RESUMO

The control of Rhipicephalus microplus is essential to prevent cattle discomfort and economic losses. However, increased resistance and acaricides inefficiency lead producers to adopt strategies that could result in the accumulation of chemical residues in meat and milk with possibilities of poisoning in animals and people. This scenario demonstrates the necessity of research into the identification of novel, effective and environmentally safe therapeutic options for cattle tick control. The objectives of this study were to develop and assess the efficacy of R. microplus biotherapic and of 5% eugenol for the control of R. microplus in artificially infested calves. Eighteen male 6-month-old Holstein calves were divided into three groups of six animals. In Group 1, the animals did not receive medication (control group); in Group 2, the animals received 1 mL of R. microplus biotherapic at dilution 6CH (centesimal Hahnemannian), orally administered twice daily. And in Group 3, they received a single application of eugenol 5% in the pour-on formulation. The median efficacy for biotherapy and eugenol 5% was respectively 10.13 and 13.97%; however, upon analyzing reproductive efficiency, it is noteworthy that the biotherapic had 45.86% efficiency and was superior to the action of eugenol (12.03%) after 37 days of treatment. The ultrastructural study provided information about the effects of R. microplus biotherapic on the ovaries of engorged females and showed disorganization in the deposition of the oocyte exochorion. The results suggest hatchability inhibition of larvae, interference in R. microplus reproduction and future possibilities for eco-friendly control of R. microplus with biotherapic 6CH.

Assuntos

RESUMO

The objective of the study was to evaluate the efficacy of pour-on formulations of fluazuron and ivermectin in different therapeutic protocols for treatment of demodicosis by means of quantifying mites with skin scraping, histological and clinical evaluation in dogs. Eighteen dogs with skin scrapings positive for Demodex canis were evaluated, divided into three groups. All the animals were treated every 14 days, completing 6 treatments for each animal (days 0, 14, 28, 42, 56 and 70). In group 1, pour-on 2.5% fluazuron was used at the dose of 20mg/kg; in the group 2 pour-on 2.5% fluazuron at a dose of 20 mg/kg in association with pour-on 0.5% ivermectin at the dose of 0.6mg/kg; and in group 3, pour-on 0.5% ivermectin alone was used, at the dose of 0.6mg/kg. The treatment was evaluated and monitored through skin scrapings and clinical follow-up of the lesions every 14 days for 84 days, and through histopathological examination at the end of each treatment protocol. The success rate was defined as the percentage of dogs in each group that had negative skin scrapings after the treatment: this was 16.67% for group 1, and 50% for groups 2 and 3. The reduction in mite counts reached effectiveness of 67.66%, 88.99% and 84.29% for groups 1, 2 and 3 respectively. The Wilcoxon test showed that there was a significant difference between the number of mites before and after treatment in groups 2 and 3. The histopathological examination revealed that only group 1 showed no significant difference in the intensity of infestation between days 0 and 84. Clinically, there was no significant difference between the evaluation before and after treatment in the three groups. pour-on 2.5% fluazuron and pour-on 0.5% ivermectin were not effective for treating canine demodicosis, either in association or as single therapy, when applied every 14 days for a period of 70 days. Quantification of mites using skin scrapings and histological evaluation proved to be ineffective, either one as sole therapeutic evaluation parameters, for canine demodicosis.(AU)

