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Morphological studies in male reproductive system of insect, and accessory glands functions, can contribute to the knowledge of reproductive aspects in Triatominae. The present study aims to describe the structure of male reproductive system under scanning electron microscopy, and the ultrastructure of accessory glands during the process of maturation, in T. brasiliensis and T. melanica of different ages. These system consist of two testis, two vas deferens, two seminal vesicles, four pair of accessory glands and one ejaculatory duct. The four mesodermal male accessory glands of T. melanica and T. brasiliensis, present secretion storage in the first days of adult life in starved males. During the maturation process of male accessory glands of T. brasiliensis and T. melanica, granules with different sizes, shapes and electron density were seen. In T. melanica small vacuoles are released into the gland lumen in one-day-old males, however, after three and five days few granules are found in the cell cytoplasm. The secretory granules in T. brasiliensis increase in size and amount, in the five days old adult. The secretory pathway in the male accessory glands of the two species seems to be merocrine and apocrine suggesting that different substances are being produced at different times. The cell microvilli in T. brasiliensis are longer and narrower, these can be absent in some regions of the cell surface of T. melanica. Maturation of male accessory glands in the triatomine species studied occurred without adult blood meal. Its function can led to new insights for the comprehension of reproductive aspects in Triatominae., (Copyright 2010 Elsevier Ltd. All rights reserved.)

Trypanosoma cruzi, the etiologic agent of Chagas' disease, is represented by a set of parasites which circulate between man, vectors, domestic and wild animals. Recently, our group isolated from Triatoma vitticeps strains of T. cruzi that were characterized as belonging to the Z3 phylogenetic lineage. Since very little is known about the biological and/or biochemical markers of sylvatic Z3 isolates, we have studied the protein and protease profiles of distinct Z3 isolates designated as SMM10, SMM53, SMM88, and SMM98. By means of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, both quantitative and qualitative differences were observed in the protein profiles of these strains. All strains produced an acidic cysteine protease of 45 kDa, resembling cruzipain activity. The strain SMM10 synthesized an additional 55 kDa metalloprotease. Using Western blotting and anti-cruzipain antibody to detect cruzipain-like molecules, a 40-kDa reactive molecule was identified in all strains; in the strain SMM10, an 80-kDa protein was also reacted. Studies about cruzipain isoforms from sylvatic parasites could be valuable tools in the comprehension of the genetic variability in the pathogenesis of Chagas' disease.

Objective: Feeding patterns of triatomines have contributed to elucidate its biology. Triatoma vitticeps, naturally infected with T. cruzi, has been found in domiciles. Its behavior and epidemiological patterns were investigated., Methods: One-hundred and twenty two specimens of T. vitticeps were captured from February 1989 to April 1993 in two areas of Triunfo municipality, a subdistrict of Santa Maria Madalena municipal district, State of Rio de Janeiro, Brazil. The insects were dissected and their intestinal contents were removed and tested. It was used antisera from: man, cow, horse, dog, pig, armadillo, opossum, rodent, and bird., Results: From the total analyzed, 79 were positive and 43 were negative to the nine antisera tested: armadillo (30.3%) > human and pig (13.1%) > bird and dog (11.5%) > horse (5.7%) > opossum (4.9%) > rodent (4. 1%) > cow (3.3%). Blood meals ranged from 0 to 4 and 6 in the following distribution: 0 = 25.41%; 1 = 45.08%; 2 = 10.66%; 3 = 6. 56%; 4 = 1.64%, and 6 = 0.82%. Nine of the 122 insects captured were not examined, 74 (65.54%) were positive for T. cruzi infection and 39 (34.51%) were negative., Conclusions: These results identified the T. vitticeps as being a sylvatic species and trypanosomiasis as being an enzootic disease. Epidemiological vigilance will be important to provide more information regarding the behavior of the species

From January 1989 to April 1995, 465 specimens of Triatoma vitticeps were collected in the locality of Triunfo, 2nd District of Santa Maria Madalena municipal district, State of Rio de Janeiro. The bugs were found indoors by local residents with predominance of adults. The flight activity was high in hot months when the incidence in the domicile also increased. Two hundred and two bugs (111 alive and 91 dead) were examined for Trypanosoma cruzi infection. This was detected in 31 of the dead bugs (34%) and 88 (79%) of the live bugs examined. With a view to investigate the possible vertebrate hosts of the T. cruzi isolates, the blood of 122 mammals was examined through Giemsa-stained smears, hemocultures and xenodiagnosis. T. cruzi was detected in three specimens of Didelphis marsupialis and T. (M.) theileri was detected in one specimen of Bos taurus. The parasites were isolated from triatomine feces, xenoculture and hemoculture. No evidence of human infection was detected in 58 inhabitants examined, as evaluated by indirect imunofluorescence technique using T. cruzi epimastigotes as antigens. These results show that T. vitticeps is still a sylvatic species although nymphs have been found inside the domicile. Thus, an epidemiological vigilance is necessary to know the behaviour of this species following the continuous modifications promoted by the presence of man.

