Effects of long-term indiscriminate use of macrocyclic lactones in cattle: Parasite resistance, clinical helminthosis, and production losses.

Our aims were to describe a case of clinical helminthosis caused by parasite resistance to macrocyclic lactones (MLs) after the long-term frequent use of these drugs in a cattle herd, and to evaluate the production losses prevented by the use of an effective anthelmintic treatment to control these resistant gastrointestinal nematodes (GINs). A case of clinical helminthosis culminating in the death of steers was investigated, the history of the antiparasitic treatments used during an 11-year period in the herd was assessed, and an efficacy test involving seven different drugs was performed. Thereafter, two groups of heifers naturally infected by ML-resistant GINs were formed and strategically treated with either a highly effective (levamisole) or less effective drug (doramectin) over a 9-month period. The heifers were evaluated monthly based on eggs per gram of feces (EPG) counts and liveweights. An evaluation of the history of parasite control in the farm revealed that MLs were used in 96.5% of the treatments aimed at controlling GINs, ticks, and myiasis in the herd. The efficacy test showed the presence of GINs resistance to all the MLs tested. However, levamisole and albendazole sulphoxide were highly effective against these parasites. Heifers treated with levamisole gained 12.1 kg more liveweight on average, compared to those treated with doramectin. Thus, we conclude that indiscriminate and long-term use of MLs in the studied herd led to the failure of GINs control, a critical situation resulting in significant production losses, and a surge of clinical helminthosis in young cattle. In addition, we showed increase in liveweight gain due to using a highly effective drug, in comparison to an ML, during a 9-month period, in heifers naturally infected by ML-resistant GINs.

Economic losses caused by the use of low-efficacy anthelmintic drugs in growing heifers.

The aim of this study was to compare the economic revenue related to the use of low- or high-efficacy anthelmintic drugs within suppressive or strategic schemes of treatment in growing heifers. Heifers raised in a semi-intensive grazing system in southern Brazil were used. Levamisole and ivermectin were selected as the high- and the low-efficacy drugs, respectively, based on a previous efficacy test. Subsequently, these drugs were used within strategic (Strat; four times per year) or suppressive (Supp; once a month) treatment regimens in the heifers, and their liveweight and eggs per gram of feces counts were monthly evaluated during a 13-month period. The total costs of the treatments and their cost-benefit ratio in regard to liveweight gain were calculated. Final mean liveweight gains (kg) observed were 126.7 (Strat-Low), 133.6 (Supp-Low), 141.3 (Strat-High), 142.9 (Supp-High), and 125.8 (Control). Treatments with a high-efficacy drug resulted in monetary gains of US$ 19.56 (Strat-High) and US$ 14.98 (Supp-High), but Supp-Low and Strat-Low treatments caused economic losses. Total cost of the efficacy test (US$ 374.79) could be paid by the additional liveweight gain of 20 heifers from the Strat-High group. These results showed that it would be preferable not to treat the heifers against GIN if compared with treating them with a low-efficacy drug. In addition, we showed that the use of four treatments per year with a high-efficacy drug-selected by efficacy test-resulted in a profitable management to control GIN in growing heifers raised in a semi-intensive gazing system in southern Brazil.

Molecular detection of Cryptosporidium spp. and the occurrence of intestinal parasites in fecal samples of naturally infected dogs and cats.

Cats and dogs are hosts of a large number of gastrointestinal parasites and can shed helminth eggs and protozoan oocysts in their feces. The close relationship between companion animals and humans intensifies human exposure to zoonosis caused by parasites. In this study, 177 fecal samples were collected: 128 from dogs and 49 from cats of both sexes and varied ages. One or more intestinal parasites were observed in 56.2% (72/128) of the dog fecal samples and in 53.0% (26/49) of the cat fecal samples. Parasitic monoinfection was present in 70.8% (51/72) of dog samples and in 46.1% (12/26) of cat samples, whereas multi-infection was observed in 29.2% (21/72) and 53.8% (14/26) of dog and cat samples, respectively. The detection frequency of Cryptosporidium spp. was 22.6% (40/177) using Ziehl-Neelsen staining. DNA was extracted from all samples and the Cryptosporidium small subunit ribosomal ribonucleic acid (SSU rRNA) gene was amplified from 5.6% (10/177) of the fecal samples using nested polymerase chain reaction (PCR). Amplification was achieved in 4.6% (6/128) of the dog samples and in 8.2% (4/49) of the cat samples. DNA sequencing of the nested PCR positive samples identified Cryptosporidium canis in 66.6% (4/6) and Cryptosporidium parvum in 33.3% (2/6) of the dog samples and Cryptosporidium felis in 75% (3/4) and Cryptosporidium parvum in 25% (1/4) in the cat samples. The present study thus demonstrated significant levels of gastrointestinal parasite infection in companion animals and highlighted the presence of zoonosis agents.