O objetivo do presente estudo foi avaliar a eficácia do fluazuron e da ivermectina pour-on em diferentes protocolos terapêuticos no tratamento da demodiciose, através da quantificação de ácaros por raspados cutâneos e exames histológicos, além da avaliação dos cães. Foram avaliados 18 cães com raspados cutâneos positivos para o ácaro Demodex canis, divididos em três grupos. Todos os animais foram tratados a cada 14 dias, totalizando seis tratamentos em cada cão (Dias 0, 14, 28, 42, 56 e 70). No grupo 1 foi utilizado fluazuron 2,5% pour-on na dosagem de 20mg/kg; no grupo 2 foi empregado fluazuron 2,5% pour-on na dosagem de 20mg/kg associado a ivermectina 0,5% pour-on, na dosagem de 0,6mg/kg e, no grupo 3, somente ivermectina 0,5% pour-on 0,6mg/kg. Raspados cutâneos e acompanhamento clínico das lesões foram realizados a cada 14 dias por 84 dias e realizado exame histopatológico ao final de cada protocolo terapêutico. A taxa de sucesso foi definida pela porcentagem de cães em cada grupo com raspados negativos ao final do tratamento, que foi 16,67% para o grupo 1 e 50% para os grupos 2 e 3. A redução na contagem no número de ácaros alcançou eficácia de até 67,66%; 88,99% e 84,29%, nos grupos 1, 2 e 3, respectivamente. O teste de Wilcoxon mostrou que houve diferença significativa entre a quantidade de ácaros antes e após o tratamento nos grupos 2 e 3. No exame histopatológico apenas o grupo 1 não apresentou diferença significativa na intensidade da infestação entre os dias 0 e 84. Clinicamente não houve diferença significativa entre as avaliações antes e após o tratamento dos três grupos. O fluazuron 2,5% pour-on e a ivermectina 0,5% pour-on associados ou como terapia única, não foram eficazes no tratamento da demodiciose canina, quando aplicados a cada 14 dias em um período de 70 dias. A quantificação de ácaros através do exame parasitológico em raspado cutâneo e em exame histopatológico demonstrou-se ineficaz como parâmetro isolado de avaliação pós-terapêutica para demodiciose canina.(AU)

Assuntos

RESUMO

The objective of the study was to evaluate the efficacy of pour-on formulations of fluazuron and ivermectin in different therapeutic protocols for treatment of demodicosis by means of quantifying mites with skin scraping, histological and clinical evaluation in dogs. Eighteen dogs with skin scrapings positive for Demodex canis were evaluated, divided into three groups. All the animals were treated every 14 days, completing 6 treatments for each animal (days 0, 14, 28, 42, 56 and 70). In group 1, pour-on 2.5% fluazuron was used at the dose of 20mg/kg, in the group 2 pour-on 2.5% fluazuron at a dose of 20 mg/kg in association with pour-on 0.5% ivermectin at the dose of 0.6mg/kg, and in group 3, pour-on 0.5% ivermectin alone was used, at the dose of 0.6mg/kg. The treatment was evaluated and monitored through skin scrapings and clinical follow-up of the lesions every 14 days for 84 days, and through histopathological examination at the end of each treatment protocol. The success rate was defined as the percentage of dogs in each group that had negative skin scrapings after the treatment: this was 16.67% for group 1, and 50% for groups 2 and 3. The reduction in mite counts reached effectiveness of 67.66%, 88.99% and 84.29% for groups 1, 2 and 3 respectively. The Wilcoxon test showed that there was a significant difference between the number of mites before and after treatment in groups 2 and 3. The histopathological examination revealed that only group 1 showed no significant difference in the intensity of infestation between days 0 and 84. Clinically, there was no significant difference between the evaluation before and after treatment in the three groups. pour-on 2.5% fluazuron and pour-on 0.5% ivermectin were not effective for treating canine demodicosis, either in association or as single therapy, when applied every 14 days for a period of 70 days. Quantification of mites using skin scrapings and histological evaluation proved to be ineffective, either one as sole therapeutic evaluation parameters, for canine demodicosis.(AU)