The present work aims at learning the period of resistance to starvation (molting/death) of Triatoma rubrofasciata in different stages of development and the respective loss of weight until death. Eggs of specimens from the greater area of the city of São Luis in the State of Maranhão, Brazil, yielded approximately 300 nymphs. These nymphs were placed in labelled Borrel glasses, in which they were weekly fed on rats (Rattus norvegicus), until reaching the stage to be observed. The experiments were conducted in a climatic chamber regulated at 29 +/- 1 degrees C, 70% relative humidity and 12 hr photoperiod. The resistance to starvation increased according to the stage of development, except for adult bugs, whose results were similar to the 3rd stage nymphs. In all these development stages there was an abrupt loss of weight in the first week, followed by a gradual loss until death. Comparing this work with those of other authors, it was observed that T. rubrofasciata is among the less resistant triatomine species.

The effect of azadirachtin was investigated using three different fresh isolates of Trypanosoma cruzi and five different triatomine species which were infected as third-instar larvae. The two T. cruzi strains which originated from sylvatic Triatoma vitticeps showed a high prevalence after the molt to the fifth instar in Panstrongylus megistus and Rhodnius neglectus and a low prevalence in Triatoma infestans and Rhodnius robustus. The third T. cruzi strain originating from a patient in Piaui showed a high prevalence in P. megistus, R. neglectus and T. infestans and a low prevalence in Triatoma sordida. Feeding the infected fifth instars with azadirachtin-supplemented blood (1 microg/ml) resulted 20 days later in some parasite/vector combinations in an increase, in others a decrease or an unchanged number of T. cruzi in comparison to bugs fed with unsupplemented blood.

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.

Observations were made on the evolutive cycle of Triatoma vitticeps, held under laboratory conditions and fed weekly in mice. Of the 435 eggs obtained, from 4 virgin couples, 149 were purposed for the biological cycle study and 286 to evaluate their resistance to starvation, which shall be a second part of this work. Only 50 specimens reached the adult stage in a period of means (S) = 270 +/- 45 days. At the incubation time, the first and second instars were of less than a month for each, while the third, fourth and fifth instars requires approximately one, two and three months, respectively. The search for the first meal occurred clearly on the 3rd, 6th and 10th day. During all the stages, more than 50% of the specimens had only one blood-meal, except the fifth one, when two blood-meals were required. In relation to the time-lapse between the presenting of the blood-meal and the beginning of feeding, as well as the length of the blood-meal, it was observed that these increased gradually according to the stage. From the 423 blood-meals performed, 390 were not followed by defecation in the settled period of 10 min. Under this point of view, T. vitticeps seems to be a poor transmissor of T. cruzi. The experiment was carried out for 13 months and by this time the averages of minimum and maximum temperatures and the humidity were 25 +/- 2 degrees C - 28 +/- 2 degrees C and 80 +/- 2%, respectively. The material belongs to the triatomine colony held at the Oswaldo Cruz Institute, Department of Entomology.

The morphogenetic effect of precocene II on 4th instar nymphs of Triatoma infestans was examined. Topical treatment with precocene II (200, 300 and 400 micrograms/nymph) induced the formation of adultoids with the following characteristics: rudimentary wings, three segmented tarsi, ocelli, deformed genitalia and mouth-parts and testes with intermediary development. Precocene II also increases the duration of the molting cycle. The survival of the adultoid insects was related to the inverse of the applied doses. These data extend our knowledge of the action of precocene II on triatominae species.

Following the study on the biology of Triatoma vitticeps (Gonçalves et al., 1988) observations have been made on its resistance to starvation. Of the 286 eggs obtained only 201 hatched and reached the intended stage for observation. The others did not eclode, neither reached the ecdisis nor died, without explanation. The nymphs were kept, separately, in Borrel flasks and properly listed. The blood-meal was performed in mice, although the insects were kept without feeding as soon as moulted. The starvation was evaluated in two ways: the time-lapse in days between the last meal/death and between moult/death. The starvation was directly related with the developmental stage. In relation to the parameters last meal/death and moult/death, both sexes were less resistant than 3rd and 2nd stage, respectively. The experiment have been carried out for 15 months and by this time the average minimum and maximum temperatures and the humidity were 25 +/- 2 degrees C - 28 +/- 2 degrees C and 81 +/- 3% UR, respectively. The material spent belongs to the triatomine colony of the Oswaldo Cruz Institute Department of Entomology.

Triatoma pseudomaculata foram capturados em entrecascas de Mimosa tenuiflora (jurema-preta) em ecótopo silvestre de sete municípios do Estado do Ceará. Esta planta apresenta alta taxa de cobertura geográfica nas áreas de caatingas, sendo freqüentemente utilizada pela população rural. A presença de triatomíneos no peridomicílio, na região do Cariri, pode estar associada ao uso pela população da madeira de M. tenuiflora, quando trazida do ambiente silvestre, repleta de triatomíneos, facilitando conseqüentemente sua mobilização e dispersão.