SHORT COMMUNICATION Importance of Triatoma pallidipennis (Hemiptera: Reduviidae) as a Vector of Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae) in the State of Morelos, Mexico, and Possible Ecotopes NORMA LETICIA BAUTISTA, 1 GUADALUPE S. GARCI ´ A DE LA TORRE, 2 IRENE DE HARO ARTEAGA, 1 AND PAZ MARI ´ A SALAZAR SCHETTINO 1 J. Med. Entomol. 36(3): 233Ð235 (1999) ABSTRACT We performed a transversal-type epidemiological study in the state of Morelos, Mexico, to determine the presence of triatomines, their ecotopes, and importance in transmission of Trypanosoma cruzi Chagas. Sampling sites included domestic, peridomestic, and wild areas with collection based on the person per hour technique. We determined the entomological indices related to infestation, density, overcrowding, colonization, infection, and dispersion, which were used to calculate transmission risk. During the study, observations were made on the predominant building material, presence of cracks and illumination as factors fostering colonization. The most important results were related to infection indices, which were higher for domestic type triatomines (29%), whereas it was 4% for peridomestic sites, and 20% for sylvatic areas. The actual risk of human contact with the vector was of 0.51%, and the predominating ecotopes were stone heaps. KEY WORDS Triatoma pallidipennis, infection index, vectorial action UNTIL 1994, 26 SPECIES OF triatomines had been re- corded in Mexico. There are now 126 recognized spe- cies worldwide. The genus Triatoma has the highest number with 21. From the other 5 (Paratriatoma, Pan- strongylus, Rhodnius, Eratyrus, and Dipetalogaster), only 1 species is known for each (Zarate and Zarate 1985, SchoÞeld 1994). Because of the importance of these insects in the transmission of Trypanosoma cruzi Chagas, the caus- ative agent of Chagas disease, that started after the 1st reports of human infections in Mexico, great concern and interest has developed in determining their geo- graphic distribution, natural infection, and ecotopes. This knowledge is fundamental to establish adequate vector management and epidemiological surveillance measures in the endemic areas. Included in the distribution of triatomines in Mex- ico (Zarate and Zarate 1985), Triatoma barberi Us- inger and T. pallidipennis Stål were reported from the state of Morelos, which is located south of the met- ropolitan area of Mexico City. The original reference did not clearly identify the speciÞc community where each species was captured or whether both species had been reported from communities listed. A map of the Mexican Republic (Fig. 1) indicates the distribution sites of T. pallidipennis, according to the records from Lent and Wygodzinsky (1979), Za ´ rate and Za ´ rate (1985), Salazar Schettino et al. (1988), and SchoÞeld (1994). To determine the dispersion, present day ecotopes, and the occurrence of T. cruzi in the Morelos area of Mexico, where the presence of T. pallidipennis was previously reported, we collected domestic, perido- mestic, and sylvatic samples and established entomo- logic indices. Materials and Methods Area of Study and Capture Methods. The State of Morelos is located between parallels 18° 11' 5'' and 19° 07' 10'' North and meridians 96° 37' 08'' and 99° 3' 08'' West from the Greenwich meridian. Central and south- east regions are located between isothermal limits from 30 to 35° C. Yearly rainfall ranges from 800 to 1,000 mm. The study was performed in 105 houses representing 24 communities within 4 municipalities, which belong to the Sanitary Jurisdiction No. 2 of the state. Triatomines were collected using the person per hour technique (Pinchin et al. 1981). Sampling sites were selected and classiÞed as domestic, peridomes- tic, or sylvatic. Domestic sites consisted of the interior of the houses and annexed buildings where the in- habitants store work clothes, forage, and other items. We determined the type of material used to construct the ceilings, walls, and ßoors in all 105 houses, noting the presence of cracks in the walls and the amount of light inside the rooms. Peridomestic sites were those located within 50 m of the actual living quarters of the inhabitants and consisted of the yards, animal resting places, chicken yards, pigeon housings, stone or wood piles, and 1 Laboratorio de Biologõ ´a de Para ´ sitos, Departamento de Micro- biologõ ´a y Parasitologõ ´a, Universidad Nacional Auto ´ noma de Mexico, Ciudad Universitaria, D.F., CP 04510. 2 Departamento de Salud Pu ´ blica, Facultad de Medicina, Univer- sidad Nacional Auto ´ noma de Mexico, Ciudad Universitaria, D.F., CP 04510. E-mail: pazmar@servidor.unam.mx 0022-2585/99/0233Ð0235$02.00/0  1999 Entomological Society of America Downloaded from https://academic.oup.com/jme/article/36/3/233/918162 by guest on 10 September 2022