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1.
PLoS One ; 15(8): e0236143, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32790679

RESUMO

The focus of gastro-intestinal parasite control in the sheep industry is increasingly on finding a balance between maintaining productivity of the flock whilst minimising selection for anthelmintic resistance to preserve anthelmintic efficacy for the future. Periparturient ewes represent the major source of gastro-intestinal parasites for growing lambs and are therefore a priority for parasite control. This study examines the impact on ewe faecal egg counts (FECs), lamb FECs, lamb daily live weight gains (DLWGs) and pasture larval counts of treating groups of ewes two weeks prior to lambing with either, a long-acting moxidectin treatment, short-acting doramectin or control. Six groups of twenty ewes were allocated to individual paddocks, two groups allocated to each treatment, and weekly faecal sampling was performed throughout from the ewes and from six weeks after the start of lambing in the lambs. Treatment group was found to have a significant effect on both ewe FEC (p<0.001) and lamb FEC (p = 0.001) with the group receiving the long-acting anthelmintic having the lowest ewe and lamb FECs. There was no significant effect on the DLWGs of the lambs. Pasture larval counts at the end of the study period were lowest in the long-acting wormer treatment group. The use of long-acting moxidectin may be helpful as part of a parasite control programme by reducing the worm burdens of ewes and their lambs, decreasing the number of anthelmintic treatments required in that year and by reducing pasture contamination for those sheep which will graze the pasture in the next year. However, like all anthelmintics, its use should be judicious to avoid selection for resistance.


Assuntos
Criação de Animais Domésticos/métodos , Anti-Helmínticos/administração & dosagem , Infecções por Nematoides/veterinária , Doenças dos Ovinos/tratamento farmacológico , Ovinos/parasitologia , Animais , Anti-Helmínticos/farmacocinética , Fazendas , Fezes/parasitologia , Feminino , Meia-Vida , Ivermectina/administração & dosagem , Ivermectina/análogos & derivados , Ivermectina/farmacocinética , Larva , Macrolídeos/administração & dosagem , Macrolídeos/farmacocinética , Nematoides/isolamento & purificação , Infecções por Nematoides/diagnóstico , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/parasitologia , Contagem de Ovos de Parasitas/veterinária , Período Pós-Parto , Gravidez , Doenças dos Ovinos/diagnóstico , Doenças dos Ovinos/parasitologia
2.
PLoS One ; 15(8): e0238228, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32857800

RESUMO

The objective was to evaluate the effect of different cultivars of Brachiaria brizantha on the dynamics and concentration of the larval stages of gastrointestinal nematodes in the soil and forage strata, as well as their effects on the performance of naturally infected lambs. Overall, 48 90-day-old lambs with an initial weight of 19.04 ± 0.96 kg were observed. Moreover, a randomised block factorial design with four cultivars of Brachiaria brizantha (Marandu, Xaraés, Piatã and Paiaguás grasses) under intermittent stocking (with a pre-grazing canopy height of 40 cm and post-grazing canopy height of 20 cm) for two grazing cycles was used. The following variables were analysed: faecal egg counting, faecal culture, mean corpuscular volume, FAMACHA© score, weight and body condition score, the recovery of larvae from pasture and soil samples, nutritional value and the production and structural components of forage. Lambs grazing Marandu grass demonstrated the highest level of nematode infection (P < 0.05). However, the nutritional value did not differ between cultivars. Marandu grass had the highest pasture density (P < 0.05), while Paiaguás grass had the highest percentage of dead material (P < 0.05). The various genera of gastrointestinal nematodes found in the faecal cultures, regardless of the cultivars, include Haemonchus (92.01%), Trichostrongylus (4.55%), Strongyloides (3.06%) and Oesophagostomum (0.37%). Lambs grazing Xaraés grass had the lowest body weight (P < 0.05). Furthermore, larvae concentrations were highest in Marandu and Paiaguás pastures; infective Haemonchus and Trichostrongylus larvae were recovered from pasture and soil samples. The different cultivars of Brachiaria brizantha produce diverse and relevant microclimatic conditions to contaminate soil, pastures and animals. Animal performance was not compromised despite the Marandu and Paiaguás cultivars having the highest levels of contamination and infection. Based on parasitological aspects, the Brachiaria brizantha cultivars Xaraés and Piatã are recommended for grass-based sheep production systems over the other cultivars since they contribute to the reduction of larval contamination and infection.


