540-549, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30502120

RESUMO

The control of parasitic nematodes impacting animal health relies on the use of broad spectrum anthelmintics. However, intensive use of these drugs has led to the selection of resistant parasites in livestock industry. In that respect, there is currently an urgent need for novel compounds able to control resistant parasites. Nicotine has also historically been used as a de-wormer but was removed from the market when modern anthelmintics became available. The pharmacological target of nicotine has been identified in nematodes as acetylcholine-gated ion channels. Nicotinic-sensitive acetylcholine receptors (N-AChRs) therefore represent validated pharmacological targets that remain largely under-exploited. In the present study, using an automated larval migration assay (ALMA), we report that nicotinic derivatives efficiently paralyzed a multiple (benzimidazoles/levamisole/pyrantel/ivermectin) resistant field isolate of H. contortus. Using C. elegans as a model we confirmed that N-AChRs are preferential targets for nornicotine and anabasine. Functional expression of the homomeric N-AChR from C. elegans and the distantly related horse parasite Parascaris equorum in Xenopus oocytes highlighted some striking differences in their respective pharmacological properties towards nicotine derivative sensitivity. This work validates the exploitation of the nicotine receptors of parasitic nematodes as targets for the development of resistance-breaking compounds.


Assuntos
Antinematódeos/farmacologia , Sistemas de Liberação de Medicamentos , Nematoides/efeitos dos fármacos , Nicotina/farmacologia , Receptores Nicotínicos/efeitos dos fármacos , Animais , Anti-Helmínticos/farmacologia , Ascaridoidea/efeitos dos fármacos , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/metabolismo , Resistência a Múltiplos Medicamentos , Haemonchus/efeitos dos fármacos , Haemonchus/fisiologia , Proteínas de Helminto/efeitos dos fármacos , Proteínas de Helminto/metabolismo , Cavalos/parasitologia , Larva/efeitos dos fármacos , Larva/fisiologia , Levamisol/farmacologia , Gado/parasitologia , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/parasitologia , Nicotina/química , Subunidades Proteicas/metabolismo , Ovinos , Xenopus laevis
11.
Int J Parasitol Drugs Drug Resist ; 8(3): 607-628, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30503202

RESUMO

Many anthelmintic drugs used to treat parasitic nematode infections target proteins that regulate electrical activity of neurons and muscles: ion channels (ICs) and neurotransmitter receptors (NTRs). Perturbation of IC/NTR function disrupts worm behavior and can lead to paralysis, starvation, immune attack and expulsion. Limitations of current anthelmintics include a limited spectrum of activity across species and the threat of drug resistance, highlighting the need for new drugs for human and veterinary medicine. Although ICs/NTRs are valuable anthelmintic targets, electrophysiological recordings are not commonly included in drug development pipelines. We designed a medium-throughput platform for recording electropharyngeograms (EPGs)-the electrical signals emitted by muscles and neurons of the pharynx during pharyngeal pumping (feeding)-in Caenorhabditis elegans and parasitic nematodes. The current study in C. elegans expands previous work in several ways. Detecting anthelmintic bioactivity in drugs, compounds or natural products requires robust, sustained pharyngeal pumping under baseline conditions. We generated concentration-response curves for stimulating pumping by perfusing 8-channel microfluidic devices (chips) with the neuromodulator serotonin, or with E. coli bacteria (C. elegans' food in the laboratory). Worm orientation in the chip (head-first vs. tail-first) affected the response to E. coli but not to serotonin. Using a panel of anthelmintics-ivermectin, levamisole and piperazine-targeting different ICs/NTRs, we determined the effects of concentration and treatment duration on EPG activity, and successfully distinguished control (N2) and drug-resistant worms (avr-14; avr-15; glc-1, unc-38 and unc-49). EPG recordings detected anthelmintic activity of drugs that target ICs/NTRs located in the pharynx as well as at extra-pharyngeal sites. A bus-8 mutant with enhanced permeability was more sensitive than controls to drug treatment. These results provide a useful framework for investigators who would like to more easily incorporate electrophysiology as a routine component of their anthelmintic research workflow.


