QLS Guest Seminar - Thu. 14 June at 11:00

[Quantitative Life Sciences]

QUANTITATIVE LIFE SCIENCES  GUEST SEMINAR

Thursday, 14 June 2018 at 11:00,
ICTP, Central Area, 2nd floor, old SISSA building, via Beirut 2


Speaker: Stéphanie Depickère, Medical Entomology UMSA - IRD - INLASA La 
Paz, Bolivia

Title: Vectors of Chagas disease: determination of species by infrared 
spectroscopy and machine learning

Abstract:
Chagas disease, caused by the parasite Trypanosoma cruzi, is widespread 
in Latin America, where the disease remains one of the major public 
health problems, with an estimation of 8 million infected people and 10 
000 deaths per year. This condition is mostly transmitted by insects, 
known as kissing bugs, belonging to the Triatominae family (Hemiptera), 
which are obligate haematophagous insects all their life. More than 150 
species have been described in the world. While the majority lives in 
the wild, some of them are highly associated to the human beings, living 
in or around the dwellings. They typically stay hidden in the wall or 
roof cracks of homes, going out at night to feed on human blood. The 
correct determination of the species involved in the transmission of the 
disease is crucial to develop efficient control strategies. This can be 
achieved by keys of determination for adult stages, or by molecular 
technics. Both technics are time and/ or money consuming, showing the 
needs of new identification methods, especially for nymphal instars. 
These last years, various publications demonstrated the potential of 
infrared spectroscopy in insect taxonomy. Bolivia is a highly endemic 
country for Chagas disease. The main vector, Triatoma infestans, lives 
on about 60% of the territory. In total, 17 species of triatomines are 
reported in the country, among them Triatoma sordida and Triatoma 
guasayana which are reported as secondary vectors. These two species are 
sympatric and morphologically similar, and so they are difficult to 
discriminate. The goal of this study was to develop a classification 
model, using living nymphal and adult stage of these three species. 1293 
spectra were taken in the invisible and near-infrared range. Different 
models were built, using different pre-processing methodologies of the 
spectra, and different types of feature selection. The performance of 
each model was evaluated for each species. After their comparison, the 
best model was tested on a different set of specimens where it showed a 
global accuracy of 97% (95-99%), an F1 score greater than 0.95 and a 
specificity greater than 0.94. This result shows that using infrared 
spectroscopy is a good strategy to predict the triatomine species. It is 
the first investigation to report the ability to identify juvenile 
instars, and moreover with a single model together with the adult stage.

Indico web page: http://indico.ictp.it/event/8607/

Everyone interested is most welcome to attend!

-- 
Erica Sarnataro
Group Secretary
Quantitative Life Sciences
The Abdus Salam International Centre for Theoretical Physics (ICTP)
Trieste,  Italy
Tel. +39-040-2240623
www.ictp.it/research/qls.aspx
e-mail: qls at ictp.it