RESUMEN

OBJECTIVE: This study was done to evaluate the in vitro and in vivo effects of the essential oil (OE-CL) and nanoemulsion (N-CL) of Cymbopogon flexuosus against Trichomonas gallinae. MATERIALS AND METHODS: In vitro assays were done with 106 parasites and OE-CL and N-CL in the concentrations: 110, 220, 330, 440, 550, 660, 770 and 880 µg/ml and four controls: CN (culture medium and trophozoites), MTZ (trophozoites plus 800 µg/ml of metronidazole), TW (trophozoites plus vehicles used for solubilization of derivatives (0.01% Tween) and NB (blank nanoemulsion 880 µg/ml). The in vivo assay was done in 35 quails (Coturnix coturnix) infected experimentally 4x104 mg/kg, were divided in seven groups (n=5): A (control-healthy), B (control infected), C (control TW 0.01%), D (NB 0.88 mg/kg), E (drug MTZ 25 mg/kg, F (OE-CL at 0.55 mg/kg) and G (N-CL at 0.44 mg/kg), during 7 consecutive days. RESULTS: The in vitro test showed that the OE-CL (550 µg/ml) and N-CL (440 µg/ml) concentrations reduced the trophozoites viability in 100%. In the in vivo test, the treatment with OE-CL was efficient on the 4th treatment day and the N-CL after the 3rd day, and the MTZ in the therapeutic concentration was efficient on the 7th day. CONCLUSION: It can be observed in this study that the lemon grass has natural potential antitrichomonal activity against T. gallinae in vitro and in vivo.

RESUMEN

Commercial formulation of the amitraz is the most used acaricide in the southern region of Rio Grande do Sul State, however scientific data about the efficacy of these products in this region are sparse. The aim of the present study was to evaluate the frequency of R. (B.) microplus populations resistant to amitraz acaricides in the Southern region of Rio Grande do Sul State. So, the efficacies of five commercial products containing amitraz were compared. Results showed that the efficacy of amitraz acaricides was lower than 69% in 23% of studied populations. Nearly 29% of the tick samples showed an acaricide efficacy equal to zero, suggesting the presence of a high level of resistance to amitraz. Moreover, the most used commercial product in the region showed the lowest efficacy index. These results alert about the possible spreading of resistant on tick populations and justify research directed toward the search for alternative products to control this parasite.

Formulações comerciais à base de amitraz são muito utilizadas como acaricidas na Região Sul do Rio Grande do Sul, contudo sem maiores estudos da sua eficácia nessa região. O presente estudo objetivou estimar a frequência de populações de R. (B.) microplus resistente ao amitraz na Região Sul do Rio Grande do Sul, e comparar a eficácia de cinco produtos comerciais à base desse princípio ativo. Os resultados demonstraram que, em 23% das populações estudadas, o amitraz teve uma eficácia inferior a 69%. Em 29% dessas amostras de carrapatos, o grau de eficácia foi igual a zero, sugerindo a presença de altos níveis de resistência ao amitraz. Além disso, o produto comercial mais utilizado na região demonstra o menor índice de eficácia. Esses resultados alertam sobre a possibilidade da dispersão de populações de carrapatos resistentes, o que justifica a necessidade de direcionar pesquisas visando a novas alternativas e produtos para o controle desse parasito.