Assuntos
Brachiaria , Meio Ambiente , Interações Hospedeiro-Parasita , Infecções por Nematoides/veterinária , Doenças dos Ovinos/parasitologia , Ovinos/parasitologia , Criação de Animais Domésticos , Animais , Peso Corporal , Fezes/parasitologia , Contagem de Ovos de Parasitas , Distribuição Aleatória , Ovinos/crescimento & desenvolvimento , Microbiologia do Solo
3.
Rev Bras Parasitol Vet ; 29(2): e023519, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32609248

RESUMO

An adult male puma (Puma concolor), hit by a car in an urban area, died three days later despite the therapeutic support provided. At necropsy, multiple firm nodules were identified in the gastric mucosa. The nodules were coated by an intact mucosa with a central opening from which reddish and cylindrical nematodes protruded into the lumen. Twenty-seven nematodes were retrieved for morphological and morphometric evaluations. During histopathological examination of the gastric tissue, the adult nematodes appear in longitudinal and transverse sections, surrounded by thick bands of collagen, interspersed with mixed inflammatory infiltrates. The nematodes had an eosinophilic cuticle with caudal serrated projections (bulbar type), coelomyarian musculature, pseudocoelom, and females with uterus containing numerous larvated eggs, characteristics consistent with the Cylicospirura genus. Morphologically, female nematodes had six large tricuspid teeth in the oral cavity and the vulva had an opening anterior to the esophagus-intestinal junction. Male nematodes had five pairs of small papillae near the tip of the tail. These findings were consistent with Cylicospirura felineus. This parasite should be included in the differential diagnosis of nodular gastric wall lesions in wild felids.


Assuntos
Gastrite , Nematoides , Puma , Animais , Doenças do Gato/parasitologia , Doenças do Gato/patologia , Gatos , Feminino , Gastrite/parasitologia , Gastrite/veterinária , Masculino , Nematoides/fisiologia , Infecções por Nematoides/parasitologia , Infecções por Nematoides/patologia , Infecções por Nematoides/veterinária , Puma/parasitologia
4.
Rev Bras Parasitol Vet ; 29(1): e015819, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32236331

RESUMO

An evaluation was made of the effect of anthelmintic treatments on the performance of Simmental X Nellore crossbred calves before and after weaning. To this end, the calves were divided into three groups: (1) treated monthly with a low efficacy anthelmintic drug, ivermectin; (2) treated monthly with a highly effective anthelmintic drug, albendazole; and (3) untreated control group. All the groups in this experiment showed an average fecal egg count of less than 400 eggs per gram (EPG), and no clinical signs of parasitic gastroenteritis. The blood variables were within the normal range and no calf presented anemia. In most of the samplings, mean EPGs were significantly lower (P<0.05) in the group treated with albendazole. The calves received dietary supplementation before and after weaning, which enabled them to gain weight in every month of the experiment and reach a body weight of about 250 kg on the last sampling date, before turning one year old. The anthelmintic treatments did not affect body weight gain, leading to the conclusion that, when fed with suitable dietary supplements, Simmental X Nellore crossbred calves are not affected by gastrointestinal nematode parasites acquired by grazing.


Assuntos
Albendazol/administração & dosagem , Anti-Helmínticos/administração & dosagem , Doenças dos Bovinos/tratamento farmacológico , Gastroenteropatias/veterinária , Ivermectina/administração & dosagem , Infecções por Nematoides/veterinária , Animais , Bovinos , Fezes/parasitologia , Feminino , Gastroenteropatias/tratamento farmacológico , Gastroenteropatias/parasitologia , Masculino , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/parasitologia , Contagem de Ovos de Parasitas/veterinária
5.
Proc Biol Sci ; 287(1922): 20200195, 2020 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-32156218

