The Benefit of a Single Oral Dose of Ivermectin in Humans: The Adverse Effects on Cimex lectularius L. Populations and Fecundity

Abstract

To measure the population size and fecundity of the common bed bug Cimex lectularius L. (C. lectularius) after feeding it with the blood obtained from human subjects who have consumed a single dose of ivermectin. Methods Serial blood samples were obtained from two human subjects at hour 0 (control) and 4-96 hours after they received a single 0.2 mg/kg dose of ivermectin. The blood samples were then fed to 2,273 bed bugs. Bed bug incapacitation rates, fecundity, and population sizes were recorded over a 54-day period. Whole blood ivermectin levels were measured in the human subjects and the insects. Results The fold change in the size of the control group population over the course of the experiment was found to be 2.16. This was significantly greater (p: <.001) than for all the post-ivermectin feeding groups (range:-11.04-1.43). Two weeks after the experiment, the number of eggs laid per live adult female bed bug per day was 10.74 for controls, which was significantly different (p: <0.001) compared to all the post-ivermectin feeding groups (range: 0-4.28). Conclusions There were significant reductions in C. lectularius population size and fecundity in insects that fed on blood obtained from human study subjects up to 96 hours after they have consumed a single oral dose of ivermectin.

Ivermectin and Moxidectin Can Incapacitate Different Strains of the Common Bed Bug Cimex lectularius L.: A Study

“…This study had several limitations; ivermectin and moxidectin were diluted in DMSO and added to blood samples and fed to the insects in the laboratory in our study. When administered in vivo, ivermectin has metabolites that are toxic to bed bugs, which could not be detected in our experiments [6,10]. Mortality in our control groups was higher than what would be expected from feeding bed bugs and may represent some DMSO toxicity [8].…”

“…Laboratory strains of bed bugs were used and pyrethroid-resistance could have waned over time without repeated exposure to pyrethroids. Lastly, all the life stages of the bed bugs were not recorded; so we were unable to ascertain from these experiments if ivermectin and moxidectin adversely affected all life stages similarly; however, this has been examined previously [5,7,[9][10].…”

“…Ivermectin is administered to about 250 million people annually, mostly as part of mass drug administration programs in developing countries [3]. The antiparasitic drugs ivermectin and moxidectin have limited human toxicity at therapeutic doses, and both have been shown to kill bed bugs that consume blood meals spiked with these drugs in a dose-dependent manner [4][5][6][7][8][9][10]. Bed bugs that survive blood meals containing ivermectin or moxidectin suffer long-term harm including reduced fecundity, inhibition of nymphal molting, delays in blood meal digestion, and reduced locomotion [5][6][7][8][9][10].…”

“…The antiparasitic drugs ivermectin and moxidectin have limited human toxicity at therapeutic doses, and both have been shown to kill bed bugs that consume blood meals spiked with these drugs in a dose-dependent manner [4][5][6][7][8][9][10]. Bed bugs that survive blood meals containing ivermectin or moxidectin suffer long-term harm including reduced fecundity, inhibition of nymphal molting, delays in blood meal digestion, and reduced locomotion [5][6][7][8][9][10]. However, previous research on ivermectin has involved laboratory-adapted bed bugs with an unknown sensitivity to the pyrethroids and neonicotinoids; and there has only been one study using moxidectin and the Irvington stain, which is known to have moderate resistance to pyrethroids [6][7][8].…”

“…Ivermectin is known to act at the invertebrate glutamate-gated chloride channel, causing nerve and muscle hyperpolarization [12]. The pharmacotoxicity of a sublethal dose of ivermectin against C. lectularius is unknown but could be multifactorial including the persistence of ivermectin in the insect, changes in gene expression, or damage to C. lectularius organs [6][7][8][9][10]. Therefore, an additional objective was to quantify ivermectin levels in fed bed bugs.…”