Occurrence and distribution of Panstrongylus megistus (Burmeister, 1835) (Hemiptera, Reduviidae) in a metropolitan area of Southern Brazil

Abstract

Two triatomine genera ( Panstrongylus and Triatoma ) have essentially been recorded in Rio Grande do Sul State, Brazil. Panstrongylus megistus should be highlighted since this species is one of the main vectors of Trypanosoma cruzi in Brazil, due to its wide geographical distribution and the high susceptibility to this protozoan. This study aimed to present not only the occurrence and distribution of P. megistus in the Porto Alegre city’s metropolitan area (PAMA), Rio Grande do Sul State, Brazil, but also the rates of T. cruzi infection, from 2009 to 2020. The PAMA, which comprises 34 cities and 4.4 million habitants, extends across the transition area in two biomes – Pampa and Mata Atlantica – found in the state. Results showed that P. megistus was recorded in 76.5% of cities (i.e., 26 out of 34), mainly in Porto Alegre city, where the vector was found in 11 out of the 12 years that were monitored. Three hundred and nineteen specimens were captured. Two hundred and sixty-seven specimens (83.7%) were located intradomicile (p < 0.0001), while 52.3% positivity for T. cruzi was found. Thus, P. megistus is important in the PAMA, because it invades and colonizes the households. Moreover, the high rates of T. cruzi infection have drawn attention.

The risk of vector transmission of Trypanosoma cruzi remains high in the State of Paraná

“…23 The data demonstrate that P. megistus , despite being considered wild in southern Brazil, has been showing domestic characteristics for some time. 50 , 51 , 52 , 53 In Paraná, according to the data presented, several colonies were found with a high number of nymphs demonstrating this domiciliation in the Southern region of Brazil. Since this species has greater vectorial capacity and greater ability to form intradomiciliary colonies, a higher proportion of specimens of this species infected with T. cruzi increases the risk of transmission of the protozoan.…”