Assuntos
Anti-Helmínticos/farmacologia , Proteínas de Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/fisiologia , Fenômenos Eletrofisiológicos/efeitos dos fármacos , Animais , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/fisiologia , Avaliação Pré-Clínica de Medicamentos/métodos , Resistência a Medicamentos , Eletrofisiologia/métodos , Humanos , Ivermectina/farmacologia , Dispositivos Lab-On-A-Chip , Levamisol/farmacologia , Microfluídica/métodos , Mutação , Infecções por Nematoides/tratamento farmacológico
12.
Vet Parasitol ; 264: 42-46, 2018 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-30503090

RESUMO

The present study was conducted to further characterize the anthelmintic activity of the 0.5% w/v topical formulation of eprinomectin (EPRINEX® Pour-on, Merial) when administered at 1 mg/kg body weight to sheep in preventing the establishment of induced gastrointestinal and pulmonary nematode infections. Thirty-six female Merino sheep (∼4 months of age, weighing 27.0-36.0 kg) were blocked by pre-treatment body weight to form blocks of four animals. Within blocks, the animals were randomly allocated to either remain untreated (control) or be treated once with EPRINEX® either on Day 0, Day 7 or Day 14. Starting on Day 15, the sheep were given trickle infections with infective larvae of seven species of gastrointestinal nematodes and Dictyocaulus filaria lungworms daily for seven consecutive days. Five weeks after completion of the daily challenge (Day 56), the animals were necropsied for parasite recovery and count. Treatment with EPRINEX® prevented the establishment (>90%, p ≤ 0.027) of D. filaria, Teladorsagia circumcincta (pinnata/trifurcata), Cooperia curticei, Nematodirus battus, Trichostrongylus colubriformis and Oesophagostomum venulosum for at least 21 days, and of Haemonchus contortus and Trichostrongylus axei for at least 14 days. Sheep in the groups treated with EPRINEX® at Days 7 and 14 had significantly (p ≤ 0.018) higher Day -1 to Day 56 wt gains than the untreated controls. No treatment-related health problems or any other health problems were observed throughout the study.


Assuntos
Administração Tópica , Antinematódeos/administração & dosagem , Ivermectina/análogos & derivados , Infecções por Nematoides/veterinária , Doenças dos Ovinos/prevenção & controle , Animais , Feminino , Trato Gastrointestinal/parasitologia , Ivermectina/administração & dosagem , Pulmão/parasitologia , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/prevenção & controle , Distribuição Aleatória , Ovinos , Doenças dos Ovinos/tratamento farmacológico , Resultado do Tratamento
13.
Parasit Vectors ; 11(1): 597, 2018 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-30454033

RESUMO

BACKGROUND: Fluralaner provides efficacy against feline ectoparasites following topical administration. Moxidectin is routinely used to treat gastrointestinal nematode infections and prevent heartworm disease caused by Dirofilaria immitis. Praziquantel is routinely used to treat feline tapeworm infections. The safety of a fluralaner plus moxidectin combination topical solution (Bravecto™ Plus, MSD Animal Health) was assessed when administered concurrently with a commercially available praziquantel topical solution (Droncit™ Spot-on, Bayer Animal Health GmbH). The highest dose rates in clinical use were tested. RESULTS: Concurrent topical administration of a fluralaner plus moxidectin and a praziquantel product did not result in adverse findings. One out of ten cats receiving praziquantel only (control group), and two out of ten cats receiving fluralaner plus moxidectin and praziquantel (treatment group) had dandruff-like flakes in their coat at the application site. Two out of the ten control cats and three cats out of the ten treatment group cats had very small amounts of unidentified material (minute crusts or crumbs) at the application site which was only visible during close inspection. CONCLUSIONS: The concurrent treatment of cats with fluralaner plus moxidectin and praziquantel at the maximum dose in clinical use was well tolerated.


