Epidemiology of Chagas disease in Jaguaruana, Ceará, Brazil. I. Presence of triatomines and index of Trypanosoma cruzi infection in four localities of a rural area

Abstract

In order to assay the triatomine infestation and domiciliation in the ruralIn the state of Ceará, the presence of triatomines has been known for a long time, as Alencar (1987) has shown in a research that compiled former surveys carried throughout the state. Alencar et al. (1976) have demonstrated that vectors have not been found in only 9 out of the 141 municipal districts that comprise the geographic division of the whole state of Ceará. The authors have cited the semi-domestic Triatoma brasiliensis as being a primary transmitting species and with larger distribution in that state, found in 91.5% houses of municipal districts, many times with high Trypanosoma cruzi infection indexes. Triatoma pseudomaculata, which is believed less domestic, was found in 68.8% of the municipal districts, with an average infection index of 4.2%. In the distribution ranking, the third species in Ceará was Panstrongylus megistus, displaying a variable infection index; this species was found in 61.7% of the municipal districts. Rhodnius nasutus, with an average of 1% infection index, was found in 17.7% of the municipal districts; Panstrongylus lutzi was found in 18.4% of the municipal districts, presenting an average of 17.9% of infection indexes (Alencar et al. 1976).The objective of the present work was to determine infestation indexes, colonization, and density of triatomines in domiciliary units (DUs) that include intradomicile, peridomicile, and ecotopes found in wild habitats of the four localities that belong to the rural area of Jaguaruana municipality, Ceará, Brazil, formerly considered to be highly infested by these vectors. The indexes were determined by relating them with variables such as type of house's wall type and number of peridomiciliary annexes. The authors have also determined the indexes of natural T. cruzi infection in triatomines captured in each studied habitat and ecotopes.

Ecological aspects of Rhodnius nasutus Stål, 1859 (Hemiptera: Reduviidae: Triatominae) in palms of the Chapada do Araripe in Ceará, Brazil

“…During the present study, specimens were frequently collected in such ecotopes (including some infected with T. cruzi), confirming these reports by the PCDCh. Sarquis et al (2004) suggested that the presence of R. nasutus in dwellings was due to the proximity of palms, as insects on the trees are attracted to light and invade houses in search of blood. This has been observed in the Amazon for R. brethesi, 1919 (Coura et al 1994).…”

“…Together with PCDCh records, these findings demonstrate the importance of the area for sylvatic T. cruzi transmission. In addition to domestic colonisation by triatomines (Martins 1968), alternative forms of T. cruzi transmission, such as house invasion without colonisation as reported from the Brazilian Amazon (Coura et al 1994) and Ecuador (Aguilar et al 1999) should be investigated to improve epidemiological vigilance of Chagas disease in Chapada do Araripe, as proposed by Sarquis et al (2004).…”

Epidemiologia da doença de Chagas em quatro localidades rurais de Jaguaruana, Estado do Ceará: soroprevalência da infecção, parasitemia e aspectos clínicos

“…A presença de triatomíneos nas quatro localidades pesquisadas foi confirmada nas investigações de Sarquis cols 31 . Esses autores capturaram, em intra e peridomicílios, exemplares de Triatoma brasiliensis, Triatoma pseudomaculata, Rhodnius nasutus e Panstrongylus lutzi.…”

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

“…The area in which these colonies were found is not covered by the Control Programme of Chagas Disease. In addition, it is important to mention the increasing infestation rates by T. brasiliensis (Costa et al 2003, Sarquis et al 2004) in semi-arid areas of the Brazilian Northeast and by Triatoma sordida Stal, 1859 in wide Cerrado areas (Diotaiuti et al 1995, Pelli et al 2007. Therefore, the positive results achieved with the control measures intended against Triatoma infestans (Klug, 1834) should not be interpreted as an endpoint in the struggle against vectorial transmission.…”