O objetivo do presente estudo foi avaliar a eficácia do fluazuron e da ivermectina pour-on em diferentes protocolos terapêuticos no tratamento da demodiciose, através da quantificação de ácaros por raspados cutâneos e exames histológicos, além da avaliação dos cães. Foram avaliados 18 cães com raspados cutâneos positivos para o ácaro Demodex canis, divididos em três grupos. Todos os animais foram tratados a cada 14 dias, totalizando seis tratamentos em cada cão (Dias 0, 14, 28, 42, 56 e 70). No grupo 1 foi utilizado fluazuron 2,5% pour-on na dosagem de 20mg/kg, no grupo 2 foi empregado fluazuron 2,5% pour-on na dosagem de 20mg/kg associado a ivermectina 0,5% pour-on, na dosagem de 0,6mg/kg e, no grupo 3, somente ivermectina 0,5% pour-on 0,6mg/kg. Raspados cutâneos e acompanhamento clínico das lesões foram realizados a cada 14 dias por 84 dias e realizado exame histopatológico ao final de cada protocolo terapêutico. A taxa de sucesso foi definida pela porcentagem de cães em cada grupo com raspados negativos ao final do tratamento, que foi 16,67% para o grupo 1 e 50% para os grupos 2 e 3. A redução na contagem no número de ácaros alcançou eficácia de até 67,66%, 88,99% e 84,29%, nos grupos 1, 2 e 3, respectivamente. O teste de Wilcoxon mostrou que houve diferença significativa entre a quantidade de ácaros antes e após o tratamento nos grupos 2 e 3. No exame histopatológico apenas o grupo 1 não apresentou diferença significativa na intensidade da infestação entre os dias 0 e 84. Clinicamente não houve diferença significativa entre as avaliações antes e após o tratamento dos três grupos. O fluazuron 2,5% pour-on e a ivermectina 0,5% pour-on associados ou como terapia única, não foram eficazes no tratamento da demodiciose canina, quando aplicados a cada 14 dias em um período de 70 dias. A quantificação de ácaros através do exame parasitológico em raspado cutâneo e em exame histopatológico demonstrou-se ineficaz como parâmetro isolado de avaliação pós-terapêutica para demodiciose canina.(AU)

Assuntos

RESUMO

Among peridomestic structures, chicken coops are sites of major importance for the domestic ecology of Triatoma infestans (Hemiptera: Reduviidae). The aim of this study was to evaluate in an experimental context the effects of a cypermethrin pour-on formulation applied to chickens on blood intake, moulting and mortality in T. infestans, under the natural climatic conditions of a region endemic for Chagas' disease. Experimental chicken huts were made of bricks and covered with plastic mosquito nets. Ninety fourth-instar nymphs were maintained in each hut. The study used a completely random design in which chickens in the experimental group were treated with a cypermethrin pour-on formulation. Five replicates (= huts) of the experimental and control groups were conducted. The number of live T. infestans, blood intake and moults to fifth-instar stage were recorded at 1, 5, 20, 35 and 45 days after the application of cypermethrin. Cumulative mortality was higher in nymphs exposed to treated chickens (> 71%) than in control nymphs (< 50%) (P < 0.01). Blood intake and moulting rate were lower in nymphs fed on treated chickens than in control nymphs (P < 0.05). Pour-on cypermethrin was able to cause significant mortality, although it did not eliminate the experimental population of T. infestans.

Assuntos

RESUMO

Triatoma infestans is the main vector of Trypanosoma cruzi, the aetiological agent of Chagas disease in the Gran Chaco region of South America. As a frequent blood meal source for triatomine bugs, domestic goats play a key role in the eco-epidemiology of Chagas disease. The aim of this study was to evaluate the mortality and blood intake of T. infestans fed on goats that had been treated with different doses of pour-on insecticide. Third-instar nymphs were fed on goats that had been treated with 0 cc, 5 cc, 10 cc or 15 cc of a pour-on formulation of cypermethrin. The exposure of T. infestans to animals treated at different post-application intervals revealed a residual activity of the insecticide. The mortality rate in the treated groups was higher than in the control groups until 30 days post-insecticide application (p = 0.03), except in the group treated with 5 cc, in which no mortality was detected after seven days of insecticide application. Rainfall affected the triatomicide effect, reducing the time of residual activity. The cypermethrin pour-on treatment decreased the blood intake of T. infestans. Thirty days after the cypermethrin application, nymph mortality was 16% (± 13) with both doses (10 cc and 15 cc). The 15 cc dose did not result in higher insect mortality or increased persistence compared to the 10 cc dose.

Assuntos

RESUMO

This article reports the effects of a pour-on formulation of cypermethrin (6 percent active ingredient) applied to chickens exposed to Triatoma infestans, the main vector of Chagas disease in rural houses of the Gran Chaco Region of South America. This study was designed as a completely random experiment with three experimental groups and five replicates. Third instar nymphs were fed on chickens treated with 0, 1 and 2 cc of the formulation. Nymphs were allowed to feed on the chickens at different time intervals after the insecticide application. Third-instar nymphs fed on treated chickens showed a higher mortality, took less blood during feeding and had a lower moulting rate. The mortality rate was highest seven days after the insecticide solution application and blood intake was affected until 30 days after the application of the solution.

Assuntos