Multiple resistance in equine cyathostomins: a case study from military establishments in Rio Grande do Sul, Brazil / Múltipla resistência de ciatostomíneos de equinos: um estudo de caso em estabelecimentos militares no Rio Grande do Sul, Brasil

Abstract Semi-intensive equine breeding system favors gastrointestinal nematode infections. The treatment of these infections is based on the use of anthelmintics. However, the inappropriate use of these drugs has led to parasitic resistance to the available active principles. The objective of this study was to evaluate the efficacy of the main classes of antiparasitic (ATP) used in control in adult and young animals, including: benzimidazoles (fenbendazole), pyrimidines (pyrantel pamoate), macrocyclic lactones (ivermectin and moxidectin), as well as the combination of active ingredients (ivermectin + pyrantel pamoate). The study was carried out in two military establishments, located in Rio Grande do Sul (RS), from January to December, 2018. The intervals between the treatments of the animals were performed from 30 to 90 days. Coproparasitological evaluations were determined by the egg count reduction in the faeces. Cyatostomine larvae were identified in pre and post-treatment cultures. The results demonstrated the multiple parasitic resistance of cyathostomins to fenbendazole, moxidectin in young animals, and to fenbendazole, pyrantel pamoate in adult animals. Thus, it is necessary to define or diagnose parasitic resistance to assist in the creation of prophylactic parasitic control, using suppressive treatment with ATP associated with integrated alternatives. The progress of parasitic resistance can be slowed.

Resumo O sistema semi-intensivo de criação de equinos favorece infecções por nematoides gastrointestinais. O tratamento dessas infecções é baseado no uso de anti-helmínticos. No entanto, o uso inadequado desses medicamentos levou à resistência parasitária aos princípios ativos disponíveis. O objetivo deste estudo foi avaliar a eficácia das principais classes de antiparasitários (ATP), utilizados no controle em animais adultos e jovens, incluindo: benzimidazois (fenbendazol), pirimidinas (pamoato de pirantel), lactonas macrocíclicas (ivermectina e moxidectina), bem como a combinação de ingredientes ativos (ivermectina + pamoato de pirantel). O estudo foi realizado em dois estabelecimentos militares, localizados no Rio Grande do Sul (RS), de janeiro a dezembro de 2018. Os intervalos entre os tratamentos foram realizados de 30 a 90 dias. As avaliações coproparasitológicas foram determinadas pela redução da contagem de ovos nas fezes. Foram identificadas larvas de ciatostomíneos nas coproculturas pré e pós tratamentos. Os resultados demonstraram a resistência parasitária múltipla dos ciatostomíneos ao fenbendazol, moxidectina em animais jovens, febendazole e pamoato de pirantel em animais adultos. Estabelecer o diagnóstico da resistência parasitária auxiliará na elaboração de um controle parasitário profilático, reduzindo o tratamento supressivo com ATP juntamente com alternativas de controle integrado. Dessa forma, o avanço da resistência parasitária poderá ser retardado.

Nematode resistance to five anthelmintic classes in naturally infected sheep herds in Northeastern Brazil / Resistência de nematódeos a cinco classes de anti-helmínticos em rebanhos de ovinos naturalmente infectados no Nordeste do Brasil

Abstract This study aimed to evaluate the occurrence of nematode resistance to anthelmintics on sheep herds from the semi-arid region of Paraíba, Northeastern Brazil. Fecal Egg Count Reduction Test (FECRT) was carried out on 20 properties. In each herd, 30 animals were divided into five groups containing six animals each: group I, treated with albendazole 10%, 4 mg/kg; group II, ivermectin 0.08%, 0.2 mg/kg; group III, closantel 10%, 10 mg/kg; group IV, levamisole hydrochloride 5%, 5 mg/kg; and group V, monepantel 2.5%, 2.5 mg/kg. All treatments were administered orally as a single dose. Fecal samples were collected on days zero and 10 after treatment, to perform FECRT and coprocultures. Multiresistance was observed in all the properties; 95% had high resistance to albendazole, 85% to ivermectin, 80% to closantel, 40% to levamisole, and 45% to monepantel. On property 15, where monepantel was ineffective, a second FECRT for this anthelmintic was carried out 4 months after the first, resulting in 75% efficacy. Immediately after the FECRT result, two ewes were euthanized and necropsied, and Haemonchus contortus, Trichostrongylus axei, Trichostrongylus colubriformis, Oesophagostomum columbianum, and Trichuris ovis were recovered. It was concluded that the resistance of sheep gastrointestinal nematodes to antthelmintic, including monepantel, is high.

