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The objective of this study was to evaluate the efficacy of carvacryl acetate (CVA) and nanoencapsulated CVA (nCVA) on gastrointestinal nematodes of sheep. The CVA was nanoencapsulated with chitosan/gum arabic and the efficacy of nanoencapsulation (EE), yield, zeta potential, nanoparticle morphology and release kinetics at pH 3 and 8 were analyzed. Acute and subchronic toxicity were evaluated in rodents and reduction of egg counts in the faeces (FECRT) of sheep. The sheep were divided into four groups (n = 10): G1, 250 mg/kg CVA; G2, 250 mg/kg nCVA; G3, polymer matrix and G4: 2.5 mg/kg monepantel. EE and nCVA yield were 65% and 57%, respectively. The morphology of the nanoparticles was spherical, size (810.6±286.7 nm), zeta potential in pH 3.2 (+18.3 mV) and the 50% release of CVA at pHs 3 and 8 occurred at 200 and 10 h, respectively. nCVA showed LD50 of 2,609 mg/kg. CVA, nCVA and monepantel reduced the number of eggs per gram of faeces (epg) by 57.7%, 51.1% and 97.7%, respectively. The epg of sheep treated with CVA and nCVA did not differ from the negative control (P>0.05). Nanoencapsulation reduced the toxicity of CVA; however, nCVA and CVA presented similar results in the FECRT. [Atividade anti-helmíntica do acetato de carvacrila nanoencapsulado sobre nematoides gastrintestinais de ovinos e toxicidade em roedores]. Resumo: O objetivo deste trabalho foi avaliar a eficácia do acetato de carvacrila (ACV) e do ACV nanoencapsulado (nACV) sobre nematóides gastrintestinais de ovinos. O ACV foi nanoencapsulado com quitosana/goma arábica e foi analisada a eficácia de nanoencapsulamento (EE), o rendimento, potencial zeta, morfologia das nanopartículas e cinética de liberação em pH 3 e 8. Foram avaliadas as toxicidades aguda e subcrônica em roedores e a redução da contagem de ovos nas fezes (RCOF) de ovinos. Os ovinos foram divididos em quatro grupos (n = 10): G1, 250 mg/kg ACV; G2, 250 mg/kg de nACV; G3, matriz polimérica e G4: 2,5 mg/kg de monepantel. A EE e o rendimento de nACV foram de 65% e 57%, respectivamente. A morfologia das nanopartículas foi esférica, tamanho (810,6±286,7 nm), potencial zeta no pH 3,2 (+18,3 mV) e a liberação de 50% de CVA nos pHs 3 e 8 ocorreu às 200 e 10 h, respectivamente. nACV apresentou DL50 de 2.609 mg/kg. ACV, nACV e o monepantel reduziram a contagem de ovos por grama de fezes (opg) em 57,7%, 51,1% e 97,7%, respectivamente. A contagem de opg de ovelhas tratadas com ACV e nCVA não diferiu do controle negativo (P>0,05). O nanoencapsulamento reduziu a toxicidade do AVC; no entanto, nACV e ACV apresentaram resultados semelhantes na RCOF. Made available in DSpace on 2020-10-01T09:12:11Z (GMT). No. of bitstreams: 1 CNPC-2020-Art-21.pdf: 1090808 bytes, checksum: b3f5b06793979fd2fe3daa1a072f8f3f (MD5) Previous issue date: 2020

INTRODUCTION: Considering the unknown situation regarding canine visceral leishmaniasis in Garanhuns, this study had the aim of investigating occurrences of anti-Leishmania spp antibodies in domesticated and partially domesticated dogs, and the possible risk factors involved. METHODS: In the first phase of the study, 256 blood samples were collected from dogs and subjected to the indirect fluorescent antibody test (IFAT) reaction at a dilution of 1:40. Additionally, 23 IFAT-positive samples were tested using an immunochromatographic dipstick test. In the second phase, new blood samples were collected from 18 dogs that were IFAT-positive in the first phase. These animals were retested using IFAT (1:40 and 1:80) and, additionally, by means of the polymerase chain reaction to investigate the Leishmania infantum DNA. Furthermore, 16 of these samples were retested using the immunochromatographic dipstick test. RESULTS: In the first phase of the study, 16% of the samples were IFAT-positive (1:40) and only three (13%) were positive in the immunochromatographic dipstick test. In the second phase, 12 samples were IFAT-positive at the dilution of 1:40, and seven were also positive at 1:80. None of the samples were positive in the polymerase chain reaction testing or in the immunochromatographic dipstick test. Clinical signs suggestive of visceral leishmaniasis were observed in 4.9% of the IFAT-positive dogs. There were no statistical differences in relation to age, sex or clinical status of the dogs, but there was a difference in relation to place of origin. CONCLUSIONS: The domesticated and partially domesticated dogs living in Garanhuns present anti-Leishmania spp antibodies, but are mostly asymptomatic.