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At least 19 recordsLinked to original sources
PubMed2000

Influence of the blood meal source on the development of Triatoma infestans, Triatoma brasiliensis, Triatoma sordida, and Triatoma pseudomaculata (Heteroptera, Reduviidae).

The objective of this study was to determine the influence of the blood meal source on the life cycle and reproductive development of female Triatoma infestans (Klug, 1834), Triatoma brasiliensis Neiva, 1911, Triatoma sordida (Stal, 1859), and Triatoma pseudomaculata Corrga & Espfinola, 1964. In all triatomine species studied the life cycle was shorter for the groups fed on mice than for those fed on pigeons, the range of differences being between 1.5 times (T pseudomaculata and T. infestans) and 2.4 times (T brasiliensis). The mortality rate of nymphs during the life cycle tended to be greater in insects fed on pigeons than in those fed on mice, the differences for T. brasiliensis being statistically significant. Females of T sordida and T pseudomaculata had a greater fecundity than those of T. infestans and T. brasiliensis independently of the blood meal source. The differences of fecundity observed probably reflect differences in the availability of blood in the silvatic ecotopes of these species, meals being more frequent for T. infestans and T brasiliensis, which live at high densities in association with rodents in highly stable ecotopes. Because T. sordida and T. pseudomaculata live in more unstable ecotopes with fewer sources of blood they form small sparse colonies and invest more energy in reproduction than maintenance.

Animal Feed↗
PubMed2000

Performance of yeast-baited traps with Triatoma sordida, Triatoma brasiliensis, Triatoma pseudomaculata, and Panstrongylus megistus in laboratory assays.

The effectiveness of a trap for triatomines baited with yeast cultures has been previously demonstrated for Triatoma infestans in laboratory assays. We report here results from laboratory assays testing yeast traps for Triatoma sordida, Triatoma brasiliensis, Triatoma pseudomaculata, and Panstrongylus megistus. All assays were conducted in an open experimental arena 100 cm x 100 cm, with two traps placed at opposite sides of the arena. One of the traps contained a yeast culture, and the other trap contained a saccharose solution as a control. Two series of experiments were done, one without a refuge for the insects and one with a refuge. The results obtained clearly demonstrated that the yeast-baited traps were effective in the laboratory in capturing both T. sordida and P. megistus. For T. sordida, yeast-baited traps captured significantly more bugs than did the control traps (t test P value = 0.03). For P. megistus, when a refuge was provided during the assay, yeast-baited traps also captured significantly more bugs than did the control traps (t test P value = 0.006). In the experiments with T. brasiliensis and T. pseudomaculata, both traps captured some insects, but the yeast traps captured many fewer bugs than was true with the T. sordida and P. megistus bugs. These results indicate that, in the laboratory, yeast traps can capture considerable numbers of T. sordida and P. megistus in one night. We discuss the potential use of yeast traps for detecting and capturing both triatomine species.

Animals↗
PubMed2000

Comparison of feeding behaviour of Triatoma infestans, Triatoma brasiliensis and Triatoma pseudomaculata in different hosts by electronic monitoring of the cibarial pump.

Feeding behaviour of Triatoma infestans, T. brasiliensis and T. pseudomaculata on pigeons and mice was compared by electronic monitoring of the cibarial pump. The methodology developed permits the study detailed of triatomine feeding behaviour using an artificial feeder as well as on live hosts. T. infestans was the species that fed most rapidly on the two hosts tested (28.03+/-1.6 mg/min for pigeon and 21.33+/-1.7 mg/min for mouse), followed by T. brasiliensis (17.09+/-1.4 mg/min and 13.1+/-1.5 mg/min for pigeon and mouse, respectively) and T. pseudomaculata, (5.23+/-0.6 mg/min and 4.09+/-0.4 mg/min for pigeon and mouse, respectively). The quantity of liquid ingested per stroke of the cibarial pump was 100.7+/-4.1 nl for T. infestans, 69.1+/-2.7 nl for T. brasiliensis and 26.8+/-1.5 nl for T. pseudomaculata. The rate of engorgement in pigeons tended to be greater than that obtained for mice in the three species studied. In the experiments carried out using mice, probing times tended to be longer and interruptions during the meal more prolonged. This reinforces the idea that feeding on mice is more difficult than on pigeons, requiring more contact time to obtain the similar quantity of blood.

