Comparative Evaluation of the Regular Ovitrap vs an Innovated Larvitrap for &amp;lt;i&amp;gt;Aedes&amp;lt;/i&amp;gt; Entomological Surveillance in Tapachula

Walter Eduardo Quezada-Yaguachi,Diego Morales-Viteri,Alma D Lopez-Solis,Americo D Rodriguez,Francisco Solís-Santoyo,William C Black Iv,Karla Saavedra-Rodriguez,Patricia Penilla-Navarro

doi:10.4236/ae.2022.101006

Abstract

Objective: The objective is to compare a regular ovitrap versus an innovated larvitrap for monitoring Aedes spp. populations. Materials and Methods: A total of 20 regular ovitraps and 20 innovated larvitraps were placed in pairs in 20 houses from the 5 de Febrero neighborhood in Tapachula, Chiapas, Mexico. The innovation consisted in the incorporation of a valve in the lower part of a half tire to drain the contents in a 2 L collection container. The evaluation was carried out during five weeks, collecting eggs and larvae from the ovitraps and innovated larvitraps, respectively. Positivity indexes and insectary production of adult Aedes spp. mosquitoes were compared by collection type. Results: Average positivity index for the five weeks period were 60% for ovitraps and 91.25% for innovated larvitraps. During the five weeks, 4043 Ae. aegypti and 703 Ae. albopictus adult mosquitoes were produced in the insectary from the eggs collected from ovitraps, while from innovated larvitraps were 9014 Ae. aegypti, 1205 Ae. albopictus, and 15 Culex spp. Conclusion: Collection by the innovated larvitrap was more efficient, collecting 3.56 times more Ae. aegypti than with ovitraps, using approximately the same effort in time for replacing the filter paper from traditional 1 L ovitraps. Since the logistics for the storage and placement of larvitraps may still be a disadvantage in comparison with ovitraps, their use could be specifically intended in sentinel sites for mosquito population monitoring for entomological surveillance purposes.

Highlights

Vector-borne diseases such as dengue, chikungunya and Zika are mainly transmitted by Aedes aegypti and represent an important problem of public health worldwide [1]
The positivity index for eggs for the ovitraps was calculated for each of the five weeks of the study resulting in 75%, 65%, 45%, 55%, and 70%, respectively (Figure 2), with an average of 60% for the five weeks period
The mean of eggs collected by ovitrap (n = 20) ± standard error is shown in Figure 3 for each of the five weeks, with 5707 eggs collected during the study

Summary

Introduction

Vector-borne diseases such as dengue, chikungunya and Zika are mainly transmitted by Aedes aegypti and represent an important problem of public health worldwide [1]. Since no vaccines or specific treatments are available, the use of insecticides is still the major component for the control of each of these diseases. The monitoring of Ae. aegypti populations is vital in the context of epidemiological surveillance including assessing susceptibility/resistance to insecticides, to see the impact of control measures [2]. This surveillance can be done by collecting adult mosquitoes, larvae, or eggs. In the context of insecticide resistance monitoring, the WHO recommends collecting mosquito larvae from the sites of interest to obtain a parental generation from which a first-generation can be used to conduct the bioassays [3]. Different types of larvitraps have been used, such as plastic containers, bamboo internodes, and tires, identifying the tires with the highest abundance of individuals [4]

Methods

Results

Conclusion