Perfil oxidativo e leucometria de ovelhas de corte acometidas por mastite crônica / White cell count and oxidative profile in sheep affected by chronic mastitis

O objetivo deste estudo foi avaliar o perfil oxidativo e o leucometria de ovelhas de corte com mastite crônica. Para isso foram utilizados 30 animais em lactação, os quais foram divididos em dois grupos de 15 animais: grupo positivo - animais que exibiram sinais clínicos de mastite e grupo negativo - ovelhas sem sinais de alteração na glândula mamária e/ou no leite. Para realização do California Mastitis Test (CMT) e exame microbiológico foram coletadas amostras de leite e para determinar o total de leucócitos, o índice de estresse oxidativo (OSI) e o óxido nítrico foram coletadas amostras de sangue. Sessenta por cento das ovelhas com mastite apresentaram CMT positivo. Não houve diferença entre os grupos nos valores de leucócitos, de OSI e no óxido nítrico. Em decorrência da redução do processo inflamatório, ovelhas com mastite crônica não apresentam alterações no perfil oxidativo e no total de leucócitos.

In this study 30 lactating sheep were used to evaluate the oxidative profile and leucocytes of animals with chronic mastitis. Groups, containing 15 animals each, were divided into: group of positive animals presenting clinical signs of mastitis, and control group containing animals which did not present alterations in the mammal gland or in the milk. Milk samples were collected and the California Mastitis Test (CMT) and microbiologic examination were performed. In addition, the total of leukocytes, total antioxidant capacity (TAC), total oxidant status (TOS) and nitric oxide were measured through blood analyses. Sixty percent of the animals with mastitis presented CMT positive. There was no difference in the values of leukocytes, OSI and nitric oxide between groups. Sheep with chronic mastitis did not present alterations in the oxidative profile and total leukocytes, due to the reduction of the inflammation

Oxidative stress by Haemonchus contortus in lambs: Influence of treatment with zinc edetate.

The aim of the present study was to assess the effects of zinc edetate on the oxidative stress of lambs infected by Haemonchus contortus. Twenty-four lambs were allocated into four groups: Group I--uninfected animals; Group II--uninfected animals treated subcutaneously with zinc edetate; Group III--animals infected by H. contortus and Group IV--animals infected and treated. The oxidative stress index (OSI) and the eggs per gram of feces (EPG) were assessed after 10, 17, 24, 31 and 38 days post-infection. Based on the EPG and the quantity of adult H. contortus, the infection did not differ between groups III and IV. Zinc edetate reduced the OSI in Group IV in relation to Group I after 24 days post-infection, and in relation to group III after 31 days post-infection. Treatment with zinc edetate could help reduce the oxidative stress induced by H. contortus in lambs.

Rhipicephalus (Boophilus) microplus in the western-central region of Rio Grande do Sul, Brazil: multiresistant tick.

The aim of the present study was to assess the acaricide resistance of tick populations in the western-central region of Rio Grande do Sul (Brazil), which has not previously been reported. Fifty-four cattle farms were visited and specimens of Rhipicephalus (Boophilus) microplus were collected and subjected to the adult immersion test, using nine commercial acaricides in the amidine, pyrethroid and organophosphate groups. Climatic data, including monthly precipitation, were recorded. The results from the present study demonstrated that seven of the acaricides analyzed presented mean efficacy values of less than 95%, with large differences among the products tested. Nine of them exhibited satisfactory and unsatisfactory acaricide results on at least one farm. In conclusion, the farms located in the western-central region of Rio Grande do Sul, Brazil, exhibited populations of R. (Boophilus) microplus with variable degrees of susceptibility to different acaricides, thus suggesting that resistance to the active compounds exists. It is suggested that treatment protocols should be implemented at the beginning of winter and summer, using the acaricides that showed efficacy in the adult immersion test.

