Screening of Wolbachia Endosymbiont Infection in Aedes aegypti Mosquitoes Using Attenuated Total Reflection Mid-Infrared Spectroscopy

Abstract

Dengue fever is the most common mosquito transmitted viral infection afflicting humans, estimated to generate around 390 million infections each year in over 100 countries. The introduction of the endosymbiotic bacterium Wolbachia into Aedes aegypti mosquitoes has the potential to greatly reduce the public health burden of the disease. This approach requires extensive polymerase chain reaction (PCR) testing of the Wolbachia-infection status of mosquitoes in areas where Wolbachia-A. aegypti are released. Here, we report the first example of small organism mid-infrared spectroscopy where we have applied attenuated total reflection Fourier transform infrared (ATR-FT-IR) spectroscopy and multivariate modeling methods to determine sex, age, and the presence of Wolbachia (wMel strain) in laboratory mosquitoes and sex and age in field mosquitoes. The prediction errors using partial least squares discriminant analysis (PLS-DA) discrimination models for laboratory studies on independent test sets ranged from 0 to 3% for age and sex grading and 3% to 5% for Wolbachia infection diagnosis using dry mosquito abdomens while field study results using an artificial neural network yielded a 10% error. The application of FT-IR analysis is inexpensive, easy to use, and portable and shows significant potential to replace the reliance on more expensive and laborious PCR assays.

Direct nucleic acid analysis of mosquitoes for high fidelity species identification and detection of Wolbachia using a cellphone

“…Morphological identification methods are inherently low throughput, require extensive technical expertise, and cannot also readily identify pathogens or biocontrol agents such as Wolbachia . Spectroscopy, such as near infrared spectroscopy [ 61 ] and Fourier transform infrared spectroscopy [ 62 ], allow identification of mosquito species, Wolbachia , and pathogens, but require expensive instruments and expertise that are generally incompatible with low-resource settings. Immunoassays can detect pathogen-carrying vectors but are insensitive and cannot also identify vector species.…”

Dsi-RNA knockdown of genes regulated by Foxo reduces glycogen and lipid accumulations in diapausing Culex pipiens

“…In this study, the effects of three candidate genes knockdown on glucose metabolism were characterized using a combined 13 C solid-state nuclear magnetic resonance (NMR) and attenuated total reflection Fouriertransform infrared spectroscopy (ATR-FTIR) methods. Solid-state NMR is a powerful technique that enables a direct measure of chemical compositions of intact whole cells [8][9][10] and entire organisms 11,12 .…”

Prediction of malaria mosquito species and population age structure using mid-infrared spectroscopy and supervised machine learning

“…For example, in the dengue and Zika vector Ae-des aegypti mosquitoes, infrared spectroscopy has recently been developed to detect Zika virus, 39 and the bacterial endosymbiont Wolbachia. 43,50 The accuracy and generalisability of the MIRS approach presented here to determine key mosquito traits shows that this tool can be used to assist the evaluation of vector control intervention in large mosquito populations. The inclusion of new species, larger sample sizes and field samples with variable ecological conditions is a prerequisite for the application of this technique.…”

“…42 Mid-infrared spectroscopy (MIRS) has therefore several advantages for this application since it allows the capture of contributions of different biochemical components to the spectrum and their variations among mosquitoes with different attributes. 43,44 However, since the mid-infrared spectral bands are affected in non-trivial ways by the development of a mosquito and the changing composition of the cuticle, it is not possible to predict traits by simply monitoring changes in band intensities. 45 Here, we show that the use of supervised machine learning 46 allows the determination of the age and species of two major malaria vectors, An.…”