Background: The emergence of macrocyclic lactone resistance in canine heartworm poses a substantial threat to what is currently the only effective, FDA-approved available method of prevention. Further study of the biotypes is necessary to understand the mechanism of resistance and evaluate novel prevention options. Identifying cases of drug-resistant infection remains problematic, however, especially when poor compliance and insufficient testing are concerns. Furthermore, a definitive demonstration of resistance requires experimental infection and treatment, which is prohibitively costly.
Methods: With the aim of identifying likely cases of macrocyclic lactone-resistant heartworm and preventing their continued spread, we describe an algorithm for determining the likelihood of drug resistance and appropriate treatment strategies for each case.
Results: This algorithm relies on the microfilarial suppression test (MFST), which has been used previously as an efficient and discrete measure of suspected resistance. By standardizing this method in a format that is readily available to practitioners, it could become possible to preliminarily survey the emergence and spread of resistance.
Conclusion: Heartworm isolates identified through this method can be used in research to better understand macrocyclic lactone resistance so prevention strategies can be adapted.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5688499 | PMC |
| http://dx.doi.org/10.1186/s13071-017-2441-9 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Preventive efficacy of six monthly doses of NexGard® PLUS or Simparica Trio® against a macrocyclic lactone-resistant isolate (JYD-34) of Dirofilaria immitis and of a single dose of NexGard PLUS against a susceptible isolate.
Parasit Vectors
December 2024
Boehringer Ingelheim Vetmedica GmbH, Binger Str. 173, 55216, Ingelheim am Rhein, Germany.
Background: Two studies were conducted assessing the efficacy of NexGard® PLUS (NP) in preventing heartworm disease. Study 1 evaluated the efficacy of six monthly doses of NP or Simparica Trio® (ST) against a macrocyclic lactone-resistant isolate of heartworm, Dirofilaria immitis, and study 2 evaluated the efficacy of a single dose of NP against a susceptible isolate.
Methods: In two studies, dogs that were negative for heartworms by antigen test and modified Knott's test were used.
Differences in constitutive gene expression of cytochrome P450 enzymes and ATP-binding cassette transporter gene expression between a susceptible and a highly macrocyclic lactone-resistant Haemonchus contortus isolate in the absence of drug-inducible expression.
Parasit Vectors
December 2024
Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
Background: Anthelmintic resistance in ruminants is a widespread problem that has a severe impact on productivity and animal welfare. The helminth Haemonchus contortus is generally considered the most important parasite in small ruminants due to its high pathogenicity and the widespread occurrence of anthelmintic resistance in it. Although the molecular mechanisms associated with resistance against the anthelmintics benzimidazoles (BZs) and levamisole are relatively well understood, the resistance mechanisms against the widely used anthelmintic macrocyclic lactones (MLs) ivermectin (IVM) and moxidectin (MOX) remain poorly understood.
View Article and Find Full Text PDFFirst case of macrocyclic lactone-resistant Dirofilaria immitis in Europe - Cause for concern.
Int J Parasitol Drugs Drug Resist
August 2024
Institute of Parasitology, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte Anne-de-Bellevue, QC, H9X3V9, Canada. Electronic address:
Article Synopsis
- Heartworm disease in dogs, caused by the parasite Dirofilaria immitis, is hard to treat but easy to prevent with medications called macrocyclic lactones (MLs).
- A recent case in Rome described a dog that tested positive for heartworms after arriving from the USA, despite treatment with MLs, indicating the presence of a resistant strain.
- Genetic analysis confirmed the dog's infection was caused by a ML-resistant strain, raising concerns about the risk of such strains spreading into Europe and underscoring the need for monitoring dogs from regions known for ML-resistance.
Efficacy of moxidectin, using various dose regimens, against JYD-34, a macrocyclic lactone resistant isolate of Dirofilaria immitis.
Parasit Vectors
April 2024
Boehringer Ingelheim Vetmedica GmbH, Binger Str. 173, 55216, Ingelheim Am Rhein, Germany.
Background: Macrocyclic lactones (MLs) are the only class of drugs currently commercially available that are effective for preventing heartworm disease. The data presented in this article provide information on the efficacy of oral moxidectin against JYD-34, a known ML-resistant Dirofilaria immitis isolate, when dogs are treated under various dosing regimens.
Methods: Fifty-two purpose-bred Beagle dogs were used in five laboratory studies.
The first report of macrocyclic lactone resistant cyathostomins in the UK.
Int J Parasitol Drugs Drug Resist
April 2023
Bristol Veterinary School, University of Bristol, Bristol, BS40 5DU, UK.
In recent years, resistance to the benzimidazole (BZ) and tetrahydropyrimidine (PYR) anthelmintics in global cyathostomin populations, has led to reliance on the macrocyclic lactone drugs (ML-of which ivermectin and moxidectin are licensed in horses) to control these parasites. Recently, the first confirmed case of resistance to both ivermectin (IVM) and moxidectin (MOX) was reported in the USA in yearlings imported from Ireland. This suggests that ML resistance in cyathostomins has emerged, and raises the possibility that regular movement of horses may result in rapid spread of ML resistant cyathostomins.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!