RESUMO

The impact of inbreeding on fitness has been widely studied and provides consequential inference about adaptive potential and the impact on survival for reduced and fragmented natural populations. Correlations between heterozygosity and fitness are common in the literature, but they rarely inform about the likely mechanisms. Here, we investigate a pathology with a clear impact on health in striped dolphin hosts (a nematode infection that compromises lung function). Dolphins varied with respect to their parasite burden of this highly pathogenic lung nematode (Skrjabinalius guevarai). Genetic diversity revealed by high-resolution restriction-associated DNA (43 018 RADseq single nucleotide polymorphisms) analyses showed a clear association between heterozygosity and pathogen load, but only for female dolphins, for which the more heterozygous individuals had lower Sk. guevarai burden. One locus identified by RADseq was a strong outlier in association with parasite load (heterozygous in all uninfected females, homozygous for 94% of infected females), found in an intron of the citron rho-interacting serine/threonine kinase locus (associated with milk production in mammals). Allelic variation at the Class II major histocompatability complex DQB locus was also assessed and found to be associated with both regional variation and with pathogen load. Both sex specificity and the identification of associating functional loci provide insight into the mechanisms by which more inbred individuals may be more susceptible to the infection of this parasite. This provides important insight towards our understanding of the impact of inbreeding in natural populations, relevant to both evolutionary and practical conservation considerations.


Assuntos
Stenella/parasitologia , Animais , Evolução Biológica , Feminino , Aptidão Genética , Heterozigoto , Antígenos de Histocompatibilidade Classe II , Endogamia/estatística & dados numéricos , Masculino , Infecções por Nematoides/veterinária , Seleção Genética , Stenella/fisiologia
6.
Parasit Vectors ; 13(1): 70, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32113470

RESUMO

BACKGROUND: Gastrointestinal nematodes are parasites that commonly infect dogs, and infections can be subclinical or may cause considerable clinical disease. Some species are zoonotic and may also cause clinical disease in humans. Year-round treatment of dogs is recommended to eliminate existing infections, which also indirectly reduces the potential for subsequent human exposure to zoonotic species. Here we present two studies that evaluated the safety and efficacy of a novel chewable oral tablet containing sarolaner, moxidectin and pyrantel against gastrointestinal nematode infections in dogs presented as veterinary patients in Europe and the USA. METHODS: Dogs naturally infected with Toxocara canis, Toxascaris leonina, Ancylostoma caninum and/or Uncinaria stenocephala were enrolled in the European study, and dogs naturally infected with T. canis were enrolled in the USA study. The animals were treated once orally with Simparica Trio™ tablets to provide 1.2-2.4 mg/kg sarolaner, 24-48 µg/kg moxidectin and 5-10 mg/kg pyrantel (as pamoate salt) or with a commercially available product according to the label directions as positive control. Efficacy was based on the post-treatment reduction in geometric mean egg counts (per gram feces) 7 or 10 days after treatment compared to pre-treatment egg counts. RESULTS: Simparica Trio™ was well tolerated in both studies. In the European study, geometric mean egg counts for T. canis, T. leonina, A. caninum and U. stenocephala were reduced by ≥ 98.3% in the Simparica Trio™ group and by ≥ 97.4% in the afoxolaner + milbemycin oxime group. In the USA study, geometric mean egg counts for T. canis were reduced by 99.2% in the Simparica Trio™ group and by 98.6% in the ivermectin + pyrantel group. In the USA study, 48 and 10 dogs in the Simparica Trio™ and the ivermectin + pyrantel group, respectively, were co-infected with A. caninum and the reduction in the post-treatment mean fecal egg counts were 98.6% and 74.7%, respectively. CONCLUSIONS: A single oral administration of Simparica Trio™ chewable tablets was well tolerated and was effective in the treatment of dogs with naturally occurring gastrointestinal nematode infections presented as veterinary patients in Europe and the USA.


Assuntos
Antinematódeos/administração & dosagem , Doenças do Cão/tratamento farmacológico , Enteropatias Parasitárias/veterinária , Nematoides/efeitos dos fármacos , Infecções por Nematoides/veterinária , Administração Oral , Animais , Azetidinas/administração & dosagem , Cães , Combinação de Medicamentos , Europa (Continente) , Feminino , Enteropatias Parasitárias/tratamento farmacológico , Macrolídeos/administração & dosagem , Masculino , Nematoides/classificação , Infecções por Nematoides/tratamento farmacológico , Contagem de Ovos de Parasitas , Pirantel/administração & dosagem , Compostos de Espiro/administração & dosagem , Resultado do Tratamento , Estados Unidos
7.
Vet Clin North Am Food Anim Pract ; 36(1): 1-15, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32029177

RESUMO

This article reviews the basics of gastrointestinal nematode biology and pathophysiology in cattle and describes how gastrointestinal nematode epidemiology is driven by environmental, host, and farm economic determinants. Adverse effects from gastrointestinal nematodes on their hosts are caused by tissue damage, nutrient absorption, immunopathologic effects, and reduced food intake induced by hormonal changes. Weather and microenvironmental factors influence the development and survival of free-living parasitic stages. A holistic control approach entails the consideration of environmental, immunologic, and socioeconomic aspects of nematode epidemiology and is key for the development and communication of sustainable control strategies.