Resumo O objetivo deste estudo foi avaliar a ocorrência de resistência de nematódeos a anti-helmínticos em rebanhos ovinos do semiárido da Paraíba, Nordeste do Brasil. Testes de Redução na Contagem de Ovos Fecais (TRCOF) foram conduzidos em 20 propriedades. Em cada rebanho, 30 animais foram selecionados e foram divididos em cinco grupos contendo seis animais cada: grupo I, tratado com albendazol 10%, 10 mg/kg; grupo II, ivermectina 0,08%, 0,2 mg/kg; grupo III, closantel 10%, 10 mg/kg; grupo IV, cloridrato de levamisol 5%, 5 mg/kg; grupo V, monepantel 2,5%, 2,5 mg/kg. Todos os tratamentos foram administrados via oral, em dose única. Amostras fecais foram coletadas nos dias zero e 10 após os tratamentos, para a realização do TRCOF e coproculturas. Multirresistência foi observada em todas as propriedades; 95% dos rebanhos obtiveram alta resistência ao albendazole, 85% a ivermectina, 80% ao closantel, 40% ao levamisole, e 45% a monepantel. Na propriedade 15, onde o monepantel foi ineficaz, um segundo TRCOF foi conduzido para este fármaco 4 meses após o primeiro, resultando em 75% de eficácia. Imediatamente após o resultado do TRCOF, duas ovelhas foram eutanaziadas e necropsiadas, e Haemonchus contortus, Trichostrongylus axei, Trichostrongylus colubriformis, Oesophagostomum columbianum, e Trichuris ovis foram recuperados. Concluiu-se que a resistência dos nematódeos gastrintestinais de ovinos aos anti-helmínticos, incluindo o monepantel, é alta.

Biocidal effect of a hexane-soluble extract of Lippia graveolens Kunth (Verbenaceae) / Efecto biocida del extracto hexánico de Lippia graveolens Kunth (Verbenaceae)

Lippia graveolens Kunth (Verbenaceae) is an economically important shrub known in Mexico as Oregano. In this work, the biocidal effect of the hexane extract of L. graveolens leaves was evaluated on two crop pests. Thus, larvae of Spodoptera frugiperda were fed with mixtures of extract and artificial diet. The nematicidal activity was evaluated on juveniles of Meloydogine javanica. Regarding S. frugiperda, quantitative differences between treatments and control were observed in dead pupae, surviving adults, and deformed adults (P < 0.05). All the surviving adults from the extract treatments were deformed. Nematicidal effect was registered, the LC50 and LC90 were 0.672 (0.654-0.690) and 0.965 (0.937-0.998) mg/mL respectively. The extract was characterized by NMR and GC-MS, being thymol the most abundant component (70.6%) in addition to carvacrol (22.8%). The results suggest the consideration of the hexane extract of L. graveolens leaves within the alternatives for the biological control of pests.

Lippia graveolens Kunth (Verbenaceae) es un arbusto con importancia económica conocido en México como Orégano. En éste trabajo se evaluó el efecto biocida del extracto hexánico de hojas L. graveolens sobre dos plagas agrícolas. Así, larvas de S. frugiperda fueron alimentadas con mezclas de dieta artificial y extracto. La actividad nematicida fue evaluada en juveniles de Meloydogine javanica, Respecto a S. frugiperda, se observaron diferencias cuantitativas entre tratamiento y control en cuanto a pupas muertas, adultos sobrevivientes y adultos deformes (P < 0.05). Todos los adultos provenientes de tratamientos con extracto estuvieron malformados. Hubo efecto nematicida, calculándose CL50 y CL90 de 0.672 (0.654-0.690) y 0.965 (0.937-0.998) mg/mL respectivamente. El extracto se caracterizó por RMN y CG-EM. Los compuestos más abundantes fueron timol (70.6%), ademas del carvacrol (22.8%). Los resultados sugieren considerar al extracto hexánico de hojas de L. graveolens dentro de las alternativas para el control biológico de plagas.

