Impact of ivermectin components on Anopheles dirus and Anopheles minimus mosquito survival
Issued Date
2024-12-01
Resource Type
eISSN
17563305
Scopus ID
2-s2.0-85193359180
Pubmed ID
38750608
Journal Title
Parasites and Vectors
Volume
17
Issue
1
Rights Holder(s)
SCOPUS
Bibliographic Citation
Parasites and Vectors Vol.17 No.1 (2024)
Suggested Citation
Khemrattrakool P., Hongsuwong T., Tipthara P., Kullasakboonsri R., Phanphoowong T., Sriwichai P., Hanboonkunupakarn B., Jittamala P., Tarning J., Kobylinski K.C. Impact of ivermectin components on Anopheles dirus and Anopheles minimus mosquito survival. Parasites and Vectors Vol.17 No.1 (2024). doi:10.1186/s13071-024-06294-6 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/98449
Title
Impact of ivermectin components on Anopheles dirus and Anopheles minimus mosquito survival
Corresponding Author(s)
Other Contributor(s)
Abstract
Background: Ivermectin mass drug administration to humans or livestock is a potential vector control tool for malaria elimination. Racemic ivermectin is composed of two components, namely a major component (> 80%; ivermectin B1a), which has an ethyl group at C-26, and a minor component (< 20%; ivermectin B1b), which has a methyl group at C-26. There is no difference between the efficacy of ivermectin B1a and ivermectin B1b efficacy in nematodes, but only ivermectin B1b has been reported to be lethal to snails. The ratios of ivermectin B1a and B1b ratios in ivermectin formulations and tablets can vary between manufacturers and batches. The mosquito-lethal effects of ivermectin B1a and ivermectin B1b have never been assessed. As novel ivermectin formulations are being developed for malaria control, it is important that the mosquito-lethal effects of individual ivermectin B1a and ivermectin B1b compounds be evaluated. Methods: Racemic ivermectin, ivermectin B1a or ivermectin B1b, respectively, was mixed with human blood at various concentrations, blood-fed to Anopheles dirus sensu stricto and Anopheles minimus sensu stricto mosquitoes, and mortality was observed for 10 days. The ivermectin B1a and B1b ratios from commercially available racemic ivermectin and marketed tablets were assessed by liquid chromatography-mass spectrometry. Results: The results revealed that neither the lethal concentrations that kills 50% (LC50) nor 90% (LC90) of mosquitoes differed between racemic ivermectin, ivermectin B1a or ivermectin B1b for An. dirus or An. minimus, confirming that the individual ivermectin components have equal mosquito-lethal effects. The relative ratios of ivermectin B1a and B1b derived from sourced racemic ivermectin powder were 98.84% and 1.16%, respectively, and the relative ratios for ivermectin B1a and B1b derived from human oral ivermectin tablets were 98.55% and 1.45%, respectively. Conclusions: The ratio of ivermectin B1a and B1b does not influence the Anopheles mosquito-lethal outcome, an ideal study result as the separation of ivermectin B1a and B1b components at scale is cost prohibitive. Thus, variations in the ratio of ivermectin B1a and B1b between batches and manufacturers, as well as potentially novel formulations for malaria control, should not influence ivermectin mosquito-lethal efficacy. Graphical abstract: (Figure presented.)