Rhipicephalus (Boophilus) microplus in the western-central region of Rio Grande do Sul, Brazil: multiresistant tick / Rhipicephalus (Boophilus) microplus na região centro-ocidental rio-grandense – Multirresistência acaricida

The aim of the present study was to assess the acaricide resistance of tick populations in the western-central region of Rio Grande do Sul (Brazil), which has not previously been reported. Fifty-four cattle farms were visited and specimens of Rhipicephalus (Boophilus) microplus were collected and subjected to the adult immersion test, using nine commercial acaricides in the amidine, pyrethroid and organophosphate groups. Climatic data, including monthly precipitation, were recorded. The results from the present study demonstrated that seven of the acaricides analyzed presented mean efficacy values of less than 95%, with large differences among the products tested. Nine of them exhibited satisfactory and unsatisfactory acaricide results on at least one farm. In conclusion, the farms located in the western-central region of Rio Grande do Sul, Brazil, exhibited populations of R. (Boophilus) microplus with variable degrees of susceptibility to different acaricides, thus suggesting that resistance to the active compounds exists. It is suggested that treatment protocols should be implemented at the beginning of winter and summer, using the acaricides that showed efficacy in the adult immersion test.

O objetivo deste estudo foi o de aferir a situação da resistência dos produtos acaricidas utilizados no controle de carrapatos de bovinos, na mesorregião centro-ocidental rio-grandense. Para isso, cinquenta e quatro propriedades foram visitadas, e as teleóginas de Rhipicephalus (Boophilus) microplus foram coletadas e submetidas ao teste de eficácia acaricida in vitro, sendo utilizados nove produtos comerciais, pertencentes às classes químicas das amidinas, piretroides e organofosforados. Além disso, os dados das temperaturas máximas e mínimas médias e da precipitação acumulada foram compilados no período estudado. Os resultados demonstraram que sete produtos analisados apresentaram eficácia inferior a 95%, com grande disparidade dos resultados. Nove produtos testados apresentaram satisfatória e não satisfatória eficácia em pelo menos uma propriedade analisada. Neste contexto, concluiu-se que as propriedades da mesorregião centro-ocidental rio-grandense apresentam cepas de R. (B.) microplus com graus variáveis de susceptibilidade a diferentes acaricidas, sugerindo, assim, que a resistência aos princípios ativos existe. Sugere-se a adoção de protocolos de tratamento acaricida no início do inverno e do verão, com a escolha do produto a ser utilizado baseado nos resultados do teste de eficácia acaricida.

Protein profile of lambs experimentally infected with Haemonchus contortus and supplemented with selenium and copper.

BACKGROUND: Gastrointestinal nematodes cause significant economic losses in the sheep industry, with frequent reports of anthelmintic resistance. Therefore, alternative methods to control these parasites are necessary. Thus, the aim of the present study was to assess the effect of treatment with selenium and copper on the protein profile of sheep that were experimentally infected with Haemonchus contortus. METHODS: Twenty-eight lambs were experimentally infected with H. contortus and divided into four experimental groups as follow: G1--untreated animals; G2--treated with sodium selenite; G3--treated with copper; G4--treated with sodium selenite and copper. The serum protein, body weight and egg count per gram of feces (EPG) were assessed at the baseline and after 20, 40, 60 and 80 days. The parasite burden was assessed 80 days after the beginning of the experiment. RESULTS: Higher levels of total protein and gamma globulin were observed in the lambs treated with sodium selenite and copper on D80. Copper acted as a growth promoter. The copper-supplemented groups exhibited higher daily and total weight gain. The association of selenium and copper altered the protein profile of sheep. Copper and selenium supplementation reduced EPG and worm burden at the end of the experiment. To the best of our knowledge, this is the first study to demonstrate the positive effect of the combined parenteral supplementation of Se and Cu on H. contortus infection. CONCLUSIONS: This injectable supplementation could be used as an auxiliary method to control H. contortus in sheep.

Copper and selenium: auxiliary measure to control infection by Haemonchus contortus in lambs.