Effect of myrrh and thyme on Trichinella spiralisenteral and parenteral phases with inducible nitric oxide expression in mice

Trichinellosis is a serious disease with no satisfactory treatment. We aimed to assess the effect of myrrh (Commiphora molmol) and, for the first time, thyme (Thymus vulgaris L.) against enteral and encysted (parenteral) phases of Trichinella spiralis in mice compared with albendazole, and detect their effect on inducible nitric oxide synthase (iNOS) expression. Oral administration of 500 mg/kg of myrrh and thyme led to adult reduction (90.9%, 79.4%), while 1,000 mg/kg led to larvae reduction (79.6%, 71.3%), respectively. Administration of 50 mg/kg of albendazole resulted in adult and larvae reduction (94.2%, 90.9%). Positive immunostaining of inflammatory cells infiltrating intestinal mucosa and submucosa of all treated groups was detected. Myrrh-treated mice showed the highest iNOS expression followed by albendazole, then thyme. On the other hand, both myrrh and thyme-treated groups showed stronger iNOS expression of inflammatory cells infiltrating and surrounding encapsulated T. spiralis larvae than albendazole treated group. In conclusion, myrrh and thyme extracts are highly effective against both phases of T. spiralis and showed strong iNOS expressions, especially myrrh which could be a promising alternative drug. This experiment provides a basis for further exploration of this plant by isolation and retesting the active principles of both extracts against different stages of T. spiralis.

Avaliação in vitro do extrato hidroalcoólico (EHA) de alecrim pimenta (Lippia sidoides Cham. ) sobre o desenvolvimento de ovos de nematódeos gastrointestinais (Trichostrongylidae) / In vitro evaluation of alecrim pimenta (Lippia sidoides Cham. ) hydroalcoholic extract (HAE) on the development of gastrointestinal nematode (Trichostrongylidae) eggs

Atualmente a fito medicina vem sendo usada no controle de diversas doenças parasitárias particularmente as parasitoses gastrointestinais. Objetivou-se com este estudo avaliar a eficácia do extrato hidroalcoólico (EHA) de Lippia sidoides Cham sobre o desenvolvimento de ovos de nematódeos gastrointestinais. O efeito ovicida foi determinado através de análise probabilística, modelo logístico, utilizados os softwares R versão 2.2.1 e EPI6. Foram obtidos ovos embrionados em fezes de cabras naturalmente infectadas com nematóides Trichostrongylidae e o número de ovos fecais foi determinado usando-se a técnica modificada de McMaster. Cinquenta μL da suspensão contendo 40 ovos foram transferidas a placas de poliestireno e incubadas com 12 concentrações diferentes do EHA sendo avaliada durante 72 horas a temperatura ambiente. Os resultados demonstraram diferentes eficácias para o fito medicamento com menor taxa de desenvolvimento de ovos na concentração de 500 mg mL-1 . Conclui-se que o EHA pode ter papel importante sobre o desenvolvimento in vitro de ovos de nematóides gastrintestinais, revelando atividade ovicida.

Phytomedicine has been currently used in the control of several parasitic diseases, particularly gastrointestinal ones. The aim of this study was to evaluate the efficacy of the hydroalcoholic extract (HAE) from Lippia sidoides Cham. on the development of gastrointestinal nematode eggs. The ovicidal effect was determined through probabilistic analysis, logistic model, by using the programs R version 2.2.1 and Epi InfoTM 6. Embryonated eggs were obtained from feces of goats naturally infected with Trichostrongylidae nematodes and the fecal egg count was determined by using the modified McMaster technique. Fifty microliters of the suspension containing 40 eggs were transferred to polystyrene plates and incubated with 12 different HAE concentrations, and evaluations were performed during 72h at room temperature. The results demonstrated different efficacy of extracts, with lower egg development rate at 500 mg mL-1. In conclusion, HAE may play an important role on the in vitro development of gastrointestinal nematode eggs, indicating ovicidal activity.

In vitro larvicidal activity of geraniol and citronellal against Contracaecum sp (Nematoda: Anisakidae)

Human infection with fish parasites can result from the ingestion of incompletely cooked or raw fish, giving origin to parasitic diseases such as anisakiasis, caused by parasites of the Anisakidae family. The present study assessed the in vitro larvicidal effect of two monoterpene compounds, geraniol and citronellal, against Contracaecum sp (Nematoda: Anisakidae). Four hundred live larvae of Contracaecum sp obtained from "traíra" fish (Hoplias malabaricus, Bloch, 1974) were analyzed on 40 Petri dishes (10 larvae each) with the compounds to be tested. The final concentrations tested for each compound were 250, 125, 62.5, and 31.2 µg/mL and the evaluation was carried out at five different times (2, 4, 8, 24, and 48 h). The larvicidal action of geraniol and citronellal was statistically superior (P < 0.005) to the control (1 percent ethanol) at concentrations of 250 and 31.2 µg/mL (geraniol) and 250, 125, and 62.5 μg/mL (citronellal). However, no larvicidal activity was observed at concentrations of 125 and 62.5 µg/mL for geraniol and 31.2 µg/mL for citronellal. When the larvicidal action of geraniol was compared to that of citronellal, the former was found to be statistically superior (P < 0.05) to the latter at concentrations of 250 and 31.2 μg/mL. On the other hand, citronellal was statistically superior (P < 0.005) to geraniol at concentrations of 125 and 62.5 μg/mL. The larval mortality rate in terms of time (hours) was higher for geraniol with the passing of time at the 250 μg/mL concentration. At this concentration (in 48 h) the best larvicidal effect was observed with 90 percent lethality. The larvae were considered to be dead using no motility and loss of structural integrity as parameters. The data indicate that natural terpene compounds should be more explored for antihelminthic activity and can be useful for other studies about anisakiasis treatment.

