03267naa a2200505 a 450000100080000000500110000800800410001902400380006010000250009824502070012326000090033052017670033965000180210665000190212465000200214365000100216365000150217365000210218865000160220965000150222565000170224065000100225765000200226765000210228765000120230865000250232065000290234565000150237465000100238965000260239965000140242565300130243965300310245265300220248365300320250570000230253770000170256070000220257770000220259970000210262170000170264270000240265970000200268377300580270320823842019-01-10       2017    bl uuuu     u00u1 u    #d7 a10.1016/j.vetpar.2017.11.0032DOI1 aSANTOS, J. M. L. dos  aHaemonchus contortus Beta-tubulin isotype 1 gene F200Y and F167Y SNPs are both selected by ivermectin and oxfendazole treatments with differing impacts on anthelmintic resistance.h[electronic resource]  c2017  aAbstract: Parasitism by Haemonchus contortus is one of the main limiting factors in small ruminant production in tropical areas. Benzimidazoles (BZ) and macrocyclic lactones (ML) are the most used anthelmintic classes in gastrointestinal nematodes control. There is considerable scientific evidence of a possible relation between the anthelmintic resistance to BZ and ML. This study aimed to characterize the dynamics of anthelmintic resistance in an H. contortus susceptible isolate under selection pressure for BZ and ML alone or in combination and the role of isotype 1 Beta-tubulin gene SNPs in these situations. A total of 12 Somali sheep were infected with 5000 third stage larvae of H. contortus Inbred-Susceptible Edinburgh (ISE) isolate. Once infection was established, animals were distributed in three groups (n=4), each treated with crescent doses of oxfendazole (OXF), ivermectin (IVM) and oxfendazole plus ivermectin (IVMOXF). An additional control group with untreated animals was maintained during the entire experiment. After each treatment, eggs were collected and real-time PCR was performed to identify single nucleotide polymorphisms (SNPs) F167Y, F200Y and E198A, in addition to egg hatch test (EHT) for BZ and larval development test (LDT) for ivermectin resistance. All treatments led to increased resistance allelic frequencies at SNPs F200Y and F167Y (p &lt0.05). In vitro results showed increased phenotypic resistance against both anthelmintic classes in groups IVM and IVMOXF while group OXF only developed resistance against BZ. Finally, we provide evidence that while isotype 1 ?-tubulin gene SNPs may have some involvement with ML resistance, the presence of these ?-tubulin SNPs alone are not sufficient to develop ML resistance.  aAnthelmintics  aBenzimidazoles  aDrug resistance  aGoats  aIvermectin  aNematode control  aOxfendazole  aParasitism  aPolymorphism  aSheep  aSmall ruminants  aAnti-helmíntico  aCaprino  aHaemonchus Contortus  aHelminto gastrintestinal  aNematóide  aOvino  aResistência química  aVerminose  aNematode  aNematódeo gastrintestinal  aPequeno ruminante  aResistance to anthelmintics1 aVASCONCELOS, J. F.1 aFROTA, G. A.1 aRIBEIRO, W. L. C.1 aANDDRÉ, W. P. P.1 aVIEIRA, L. da S.1 aTEIXEIRA, M.1 aBEVILAQUA, C. M. L.1 aMONTEIRO, J. P.  tVeterinary Parasitologygv. 248, p. 90-95, Dec. 2017.