Prevalence and Susceptibility Status of Body Louse (Pediculus humanus humanus) - Anoplura: Pediculidae to Deltamethrin in Urmia City, Iran (2024)

Sep 30, 2026

Background: Body lice spread epidemic typhus and louse-borne relapsing fever and can show resistance to insecticides, while deltamethrin use for infestations exists but evidence on effectiveness against body lice remains limited. Methods: Body lice from an addiction treatment camp in Urmia were exposed in Petri dishes to acetone solutions of deltamethrin across multiple concentrations, and mortality was recorded at 24 hours; LC50 and LC90 were calculated with Minitab and analyzed using SPSS. Results: Concentration correlated with probit mortality; LC50 and LC90 were 0.11 ppm and 2.15 ppm. Conclusions: The population was susceptible, suggesting deltamethrin as an alternative treatment pending further clinical studies.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages10

Reading Time25 min

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Abstract

Background

Methods

Results

Conclusions

Introduction

Epidemiology and clinical concerns

Transmission and risk settings

Control and treatment context

Original Article Prevalence and Susceptibility Status of Body Louse (Pediculus humanushumanus) (Anoplura: Pediculidae) to Deltamethrin in Urmia City, Iran (2024) Samira Firooziyan1,2, Ahmadali Enayati3, Ehsan Rikhtegar4,5, Tahereh Sadat Asgarian6, *Mohammad Mehdi Sedaghat6 1Pathogens and Vectors Research Center, Cellular and Molecular Medicine Research Institute, Urmia University of Medical Sciences, Urmia, Iran 2Department of Medical Entomology and Vector Control, School of Public Health, Urmia University of Medical Sciences, Urmia, Iran 3Department of Medical Entomology and Vector Control, School of Public Health and Health Sciences Research Center, Mazandaran University of Medical Sciences, Sari, Iran 4Department of Internal Medicine, Taleghani Hospital, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran 5Urmia Deputy for Health Affairs, Urmia University of Medical Sciences, Urmia, Iran 6Department of Vector Biology and Control of Diseases, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran *Corresponding author: Dr Mohammad Mehdi Sedaghat, E-mail: [sedaghmm@tums.ac.ir](sedaghmm@tums.ac.ir) (Received 26 Feb 2025; accepted 26 May 2025) Abstract Background: The body louse spreads diseases such as epidemic typhus and louse-borne relapsing fever and has shown resistance to various insecticides. While deltamethrin is used to treat infestations in some countries, research on its effectiveness against body lice is limited. This study assessed the susceptibility of body lice to deltamethrin using a bioassay. Methods: Body lice specimens were collected from an addiction treatment camp in Urmia City, West Azerbaijan Province, Iran. They were treated in 5 cm Petri dishes lined with 1 ml of various concentrations of deltamethrin (0.01, 0.02, 0.04, 0.08, 0.16, 0.32, 0.64, 1.28 , and 2.56 ppm) in acetone. Thirty lice were tested per concentration, with mortality recorded after 24 hours. Lethal concentrations of 50% and 90%(LC 50 and LC90) were calculated using Minitab and compared with SPSS. The regression line was plotted in Excel 2013. Results: A positive correlation was observed between the concentrations of deltamethrin and probit mortality in the regression analysis. The calculated LC50 and LC90 values for deltamethrin against body lice were 0.11 ppm and 2.15 ppm, respectively. Conclusions: These findings suggest that the body lice population was susceptible to deltamethrin, suggesting its potential as an alternative treatment, pending further clinical studies. Keywords: Bioassay; Pediculus humanus; Insecticide resistance; Pyrethroid; Iran Introduction Pediculosis is a common ectoparasitic infestation worldwide. Lice, which are brown or gray wingless insects, have been spread through human migration for thousands of years. They have a soft, relatively leathery, dorsoventrally flattened body. Both males and females can feed at anytime of day or night. Human lice are found in all parts of the world, but more frequently occur in temperate regions. Although improvements in living conditions have reduced the prevalence of body lice (Pediculus humanushumanus) in many societies, infestations remain a global concern (1–3). Body lice are more resilient to environmental conditions than head lice and can survive for over 72 hours off a human host (3, 5, 6) . 173 [http://jad.tums.ac.ir](http://jad.tums.ac.ir) Published Online: June 30, 2025 Copyright © 2025 The Authors. Published by Tehran University of Medical Sciences. This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International license ([https://creativecommons.org/licenses/by](https://creativecommons.org/licenses/by)nc/4 .0/) . Non-commercial uses of the work are permitted, provided the original work is properly cited. Despite advancements in personal care products and hygiene practices, the prevalence of body lice is increasing in developing countries, particular

FAQs

What is the purpose of the study?

To assess the susceptibility of body lice to deltamethrin using a bioassay, producing LC50 and LC90 estimates.

How were the body lice and deltamethrin exposure prepared?

Body lice specimens were collected from an addiction treatment camp in Urmia City and exposed in 5 cm Petri dishes lined with 1 ml of acetone solutions at various deltamethrin concentrations.

What were the key susceptibility results?

A positive concentration–mortality relationship was found, with LC50 and LC90 values of 0.11 ppm and 2.15 ppm, respectively.

Sep 30, 2026

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