Assuntos
Doenças dos Bovinos/parasitologia , Gastroenteropatias/veterinária , Infecções por Nematoides/veterinária , Animais , Bovinos , Doenças dos Bovinos/epidemiologia , Indústria de Laticínios/estatística & dados numéricos , Fezes/parasitologia , Feminino , Gastroenteropatias/parasitologia , Trato Gastrointestinal/parasitologia , Nematoides/isolamento & purificação , Infecções por Nematoides/epidemiologia
8.
Vet Clin North Am Food Anim Pract ; 36(1): 17-30, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32029182

RESUMO

Control of gastrointestinal nematodes has been based on anthelmintics. However, this strategy is unsustainable owing to anthelmintic resistance. Parasitic nematodes have biologic and genetic features that favor the development of drug resistance, making the emergence of resistant nematodes inevitable. The rate of resistance development is affected controllable factors. There is a need to change the paradigm of how gastrointestinal nematodes are controlled to decrease the rate at which resistance develops. This article reviews the biology and prevalence of anthelmintic resistance, and provides recommendations for diagnosing resistance and for strategies that should be implemented to reduce the development of resistance.


Assuntos
Anti-Helmínticos/farmacologia , Doenças dos Bovinos/tratamento farmacológico , Doenças das Cabras/tratamento farmacológico , Gado/parasitologia , Infecções por Nematoides/veterinária , Doenças dos Ovinos/tratamento farmacológico , Animais , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/parasitologia , Resistência a Medicamentos , Doenças das Cabras/epidemiologia , Doenças das Cabras/parasitologia , Cabras , Nematoides/isolamento & purificação , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/epidemiologia , Prevalência , Ovinos , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/parasitologia
9.
Vet Clin North Am Food Anim Pract ; 36(1): 45-57, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32029188

RESUMO

Control of gastrointestinal nematodes (GIN) can have both economic and health benefits for cattle operations in the southern United States. In the past several decades, GIN control has relied almost exclusively on the use of anthelmintics. With the increase in anthelmintic resistance new strategies must be developed. Anthelmintic use should be minimized by integrating grazing management and a good herd health program into GIN control programs. This takes knowledge of GIN biology and epidemiology in the region (climate and weather) combined with specific information from the ranch.


Assuntos
Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/prevenção & controle , Gastroenteropatias/veterinária , Infecções por Nematoides/veterinária , Animais , Anti-Helmínticos/administração & dosagem , Canadá/epidemiologia , Bovinos , Doenças dos Bovinos/parasitologia , Clima , Fezes/parasitologia , Gastroenteropatias/epidemiologia , Gastroenteropatias/parasitologia , Gastroenteropatias/prevenção & controle , Trato Gastrointestinal/parasitologia , Nematoides/isolamento & purificação , Infecções por Nematoides/epidemiologia , Infecções por Nematoides/parasitologia , Infecções por Nematoides/prevenção & controle , Estados Unidos/epidemiologia
10.
Vet Clin North Am Food Anim Pract ; 36(1): 59-71, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32029189

RESUMO

Parasite species infecting cattle throughout northern North American are generally the same as those found throughout North America. Throughout Canada, cattle are primarily infected with Ostertagia ostertagi and Cooperia oncophora, whose larvae survive cold winters within soil of pastures. Overwintering larvae of these species maintain a temporary population of refugia available in spring to grazing cattle. Cattle from northern United States are also infected with Cooperia punctata and Haemonchus placei, whose larvae cannot survive cold winters within pastures. Anthelmintics with persistent activity are used during spring to recover some of these losses; however, anthelmintic resistance limits effectiveness of this strategy.


