Date Published: January 06, 2018
Publisher: The American Society of Tropical Medicine and Hygiene
Author(s): Rachel Curtis-Robles, Sarah A. Hamer, Sage Lane, Michael Z. Levy, Gabriel L. Hamer.
Defining spatial and temporal occurrences of triatomine vectors of Trypanosoma cruzi, the agent of Chagas disease, in the US is critical for public health protection. Through a citizen science program and field collections from 2012 to 2016, we collected 3,215 triatomines, mainly from Texas. Using morphological and molecular approaches, we identified seven Triatoma species and report sex, length, and blood engorgement status. Many citizen-collected triatomines (92.9%) were encountered indoors, in peridomestic settings, or in dog kennels and represent spillover transmission risk of T. cruzi to humans and domestic animals. The most commonly collected species were Triatoma gerstaeckeri and Triatoma sanguisuga. Adult T. gerstaeckeri were collected from May to September, peaking from June to July, whereas adult T. sanguisuga were active later, from June to October, peaking from July to September. Based on cross correlation analyses, peaks of captures varied by species and across years. Point pattern analyses revealed unique occurrences of T. sanguisuga in north and east Texas, T. gerstaeckeri in south and west Texas, Triatoma indictiva and Triatoma lecticularia in central Texas, and Triatoma rubida in west Texas. These relatively unique spatial occurrences suggest associations with different suitable habitats and serve as a basis for future models evaluating the ecological niches of different vector species. Understanding the temporal and spatial heterogeneity of triatomines in the southern United States will improve targeted interventions of vector control and will guide public outreach and education to reduce human and animal contact with vectors and reduce the risk of exposure to T. cruzi.
Triatomine insects (Reduviidae: Triatomine) are vectors of Trypanosoma cruzi, the protozoan parasite responsible for Chagas disease in over 5.7 million people throughout the Americas.1 Triatomines are obligatory hematophagous arthropods and become infected with T. cruzi when blood feeding on infected mammalian hosts. The parasite replicates in the gut of the insect, and the insect passes the parasite through fecal material. The study of these vectors has been key to public health initiatives aimed at reducing risk of Chagas disease.
Although Chagas disease is increasingly recognized as a disease of human and veterinary significance in the southern United States, there have been relatively few studies of the phenology and spatial patterns of triatomine vectors in the United States. We established a collection of 3,215 triatomines, mainly from Texas, to examine unique phenological and spatial patterns.