Journal Article↗
PubMed1983

Experimental parasitization of eggs of Triatoma maculata (Erichson) by the oriental microhymenopteran, Gryon triatomae Masner and comment on the susceptibility of other neotropical triatomines.

The oriental microhymenopteran wasp, Gryon triatomae Masner, 1975 was reared in eggs of triatomine bugs, including vectors of Chagas' disease. In particular, G. triatomae was maintained for 31 generations in eggs of Triatoma maculata (Erichson). Only one parasite develops in each bug egg and 30 to 40 days are required for completion of development at 24 +/- 1 degrees C. Mean parasitization rate of 7484 eggs of T. maculata, in 54 rearings, was 34.7% with a range from zero to the highest rate of 86.7%. Mated females produce predominantly female progeny (mean sex ratio, 1 male:6.7 females). Unmated females produce parthenogenetic males. The wasp reproduces in fertile eggs, from those recently laid to those with well-advanced bug embryos. Infertile eggs are not usually parasitized. Both sexes survive for one to two weeks unfed, but for several weeks (up to 16 for females) if fed (on honey). Frequent ovipositions may reduce survival. Successful parasitization by females persisted for about three weeks but declined subsequently. Abortions of developing Gryon were usually 10% or less. Brief comparison with other neotropical triatomine species indicates that eggs of Triatoma spp. are susceptible to G. triatomae; Panstrongylus spp. seem relatively poor hosts, and there is little or no parasitization of Rhodnius spp.

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PubMed1999

The effect of azadirachtin on Blastocrithidia triatomae and Trypanosoma cruzi in Triatoma infestans (Insecta, Hemiptera).

The effect of azadirachtin on Blastocrithidia triatomae and Trypanosoma cruzi, which colonise the intestinal tract of the blood-sucking bug Triatoma infestans, was investigated. In established infections of controls without azadirachtin treatment, the small intestine of fifth-instar T. infestans contained up to 7 x l0(6) B. triatomae and the rectum 3 x 10(6). In comparison to this homoxenous flagellate, the population densities of T. cruzi in the respective regions were 99.3 and 76% lower. Treatment with azadirachtin (1 microg ml(-1)) via a blood meal and a concurrent infection with B. triatomae resulted in an increase of the population density (3 weeks p.i.), caused mainly by the mastigote stages in the rectum. In an established B. triatomae infection (12 weeks p.i.), feeding of azadirachtin did not affect the population density and composition. In an optimal T. cruzi-vector system, i.e. parasite and bug originate from the same locality, the treatment with azadirachtin at 20 weeks p.i. strongly reduced the population density in the small intestine of all bugs up to 100 days after treatment, but only in a minor percentage of the bugs in the rectum. Trypanosoma (cruzi incubated for up to 24 h in faeces of azadirachtin-treated bugs were not affected, indicating that the rectum of these bugs contained no toxic substances. The importance of these findings is that investigations of the mechanisms of action of azadirachtin offer a possibility to identify vector-derived compounds, which are necessary for the development of T. cruzi, thereby, giving us a possible new strategy to combat Chagas' disease.

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PubMed2000

Peridomestic distribution of Triatoma garciabesi and Triatoma guasayana in north-west Argentina.

The Reduviid bugs Triatoma garciabesi Carcavallo et al. (Hemiptera: Reduviidae: Triatominae), previously known as T. sordida Ståhl in the semi-arid chaco region, and T. guasayana Wygodzinsky & Abalos, vectors of Trypanosoma cruzi Chagas (Kinetoplastida: Trypanosomatidae), were found to occupy wide but different ranges of ecotopes in the peridomestic environment. At Amamá and nearby rural villages in north-western Argentina, a combined total of 1233 specimens were collected from 325/2314 (14%) sites surveyed at 6-monthly intervals from November 1994 to November 1996. Triatoma garciabesi and T. guasayana displayed a significantly different distribution among peridomestic ecotopes. Triatoma garciabesi predominated over T. guasayana in the prevalence of infested sites, the number of colonies and the number of bugs collected. For T. garciabesi, the predominant ecotopes most likely to yield T. garciabesi repeatedly were the rugged bark of Prosopis alba or P. nigra (Fabaceae) trees, where chickens roosted, and chicken coops. For T. guasayana the main ecotopes were goat or sheep corrals, piled materials and orchard fences. Triatoma garciabesi and T. guasayana were collected concurrently from the same site on 9/2314 (0.4%) occasions, and on different dates at the same site on 12 (0.5%) occasions. The observed low frequency of mixed populations (< 1%) was not significantly different from that expected from a hypothesis of independence. Triatoma garciabesi clearly outnumbered T. guasayana in four of the nine mixed populations, none of which persisted as such. Neither T. garciabesi nor T. guasayana colonized human habitations, even in the absence of T. infestans (formerly the predominant domestic vector of T. cruzi in this area), a situation that apparently has not changed in the last 50 years in northern Argentina.