Assuntos
Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/prevenção & controle , Infecções por Nematoides/veterinária , Animais , Anti-Helmínticos/administração & dosagem , Bovinos , Doenças dos Bovinos/tratamento farmacológico , Doenças dos Bovinos/parasitologia , Indústria de Laticínios/métodos , Feminino , Trato Gastrointestinal/parasitologia , Nematoides/isolamento & purificação , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/epidemiologia , Infecções por Nematoides/prevenção & controle , América do Norte/epidemiologia , Estações do Ano
11.
Vet Clin North Am Food Anim Pract ; 36(1): 73-87, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32029190

RESUMO

Strongylid gastrointestinal nematodes are an important cause of disease and economic loss in small ruminants. These parasites are important in most of the United States, with the bloodsucking parasite Haemonchus contortus being the predominant species of concern. Sheep and goats are infected while grazing, and the biology of infective larvae on pastures is important in the design of parasite management programs. Widespread resistance to anthelmintics requires strategies designed to preserve remaining drug activity; these include combination treatments with multiple classes of anthelmintics and targeted treatments.


Assuntos
Doenças das Cabras/epidemiologia , Doenças das Cabras/prevenção & controle , Infecções por Nematoides/veterinária , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/prevenção & controle , Animais , Anti-Helmínticos/administração & dosagem , Trato Gastrointestinal/parasitologia , Doenças das Cabras/tratamento farmacológico , Doenças das Cabras/parasitologia , Cabras , Nematoides/isolamento & purificação , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/epidemiologia , Infecções por Nematoides/prevenção & controle , Ovinos , Doenças dos Ovinos/tratamento farmacológico , Doenças dos Ovinos/parasitologia
12.
Acta Vet Scand ; 62(1): 9, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-32024529

RESUMO

The study aimed to compare the gastrointestinal helminthofauna of free-ranging wild boars from arable lands and forests, which are the natural habitats for wild boar in Poland and further to investigate if wild boars living in agricultural environments could acquire helminths commonly detected in domestic pigs. In 2011-2014, a total of 57 wild boars were examined post-mortem for the presence of gastrointestinal nematodes. Altogether, all but two of the animals were infected, and seven nematode species were found. The mean infection burden was 68.9 parasites, ranging from 1 to 381 worms. In forest areas, Ascarops strongylina, Physocephalus sexalatus, and Globocephalus urosubulatus were common, whereas on arable lands, the animals were more frequently infected (P < 0.05) by Ascaris suum and Trichuris suis, which are parasites that commonly occur in domestic pigs. Oesophagostomum dentatum was observed only in wild boars on arable lands, and Bourgelatia diducta, which is alien to European suids, appeared irrespective of habitat type. These results show significant differences in parasite spectra among wild boars living in forests or arable lands in Poland and indicates the risks of parasite transfer from domestic pigs to free-ranging wild boars. Furthermore, in farmed game, organic farming, or in the case of agritourism farms, one should be aware of the risk of related animals acquiring new and alien parasite infections by being kept outdoors.


Assuntos
Trato Gastrointestinal/parasitologia , Infecções por Nematoides/veterinária , Sus scrofa/parasitologia , Doenças dos Suínos/parasitologia , Agricultura , Animais , Biodiversidade , Florestas , Nematoides/classificação , Nematoides/isolamento & purificação , Infecções por Nematoides/parasitologia , Contagem de Ovos de Parasitas/veterinária , Polônia , Suínos
13.
Rev Bras Parasitol Vet ; 29(1): e014619, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32049140

RESUMO

Parasitic myelopathy caused by Gurltia paralysans in domestic cats is a disease commonly reported in several South American countries. The adult parasite is lodged in the meningeal veins and spinal cord, often causing clinical manifestations of vascular proliferation, thrombophlebitis, and medullary compression. Wild felines are believed to be the definitive hosts of this parasite. The infection occurs through the ingestion of paratenic hosts, but the life cycle of G. paralysans is not yet clearly understood. In this paper, we discuss a case of parasitic myelopathy in a margay (Leopardus wiedii) that died during post-surgical care. Necropsy revealed focal hemorrhages in the thoracolumbar spinal cord. A microscopic examination revealed adult nematodes and eggs inside the veins of subarachnoid space in spinal cord, suggesting G. paralysans infection. This is first description of parasitic myelopathy in a margay in Brazil.