Assuntos
Anti-Helmínticos/administração & dosagem , Doenças do Gato/tratamento farmacológico , Inseticidas/administração & dosagem , Isoxazóis/administração & dosagem , Macrolídeos/administração & dosagem , Praziquantel/administração & dosagem , Acaricidas/administração & dosagem , Acaricidas/efeitos adversos , Administração Tópica , Animais , Anti-Helmínticos/efeitos adversos , Anti-Helmínticos/uso terapêutico , Doenças do Gato/parasitologia , Doenças do Gato/prevenção & controle , Gatos , Dirofilariose/tratamento farmacológico , Dirofilariose/prevenção & controle , Quimioterapia Combinada/métodos , Quimioterapia Combinada/estatística & dados numéricos , Quimioterapia Combinada/veterinária , Ectoparasitoses/tratamento farmacológico , Ectoparasitoses/prevenção & controle , Ectoparasitoses/veterinária , Feminino , Inseticidas/efeitos adversos , Inseticidas/uso terapêutico , Isoxazóis/efeitos adversos , Isoxazóis/uso terapêutico , Macrolídeos/efeitos adversos , Macrolídeos/uso terapêutico , Masculino , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/prevenção & controle , Praziquantel/efeitos adversos , Praziquantel/uso terapêutico , Distribuição Aleatória , Resultado do Tratamento
14.
Dokl Biochem Biophys ; 482(1): 264-267, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30397889

RESUMO

We investigated the mechanisms of action of selenium nanoparticles obtained by laser ablation for their use as an abiogenic elicitor of tomato resistance to parasitic nematodes. Selenium nanoparticles induced systemic resistance of tomatoes to the root-knot nematode, stimulated plant growth and development, was involved in the PR-6 gene expression in the roots and leaves of plants subjected to invasion, and increased the activity of proteinase inhibitors (markers of systemic resistance of plants to infection). Exogenous treatment of plants with solutions of selenium nanoparticles reduced the invasion of plants by affecting the morphological and physiological parameters of the parasites in the roots.


Assuntos
Resistência à Doença/efeitos dos fármacos , Lycopersicon esculentum/efeitos dos fármacos , Nanopartículas , Raízes de Plantas/efeitos dos fármacos , Selênio/farmacologia , Infecções por Nematoides/tratamento farmacológico , Peptídeo Hidrolases/efeitos dos fármacos , Peptídeo Hidrolases/metabolismo
15.
Parasit Vectors ; 11(1): 589, 2018 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-30449275

RESUMO

BACKGROUND: A spot-on formulation containing fluralaner (280 mg/ml) plus moxidectin (14 mg/ml) (Bravecto® Plus) was developed for the treatment of nematode infections as well as providing 12 weeks of protection against insect and acarine parasites in cats. The effectiveness and safety of this product against feline gastrointestinal nematodes was assessed in naturally-infested, client-owned cats under field conditions in Albania, Bulgaria, Germany and Hungary. METHODS: To be eligible for enrollment in this investigator-blinded study cats had to be at least 10 weeks-old, weigh at least 1.2 kg, be clinically healthy, and have a faecal sample testing positive for nematodes no more than eight days prior to treatment. Cats were stratified into blocks of three in order of presentation at each center and randomly allocated in a 2:1 ratio to be treated topically on Day 0 with fluralaner plus moxidectin (minimum dose rates 40 mg/kg and 2 mg/kg, respectively) or emodepside plus praziquantel (minimum dose rates 3 mg/kg and 12 mg/kg, respectively) (Profender®). Faecal samples were collected from cats prior to treatment and 14 ± 4 days later. RESULTS: There were 182 cats randomized to the fluralaner plus moxidectin group, and 91 to the emodepside plus praziquantel group. Prior to treatment the most commonly identified nematode egg was Toxocara cati, found in 79.1 and 82.4% of cats in the fluralaner plus moxidectin and emodepside plus praziquantel groups, respectively. Eggs of Toxascaris leonina were found in 8.2 and 6.6% of cats; of hookworms in 30.8 and 24.2%; and of Capillaria spp. in 7.1 and 4.3%, respectively. After treatment, faecal samples from 98.3% of fluralaner plus moxidectin treated and 96.6% of emodepside plus praziquantel-treated cats were free of nematode ova. Geometric mean faecal egg count reductions for T. cati, the only eggs found in post-treatment faecal samples, were 99.97% and 99.93%, respectively. Treatment with fluralaner plus moxidectin was non-inferior to emodepside plus praziquantel. Both products were safe and well tolerated by cats treated under field conditions. CONCLUSIONS: This field study confirms that, in addition to 12-week extended duration flea and tick control, fluralaner plus moxidectin provides broad spectrum treatment of nematodes in cats.


