Combining Public Health Education and Disease Ecology Research: Using Citizen Science to Assess Chagas Disease Entomological Risk in Texas

Abstract

Background: Chagas disease is a zoonotic parasitic disease well-documented throughout the Americas and transmitted primarily by triatomine 'kissing bug' vectors. In acknowledgment of the successful history of vector control programs based on community participation across Latin America, we used a citizen science approach to gain novel insight into the geographic distribution, seasonal activity, and Trypanosoma cruzi infection prevalence of kissing bugs in Texas while empowering the public with information about Chagas disease.

Methodology/principal findings: We accepted submissions of kissing bugs encountered by the public in Texas and other states from 2013-2014 while providing educational literature about Chagas disease. In the laboratory, kissing bugs were identified to species, dissected, and tested for T. cruzi infection. A total of 1,980 triatomines were submitted to the program comprised of at least seven species, of which T. gerstaeckeri and T. sanguisuga were the most abundant (85.7% of submissions). Triatomines were most commonly collected from dog kennels and outdoor patios; Overall, 10.5% of triatomines were collected from inside the home. Triatomines were submitted from across Texas, including many counties which were not previously known to harbor kissing bugs. Kissing bugs were captured primarily throughout April-October, and peak activity occurred in June-July. Emails to our dedicated account regarding kissing bugs were more frequent in the summer months (June-August) than the rest of the year. We detected T. cruzi in 63.3% of tested bugs.

Conclusions/significance: Citizen science is an efficient approach for generating data on the distribution, phenology, and infection prevalence of kissing bugs-vectors of the Chagas disease parasite-while educating the public and medical community.

Fig 1. Three species of kissing bugs commonly found in Texas.

(Left to right) Triatoma protracta, the most common species in the western U.S.; Triatoma gerstaeckeri, the most common species in Texas; Triatoma sanguisuga, the most common species in the eastern U.S. Scale bar represents 25mm or approximately 1 inch.

Fig 2. Historical and current collections from across Texas.

A) States from which our program received kissing bugs in 2013–2014 overlaid on historical state-level records of kissing bugs throughout the U.S. [5,29]; B) Historical county-level records of kissing bugs in Texas (1928–2006, as from [11]) and submissions of kissing bugs through our citizen science program (2013–2014).

Fig 3. Kissing bug collection phenology.

Seasonal occurrence of the collection of kissing bugs by citizens, 2013–2014.

Fig 4. Email activity.

Number of daily emails to kissingbug@cvm.tamu.edu from the public, 2014. Peaks generally correspond with a media event featuring Chagas disease and/or kissing bugs: A) July 17/18, Amarillo, Texas newscast and National Public Radio website article; B) July 24, articles about Chagas disease in Virginia; C) July 27, USA Today online article; D) August 2, Arkansas newscast; E) August 11, Cat Channel online article; F) August 18, Lubbock, Texas newscast. The regular pattern of decreasing and increasing activity (most noticeable throughout September) corresponds with weekends and weekdays, respectively.

Fig 5. Key features of non-kissing bugs.

Key morphologic features distinguish similar-looking insects: (A) Gray color and dorsal crest of wheel bugs (Arilus cristatus) (B) Wide, flattened back legs of leaf-footed bugs (Leptoglossus sp.) (C) Short head of squash bugs (Mozena sp.) (D) Close view of mouthparts of a kissing bug (left; thin and straight) and non-kissing bug (right; thick and curved); Photos courtesy of M. Merchant (A), P. Porter (B, C), and R. Bardin (D).