Assuntos
Felidae/parasitologia , Nematoides/isolamento & purificação , Infecções por Nematoides/veterinária , Doenças da Medula Espinal/parasitologia , Animais , Animais Selvagens , Brasil , Gatos , Felidae/classificação , Feminino , Nematoides/classificação , Infecções por Nematoides/diagnóstico , Infecções por Nematoides/parasitologia , Doenças da Medula Espinal/diagnóstico
14.
J Helminthol ; 94: e125, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-32036795

RESUMO

Our objective was to measure the efficacy of ivermectin (IVM) and benzimidazoles (BZ, i.e. fenbendazole and albendazole) in 15 cattle farms in western France and southern Italy. A total of 11 groups were treated with IVM and 11 with BZ. Efficacy was assessed by calculating the percentage of faecal egg count reduction (%FECR) using the pre- and post-treatment arithmetic means. Anthelmintic resistance was considered to be present when the %FECR was <95% and the lower limit of the 95% confidence interval <90%. For IVM, the percentages of FECR ranged from 73% to 100%. Lack of efficacy to IVM was detected in two farms out of four in France, but was not detected in any of the seven farms in Italy. For BZ, the percentages of FECR ranged from 95% to 100%. No case of BZ resistance was detected in the five farms in France and the six farms in Italy.


Assuntos
Anti-Helmínticos/uso terapêutico , Doenças dos Bovinos/tratamento farmacológico , Gastroenteropatias/veterinária , Nematoides/efeitos dos fármacos , Infecções por Nematoides/veterinária , Animais , Benzimidazóis/uso terapêutico , Bovinos , Doenças dos Bovinos/parasitologia , Fazendas , Fezes/parasitologia , França , Gastroenteropatias/tratamento farmacológico , Gastroenteropatias/parasitologia , Trato Gastrointestinal/parasitologia , Itália , Ivermectina/uso terapêutico , Infecções por Nematoides/tratamento farmacológico , Contagem de Ovos de Parasitas
15.
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
16.
J Helminthol ; 94: e115, 2020 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-31931890

RESUMO

Drug resistance to helminth parasites is one of the most serious problems to threaten the livestock industry. The problem also poses a major threat to public health. Therefore, novel and safe agents should urgently be investigated to control parasitic infections. The current study was conducted to evaluate the possible antiparasitic effects of zinc oxide nanoparticles (ZnO-NPs) on one of the most prevalent gastrointestinal nematodes, Teladorsagia circumcincta. The worms were incubated with various concentrations of ZnO-NPs: 1, 4, 8, 12 and 16 ppm for 24 hours. Mobility and mortality of the parasites were recorded at four-hour intervals. At the endpoint, several biomarkers of oxidative/nitrosative stress, including superoxide dismutase, glutathione peroxidase and catalase, as well as lipid peroxidation, protein carbonylation, total antioxidant status, nitric oxide contents and DNA damage, were measured in the homogenized samples. ZnO-NPs showed significant anthelminthic effects, depending on time and concentration. Furthermore, the nanoparticle induced severe oxidative/nitrosative stress and DNA damage. ZnO-NPs could be considered as a novel and potent anthelminthic agent.


Assuntos
Anti-Helmínticos/farmacologia , Infecções por Nematoides/veterinária , Óxido de Zinco/farmacologia , Animais , Biomarcadores Farmacológicos , Dano ao DNA , Gado/parasitologia , Nanopartículas/parasitologia , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/parasitologia , Estresse Oxidativo
17.
Int J Parasitol ; 50(2): 133-144, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31981671

RESUMO

Gastrointestinal nematodes are a significant threat to the economic and environmental sustainability of keeping livestock, as adequate control becomes increasingly difficult due to the development of anthelmintic resistance in some systems and climate-driven changes to infection dynamics. To mitigate any negative impacts of climate on gastrointestinal nematode epidemiology and slow anthelmintic resistance development, there is a need to develop effective, targeted control strategies that minimise the unnecessary use of anthelmintic drugs and incorporate alternative strategies such as vaccination and evasive grazing. However, the impacts climate and gastrointestinal nematode epidemiology may have on the optimal control strategy are generally not considered, due to lack of available evidence to drive recommendations. Parasite transmission models can support control strategy evaluation to target field trials, thus reducing the resources and lead-time required to develop evidence-based control recommendations incorporating climate stochasticity. Gastrointestinal nematode population dynamics arising from natural infections have been difficult to replicate and model applications have often focussed on the free-living stages. A flexible framework is presented for the parasitic phase of gastrointestinal nematodes, GLOWORM-PARA, which complements an existing model of the free-living stages, GLOWORM-FL. Longitudinal parasitological data for two species that are of major economic importance in cattle, Ostertagia ostertagi and Cooperia oncophora, were obtained from seven cattle farms in Belgium for model validation. The framework replicated the observed seasonal dynamics of infection in cattle on these farms and overall, there was no evidence of systematic under- or over-prediction of faecal egg counts. However, the model under-predicted the faecal egg counts observed on one farm with very young calves, highlighting potential areas of uncertainty that may need further investigation if the model is to be applied to young livestock. The model could be used to drive further research into alternative parasite control strategies such as vaccine development and novel treatment approaches, and to understand gastrointestinal nematode epidemiology under changing climate and host management.


