José Jurberg

Trapping Triatominae in Silvatic Habitats

Large-scale trials of a trapping system designed to collect silvatic Triatominae are reported. Live-baited adhesive traps were tested in various ecosystems and different triatomine habitats (arboreal and terrestrial). The trials were always successful, with a rate of positive habitats generally over 20% and reaching 48.4% for palm trees of the Amazon basin. Eleven species of Triatominae belonging to the three genera of public health importance (Triatoma, Rhodnius and Panstrongylus) were captured. This trapping system provides an effective way to detect the presence of triatomines in terrestrial and arboreal silvatic habitats and represents a promising tool for ecological studies. Various lines of research are contemplated to improve the performance of this trapping system.

Nuclear rDNA ITS-2 sequences reveal polyphyly of Panstrongylus species (Hemiptera: Reduviidae: Triatominae), vectors of Trypanosoma cruzi.

Panstrongylus species are widely distributed throughout the Americas, where they act as vectors of Trypanosoma cruzi, agent of Chagas disease. Their intraspecific relationships, taxonomic position and phylogeny in relation to other Triatomini were explored using ribosomal DNA (rDNA) internal transcribed spacer 2 (ITS-2) sequence polymorphisms and maximum parsimony, distance and maximum likelihood analyses of 10 populations representing six species of the genus (P. megistus, P. geniculatus, P. rufotuberculatus, P. lignarius, P. herreri and P. chinai). At the subspecific level, P. megistus appeared more homogeneous than P. rufotuberculatus and P. geniculatus (both with broader distribution). Several dinucleotide microsatellites were detected in the sequences of given species. Many of these microsatellites (GC, TA, GT and AT) showed different number of repeats in different populations and thus, may be very useful for population differentiation and dynamics analyses in future studies. The sequences of P. lignarius (considered sylvatic) and P. herreri (a major disease vector in Peru) were identical, suggesting that these species should be synonymised. Intrageneric analysis showed a clear separation of P. rufotuberculatus, with closest relationships between P. geniculatus and P. chinai, and P. megistus occupying a separate branch. Genetic distances between Panstrongylus species (0.11585-0.22131) were higher than those between Panstrongylus and other Triatomini (16 species from central and North America and South America) (0.08617-0.11039). The distance between P. megistus and P. lignarius/herreri (0.22131) was the largest so far recorded in the tribe. The pronounced differences in length and nucleotide composition suggest a relatively old divergence of Panstrongylus species. P. rufotuberculatus was closer to Mesoamerican Triatoma, Meccus and Dipetalogaster species than to other Panstrongylus. All Panstrongylus clustered with the Mesoamerican clade; P. rufotuberculatus clustered with the phyllosoma complex and T. dimidiata, with D. maxima and T. barberi in a basal position. The rest of Panstrongylus appeared paraphyletically in the tree. This is evidence suggesting polyphyly within the genus Panstrongylus, whose species may be related to the ancestors giving rise to central and North American Triatomini.

Sylvatic population of Triatoma infestans from the Bolivian Chaco: from field collection to characterization

A sylvatic Triatoma infestans DM (dark morph) population detected in the Bolivian Chaco was characterized and compared with various domestic ones. The degree of differentiation of DM was clearly within the T. infestans intra-specific level. Nevertheless marked chromatic and morphometric differences as well as differences in antennal pattern, chromosome banding and randomly amplified polymorphic DNA support the hypothesis of a distinct population. Continuous exchange of insects between wild and domestic habitats seems unlikely in the Chaco.

Revalidação do gênero Mepraia, Mazza, Gajardo & Jorg, 1940 (Hemiptera, Reduviidae, Triatominae)

The authors revalidate the genus Mepraia, described in 1940 by Mazza, Gajardo & Jorg. The genus is monotypic and represented by the species M. spinolai (Porter, 1934). Based on the characteres described below the authors considered the separation of the genus Triatoma Laporte, 1832 and the return of the genus Mepraia. Strongly alar polymorphism, the abdomen of female with connexivum like in genus Dipetalogaster Usinger 1939, seven testicular follicles, like in Triatoma, however with a different relation of lenghts; external male genitalia showing a big and foliar process of the conjunctiva, vesica with an arch-shape, struts and endosoma process absent.

Feeding sources and natural infection of Belminus herreri (Hemiptera, Reduviidae, Triatominae) from dwellings in Cesar, Colombia

Belminus herreri, originally described from specimens collected in Panama, was considered entirely silvatic until to 2000 when it was found for the first time in a domestic habitat in Colombia. In 2001, during a new search of houses in the Department of Cesar, Colombia, 121 specimens were collected. Study of their feeding sources using an ELISA test revealed that 96% of these specimens had fed on cockroaches (Blattidae). However, a small proportion of these B. herreri specimens also showed the presence of Trypanosoma cruzi in their gut contents, suggesting a possible role for these insects in the epidemiology of Chagas disease.