Animals↗
PubMed2002

The development of Blastocrithidia triatomae (Trypanosomatidae) in the reduviid bug Triatoma infestans (Insecta): influence of feeding.

The population density and composition of an established infection of Blastocrithidia triatomae in the intestinal tract of fifth instars of Triatoma infestans were compared in unfed bugs, at 4 h and up to 15 days after feeding, and also in feces and urine deposited in the first 4 h after feeding. In unfed bugs, about 1-2 million B. triatomae colonized the small intestine and rectum, mainly epimastigotes (85% and 80%, respectively). During excretion, the percentage of cysts increased within the first two drops (from 15% to 35%) and then decreased slowly, indicating a washing-out of these unattached stages. The initial reduction in the B. triatomae population lasted up to 6 days after feeding. By 15 days after feeding, the populations had strongly increased in the small intestine and rectum, to 22 million and 2 million flagellates, respectively, as had cysts, comprising some 50% of the total population in the rectum.

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PubMed1983

Parasitization by the microhymenopteran Gryon triatomae Masner of eggs of Triatoma maculata (Erichson) in holes and mazes of artificial walls.

Oriental parasitoid wasps, Gryon triatomae, were confined for several weeks in transparent tanks (400 X 180 X 200 mm) with eggs of the neotropical triatomine bug Triatoma maculata. The eggs were lodged in moulded holes (about 50 mm deep and 15 mm diameter) of polystyrene blocks, to simulate walls. The blocks were arranged with the holes either vertical or horizontal; openings of the holes were either 5 mm or 15 mm diameter. One wall included three mazes of linked holes, each maze with one entrance. Eggs were also accessible in an open petri-dish and on top of one wall. Some eggs in the walls and the maze block were in holes sealed off from access by wasps to provide controls, in order to assess fertility of the eggs, since this favours parasitization. This was satisfactory at 82.2% and 88.5% in two tanks studied. Parasitization rates were 32% of 50 eggs exposed to one female G. triatomae, with one male wasp, in one tank, and in the other 55.9% of 136 eggs exposed to 14 female wasps, with five males. In both tanks, eggs in the open petri-dish, in accessible vertical and horizontal holes and on top of walls were parasitized, but parasitization of eggs in the mazes occurred only in the tank with 14 female Gryon and then as far as the last, 18th, hole of the longest maze, a linear penetration by a searching wasp of about 270 mm; the distance travelled could be considerably greater. Late wasp oviposition after protracted questing may have caused the observed 15.8% abortion rate of G. triatomae. The few wasps seen by night were at rest, but at daybreak many more emerged from the walls and flew actively.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1990

The effect of Blastocrithidia triatomae (Trypanosomatidae) on the midgut of the reduviid bug Triatoma infestans.

The pathogenic flagellate Blastocrithidia triatomae disrupts the digestion of Triatoma infestans; the midgut ultrastructure of bugs infected with the flagellate and of uninfected bugs is compared. Third or fourth instar larvae were dissected either unfed or 1 week after feeding. In all uninfected bugs extracellular membrane layers (e.m.l.) covered the apical microvillar border of the epithelial cells. Some midgut regions of bugs infected with B. triatomae appeared normal but often adjacent cells showed pathological effects. In affected cells the e.m.l. and the microvilli and finally the cells themselves were reduced or destroyed. Correlated with these observations of pathogenicity the method of attachment of parasites changed. When the e.m.l. were present only rarely were flagella found, but on extracellular membrane-free cells B. triatomae attached by flagellar enlargement to the microvillar border or, if this was reduced, to the apical host cell membrane. No hemidesmosome-like plaques were found at the attachment site. Although some flagella were inserted into the apical region of the cells no intracellular flagellates were observed.