Assuntos
Doenças do Gato/tratamento farmacológico , Inseticidas/uso terapêutico , Isoxazóis/uso terapêutico , Macrolídeos/uso terapêutico , Nematoides/efeitos dos fármacos , Infecções por Nematoides/veterinária , Administração Tópica , Animais , Doenças do Gato/epidemiologia , Doenças do Gato/parasitologia , Gatos , Depsipeptídeos/administração & dosagem , Depsipeptídeos/efeitos adversos , Depsipeptídeos/uso terapêutico , Europa Oriental/epidemiologia , Fezes/parasitologia , Feminino , Alemanha/epidemiologia , Inseticidas/administração & dosagem , Inseticidas/efeitos adversos , Isoxazóis/administração & dosagem , Isoxazóis/efeitos adversos , Macrolídeos/administração & dosagem , Macrolídeos/efeitos adversos , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/epidemiologia , Infecções por Nematoides/parasitologia , Contagem de Ovos de Parasitas/veterinária , Praziquantel/administração & dosagem , Praziquantel/efeitos adversos , Praziquantel/uso terapêutico , Distribuição Aleatória , Método Simples-Cego , Sifonápteros/efeitos dos fármacos , Sifonápteros/parasitologia , Resultado do Tratamento
16.
Parasitol Res ; 117(12): 3993-4002, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30302586

RESUMO

The aim of the present study was to evaluate the effects of treatment with different anthelmintic compounds on the productivity of naturally infected calves and the economic viability of these treatments within extensive breeding systems employing different nutritional strategies after weaning. For this purpose, 4 farms with 42-60 calves naturally infected with gastrointestinal nematodes were selected. The calves were distributed into 6 groups (7-10 animals each) per farm and treated with ivermectin 1%, ivermectin 3.15%, eprinomectin 5%, levamisole 7.5%, albendazole 15%, and control group (no treatment). These animals were evaluated over an experimental period of 150 days. Levamisole 7.5% presented the best capacity for the reduction of eggs per gram (EPG) of feces in all herds evaluated, followed by albendazole 15% and eprinomectin 5%. Parasite resistance to multiple drugs was found in all herds, especially those of Cooperia, Haemonchus, Oesophagostomum, and Trichostrongylus. For farm 1, differences in weight gain and EPG reduction percentages led to a difference of US$285.06 between the levamisole and ivermectin 3.15% groups. Similar findings were noted for the levamisole and ivermectin 1% groups of farm 3, with a difference of US$399.37 because of the final weight gain in these groups. For farms 2 and 4, the ivermectin 3.15% and control groups, respectively, were the most profitable; these unexpected results were possibly influenced by variables not measured during the experimental period. This study suggested that anthelmintic treatments should always precede an efficacy test, once they are demonstrated to be most profitable under adequate breeding conditions, to ensure adequate control of gastrointestinal nematode infection.


Assuntos
Anti-Helmínticos/uso terapêutico , Doenças dos Bovinos/tratamento farmacológico , Haemonchus/efeitos dos fármacos , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/veterinária , Oesophagostomum/efeitos dos fármacos , Carne Vermelha/parasitologia , Trichostrongylus/efeitos dos fármacos , Albendazol/uso terapêutico , Animais , Bovinos , Doenças dos Bovinos/parasitologia , Fezes/parasitologia , Hemoncose/tratamento farmacológico , Hemoncose/veterinária , Ivermectina/análogos & derivados , Ivermectina/uso terapêutico , Levamisol/uso terapêutico , Esofagostomíase/tratamento farmacológico , Esofagostomíase/veterinária , Contagem de Ovos de Parasitas/veterinária , Tricostrongilose/tratamento farmacológico , Tricostrongilose/veterinária , Desmame
18.
Vet Parasitol ; 258: 8-13, 2018 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-30105984

