Population dynamics of Triatoma vitticeps (Stål, 1859) in Itanhomi, Minas Gerais, Brazil

Abstract

(Galvão et al. 2003, Galvão & Angulo 2006, Costa et al. 2006, Costa & Felix 2007, Sandoval et al. 2007, Bérenger & Blanchet 2007, Martinez et al. 2007) and is a vector of Trypanosoma cruzi. Its geographical distribution is limited to the Brazilian states of Bahia, Espírito Santo, Minas Gerais (MG), and Rio de Janeiro (Galvão et al. 2003). Although considered to be of secondary importance in T. cruzi transmission to man, this species shows high rates of trypanosome infection (Santos et al. 1969a,c, Pinto et al. 1969, Barros et al. 1975, Sessa & Carias 1986, Dias et al. 1989, Gonçalves et al. 1998, Santos et al. 2005 and is often captured in man-made habitats, with frequent reports of adult bugs invading houses (Santos et al. 1969b, Ferreira et al. 1986, Sessa & Carias 1986, Dias et al. 1989, Gonçalves et al. 1998, possibly attracted by light (Ferreira et al. 1986 to T. cruzi are very high, especially in adult bugs captured indoors in Itahomi. However, Chagas disease is rare in the area, a prevalence of only 0.4% has been recorded as part of a national serological survey (Camargo et al. 1984). It is not known whether the low transmission of T. cruzi to man is due to characteristics of the vector (the long interval between feeding and defecation) or the strain of parasite involved.Among the available taxonomic marker techniques, morphometry of the head, random amplified polymorphism of DNA (RAPD) and isoenzyme analysis have been most used in triatomine population studies (Costa et al. 1997, Dujardin et al. 1998, Borges et al. 2000, Soares et al. 2001, Barbosa et al 2003. We used these three techniques to investigate T. vitticeps population dynamics in the Itanhomi district. MATERIALS AND METHODSStudy area -Itanhomi (19°11'15"S, 41°48'45"W) has an estimated population of 11,012 inhabitants. The urban and rural area comprise 93 localities. In 11 of the rural sites (Adão Daniel, Cabeceira do Guido, Francisco Inácio, Jesus Julião, Jose Horta, Jose Noberto, João Caboclo, Júlio Carlos, Liés Alves, Orides I, and Valico) the search for T. vitticeps was intensively performed in 2002 in domestic and peridomestic environments. The following year, sylvatic sampling was attempted in Cabeceira do Guido, particularly in a wooded area 100 m from a house where adult triatomines are periodically detected.Houses in Itanhomi in which T. vitticeps was sampled conform to a distinct pattern of construction, being built on stilts.The floors of these dwellings are wooden 15 Mem Inst Oswaldo Cruz, Rio de Janeiro, Vol. 103(1), February 2008 and often have cracks that allow triatomines to pass in and out; the floor is a kind of roof for the open basement (classified as the peridomicile). Houses are built on stilt, providing shelter for domestic animals and storage of materials. Furthermore, 100-500 m from the houses there are remnants of Atlantic forest and rocks, constituting sylvatic habitat for the bugs. This peculiar characteristic of the locality is the proximity of the habitats.Insects -A pool of T. vitticeps captured in Itanhomi ...

Biology, diversity and strategies for the monitoring and control of triatomines - Chagas disease vectors

“…Today, field data have shown that the following sylvatic species are frequently found in domiciliary and peridomiciliary areas: Triatoma vitticeps (Stål, 1859), Triatoma rubrovaria (Blanchard, 1843) and Panstrongylus lutzi (Neiva & Pinto, 1923) (Gonçalves et al 1998, Almeida et al 2000, Freitas et al 2004, Souza et al 2008, among others. More recently, Triatoma sherlocki Papa, Jurberg, Carcavallo, Cerqueira & Barata 2002 was captured in Gentio do Ouro, in the north central part of BA, colonising human dwellings (Almeida et al 2009, unpublished observations).…”

Evaluation of the Chagas Disease Control Program in Açucena Municipality, Rio Doce Valley, State of Minas Gerais, Brazil

“…The high rate of positivity for T. cruzi fl agellates was similar to what has been described in other areas where this species is present. Several studies have demonstrated the high dispersion capacity of T. vitticeps, primarily in the States of Espírito Santo, Minas Gerais, Rio de Janeiro and Bahia [22][23][24] . Other authors have confi rmed high rates of natural infection with T. cruzi, with a rate of positivity between 25% and 65% of insects examined [24][25][26][27] .…”

“…Several studies have demonstrated the high dispersion capacity of T. vitticeps, primarily in the States of Espírito Santo, Minas Gerais, Rio de Janeiro and Bahia [22][23][24] . Other authors have confi rmed high rates of natural infection with T. cruzi, with a rate of positivity between 25% and 65% of insects examined [24][25][26][27] . Curiously, in the State of Espírito Santo where the frequency of T. vitticeps and positivity for T. cruzi is higher in rural dwellings, the prevalence of Chagas disease is low and limited to autochthonous cases of transmission by this species 28 .…”

“…In the entomological evaluation conducted by the Ministry of Health in 1982, three vector species were predominantly detected: 1) Triatoma sordida with 57.5% prevalence, 1.2% positivity for T. cruzi and present in 10.7% of intradomiciliary captures; 2) Panstrongylus megistus with 27% prevalence, 1.9% positivity and present in 24 In 2000, the responsibility for health-related activities, including vector control, was transferred to the municipalities 8 . Consequently, there were considerable failures in the CDCP because the municipalities were not prepared to assume such responsibilities, and the program resumed its activities in 2005.…”

Feeding behavior of Triatoma vitticeps (Reduviidae: Triatominae) in the state of Minas Gerais, Brazil

“…106(1): 16-22, February 2011 Triatoma vitticeps is a triatominae species found in the Brazilian states of Espírito Santo (ES), Minas Gerais (MG), Rio de Janeiro (RJ) and the southernmost regions of Bahia (Lent & Wygodzinsky 1979, Silveira et al 1984. Studies carried out on T. vitticeps populations in ES, RJ and MG demonstrated the capacity of this triatomine to invade houses (Santos et al 1969c, Ferreira et al 1986, Sessa & Carias 1986, Dias et al 1989, Gonçalves et al 1998, Souza et al 2008. Similarly, these invasive insects were always highly infected with flagellates similar to Trypanosoma cruzi (Pinto et al 1969, Santos et al 1969a, b, Barros et al 1975, Sessa & Carias 1986, Dias et al 1989, Gonçalves et al 1998, dos Santos et al 2005.…”