Animals↗
PubMed1989

Cultivation of Blastocrithidia triatomae (Trypanosomatidae) on a cell line of its host Triatoma infestans (Reduviidae).

Blastocrithidia triatomae parasitizes vectors of Chagas' disease and is very difficult to cultivate in conventional media. However, co-cultivation with a cell line of its host Triatoma infestans (TI-32; in Schneider's Drosophila medium supplemented with 20% foetal calf serum and 10% tryptose phosphate broth) led to vigorous growth at 24 or 28 degrees C without an adaptation phase. More than 60 primary cultures were initiated successfully without any failures. Subcultures could be started immediately at weekly intervals. The doubling time was similar in both the primary cultures (41 h) and the 33rd subculture (39 h). The importance of the reduviid cells for B. triatomae became clear after removal of the insect cells, when multiplication of epimastigotes stopped and mainly cysts were formed. Cysts produced in vitro were infective for reduviids. Scanning electron microscopy showed that B. triatomae attached to the host cells, inserted its flagellum into them and destroyed them.

Animals↗
PubMed2001

Population morphometric analysis of the tropicopolitan bug Triatoma rubrofasciata and relationships with old world species of Triatoma: evidence of New World ancestry.

Quantitative analysis of morphological characters of the head was used to reconstruct the evolutionary history of the tropicopolitan bug Triatoma rubrofasciata (De Geer) (Hemiptera: Reduviidae) and seven species of Old World Triatoma. Multivariate analysis demonstrates that T. rubrofasciata and the Old World species have a high degree of similarity with Nearctic Triatoma species, particularly T. rubida (Uhler). We interpret this to imply a common ancestry for these groups. Dissemination of T. rubrofasciata and subsequent derivation of the Old World species of Triatoma is deduced to have occurred over a period of not more than 350 years.

Animals↗
PubMedDate not supplied

[Biological susceptibility of Triatoma sordida and Triatoma infestans to deltamethrin and lambdacyhalothrin under field conditions].

The biological susceptibility of Triatoma sordida and Triatoma infestans to deltamethrin and lambdacyhalothrin was evaluated in three homogeneous groups of houses in the municipality of Posse, Goiás. Each group of houses was treated according to one of the following protocols: deltamethrin 5% wetted powder at 25 mg a.i./m2; deltamethrin 5% concentrated suspension at 25 mg a.i./m2; and lambdacyhalothrin 10% wetted powder at 30 mg a.i./m2. Monitoring of susceptibility to the insecticides was done after 90, 210, 270 and 360 days after the spraying. Each test consisted of an exposure of 10 third-instar nymphs of each species for every house. The insects were kept in contact with the sprayed wall for a period of 72 hours in plastic containers developed by WHO for studies with adult mosquitos. Thirty days after the exposure the death numbers were scored. Results demonstrate persistent activity of the three insecticides for up to a year after spraying and equal biological susceptibilities for both Triatoma sordida and Triatoma infestans to each formulation.

Animals↗
PubMed1987

Differences in binding of lectin-gold conjugates by Trypanosoma cruzi and Blastocrithidia triatomae (Trypanosomatidae) in the intestine of Triatoma infestans (Reduviidae).

Two species of trypanosomatid flagellates, Trypanosoma cruzi and Blastocrithidia triatomae which develop in the intestine of Triatoma infestans, were incubated with lectin-gold conjugates to demonstrate sugar components of the cell surface with the electron microscope. T. cruzi, strain "Chile 5" (zymodeme 1), bound SBA-gold, revealing N-acetyl-galactosamine and/or galactose residues. WGA-BSA-gold, specific for N-acetylglucosamine, did not bind to the surface of this flagellate. On the other hand, N-acetyl-glucosamine bound WGA-BSA-gold on the cell membrane of epimastigotes and cysts of B. triatomae, whereas SBA-gold was not bound by flagellates which were attached to the midgut epithelium and the rectum cuticle. Among other criteria, these differences in lectin binding may facilitate the discrimination of the two parasite species in the vector of Chagas' disease.

Animals↗
PubMed1990

Membrane feeding for infection of the reduviid bug Triatoma infestans with Blastocrithidia triatomae (Trypanosomatidae) and pathogenic effects of the flagellate.

