A Beauveria bassiana-based “trap and kill” device to control de major Chagas disease vector in southern South America

N. PEDRINI; J.R. GIROTTI; M.P. JUÁREZ

Park City, Utah, USA

Congreso; 42nd Annual Meeting of the Society for Invertebrate Pathology; 2009

Society for Invertebrate Pathology

Chagas disease is the most relevant parasitic disease in Latin America, being a major burden that affects mostly poor human populations living in rural areas, with current estimates of ~10 million people infected and ~40 million at risk. The parasite Trypanosoma cruzi is mainly transmitted through blood-feeding triatomine bugs. Current strategies to control Triatoma infestans, based on residual chemical insecticide application, are threatened by the emergence of pyrethroid-resistance. Among alternative control tools, we investigated the potential of the entomopathogenic fungus Beauveria bassiana in the field. We designed a “trap and kill” device based on manipulating T. infestans behavior in order to facilitate close contact with a virulent strain of B. bassiana. The device consisted in a box containing a CO2 source, a known blood-sucking insect attractant, combined with a powder formulation of B. bassiana conidia and diatomaceous earth. The trap was tested in field assays performed in 9 houses from two rural villages in the Argentina/Bolivia border infested with pyrethroid-resistant insects. After one intervention, more than 50% of the collected bugs were killed by fungal infection. Based on available T. infestans population models, we estimated the impact of the bioinsecticide performance in reducing the risk of acquiring the parasite infection. The potential T. cruzi transmission risk index, defined as the maximum number of risky bites a human can receive per night, was estimated to drop from 5.2 to 2.4. According to this model, a second bioinsecticide application is expected to reduce the infection risk to 0.88 bites per human per night, and further decline thereafter. This approach might also prove useful at different settings, e.g. peridomiciliary environments where current tactics and procedures are reported to fail, and rural communities located in remote areas inaccessible to sanitary control teams. These results might help to provide a safe and efficient alternative to overcome bug pyrethroid-resilience, and might be useful to control other Chagas disease vectors as well.