Assuntos
Trato Gastrointestinal/parasitologia , Gado/parasitologia , Nematoides/isolamento & purificação , Infecções por Nematoides , Animais , Anti-Helmínticos/uso terapêutico , Bélgica/epidemiologia , Bovinos , Doenças dos Bovinos/parasitologia , Clima , Fezes/parasitologia , Ivermectina/uso terapêutico , Infecções por Nematoides/epidemiologia , Infecções por Nematoides/veterinária , Ostertagia/isolamento & purificação , Ostertagíase/epidemiologia , Ostertagíase/veterinária , Contagem de Ovos de Parasitas/veterinária , Dinâmica Populacional , Estações do Ano , Strongyloidea/isolamento & purificação , Trichostrongyloidea/isolamento & purificação
18.
Parasitol Res ; 119(2): 529-543, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31834492

RESUMO

Standard diagnostic methods currently in use for the identification of helminth infections in ruminants are based on the morphological analysis of immature and adult stages of parasites. This paper describes a method for the semiquantitative identification of nematodes, mainly Trichostrongyloidea, at species-level resolution. The method is based on amplification and fragment analysis followed by minisequencing of the ITS-2 region (internal transcribed spacer 2) of the ribosomal DNA of parasite eggs or larvae. This method allows for the identification of seven genera (Chabertia, Cooperia, Haemonchus, Oesophagostomum, Ostertagia, Teladorsagia, and Trichostrongylus) and 12 species (Chabertia ovina, Cooperia curticei, Cooperia punctata, Cooperia oncophora/Cooperia surnabada, Haemonchus contortus, Haemonchus placei, Haemonchus longistipes, Oesophagostomum asperum, Oesophagostomum radiatum, Ostertagia ostertagi, Trichostrongylus axei, and Trichostrongylus colubriformis) of infectious nematodes of domestic ruminants. The concordance between the morphological and molecular analyses in the detection of genera ranged from 0.84 to 0.99, suggesting the proposed detection method is specific, semiquantitative, less laborious, and highly cost-efficient.


Assuntos
Infecções por Nematoides/veterinária , Ruminantes/parasitologia , Trichostrongyloidea/isolamento & purificação , Animais , Bovinos , Doenças dos Bovinos/parasitologia , DNA de Helmintos , DNA Ribossômico , Cabras , Haemonchus/genética , Haemonchus/isolamento & purificação , Infecções por Nematoides/parasitologia , Técnicas de Amplificação de Ácido Nucleico/veterinária , Oesophagostomum/genética , Oesophagostomum/isolamento & purificação , Ostertagia/genética , Ostertagia/isolamento & purificação , Ovinos , Strongyloidea/genética , Trichostrongyloidea/genética , Trichostrongylus/genética
19.
Rev. bras. parasitol. vet ; 29(1): e015819, 2020. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1092688

RESUMO

Abstract An evaluation was made of the effect of anthelmintic treatments on the performance of Simmental X Nellore crossbred calves before and after weaning. To this end, the calves were divided into three groups: (1) treated monthly with a low efficacy anthelmintic drug, ivermectin; (2) treated monthly with a highly effective anthelmintic drug, albendazole; and (3) untreated control group. All the groups in this experiment showed an average fecal egg count of less than 400 eggs per gram (EPG), and no clinical signs of parasitic gastroenteritis. The blood variables were within the normal range and no calf presented anemia. In most of the samplings, mean EPGs were significantly lower (P<0.05) in the group treated with albendazole. The calves received dietary supplementation before and after weaning, which enabled them to gain weight in every month of the experiment and reach a body weight of about 250 kg on the last sampling date, before turning one year old. The anthelmintic treatments did not affect body weight gain, leading to the conclusion that, when fed with suitable dietary supplements, Simmental X Nellore crossbred calves are not affected by gastrointestinal nematode parasites acquired by grazing.