To investigate the pathogenic effects of the trypanosome Blastocrithidia triatomae on Triatoma infestans, a method for direct infection by in vitro feeding was developed. After isolation of B. triatomae cysts from infected dead bugs, a suspension of cysts was disinfected with Desogen and Chloramin T, then mixed with sterile blood, spread on a sterile, parallel-grooved glass plate or a hammered aluminium plate and covered with a thin, sterile silicone membrane. The blood and plate were warmed to 36 degrees-38 degrees C by a heating plate. For investigation of the pathological effects, first instars of T. infestans were allowed to feed through the membrane on a mixture containing 10(6) cyst stages/cm3 blood. Development of about 30% of the third and fourth instar larvae was retarded as compared with that in uninfected control groups, and mortality rates increased in fourth and/or fifth instar larvae. Whereas total mortality rates of about 5% occurred in control groups, about 85% of the larvae died in the infected groups. These effects are very similar to those obtained in previous studies with coprophagic infections.

Animals↗
PubMed1988

Influence of Blastocrithidia triatomae (Trypanosomatidae) on the reduviid bug Triatoma infestans: alterations in the Malpighian tubules.

To investigate the cellular basis of our recent observation that the trypanosome Blastocrithidia triatomae disturbs excretion in Triatoma infestans, we compared the morphology and ultrastructure of Malpighian tubules in infected and noninfected bugs. Tubules of bugs infected 3-4 months before dissection did not show any morphological alterations in either the upper or lower regions. In fifth instars with a long lasting infection (9-10 months) and a correspondingly retarded larval development, the tracheal system supplying the Malpighian tubules was reduced and alterations were conspicuous in the upper region, where the tubules were slightly widened, sometimes having parts with conspicuous swellings. The cells were filled with white concretions and a strong autofluorescence was evident by fluorescence microscopy. Transmission electron microscopy demonstrated an increase in the number of these concretions, even after short infection periods. In the extremely swollen parts of the tubules there was a reduction in basal cell interdigitations, mitochondria, and microvilli. B. triatomae (but also gram-negative bacteria) occurred only in these swollen parts.

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PubMed2002

The development of Blastocrithidia triatomae (Trypanosomatidae) in the reduviid bug Triatoma infestans (Insecta): influence of starvation.

Fifth instars of Triatoma infestans with established Blastocrithidia triatomae infections were dissected after different periods of starvation. After a short starvation period of 30 days, 60% of the total population (2,700,000 flagellates) occurred in the small intestine. Within the following 3 months, the numbers of living flagellates there (epimastigotes, cysts) were reduced by about 70% and the percentage of dead mastigotes increased to 30% of the respective total population. Epimastigotes always dominated (about 90%), followed by cysts and only up to 3% spheromastigotes. These relations were only slightly changed by starvation. In the rectum, at 30-120 days after feeding, the total population of living epimastigotes was reduced by 90% and the percentage of those attached to the rectal wall decreased from 10% to <3%. During this period, the proportion of dead from all epimastigotes increased from 34% to >99%. In the rectum, the percentage of cysts from the total population of living parasites increased from 41% to 88% at 30-60 days after feeding and remained at this percentage and total numbers, showing that especially the early phase of starvation strongly induced the encystment of B. triatomae.

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PubMed1990

The effect of Blastocrithidia triatomae (Trypanosomatidae) on the reduviid bug Triatoma infestans: influence of group size.

Developmental time and mortality in uninfected larvae of the reduviid bug Triatoma infestans and in those infected by feeding a mixture of blood and cysts of the homoxenous trypanosomatid Blastocrithidia triatomae were compared. Larvae were maintained isolated in 77-cm3 (area 9.6 cm2) beakers or in groups of 20, 30, 40, and 50 bugs per 1-liter beaker (area 722 cm2). In uninfected groups, only a minor proportion of isolated bugs showed delayed development, but in groups infected with B. triatomae, additionally, a retardation in groups of 50 larvae occurred. Infected bugs needed more time to complete development in fourth and fifth instar than did uninfected bugs. Mean mortality rates of about 10% in uninfected groups were unaffected by group size. Mortality rates in most groups of infected bugs were about 50%, but in groups consisting of 50 larvae a statistically significant higher mortality rate of 75% was observed. This indicates a subpathological overcrowding stress, increased by the synergistic action of the flagellate.

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