Triatoma sordida Stål 1859 (Hemiptera, Reduviidae: Triatominae) in Palms of Northeastern Argentina

Vol. 96(7): 895-899, October 2001

María Esther Bar/⁺, Cristina Wisnivesky-Colli*

Cátedra de Artrópodos, Departamento de Biología, Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad Nacional del Nordeste, Avenida Libertad 5600, 3400 Corrientes, Argentina *Unidad de Ecología de Reservorios y Vectores de Parásitos, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina

Several palms species provide an important habitat for triatomines and associate vertebrates in tropical America. The objective of this work is to identify the triatomine species living in the palms of rural areas in the Province of Corrientes, and to estimate the potential epidemiological risk they represent for the residents of nearby houses.

The survey was carried out in a palm community in Colonia Laurel, Department San Roque, Province of Corrientes, Argentina. Samplings were performed in October, November and December 1998; January, February and March 1999; May and June 1999. Thirty palms: 27 (90%) Butia yatay (Mart.) Becc. and 3 Acrocomia aculeata (Jacq.) Lodd ex Mart. were dissected. Triatoma sordida Stål 1859 was found in 96.2% of B. yatay and in all the A. aculeata palms. A total of 272 live T. sordida was collected; 36 of them (13.2%) were found in bird nests in the frond and the remainder in other locations of the tree. The mean number of triatomines per palm was 9.6 (range 1-60, mode 2). T. sordida was collected during all the sampling months and all stages were present at all seasons. The highest population density was reached in spring and the lowest in autumn. Trypanosoma cruzi was detected in 38.5% in feces of 174 examined insects and identified as such, both by microscopical examination and PCR.

This is the first finding of T. sordida populations in B. yatay, an endemic palm of South America distributed in southern Brazil, Uruguay and northeastern Argentina. The high infection prevalence found in this work suggests that T. sordida plays an essential role in the maintenance of the wild T. cruzi transmission cycle in northeastern Argentina.

Key words: Triatoma sordida - palms - wild triatomines - Butia yatay - Argentina

In America, palm trees have been found infested with different species of triatomines. The most frequently cited are Rhodnius prolixus, R. neglectus, R. pictipes, R. nasutus, R. pallescens, R. neivai, R. robustus, Triatoma maculata, T. pseudomaculata, T. dimidiata, T. sordida, Panstrongylus megistus, P. lignarus, Eratyrus mucronatus and E. cuspidatus (Barretto et al. 1969, Forattini et al. 1971, Gamboa 1973, Feliciangeli & Torrealba 1977, Whitlaw & Chaniotis 1978, D' Alessandro et al. 1984, Rossell-Reyes 1984, Diotaiuti et al. 1993).

Regarding their epidemiological role, some species like R. prolixus and P. megistus are more important vectors of T. cruzi than others like R. robustus, R. neglectus and R. pictipes. Palms could also represent dispersion foci of triatomines to human dwellings and peridomestic premises such as chicken houses.

In Argentina there are few records about the presence of T. sordida in palm trees (Carcavallo et al. 1988) but neither longitudinal nor systematic studies have ever been performed on triatomine populations colonizing palms.

The aims of this work were to identify the triatomine species living in the palms of rural areas in the Province of Corrientes, as well as to estimate the potential epidemiological hazard that these T. cruzi vectors represent for the residents of nearby houses.

MATERIALS AND METHODS

RESULTS

DISCUSSION

ACKNOWLEDGMENTS

To E Oscherov, M Damborsky, M Alvarez, G Avalos, H Presmann for their assistance on the field and laboratory work. To J Vargas for his valuable help and to S Pîetrokovsky for the English version of the manuscript.

REFERENCES

Figure | Table I | Table II

⁺Corresponding author. Fax: +54-3783-473930. E-mail: mebar@exa.unne.edu.ar

Received 20 September 2000

Accepted 20 June 2001