Quantitative molecular diagnosis of levamisole resistance in populations of Haemonchus contortus
| Autor: | Claudia Maria Leal Bevilaqua, Janaélia Ferreira Vasconcelos, G. A. Frota, J. P. Monteiro, Jessica Maria Leite dos Santos, Marcel Teixeira, Luiz da Silva Vieira, Edilson Pereira de Freitas |
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| Rok vydání: | 2018 |
| Předmět: |
Veterinary medicine
Immunology Drug Resistance Neuromuscular Junction Tetramisole Sheep Diseases Drug resistance Receptors Nicotinic Real-Time Polymerase Chain Reaction law.invention Feces Inbred strain Gene Frequency law parasitic diseases medicine Animals Receptors Cholinergic Anthelmintic Allele frequency Polymerase chain reaction Sheep biology Antinematodal Agents General Medicine Levamisole DNA Helminth biology.organism_classification Infectious Diseases Parasitology Larva Benzimidazoles Haemonchus Haemonchiasis Sequence Alignment Haemonchus contortus medicine.drug |
| Zdroj: | Experimental parasitology. 205 |
| ISSN: | 1090-2449 |
| Popis: | Parasitism by Haemonchus contortus is one of the main limiting factors in small ruminant production around the globe. Although several studies suggest the use of integrated management practices, these parasites have been controlled essentially with synthetic anthelmintic drugs. The resistance mechanism against the imidazothiazole derivative levamisole in Haemonchus contortus has not been fully described. Recently, resistance was associated with a 63bp deletion in the Hco-acr-8b gene that encodes a subunit for a nicotinic acetylcholine receptor. This study aimed to standardize a real time PCR (qPCR) protocol for levamisole resistance diagnosis in H. contortus populations based on this polymorphism and use it to characterize 23 field H. contortus populations obtained from different localities of Ceara State, Northeast Brazil. In addition, two populations of H. contortus were used as a standard of susceptibility and resistance, Inbred Strain Edinburgh (ISE) and Kokstad, respectively. Larval development tests (LDT) were performed on five field isolates and both EC50 and EC95 were estimated. LDT EC95 values provided a wider interval between susceptible and resistant populations than EC50 values (EC95 = 1.96–57.93 μM; EC50 = 0.05–0.39 μM), and were found to be more appropriate for differentiating them. Real time PCR results showed resistance allele frequencies ranged from 20.9 to 76.7%. Our results suggest that levamisole resistance may be present in field populations but it is not as widespread as benzimidazole resistance. This methodology may be useful to monitor levamisole resistance in field populations of H. contortus. |
| Databáze: | OpenAIRE |
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