RESUMO

Targeted selective treatment (TST) has been proposed as a sustainable method of gastrointestinal nematode control that reduces the number of anthelmintic treatments administered, thereby preserving a susceptible nematode population in refugia. In order to minimise the impact of withholding treatment on animal performance, animals that would benefit most should be selected for treatment. However, the most suitable criteria for selecting which animals to treat remain a subject of research. The impact of implementing a TST strategy based on lamb live weight was investigated, and whether heavy lambs were more resilient than light lambs if left untreated. The study was conducted using weaned lambs on 3 sheep farms, and over 2 years. On each farm lambs were weighed and divided into heavy, medium and light weight classes. Within the heavy (n = 225) and light (n = 218) weight classes lambs were randomly allocated to two treatments; anthelmintic treatment or no anthelmintic treatment. All lambs in the medium weight class were treated. Animal performance and parasitological parameters were assessed over a 28-day period. Anthelmintic treatment had a significant effect (P < 0.01) on faecal egg count, average daily weight gain, body condition score and dag score; there was no treatment by weight class interaction. Anthelmintic treatment had no effect on plasma pepsinogen concentration or on blood leukocyte numbers. Withholding anthelmintic treatment from lambs therefore had a negative effect on worm egg count and animal performance with no evidence that heavy lambs were more resilient than light lambs when left untreated.


Assuntos
Anti-Helmínticos/uso terapêutico , Peso Corporal/efeitos dos fármacos , Infecções por Nematoides/veterinária , Doenças dos Ovinos/tratamento farmacológico , Animais , Anti-Helmínticos/administração & dosagem , Fezes/parasitologia , Feminino , Trato Gastrointestinal/efeitos dos fármacos , Trato Gastrointestinal/parasitologia , Leucócitos/efeitos dos fármacos , Nematoides/efeitos dos fármacos , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/parasitologia , Contagem de Ovos de Parasitas , Pepsinogênio A/sangue , Pepsinogênio A/efeitos dos fármacos , Ovinos , Doenças dos Ovinos/parasitologia , Desmame , Ganho de Peso
19.
Parasit Vectors ; 11(1): 388, 2018 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-29973276

RESUMO

BACKGROUND: Gastrointestinal nematodes (GINs) can cause significant economic losses in alpacas due to lowered production of fibre and meat. Although no anthelmintics are registered for use in alpacas, various classes of anthelmintics are frequently used to control parasitic gastroenteritis in alpacas in Australia and other countries. Very little is known about the current worm control practices as well as the efficacy of anthelmintics used against common GINs of alpacas. This study aimed to assess the existing worm control practices used by Australian alpaca farmers and to quantify the efficacy of commonly used anthelmintics against GINs of alpacas. METHODS: An online questionnaire survey was conducted to assess current worm control practices on 97 Australian alpaca farms, with an emphasis on the use of anthelmintics. Of this group of 97 alpaca farms, 20 were selected to assess the efficacy of eight anthelmintics and/or their combinations (closantel, fenbendazole ivermectin, monepantel, moxidectin and a combination of levamisole, closantel, albendazole, abamectin) using the faecal egg count reduction test (FECRT). A multiplexed-tandem PCR (MT-PCR) was used to identify the prevalent nematode genera/species. RESULTS: The response rate for the questionnaire was 94% (91/97). Almost half of the respondents kept alpacas with sheep and cattle, and 26% of respondents allowed alpacas to co-graze with these ruminants. Although only 63% respondents perceived worms to be an important health concern for alpacas, the majority of respondents (89%) used anthelmintics to control GINs of alpacas. The commonly used anthelmintics were macrocyclic lactones, monepantel, benzimidazoles, levamisole, closantel and their combinations, and they were typically administered at the dose rate recommended for sheep. The FECRT results showed that a combination of levamisole, closantel, albendazole and abamectin was the most effective dewormer followed by single drugs, including monepantel, moxidectin, closantel, fenbendazole and ivermectin. Haemonchus spp. were the most commonly resistant nematodes followed by Trichostrongylus spp., Camelostrongylus mentulatus, Ostertagia ostertagi and Cooperia spp. CONCLUSIONS: This is the first study aimed at assessing worm control practices and efficacy of commonly used anthelmintics in alpacas in Australia. Our findings document the extent of anthelmintics resistance on Australian alpaca farms and identify those anthelmintics that are still effective against GINs of alpacas.