The aim of this study was to evaluate the effects of selenium and copper on oxidative stress and its performance in lambs experimentally infected with Haemonchus contortus. Twenty-eight five-months old lambs were experimentally infected by the oral route with 5000 third-stage infective larvae and allocated into four groups, i.e., untreated animals, animals treated intramuscularly with sodium selenite (0.2 mg kg(-1)), animals treated subcutaneously with copper (3.5 mg kg(-1)), and animals treated with sodium selenite (IM; 0.2 mg kg(-1)) and copper (SC; 3.5 mg kg(-1)). These animals received oat hay (Avena sativa) and commercial concentrate, totaling 15% of crude protein, 30% being derived from oat hay and 70% of the concentrate. Lipid peroxidation, antioxidant enzymes, eggs per gram of feces (EPG) and body weight were assessed on the day of infection and after 20, 40, 60 and 80 days post-infection. The number of H. contortus adults was assessed at the end of the experiment. The selenium associated or not with copper reduced the effects of oxidative stress caused by infection. The groups supplemented with copper had increased body weight, and the combination of these two minerals reduced the EPG and number of H. contortus adults in lambs. The use of selenium associated with copper may help the control of infection by H. contortus.

Improving liveweight gain of lambs infected by multidrug-resistant nematodes using a FECRT-based schedule of treatments.

The aim of this study was to compare the liveweight gain of lambs, infected by multidrug-resistant nematodes, treated by conventional schemes of helminth control or using a schedule based on fecal egg count reduction test (FECRT). The flock was selected after a FECRT (experiment 1) which revealed a parasite population resistant to benzimidazoles, imidazothiazoles, macrocyclic lactones (ivermectin), salicylanilides, nitrophenols, and organophosphates. Despite the parasite resistance to ivermectin (an avermectin), the moxidectin (a milbemycin) was effective against the gastrointestinal nematodes (PR > 90%). In experiment 2, 48 suckling lambs were distributed in four randomized blocks (G1, G2, G3, and G4) by previous body weighings. G1 was kept as untreated control; G2 was treated following a FECRT-based schedule with drugs chosen based on fecal analysis (first drench with moxidectin, second drench with a combination of moxidectin and levamisole, and third drench with praziquantel, an anti-cestode drug); G3 and G4 received three drenches with ivermectin or disophenol, respectively. Body weighings and fecal analysis of these lambs were performed every 2 weeks over a 98-day period. An effective control of gastrointestinal nematodes was obtained with two nematicidal drenches following the FECRT-based schedule of treatments. On the other hand, eggs per gram of feces (EPG) counts were no different among untreated control, G3, and G4. Lambs treated using the FECRT-based schedule had the greatest liveweight gain among the groups tested. Additionally, liveweight gain was no different among the groups G3, G4, and G1. The FECRT-based schedule of anthelmintic treatments was beneficial regarding productivity and sustainability of helminth control in lambs infected by multidrug-resistant nematodes.

Serological status of mares in parturition and the levels of antibodies (IgG) against protozoan family Sarcocystidae from their pre colostral foals.

Protozoa from the family Sarcocystidae are agents of reproductive and neurological disorders in horses. The transmission of these protozoa may occur via horizontal or vertical means, and the frequency and potential of the later is not fully elucidated in horses. Thus, the aim of study was to correlation levels of antibodies in mares with pre colostral foals seropositive and assess the level and distribution of antibodies against Neospora spp., Sarcocystis neurona and Toxoplasma gondii, in mares and pre colostral foals at the parturition. The blood samples were collected from mares immediately after parturition and from newborns before the ingestion of colostrum, and sera were analyzed for the presence of IgG by ELISA. It was found that 21.5%, 33.7% and 27.6% of mares were seropositive for Neospora spp., S. neurona and T. gondii, respectively; foals had antibodies at a rate of 8.3%, 6.6% and 6.6% for Neospora spp., S. neurona and T. gondii, respectively. Additionally, paired samples from mares and pre-colostral foals revealed an overall negative correlation between the serum reactivity against these three parasites and suggested that seronegative mares, or those with low to intermediate antibody levels, have a higher risk of giving birth to seropositive foals.

