Pyriproxyfen, a juvenile hormone analog, damages midgut cells and interferes with behaviors of Aedes aegypti larvae.

Muhammad Fiaz,Luis Carlos Martínez,Paulo Eduardo Gomes Rodrigues Carvalho,Gustavo Ferreira Martins,Jamile Fernanda Silva Cossolin,José Eduardo Serrão,Angelica Plata-Rueda,Wagner Gonzaga Gonçalves,Debora Linhares Lino De Souza

doi:10.7717/peerj.7489

Muhammad Fiaz, Luis Carlos Martínez + Show 7 more

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https://doi.org/10.7717/peerj.7489

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Journal: PeerJ	Publication Date: Sep 4, 2019
Citations: 39	License type: CC BY 4.0

Affiliation: Universidade Federal de Viçosa

Abstract

Juvenile hormone analogs (JHA) are known to interfere with growth and biosynthesis of insects with potential for insecticide action. However, there has been comparatively few data on morphological effects of JHA on insect organs. To determine pyriproxyfen effects on Aedes aegypti larvae, we conducted toxicity, behavioral bioassays and assessed ultrastructural effects of pyriproxyfen on midgut cells. A. aegypti larvae were exposed in aqueous solution of pyriproxyfen LC50 concentrations and evaluated for 24 h. This study fulfilled the toxic prevalence of pyriproxyfen to A. aegypti larvae (LC50 = 8.2 mg L−1). Behavioral observations confirmed that pyriproxyfen treatment significantly changes swimming behavior of larvae, limiting its displacement and speed. The pyriproxyfen causes remarkable histopathological and cytotoxic alterations in the midgut of larvae. Histopathological study reveals presence of cytoplasmic vacuolization and damage to brush border of the digestive cells. The main salient lesions of cytotoxic effects are occurrence of cell debris released into the midgut lumen, cytoplasm rich in lipid droplets, autophagosomes, disorganized microvilli and deformed mitochondria. Data suggest that pyriproxyfen can be used to help to control and eradicate this insect vector.

Highlights

Among the main pathogen vectors in tropical regions, insects share a major part, causing serious diseases resulting in high mortality and economic loss (Sachs & Malaney, 2002; Shepard et al, 2011)
Toxicity Larval mortality of the Aedes aegypti population treated with pyriproxyfen was different from that the control, as expected
Larval mortality increased with pyriproxyfen concentration in the aqueous solution with highest value obtained with 8.20 mg L−1 of this insecticide (Table 1)

Summary

Introduction

Among the main pathogen vectors in tropical regions, insects share a major part, causing serious diseases resulting in high mortality and economic loss (Sachs & Malaney, 2002; Shepard et al, 2011). Mosquitoes are major public health threats which transmit deadly and debilitating diseases throughout the world. Container-inhabiting mosquitoes, Aedes aegypti Linnaeus (Diptera: Culicidae), are considered the most important vector of viral diseases in humans, including dengue fever (Jansen & Beebe, 2010; Rosen et al, 1983), urban yellow fever (Reiter, 2010), Chikungunya (Burt et al, 2012; Paupy et al, 2010) and more recently Zika virus (ZIKV) (Gardner, Chen & Sarkar, 2016; Marcondes & Ximenes, 2016; Thangamani et al, 2016). During the last few years, mosquitoes have been responsible for transmitting ZIKV in Brazil and Colombia with 146,675 recognized cases (World Health Organization, 2015, 2017). There have been strong associations between existence of diseases and distribution of vectors, transmitting them (Carlson, Dougherty & Getz, 2016; Messina et al, 2016)

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