Rhodnius stali n. sp., afim de Rhodnius pictipers Stal, 1872 (Hemiptera, Reduviidae, Triatominae)

Rhdnius stali n. sp. was described based on specimens deposited in the Herman Lent Collection of Entomological Collection of Oswaldo Cruz Institute, until now identified as Rhodnius pictipes Stal, 1872 and compared with specimens of R. pictipes proceeding from state of Amazonas and Para, Brazil. R. stali is related to R. pictipes though distinguished by the total length, 15 to 17 mm male and 16,5 to 19 mm female, the anteocular region 2,5 times larger than postocular region and by the shape of phallic strictures known as: phallosoma, struts, gonopore process and endosoma process.

Synanthropic triatomines (Hemiptera, Reduviidae) in the state of Pernambuco, Brazil: geographical distribution and natural Trypanosoma infection rates between 2006 and 2007

INTRODUCTION The present study shows a descriptive analysis of triatomine occurrence and its natural Trypanosoma infection rates in the state of Pernambuco, Brazil, between 2006 and 2007. METHODS Entomological data for the species, such as specimens captured in both intra and peridomiciles and natural infection index, were obtained via domiciliary capture in 147 municipalities from 11 Regional Managements of Health. The database was obtained from a sample of insects (100% infected and 20% non-infected) sent to the Central Laboratory of Pernambuco. RESULTS A total of 18,029 triatomines were analyzed from 138 municipalities of the state. Triatoma pseudomaculata (35%), Triatoma brasiliensis (34%), and Panstrongylus lutzi (25%) were the most captured species. These species also showed a widespread geographical distribution in the state. Panstrongylus megistus, Triatoma petrocchiae, Triatoma melanocephala, Triatoma sordida, Rhodnius nasutus, Rhodnius neglectus, and Triatoma infestans showed more limited geographical distribution and lower relative abundance. The parasitological research showed that 8.8% of the triatomines were naturally infected with flagellates morphologically similar to Trypanosoma cruzi and 91.3% of them were captured inside houses in 113 municipalities. P. lutzi showed the highest rates of natural infection. CONCLUSIONS After the control of T. infestans, synanthropic species, such as T. brasiliensis, T. pseudomaculata, and P. lutzi, maintain the risk of T. cruzi transmission to humans in the state of Pernambuco. These species are widely distributed, and infected specimens have been found inside houses. Thus, an enhanced surveillance and vector control of Chagas disease is recommended in Pernambuco.

Rhodnius zeledoni sp. nov. afim de Rhodnius paraensis Sherlock, Guitton & Miles, 1977 (Hemiptera, Reduviidae, Triatominae)

A new species of Rhodnius is described and illustrated from a male specimen from northeastern Brazil. The specimen was found died and dried. This species can be distinguished from its similar congener R. paraensis Sherlock, Guitton & Miles by the greater size, the general aspect of the color of the body, by the uniform color of the legs, different proportions between the morphological structures of the head and the segments of the rostrum; also, in the male genitalia by the aspect of median process of pygophore, dorsal phallotheca plate and phallotheca process.

Triatoma melanosoma, novo status para Triatoma infestans melanosoma Martinez, Olmedo & Carcavallo, 1987 (Hemiptera: Reduviidae)

Triatoma infestans melanosoma was described in 1987 by Martinez, Olmedo & Carcavallo. In the present work the authors make a redescription, adding new characters, and based on biological and morphological aspects raise up to the level of species and being identified as Triatoma melanosoma. A detailed morphological study of the external male genitalia was made.

Alguns aspectos da biologia de Triatoma pseudomaculata Correa & Espinola, 1964, em condicoes de laboratorio (Hemiptera: Reduviidae: Triatominae)

: Observations were made on the evolutive cycle of Triatoma pseudomaculata, held under laboratory conditions, fed weekly on bird (pigeon). Of 60 eggs obtained, only 34 nymphs reached the adult stage in a period of X(S) = 398 +/- 76 days. The following parameters were observed: the time immature stages took to develop from egg to adult emergence; the occurrence of the first meal; the time-lapse between the presenting of the blood-meal and the beginning of feeding; time of feeding; amount of blood ingested; variation of weight 24 hr after the blood-meal and until the next blood-meal; and the defecation pattern. The experiment was carried out for 20 months, held in BOD incubator with the average of temperature and humidity of 28 +/- 1 degrees C and 80 +/- 5% RU, respectively.