RESUMO
In Brazil, orally acquired T. cruzi infection has become the most relevant transmission mechanisms from public health perspective. Around 70% of new Chagas disease cases have been associated with consumption of contaminated food or beverages. Açai (Euterpe oleracea and Euterpe precatoria) is currently one of the most commercialized Amazonian fruits in the Brazilian and international markets. Therefore, it has become important to incorporate in the production process some procedures to measure out effective hygiene and product quality control required by global market. Molecular methods have been developed for rapid detection and quantification of T. cruzi DNA in several biological samples, including food matrices, for epidemiological investigation of Chagas disease and food quality control. However, a high-performance molecular methodology since DNA extraction until detection and quantification of T. cruzi DNA in açai berry pulp is still needed. Herein, a simple DNA extraction methodology was standardized from the supernatant of açai berry pulp stabilized in a 6M Guanidine-HCl/0.2M EDTA buffer. In addition, a multiplex real time qPCR assay, targeting T. cruzi DNA and an Exogenous Internal Positive Control was developed and validated, using reference from all T. cruzi DTUs and commercial samples of açai pulp, from an endemic municipality with previous history of oral Chagas disease outbreak. Thus, a high-sensitivity qPCR assay, that could detect up to 0.01 parasite equivalents/mL in açai, was reached. As of the 45 commercial samples analyzed, 9 (20%) were positive for T. cruzi. This high-sensitive, fast, and easy-to-use molecular assay is compatible with most of the laboratories involved in the investigations of oral Chagas disease outbreaks, representing an important tool to the epidemiology, control, and surveillance of Chagas disease.
Assuntos
Doença de Chagas/parasitologia , Euterpe/parasitologia , Reação em Cadeia da Polimerase Multiplex/métodos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Trypanosoma cruzi/genética , Brasil/epidemiologia , Doença de Chagas/epidemiologia , DNA/análise , DNA/genética , Humanos , Limite de Detecção , Trypanosoma cruzi/isolamento & purificaçãoRESUMO
Background: Triatomines are responsible for the vector transmission of the protozoan parasite Trypanosoma cruzi, which causes Chagas disease. Triatoma brasiliensis is the main vector of the parasite in Brazil, and dogs are an important reservoir of the parasite. The aim of this study was to evaluate the insecticidal efect of furalaner (Bravecto®) on T. brasiliensis after a blood meal in treated dogs. Methods: Healthy mongrel dogs (n=8) were recruited from the Zoonoses Control Center (ZCC) in the city of Natal, Rio Grande do Norte, Brazil, and randomized into two groups, a furalaner (Bravecto®)-treated group (n=4) and a control group (n=4). Colony-reared third-, fourth- and ffth-instar nymphs of T. brasiliensis nymphs (n=10) were allowed to feed on dogs from both groups for 3040 min, once monthly, for up to 12 months. Bug mortality was observed up to 5 days after each blood meal. Results: Mortality in triatomines which had a blood meal on furalaner (Bravecto®)-treated dogs was 100% for up to 7 months after treatment, with mortality decreasing to 66.4% after 8 months, 57% after 9 months, 35% after 10 months, 10% after 11 months and 0% after 12 months. The mortality of triatomines that fed on non-treated control dogs was always ≤ 2.5%. Conclusions: Our results suggest that furalaner (Bravecto®) treatment of dogs induces long-term mortality of T. brasiliensis after the blood meal. This is a potential approach to be used to control vector transmission of T. cruzi, the etiological agent of Chagas disease, especially in endemic areas.