RESUMO
Benzimidazole resistance is common amongst many ovine trichostrongylid nematodes species globally. Although anthelmintics have been used for over half a century in some areas of the world for the control of Nematodirus battus, resistance has never been detected. Veterinary investigations conducted in 2010 demonstrated reduced efficacy in a flock that had been treated previously with fenbendazole (FBZ), suggesting probable resistance in N. battus. Infective larvae (L3; designated MNba2) were generated from the original material to conduct a controlled efficacy test (CET). Faecal egg counts showed an average of 37% reduction in the FBZ treated group 7 days post treatment compared to the untreated lambs. Average worm burden results showed no reduction after FBZ treatment compared to the untreated group (3850 and 3850 worms respectively). A molecular assay to assess the frequency of the commonly associated single nucleotide polymorphisms (SNP) in the ß-tubulin isotype 1 gene, F200Y and E198A, was developed. Larval genotypes were predominantly homozygous resistant at codon 200 SNP, ranging from 56%-83% and remained stable at 70% for adult worm populations taken from treated and control lambs in the CET. Only susceptible genotypes were found at codon 198. The allele frequency for F200Y ranged between 80-83% in adult worms taken from the CET from treated and control lambs. The results confirmed initial findings and demonstrated the first report of FBZ resistance in N. battus whilst providing evidence that the P200 point mutation in the ß-tubulin isotype 1 gene is a potential mechanism of resistance in the species.
Assuntos
Benzimidazóis/farmacologia , Resistência a Medicamentos/genética , Proteínas de Helminto/genética , Nematodirus/efeitos dos fármacos , Nematodirus/genética , Contagem de Ovos de Parasitas/veterinária , Tubulina (Proteína)/genética , Animais , Anti-Helmínticos/farmacologia , Fezes/parasitologia , Genótipo , Proteínas de Helminto/metabolismo , Larva/efeitos dos fármacos , Reação em Cadeia da Polimerase/veterinária , Polimorfismo de Nucleotídeo Único , Ovinos , Doenças dos Ovinos/parasitologia , Doenças dos Ovinos/prevenção & controle , Infecções por Strongylida/parasitologia , Infecções por Strongylida/prevenção & controle , Infecções por Strongylida/veterinária , Tubulina (Proteína)/metabolismoRESUMO
Louping ill virus (LIV) is a zoonotic virus causing fatal encephalitis in young sheep and grouse. We have recovered the complete genome sequence from a spinal cord sample prepared from a lamb that was naturally infected with LIV. This is only the second LIV genome sequence reported and the first prepared from a clinical sample.
RESUMO
Using PCR on aborted foetal material, Coxiella burnetii infection was confirmed as the cause of abortions in a dairy goat herd with over 1000 adults. Ninety-five (22%) abortions and 355 normal births were recorded from 440 goats over 2 months. The herd was sampled three times in 6 months to look at the within-herd seroprevalence, with the 1st visit done 24 days after the last recorded abortion. The true seroprevalence in the herd was 79.2%, 66.5% and 45.7% on each of these visits, but introduction of a group of young goats prior to the 3d visit influenced these results. Using PCR, widespread environmental contamination was demonstrated in surface dust, bedding, muck heaps, milk, bird droppings and drinking water in the goat shed. MST and MLVA analysis showed the C. burnetii from this outbreak to be of a genotype previously observed in the UK and different from those recorded in the Netherlands outbreak of 2007-2011.
