Submitted by Eraldo Medeiros Costa Neto* and Rodrigo Gurgel Gonçalves1

The American trypanosomiasis, or Chagas disease, is an endemic zoonosis in the Americas and its etiologic agent is the haemoflagellate parasite Trypanosoma cruzi, which is transmitted by feces of blood-sucking insects of the subfamily Triatominae (Hemiptera, Reduviidae). The total prevalence of Chagas disease was reduced from >16 million to 8 million people, estimated in 2005 (Rassi Júnior et al., 2010), and numbers of deaths were also reduced drastically (Moncayo and Silveira, 2009).

Collecting of triatomines inside the houses and surroundings

In 2006, the Intergovernmental Initiative of Southern Cone, OMS, certified Brazil as free of vectorial transmission by Triatoma infestans (Schofield at al., 2006; Silveira and Dias, 2011). In Brazil, the current estimate is that 1.9 million people are infected (Rassi Júnior et al., 2010), much lower than the 6 million estimated in the 1980s (WHO 2002).

Nevertheless, acute disease human cases caused by vectorial transmission are still being registered and triatomines continue infesting homes in different states of Brazil (Gurgel-Gonçalves et al. 2012).

There are few available studies about local perceptions concerning Chagas disease in Brazil. Studies on popular representation of this disease and about triatomines in Mambaí-GO (Bizerra et al., 1981; Silveira et al. 2009), Posse-GO (Willians-Blangero et al., 1999) and Federal District (Maeda and Gurgel-Gonçalves 2012) showed that the majority of the population had a high degree of knowledge on the subject.

In a study conducted in Guatemala, on the other hand, 11% of the seropositive did not recognize both the signs and symptoms of Chagas disease (Nix et al., 1995). These authors suggest that the success or failure of the control of this disease in the Americas depends on the participation of the local population in detecting the vectors (blood-sucking bugs) and notify government authorities responsible for the application of insecticides.

These cultural representations on Chagas disease and its vectors may have a significant impact on the effectiveness of interventions, since local beliefs about the cause of the disease should be evaluated to determine whether education programs in public health are effective to ensure a better form of control.

A recent review indicates that an entomological surveillance system based on community participation requires specific actions for communication and education in long-term health (Abad-Franch et al., 2011).

Actions designed for individuals seeking health promotion should be directed to their habits, behaviors and social practices. The process of detecting triatomines with the participation of the population means continued vigilance, compared to routine activities performed by field staff from the Health Ministry (Falavigna-Guilherme et al., 2002).

For this reason, this project aimed at recording the perception of residents of different localities in Bahia State, Brazil, on the identification, biology, and control of insects, and also how they view Chagas disease.

Ethnobiological survey

Methodology
The ethnobiological data were obtained by means of open-ended interviews performed from March 2011 to July 2012 with both men and women from rural areas of 12 municipalities within Bahia States: Alagoinhas, Vitória da Conquista, Feira de Santana, Barra, Ipirá, São Félix, Santo Estevão, Cruz das Almas, Santa Teresinha, Santo Amaro, Conceição do Coité, and Tremedal.

A free and informed consent form was read out and made available to those who participated in the study. The aims of the research were explained clearly at the beginning of each interview and those involved were asked whether they would like to participate in the study.

Data were analyzed using the union model. According to this model, all available information on the surveyed subject is to be considered. Controls were done both through consistency checking tests and reply validity tests, which make use of repeated inquiries in synchronic and diachronic conditions, respectively. The former occurred when the same question was put to different people soon after each other; the latter occurred when the same question was asked to the same person at different times.

All ethnographic material (recordings, transcriptions, field notes and photographs) is stored at the Laboratory of Ethnobiology and Ethnoecology of Universidade Estadual de Feira de Santana, to the attention of the curator of the Ethnozoology Section.

Main Results

Specimens of triatomine collected in the surroundings of domiciles in Bahia. A. Triatoma pseudomaculata. B. Nymph (top) and female (bottom) of Triatoma infestans

Specimens of triatomine collected in the surroundings of domiciles in Bahia. A. Triatoma pseudomaculata. B. Nymph (left) and female (right) of Triatoma infestans

Most respondents (91%) said that these bugs cause illness and knew some way to prevent home infestation. The practices that were cited when someone sees a bug inside his houses were capturing and sending the insects to surveillance agents (58%), and kill the insect (40%).