Ocorrência de parasitos gastrointestinais e fatores de risco de parasitismo em gatos domésticos urbanos de Santa Maria, RS, Brasil / Occurrence of gastrointestinal parasites and parasitism risk factors in domestic cats in Santa Maria, RS, Brazil

Neste trabalho, verificou-se a ocorrência de parasitos gastrointestinais em gatos urbanos domiciliados no município de Santa Maria, RS, no período de março a junho de 2011. Além disso, foram avaliados os fatores de riscos relacionados com a infecção dos parasitos gastrointestinais. Coletou-se 191 amostras de fezes de felinos para a realização de exames coproparasitológico e aplicado um questionário epidemiológico aos proprietários, contendo questões relativas aos hábitos e manejo dos seus animais. Das amostras fecais analisadas, 47,1% (90/191) foram positivas para um ou mais parasitas gastrointestinais, sendo 33,5% (64/191) identificadas como mono-infecção e 13,6% (26/191) como multi-infecção. Toxocara spp. (18,8%) e Giardia spp. (4,2%) foram os principais parasitos encontrados na mono-infecção. Na multi-infecção, as principais associações de parasitos detectadas incluíram: Ancylostoma spp. + Toxocara spp. (3,1%) e Cystoisospora spp. + Cryptosporidium spp. + Giardia spp. + Toxoplasma spp. + Toxocara spp. (1,5%). Os dados epidemiológicos foram submetidos ao teste qui-quadrado, Fischer, análise da relação de chances (OR), também analisada a relação entre os diferentes fatores epidemiológicos e a presença de parasitos gastrointestinais (P>0,05). Os principais fatores de risco identificados foram: a escolaridade dos proprietários e a frequência de realização de tratamentos antiparasitários, os quais exerceram influência direta na ocorrência de parasitos gastrointestinais. Os dados obtidos contribuem para o conhecimento da epidemiologia das parasitoses gastrointestinais, bem como poderão auxiliar médicos veterinários e proprietários na elaboração de estratégias de controle e profilaxia antiparasitária para gatos domésticos.

This study verified the gastrointestinal parasites occurrence in household cats in Santa Maria, RS, Brasil from March to June, 2011. In addition, the risk factors associated with gastrointestinal parasites infection were evaluated. One hundred ninety -one felines fecal samples were submitted to parasitological examination, as well as to an epidemiological questionnaire about the management and the animal habits, which was applied to the owners. Fecal samples were positive for one or more gastrointestinal parasites (47.1% - 90/191). Occurrence of mono-infection was 33.5% (64/191) and multi-infection 13.6% (26/191). Toxocara spp. (18.8%) and Giardia spp. (4.2%) were the main parasites found in mono-infection. The main association of parasites detected included: Ancylostoma spp. + Toxocara spp. (3.1%) and Cystoisospora spp. + Cryptosporidium spp. + Giardia spp. + Toxoplasma spp. + Toxocara spp. (1.5%). Epidemiological data were submitted to chi-square, Fisher and odds ratio tests, as well as analyzed the relationship between the epidemiological factors and the presence of gastrointestinal parasites (P>0.05). The main risk factors identified were: the scholar level of owners and frequency of antiparasitic treatments, which showed a direct influence on the occurrence of gastrointestinal parasites. The data contribute to the understanding of the epidemiology of gastrointestinal parasites and could aid veterinarians and owners in developing of antiparasitic strategies for domestic cats.

The importance of vertical transmission of Neospora sp. in naturally infected horses.

Neospora spp. is a intracellular protozoan phylogenetically closely related to Toxoplasma gondii and Sarcocystis neurona, and it can infect horses leading to the development of reproductive or neurological diseases. We determined the presence of antibodies to Neospora sp. in mares at their parturition time and determine the frequency of vertical transmission in healthy foals to verify the importance of transplacental transmission. The samples were analyzed by indirect immunofluorescence antibody test, showing that seroprevalence in mares is higher than in foals and seropositive mares are likely to transmit the neosporosis to their offspring. This shows that endogenous challenge occurs in horses, and it suggests that this protozoan can be disseminated by means of transplacental transmission in horse species.

Acaricide activity of leaves extracts of Sambucus australis Schltdl. (Caprifoliaceae) at 2 percent on engorged females of Rhipicephalus (Boophilus) microplus / Atividade acaricida de extratos de folhas de Sambucus australis Schltdl (Caprifoliaceae) a 2 por cento sobre teleóginas de Rhipicephalus (Boophilus) microplus