Praziquantel, levamisol e diflubenzuron no controle de Dolops carvalhoi (Crustacea: Branchiura) e Anacanthorus penilabiatus (Monogenea: Dactylogyridae) em Piaractus mesopotamicus Holmberg, 1887 (Osteichthyes: Characidae) / Praziquantel, levamisole and diflubenzuron in the control of Dolops carvalhoi (Crustacea: Branchiura) and Anacanthorus penilabiatus (Monogenea: Dactylogyridae) in Piaractus mesopotamicus Holmberg, 1887 (Osteichthyes: Characidae)

Neste trabalho, avaliou-se a eficácia antiparasitária do praziquantel, levamisol e diflubenzuron administrados via oral, adicionados à ração, para pacus (Piaractus mesopotamicus) infectados por Anacanthorus penilabiatus e Dolops carvalhoi. Foram utilizadas 19 caixas d'água de 300 L de capacidade, comportando 28 peixes cada. Os tratamentos foram feitos misturando os princípios ativos nas dietas. A intensidade parasitária e eficácia foram avaliadas 1 dia antes e 3, 7 e 15 dias após o início da alimentação com ração contendo diflubenzuron, levamisol e praziquantel isolados ou associados em diferentes concentrações por 7 dias. Os resultados da eficácia terapêutica sugerem que, isoladamente ou associado com levamisol e praziquantel, o diflubenzuron é eficiente contra o crustáceo D. carvalhoi, demonstrando que a eficácia dos tratamentos nos dias 3, 7 e 15 variou de 96,2 a 100 por cento. Contra os monogenóides, as drogas não apresentaram eficácia satisfatória. Os resultados sugerem o uso do diflubenzuron para o controle de D. cavalhoi em peixes de cativeiro e em condições de quarentenário.

This assay evaluated the control efficacy of diflubenzuron, praziquantel and levamisole added to the diet of pacu (Piaractus mesoptamicus) infected with Anacanthorus penilabiatus and Dolops carvalhoi. 19 water tanks of 300 L capacity were utilized with 28 fish in each one. The treatments were made by mixing the active principles in the diet. The experiment was evaluated in four harvests done 1 day before and 3, 7 and 15 days after the treatment. The medicated feeding was applied for 7 days. The results of efficacy suggest that the diflubenzuron alone or associated with levamisole and praziquantel was efficient against the crustacean D. carvalhoi and the efficacy in the 3, 7 and 15 days evaluations ranged from 96,2 to 100 percent. Against the monogenean the drugs did not present efficacy. The results suggest the use of diflubenzuron for the control of D. carvalhoi in captive fishes in special conditions.

Management of the root-knot nematode, meloidogyne javanicam on cucumber [cucumis sativus] with biological control agent

Two biological control agents, Nemaless [a commercial suspension of the bacterium Serratia marcescens; 1 x 10 [9] bacterial cells/ml] and Nemastop plus [a commercial suspension presumably of garlic, allium sativum, extract and the fungus Paeciiomyces lilacinus], were tried to determine their effects on cucumber growth parameters and Meloidogyne javanica development and reproduction. Both have significantly [P

In vitro study on thiabendazole action on viability of Ascaris lumbricoides (Lineu, 1758) eggs

The in vitro activity of thiabendazole on Ascaris lumbricoides eggs, which were recovered from uteri of worm excreted after chemotherapeutic treatment, was studied. Four concentrations of the drug were used: 1 - 2.5 - 5 - and 10 ppm during 24, 48 and 72 hours of exposure. Subsequently, the eggs were centrifuged, washed three times and H(2)SO(4)0.1N was added. The eggs were maintained in an incubator for 20 days at 28 degrees C. Finally, the percentage of embryonated eggs was determined under a lightmicroscope at a 100X magnification. After 48 and 72 hours of thiabendazole exposure, at a concentration of 10ppm, the drug showed complete inhibition of egg embryonation.