People generally recognize different types of insects that exhibit similar morphological appearance to triatomines, thus eliminating harmless specimens. Traditional resources (medicinal plants and prayers) are also used in the treatment of their diseases (Costa Neto, 2004).

The results indicate that residents of rural areas of Bahia have a satisfactory knowledge about the identification, prevention methods and practices in relation to the triatomines. However, they do not have an adequate notion of the impact of Chagas disease to their lives. Health education programs emphasizing this zoonosis could further encourage population to prevent themselves and to control bugs in Bahia.


References

  1. Abad-Franch, F., Vega, M.C., Rolon, M.S., Santos, W.S., Rojas de Arias, A. Community participation in Chagas disease vector surveillance: systematic review. PLoS Negl Trop Dis 5: e1207, 2011.
  2. Costa-Neto, E. M.. Os insetos que ofendem: Artropodoses na visão dos moradores da região da Serra da Jibóia, Bahia, Brasil. Sitientibus Série Ciências Biológicas 4: 59-68, 2004.
  3. Gurgel-Gonçalves, R., Galvão, C., Costa, J., Peterson, A. T.  Geographic distribution of Chagas disease vectors in Brazil based on ecological niche modeling. J Trop Med 2012: 1-15, 2012.
  4. Falavigna-Guilherme, A. L., Costa, A. L., Batista, O., Pavanelli, G. C., Araújo, S. M. Atividades educativas para o controle de triatomíneos em área de vigilância epidemiológica do Estado do Paraná, Brasil. Cadernos de Saúde Pública 18: 1543-1550, 2002.
  5. Maeda, M. H., Gurgel-Gonçalves, R.. Conhecimentos e práticas de moradores do Distrito Federal, Brasil, em relação à doença de Chagas e seus vetores. Revista de Patologia Tropical 41: 15-26, 2012.
  6. Moncayo, A. A., Silveira, A. C. Current epidemiological trends for Chagas disease in Latin America and future challenges in epidemiology, surveillance and health policy. Memorias do Instituto Oswaldo Cruz 104: 17-30, 2009.
  7. Nix, N. A., Hernández, B., Mendoza, C., Klein, R.E. Knowledge, attitudes, and practices (KAP) survey for Chagas disease in an endemic area of Guatemala. American Journal of Tropical Medicine and Hygiene 53, S187, 1995.
  8. Rassi Jr., A., Rassi, A., Marin-Neto, J. A. Chagas disease. The Lancet, 375: 1388-1402, 2010.
  9. Schofield, C. J., Jannin, J., Salvatella, R. The future of Chagas disease control. Trends in Parasitology, v. 22: 583-588, 2006.
  10. Silveira, A. C., Dias, J. C. P. O controle da transmissão vetorial. Rev Soc Bras Med Trop 44: 52-63, 2011.
  11. Silveira, A.C., Rezende, D.F., Nogales, A.M., Cortez-Escalante, J.J., Castro, C., Macêdo, V. Avaliação do sistema de vigilância entomológica da doença de Chagas com participação comunitária em Mambaí e Buritinópolis, Estado de Goiás. Rev Soc Bras Med Trop 42: 39-46, 2009.
  12. Williams-Blangero, S., Vandeberg, J. L., Teixeira, A. R. L. Attitudes towards Chagas disease in an endemic Brazilian community. Cadernos de Saúde Pública 15: 7-13, 1999.

*Coordinator of the study; Board member of SOLAE, the Latin American Society of Ethnobiology. ISE and SOLAE members share their research with each other’s communities through website announcements and newsletters.

1Grant by Fundação de Apoio à Pesquisa do Estado da Bahia (FAPESB). The other members of the project are undergraduates Nilmara Saturnino de Souza, Luiz Rodrigo Lima da Motta, and Karine de Cerqueira Silva Oliveira.