Review
Parasitology
Roger K. Prichard
Summary: Heartworm disease, caused by Dirofilaria immitis and transmitted by mosquitoes, is a lethal disease in dogs and cats. Prevention primarily relies on macrocyclic lactones, with resistance to these drugs being an important issue that requires better testing methods for confirmation and surveillance of resistance levels. Additional research and development of new classes of heartworm preventives are needed to combat the spread of resistance and further disease.
INTERNATIONAL JOURNAL FOR PARASITOLOGY
(2021)
Review
Parasitology
Molly D. Savadelis, Tom L. McTier, Kristina Kryda, Steven J. Maeder, Debra J. Woods
Summary: Heartworm disease remains a significant and pathogenic disease in dogs, despite the regular use of preventive products. Some strains of D. immitis have developed resistance to the only available drug class, macrocyclic lactones (MLs), for heartworm prevention in the United States. The optimization of dose and formulation of moxidectin provides a unique opportunity to improve efficacy against ML-resistant strains. Two new products, ProHeart (R) 12 and Simparica Trio (R), have demonstrated 100% preventive efficacy against recent field strains of heartworm, offering important advances in heartworm prevention for veterinarians and pet owners.
PARASITES & VECTORS
(2022)
Article
Microbiology
Kaetlyn T. Ryan, Nicolas J. Wheeler, Isaac K. Kamara, Hailey Johnson, Judith E. Humphries, Mostafa Zamanian, John D. Chan
Summary: Macrocyclic lactones are commonly used to treat parasitic roundworm infections, but their activity against parasitic flatworms has not been thoroughly studied. Ivermectin, a prototypical macrocyclic lactone, is known to be ineffective against flatworms. However, other macrocyclic lactones may have antiparasitic activity on flatworms. In this study, an automated imaging assay combined with measurement of lactate levels was used to screen 21 macrocyclic lactones against adult schistosomes. Several macrocyclic lactones were identified to cause paralysis and lack of lactate production in vitro, but further testing in mice did not show a reduction in worm burden.
ANTIMICROBIAL AGENTS AND CHEMOTHERAPY
(2023)
Article
Entomology
Larissa Claudino Ferreira, Estefany Ferreira Lima, Ana Luzia Peixoto Silva, Clarisse Silva Menezes Oliveira, Geraldo Moreira Silva Filho, Luana Carneiro Sousa, Guilherme Marcondes Klafke, Thais Ferreira Feitosa, Vinicius Longo Ribeiro Vilela
Summary: The study found that Brazilian populations of cattle ticks exhibited cross-resistance between ivermectin and moxidectin, potentially increasing resistance to moxidectin with regular use of ivermectin, but no cross-resistance was observed with eprinomectin in three populations of ticks.
EXPERIMENTAL AND APPLIED ACAROLOGY
(2022)
Article
Microbiology
Kathryn S. Evans, Janneke Wit, Lewis Stevens, Steffen R. Hahnel, Briana Rodriguez, Grace Park, Mostafa Zamanian, Shannon C. Brady, Ellen Chao, Katherine Introcaso, Robyn E. Tanny, Erik C. Andersen
Summary: Researchers used Caenorhabditis elegans as a model organism to study macrocyclic lactone (ML) resistance, identifying three genomic regions on chromosome V that contribute to natural differences in response to abamectin. Two novel loci were discovered, likely representing new resistance mechanisms. By comparing genes in these new loci to those in the parasitic nematode Haemonchus contortus, potential shared resistance genes between nematode species were identified. Overall, this study highlights the advantages of using C. elegans to understand anthelmintic resistance in parasitic nematodes.
Article
Parasitology
Thomas Geurden, Filip De Keersmaecker, Sofie De Keersmaecker, Edwin Claerebout, Dave M. Leathwick, Martin K. Nielsen, Christian W. Sauermann
Summary: The study evaluated a reduced treatment frequency anthelmintic regimen in horses at two study sites in Belgium over three consecutive summer pasture seasons. It was observed that there was no increase in parasitic disease over the three-year period of the study. Model simulations indicated that a whole-herd treatment regimen with at least 4 macrocyclic lactone treatments annually led to faster resistance development compared to other treatment regimens evaluated.
VETERINARY PARASITOLOGY
(2021)
Article
Agriculture, Dairy & Animal Science
Maria Victoria Miro, Livio Martins Costa-Junior, Mercedes Lloberas, Patricia Cardozo, Carlos Lanusse, Guillermo Virkel, Adrian Lifschitz
Summary: In the past 50 years, the limited incorporation of modern drugs with new mechanisms of action has led to an increase in drug resistance worldwide. Therefore, finding alternative pharmacological tools is a priority in ruminant production systems. Natural products have historically played a relevant role in drug discovery. Although many phytochemicals have shown anthelmintic activity in vitro, their in vivo pharmacological properties have not been extensively explored. This study aimed to evaluate the combined administration of ivermectin and carvone to lambs infected with resistant nematodes and found that innovative pharmaceutical formulations are needed to fully utilize the anthelmintic activity of phytochemicals.