Resumo O objetivo do experimento foi avaliar o efeito de tratamentos anti-helmínticos no desempenho de bezerros Simental x Nelore antes e após o desmame. Os bezerros foram alocados em três grupos: (1) tratado mensalmente com anti-helmínticos de baixa eficácia, ivermectina; (2) tratado mensalmente com anti-helmíntico de alta eficácia, albendazol e (3) controle não tratado. A média das contagens de ovos de nematoides durante o experimento foi inferior a 400 ovos por grama (OPG) em todos os grupos sem manifestação clínica de gastroenterite parasitária. As variáveis ​​sanguíneas mantiveram-se dentro dos limites de normalidade e nenhum bezerro apresentou anemia. Na maioria das coletas, as médias de OPG foram significativamente inferiores (P<0,05) no grupo tratado com albendazol. Os bezerros receberam suplementação antes e depois do desmame, o que lhes permitiu ganhar peso em todos os meses do experimento, atingindo peso corporal em torno de 250 kg, ao final do experimento, antes de completarem um ano de idade. Não houve efeito dos tratamentos anti-helmínticos no ganho em peso, o que permitiu concluir que bezerros Nelore x Simental não são afetados pelo parasitismo por nematoides gastrintestinais sob condições de pastejo, quando devidamente suplementados com concentrado.


Assuntos
Animais , Masculino , Feminino , Bovinos , Ivermectina/administração & dosagem , Albendazol/administração & dosagem , Doenças dos Bovinos/tratamento farmacológico , Gastroenteropatias/veterinária , Anti-Helmínticos/administração & dosagem , Infecções por Nematoides/veterinária , Contagem de Ovos de Parasitas/veterinária , Fezes/parasitologia , Gastroenteropatias/parasitologia , Gastroenteropatias/tratamento farmacológico , Infecções por Nematoides/parasitologia , Infecções por Nematoides/tratamento farmacológico
20.
Rev. bras. parasitol. vet ; 29(1): e014619, 2020. graf
Artigo em Inglês | LILACS | ID: biblio-1058010

RESUMO

Abstract Parasitic myelopathy caused by Gurltia paralysans in domestic cats is a disease commonly reported in several South American countries. The adult parasite is lodged in the meningeal veins and spinal cord, often causing clinical manifestations of vascular proliferation, thrombophlebitis, and medullary compression. Wild felines are believed to be the definitive hosts of this parasite. The infection occurs through the ingestion of paratenic hosts, but the life cycle of G. paralysans is not yet clearly understood. In this paper, we discuss a case of parasitic myelopathy in a margay (Leopardus wiedii) that died during post-surgical care. Necropsy revealed focal hemorrhages in the thoracolumbar spinal cord. A microscopic examination revealed adult nematodes and eggs inside the veins of subarachnoid space in spinal cord, suggesting G. paralysans infection. This is first description of parasitic myelopathy in a margay in Brazil.


Resumo Mielopatia parasitária causada por Gurltia paralysans em gatos domésticos é uma doença comumente relatada em vários países da América do Sul. O parasita adulto aloja-se nas veias das meninges e da medula espinhal, muitas vezes causando proliferação vascular, tromboflebite e compressão medular, que se manifestam como sinais clínicos. Acredita-se que os felídeos selvagens sejam hospedeiros definitivos deste parasita e que a infecção ocorre por ingestão de hospedeiros paratênicos, entretanto seu ciclo de vida completo é desconhecido. Aqui, apresentamos um caso de um gato-maracajá (Leopardus wiedii) que morreu durante a assistência pós-cirúrgica. Na necropsia, foram observadas hemorragias focais na medula espinhal toracolombar. A microscopia revelou presença de nematódeos adultos e ovos, localizados dentro das veias do espaço subaracnoide da medula espinhal, o que sugeriu a infecção por G. paralysans. Esta é a primeira descrição de mielopatia parasitária em um gato-maracajá no Brasil.


Assuntos
Animais , Gatos , Doenças da Medula Espinal/parasitologia , Felidae/classificação , Nematoides/isolamento & purificação , Infecções por Nematoides/veterinária , Doenças da Medula Espinal/diagnóstico , Brasil , Felidae/parasitologia , Animais Selvagens , Nematoides/classificação , Infecções por Nematoides/diagnóstico , Infecções por Nematoides/parasitologia
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