Assuntos
Anti-Helmínticos/efeitos adversos , Camelídeos Americanos/parasitologia , Resistência a Múltiplos Medicamentos , Trato Gastrointestinal/parasitologia , Enteropatias Parasitárias/veterinária , Nematoides/efeitos dos fármacos , Infecções por Nematoides/veterinária , Animais , Anti-Helmínticos/uso terapêutico , Austrália/epidemiologia , Controle de Doenças Transmissíveis/estatística & dados numéricos , Fazendas , Fezes/parasitologia , Feminino , Trato Gastrointestinal/efeitos dos fármacos , Enteropatias Parasitárias/epidemiologia , Masculino , Nematoides/genética , Nematoides/isolamento & purificação , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/epidemiologia , Infecções por Nematoides/parasitologia , Contagem de Ovos de Parasitas , Reação em Cadeia da Polimerase , Ruminantes/parasitologia , Inquéritos e Questionários
20.
Vet Parasitol ; 256: 43-49, 2018 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-29887029

RESUMO

The study compared the pharmacokinetic (PK) behaviour and anthelmintic efficacy against susceptible and resistant nematodes following subcutaneous (SC) and oral administration of ivermectin (IVM) to cattle. Six commercial farms were involved: Farms 1 and 2 (IVM-susceptible nematode population) and Farms 3, 4, 5 and 6 (IVM-resistant nematode population). On each farm, forty-five calves naturally infected with gastrointestinal (GI) nematodes were randomly allocated into three groups (n = 15): untreated control, IVM SC administration, and IVM oral administration (both at 0.2 mg/kg). PK assessment (plasma and faeces) was performed on Farm 1. Efficacy was determined by Faecal Egg Count Reduction Test. IVM systemic availability upon SC administration (421 ±â€¯70.3 ng·d/mL) was higher (P < 0.05) compared to the oral treatment (132 ±â€¯31.3 ng·d/mL). However, higher (P < 0.05) faecal IVM concentrations were observed following oral treatment (9896 ±â€¯1931 ng·d/mL) compared to SC administration (4760 ±â€¯924 ng·d/mL). Similar (91-93%) IVM efficacy was observed on Farms 1 and 2 by both routes. Efficacy against resistant nematodes was slightly higher on Farms 3 and 4 after the oral (63 and 82%, respectively) compared to the SC (36 and 68%, respectively) treatment. However, there was complete therapeutic failure (0% efficacy) on Farm 5 and a very low response on Farm 6 (40 and 41% for SC and oral administration, respectively). Although larger faecal concentrations following IVM oral administration may increase drug exposure of GI adult worms, this does not always improve efficacy against resistant nematodes. The potential therapeutic advantages of oral treatments should be cautiously assessed, especially in presence of anthelmintic resistance.


Assuntos
Ivermectina/farmacologia , Ivermectina/farmacocinética , Nematoides/efeitos dos fármacos , Administração Intravenosa , Administração Oral , Animais , Antiparasitários/administração & dosagem , Antiparasitários/farmacocinética , Antiparasitários/farmacologia , Antiparasitários/uso terapêutico , Bovinos , Doenças dos Bovinos/tratamento farmacológico , Resistência a Medicamentos/efeitos dos fármacos , Ivermectina/administração & dosagem , Ivermectina/uso terapêutico , Infecções por Nematoides/tratamento farmacológico , Distribuição Aleatória
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