Foi estudada, in vitro, a ação do tiabendazol, contra ovos de Ascaris lumbricoides , retirados de úteros de vermes eliminados após tratamento. Foram utilizadas quatro concentrações da droga: 1 ¾ 2,5 - 5 e 10 ppm em três diferentes períodos de tempo: 24, 48 e 72 horas. Decorridos estes tempos a suspensão com os ovos foi centrifugada, lavada por três vezes com água destilada, adicionada de solução de H2SO4, 0,1N e mantida em estufa a 28°C por 20 dias. Em seguida, os ovos foram levados ao microscópio óptico, no aumento de 100X, para observação do percentual de embrionamento. Na concentração de 10ppm, nos tempos de 48 e 72 horas de exposição à droga, verificou-se completa inibição do embrionamento dos ovos.

Lack of efficacy of quinine and artemether against advanced third-stage larvae of Gnathostoma spinigerum in vitro.

The efficacy of quinine and artemether--the effective blood schizontocide in malarial treatment--has been in vitro tested with the advanced third-stage larvae of Gnathostoma spinigerum. All larvae were collected from freshwater eel (Fluta alba) and exposed to the culture medium, each containing either quinine dihydrochloride or artemether at a final concentration of 20 microg/ml and 0.5 microg/ml, respectively for 21 consecutive days. Larval motility was assessed daily and the topographical changes were assessed using scanning electron microscope after 21-days of drug exposure. All worms moved actively for 21 days of study period and no change in surface ultrastructure was observed. Quinine and artemether at these concentrations have no effect on movement and topographical changes on the advanced third-stage larvae of this parasite.

Regulation of cholinomimetic action of pyrantel pamoate by calcium channels in Setaria cervi.

Nerve muscle preparation of Setaria cervi (Nematoda:Filarioidea) exhibits spontaneous rhythmical movements when suspended in isolated organ bath containing modified Ringer's solution. Pyrantel pamoate (50 ng/ml) when applied caused initial short lasting stimulation followed by irreversible paralysis. When suspended in calcium free bathing fluid the movements of n.m. preparation showed a gradual decrease both in amplitude and rate of contraction til the movements ceased completely. The effect was similar when EDTA was added to the bath fluid. The stimulant effect of Pyrantel pamoate was blocked in calcium free solution and in bath applied EDTA. Calcium channel blocker Nifedipine in a concentration of 500 ng/ml blocked the effect of Pyrantel pamoate (50 ng/ml). Neither stimulation nor depression of movements was evident with higher concentration of PP (250 mg/ml) the stimulant effect of Pyrantel pamoate was blocked while the depressant effect characterized by decrease in amplitude of calcium is essential for the stimulant effect of Pyrantel pamoate and its response on n.m. preparation is similar to Acetylcholine.

Anti-nematode activity of sixteen compounds against Trichinella spiralis in mice--a possible new screen for macrofilaricides.

There are few small animals models for filariasis, even more so for onchocerciasis. Therefore it is difficult to test under drug screening conditions large numbers of potentially macrofilaricidal compounds. One way around this difficulty is to use mice infected with Trichinella spiralis which by reason of anatomical location in the host would show some correlation in antinematode activity between the test and target organisms. This study investigated the activity of 16 compounds against the immature larval stage of T. spiralis. All the nine benzimidazole compounds (albendazole, flubendazole, mebendazole, oxfendazole, oxibendazole 780118, 780120, 790163, and 790392) were active, the most potent being oxfendazole. The benzothiazoles (CGP21306, CGP20376, CGP21833 and CGP24588A) also indicated some anti-nematode activity together with 35vr, an imidazopyridine, but not as marked as the benzimidazole group. However, the organic arsenical compounds (Mel Ga and Mel Ni) showed little activity and this was at a rather highly toxic level. The prospects of using the Trichinella-mouse model as a primary screen to test for potential macrofilaricides are discussed.

Determinaçäo da atividade inibitória do desenvolvimento larvar de ancilostomídios por extratos de plantas tidas como medicamentosas no município de Araraquara / Inhibitory activity of larval stage development of Ancylostomatidae by extracts of some popular medical plants

Säo apresentados os resultados obtidos com os extratos aquosos e hidroalcoólicos de 27 espécies vegetais, e que säo utilizadas como medicamentos pela populaçäo de Araraquara; empregamos neste experimento as diversas partes dos vegetais. De todos os extratos vegetais examinados, apenas dois apresentaram alguma atividade inibitória do desenvolvimento larvar de Ancilostomídeos, foram eles obtidos das plantas cujos nomes populares säo Beijo-Branco (Vinca alba Lineu) e Pau-Ferro (Caesalpina ferrea, Martius)