Parasite infections caused by Rhipicephalus (Boophilus) microplus are responsible for the most of economic losses in producing-cattle countries in tropical and subtropical areas. Indiscriminate uses of chemical acaricides have contributed with the appearance of tick resistance to many drugs available in the marketplace, and it is a serious problem in the tick control. Flowers of Sambucus australis (South America), called "sabugueiro-from-Brazil", are used on infusions or decoctions forms in the folk medicine with diuretic, antipyretic, anti-inflammatory, and laxative purpose, also employed for treating respiratory diseases in human. The main goal of this study was to evaluate in vitro potential of S. australis leaves extracts as an acaricide agent. Ethanol extract at 70 percent has been dehydrated and a fraction was suspended in 70 percent ethanol or in distillated water at final concentration of 2 percent (0.2mg-1). Using the immersion test of engorged females the efficiency results were obtained in 34 percent and 66 percent with the leaves extract diluted in water and 70 percent ethanol, respectively. This study is the first report on acaricidal activity of S. australis against cattle tick. Further studies to determine the active metabolites in different stages of S. australis could aid to identify suitable extracts to be tested in the R. (B.) microplus control.

A infestação por Rhipicephalus (Boophilus) microplus é responsável por grandes perdas econômicas em países produtores de bovinos nas áreas tropicais e subtropicais. Usos indiscriminados de acaricidas químicos têm contribuído para o aparecimento da resistência dos ixodídeos a múltiplas drogas, representando um sério problema no controle de carrapatos. As flores da planta Sambucus australis, conhecidas pelo nome popular de sabugueiro do Brasil, são usadas, na forma de infusão ou emplastros, na medicina popular como diurético, antipirético, antiinflamatório e laxativo; também empregado no tratamento de doenças respiratórias em humanos. O objetivo principal deste trabalho foi avaliar o potencial in vitro de extratos de folhas de S. australis, como agente carrapaticida. O extrato etanólico a 70 por cento foi dessecado e retomado parte em etanol a 70 por cento ou em água destilada, numa concentração final de 2 por cento (0,2mg-1). No biocarrapaticidograma obteve-se resultados de eficácia entre 34 por cento e 66 por cento para o extrato de folhas diluído em água e etanol a 70 por cento, respectivamente. Esse estudo é o primeiro relato de ação carrapaticida de S. australis. Estudos adicionais para determinar os metabólitos ativos, em diferentes estágios de S. australis, fornecerão subsídios para identificar os extratos apropriados a serem testados no controle do R. (B.) microplus.

Atividade acaricida in vitro de Glechon spathulata Benth. sobre teleóginas de Rhipicephalus (Boophilus) microplus / Acaricide activity in vitro of Glechon spathulata Benth. On engorged females of Rhipcephalus (Boophilus) microplus

O objetivo deste estudo foi avaliar a atividade acaricida in vitro de extratos vegetais de Glechon spathulata (manjeroninha do campo) sobre teleóginas de Rhipicephalus (Boophilus) microplus. Fêmeas ingurgitadas desse carrapato foram coletadas de bovinos mestiços de uma propriedade do município de São Pedro do Sul, Rio Grande do Sul, Brasil. A experimentação in vitro consistiu na realização de testes de imersão de fêmeas ingurgitadas. O extrato bruto seco e a fração clorofórmica utilizados nos testes in vitro foram preparados na concentração de 2 por cento e diluídos em água e etanol, sendo todos os tratamentos realizados em triplicata. O extrato bruto seco de G. spathulata retomado em etanol a 70 por cento apresentou uma eficácia média de 99 por cento, enquanto que quando o mesmo extrato foi diluído em água, demonstrou eficácia média de 72 por cento. Observou-se que no controle etanol a 70 por cento houve diferença na eclodibilidade dos ovos, porém não interferiu no peso da postura. A fração clorofórmica de G. spathulata não apresentou eficácia no ensaio efetuado. Os resultados obtidos nesse estudo demonstraram que o extrato hidroetanólico a 70 por cento de G. spathulata apresenta eficácia acaricida in vitro. Este estudo é o primeiro relato de ação acaricida de G. spathulata.

The aim of this study was to evaluate the in vitro acaricide efficiency of Glechon spathulata extracts on engorged females of Rhipcephalus (Boophilus) microplus. Engorged ticks were collected from crossbred cattle from one farm in São Pedro do Sul municipality, Rio Grande do Sul, Brazil. in vitro experiments consisted on the immersion tests of engorged females in solutions of G. spathulata, where treatments were made at triplicate with fractions and extracts at 2 percent concentration, diluted in water and ethanol. Crude dry extract of G. spathulata suspended in 70 percent ethanol presented an efficiency average of 99 percent, while the same extract diluted in water demonstrated efficiency average of 72 percent. It was observed in 70 percent ethanol control difference in egg eclodibility; however there was no interference in egg weight. The chloroform fraction of G. spathulata showed no efficacy in the test. The results obtained suggest that the hydroethanolic extract at 70 percent of G. spathulata has significant acaricide activity in vitro. This research is the first communication of acaricidal effect of. G. spathulata.