Article
Parasitology
Tom L. McTier, Susan Holzmer, Kristina Kryda, Sean Mahabir, John W. McCall, Jami Trombley, Steven J. Maeder
Summary: ProHeart 12 was more effective in preventing the development of ML-resistant heartworm strain JYD-34 compared to Heartgard Plus and Interceptor Plus in both studies. Heartgard Plus and Interceptor Plus showed lower efficacy with consecutive monthly doses.
PARASITES & VECTORS
(2021)
Article
Parasitology
Jamie A. E. Myers, Susan Holzmer, John W. McCall, Sean P. Mahabir, Tom L. McTier, Steven J. Maeder, Kristina Kryda
Summary: This study compared the efficacy of Simparica Trio with Heartgard Plus and Interceptor Plus in preventing the development of ML-resistant heartworm strain. The results showed that six consecutive monthly doses of Simparica Trio had the highest effectiveness in preventing heartworm development.
PARASITES & VECTORS
(2022)
Article
Chemistry, Analytical
Nilusha Padivitage, Jingzhi Tian, Abu Rustum
Summary: The study aimed to develop and validate a stability-indicating HPLC method for assay and determination of related substances of eprinomectin in bulk batches of eprinomectin API. The newly developed method successfully separated all analytes of interest, and was found to be specific, linear, accurate, precise, robust, and sensitive according to ICH and VICH guidelines.
JOURNAL OF AOAC INTERNATIONAL
(2021)
Article
Biology
Klodeta Kura, Philip Milton, Jonathan I. D. Hamley, Martin Walker, Didier K. Bakajika, Eric M. Kanza, Nicholas O. Opoku, Hayford Howard, Maurice M. Nigo, Sampson Asare, George Olipoh, Simon K. Attah, Germain L. Mambandu, Kambale Kasonia Kennedy, Kambale Kataliko, Mupenzi Mumbere, Christine M. Halleux, Adrian Hopkins, Annette C. Kuesel, Sally Kinrade, Maria-Gloria Basanez
Summary: Epidemiological and modelling studies suggest that annual mass drug administration (MDA) of ivermectin alone may not be enough to eliminate Onchocerca volvulus transmission. Clinical trials have shown that moxidectin is more effective in clearing O. volvulus microfilariae. The EPIONCHO-IBM model predicts that biannual moxidectin MDA can achieve elimination in mesoendemic and hyperendemic areas faster than ivermectin.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
(2023)
Article
Medicine, General & Internal
Cord Sunderkoetter, Johannes Wohlrab, Henning Hamm
Summary: Scabies is a skin infestation with symptoms including burrows, intense pruritus, and dermatitis. Treatment options range from topical permethrin to systemic ivermectin, with combination therapy used for challenging cases. Failure of treatment can be due to various factors, and new treatments like moxidectin are being explored. Following treatment guidelines can lead to effective resolution of scabies.
DEUTSCHES ARZTEBLATT INTERNATIONAL
(2021)
Article
Microbiology
Nilima Dinesh Kumar, Bram M. ter Ellen, Ellen M. Bouma, Berit Troost, Denise P. van de Pol, Heidi H. van der Ende-Metselaar, Djoke van Gosliga, Leonie Apperloo, Orestes A. Carpaij, Maarten van den Berge, Martijn C. Nawijn, Ymkje Stienstra, Izabela A. Rodenhuis-Zybert, Jolanda M. Smit
Summary: Antiviral therapies, particularly for severe COVID-19, are urgently needed. Ivermectin has shown anti-SARS-CoV-2 activity in Vero cells, but its in vivo concentration may be too low. This study compares the antiviral activity of ivermectin and moxidectin in multiple in vitro models, finding that both drugs are effective in Vero E6 cells but fail to inhibit SARS-CoV-2 infection in human-airway-derived cell models. These results caution against relying solely on Vero cell activity in assessing anti-SARS-CoV-2 efficacy.
ANTIMICROBIAL AGENTS AND CHEMOTHERAPY
(2022)
Article
Cell Biology
Stephen R. Doyle, Roz Laing, David Bartley, Alison Morrison, Nancy Holroyd, Kirsty Maitland, Alistair Antonopoulos, Umer Chaudhry, Ilona Flis, Sue Howell, Jennifer McIntyre, John S. Gilleard, Andy Tait, Barbara Mable, Ray Kaplan, Neil Sargison, Collette Britton, Matthew Berriman, Eileen Devaney, James A. Cotton
Summary: Understanding the genetic basis of anthelmintic drug resistance in parasitic nematodes is crucial for improving parasite control. By using an in vivo genetic cross, this study successfully mapped resistance loci for three major classes of anthelmintics and identified new alleles for resistance. The study also implicated a transcription factor in ivermectin resistance and demonstrated the feasibility of high-resolution forward genetics in parasitic nematodes.
Review
Veterinary Sciences
Jaskaran Bains, Scott Carver, Susan Hua
Summary: Sarcoptic mange is a serious parasitic infection in wombats that can potentially be treated through transdermal drug delivery. This review discusses the physiological impact of sarcoptic mange on wombats, the commonly used antiparasitic drugs, and the prospects for improving drug absorption.
FRONTIERS IN VETERINARY SCIENCE
(2022)