Combinação de drogas antiparasitárias como uma alternativa para o controle de nematódeos gastrintestinais multirresistentes em ovinos / Combination of drugs as an alternative to control multi-resistant gastrointestinal nematodes in sheep

Este estudo foi realizado com o objetivo de encontrarem-se tratamentos anti-helmínticos eficazes sobre uma população de nematódeos gastrintestinais de ovinos, a qual desenvolveu resistência a todas as classes de drogas com ação nematicida disponíveis para ruminantes no mercado brasileiro. Valendo-se da eficácia calculada de tratamentos convencionais a partir de um estudo prévio e, assim, conhecendo-se sua ação sobre diferentes gêneros de nematódeos presentes no rebanho, selecionaram-se drogas as quais, utilizadas em combinações ou em altas doses, pudessem aumentar significativamente a eficácia dos tratamentos. Utilizou-se o percentual de redução da contagem de ovos nas fezes e as culturas de larvas para avaliar a ação anti-helmíntica dos tratamentos testados. A combinação de moxidectina 1 por cento + disofenol 20 por cento apresentou 99 por cento de eficácia, e as combinações de moxidectina 1 por cento + triclorfon 10 por cento e de moxidectina 1 por cento + fosfato de levamisol 22,3 por cento superaram os 90 por cento de eficácia. A utilização de combinações de princípios ativos, com diferentes mecanismos de ação, pode promover a recuperação da eficácia dos tratamentos anti-helmínticos sobre populações multirresistentes de nematódeos gastrintestinais de ovinos.

This study was conducted to find effective anthelmintic treatments on a multi-resistant population of gastrointestinal nematodes of sheep, which was found resisting to all the classes of nematicidal drugs available in the Brazilian market. We took as a starting point the data obtained in a previous study performed in the targeted flock, in which were tested conventional treatments. Thus, using the calculated efficacy of the drugs (tested previously) for the genera of nematodes found in the flock, we selected drugs which, combined or used in higher doses, could improve the efficacy of the treatments. We evaluated the anthelmintic action of each treatment using the percentage of reduction of eggs in the feces, along with larvae cultures. A combination of moxidectin 1 percent + disophenol 20 percent showed 99 percent of efficacy, and combinations of moxidectin 1 percent + trichlorphon 10 percent and moxidectin 1 percent + levamisole phosphate 22.3 percent showed efficacy over 90 percent. Combinations of drugs, with different mechanisms of action, can provide effective anthelmintic treatments on multidrug-resistant populations of gastrointestinal nematodes of sheep.

Ação acaricida in vitro de Tropaeolum majus sob teleóginas de Rhipicephalus (Boophilus) microplus / in vitro acaricidal effect of Tropaeolum majus on the engorged female of Rhipicephalus (Boophilus) microplus

O objetivo desse estudo foi o de avaliar a eficácia acaricida in vitro do extrato aquoso e etanólico a 70 por cento da Tropaeolum majus em teleóginas do Rhipicephalus (Boophilus) microplus. Extrato das partes aéreas (caule e folhas) e de flores foram testados na concentração final de 2 por cento. A coleta de teleóginas de Rhipicephalus (Boophilus) microplus foi realizada em propriedades do município de São Francisco de Assis e São Pedro do Sul, Rio Grande do Sul, Brasil. O extrato das partes aéreas em etanol a 70 por cento alcançou eficácia de 99,1 por cento. Esse estudo é o primeiro relato de ação carrapaticida de Tropaeolum majus.

The aim of this study was to evaluate the in vitro acaricide effect of aqueous and ethanolic extracts of Tropaeolum majus on Rhipicephalus (Boophilus) microplus engorged females. Extracts from the aerial parts (stems and leaves) and from the flowers were tested at a final concentration of 2 percent. The Rhipicephalus (Boophilus) microplus engorged females were collected in farms in two municipalities (São Francisco de Assis and São Pedro do Sul), in Rio Grande do Sul state, Brazil. An efficacy of 99,1 percent was found using extract of aerial parts in ethanol at 70 percent. This is the first report of acaricidal effect of Tropaeolum majus.