341 resultados para Eggs parasitoid
Resumo:
The aim of this note was to record for the first time the finding of Hemilucilia segmentaria acting as biological vector of Dermatobia hominis, during a study of the diversity of Calliphoridae at Reserva Biológica do Tinguá, Rio de Janeiro, Brazil. The insects were captured using traps baited with chicken vicera, for a period of 28-30 h twice per month. In the period of one year, 1987 insects were collected, 7.5% of which belonged to the H. segmentaria; of these a female was captured in May 2001, carrying a mass of 20 eggs on the left side of its abdomen.
Resumo:
Random amplified polymorphic DNA analysis was applied to DNAs extracted from Trichuris trichiura eggs recovered from human fecal samples. Four out of 6 primers tested displayed 18 distinct and well defined polymorphic patterns, ranging from 650 to 3200 base pairs. These results, upon retrieval and DNA sequencing of some of these bands from agarose gels, might help in establishing T. trichiura specific genetic markers, not available yet, and an important step to design primers to be used in molecular diagnosis approaches.
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Excavations at two sites dating from 2000 BC-1900 AD in southeastern areas of the Republic of Korea, revealed the remains of several structures. Examination of the contents suspected privies revealed the presence of eggs from 5 kinds of parasite: Ascaris, Trichuris, Clonorchis, and two species of unknown trematodes. Clonorchis sinensis eggs were found in a soil dating from around AD 668-935. This is the first record of C. sinensis eggs in archaeological materials in the Republic of Korea.
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On the archaeological site of Menez-Dregan in Brittany, France, dated 300,000-500,000 years-old, paleoparasitological analysis of cave deposits led to the detection of well-preserved helminth eggs, which morphology and morphometry pointed to the diagnosis of Toxocara canis eggs, a parasite of carnivore mammals. Paleolithic remains suggested a parasitism of the hyena Crocuta spelaea or other canids that inhabited the region.
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Schistosoma mansoni eggs are classified, according to morphological characteristics, as follows: viable mature and immature eggs; dead mature and immature eggs, shells and granulomas. The scope of this study was to compare the staining characteristics of different morphological types of eggs in the presence of fluorescent labels and vital dyes, aiming at differentiating live and dead eggs. The eggs were obtained from the intestines of infected mice, and put into saline 0.85%. The fluorescent labels were Hoechst 33258 and Acridine Orange + Ethidium Bromide and vital dyes (Trypan Blue 0.4% and Neutral Red 1%). When labelled with the probe Hoechst 33258, some immature eggs, morphologically considered viable, presented fluorescence (a staining characteristic detected only in dead eggs); mature eggs did not present fluorescence, and the other types of dead eggs, morphologically defined, showed fluorescence. As far as Acridine Orange + Ethidium Bromide are concerned, either the eggs considered to be live, or the dead ones, presented staining with green color, and only the hatched and motionless miracidium was stained with an orange color. Trypan Blue was not able to stain the eggs, considered to be dead but only dead miracidia which had emerged out of the shell. Neutral Red stained both live and dead eggs. Only the fluorescent Hoechst 33258 can be considered a useful tool for differentiation between dead and live eggs.
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Discriminant analysis was used to identify eggs of Capillaria spp. at specific level found in organic remains from an archaeological site in Patagonia, Argentina, dated of 6,540 ± 110 years before present. In order to distinguish eggshell morphology 149 eggs were measured and grouped into four arbitrary subsets. The analysis used on egg width and length discriminated them into different morphotypes (Wilks' lambda = 0.381, p < 0.05). The correlation analysis suggests that width was the most important variable to discriminate among the Capillaria spp. egg morphotypes (Pearson coefficient = 0.950, p < 0.05). The study of eggshell patterns, the relative frequency in the sample, and the morphometric data allowed us to correlate the four morphotypes with Capillaria species.
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The effect of relative humidity (43%, 75%, 86% and > 98%) on Aedes aegypti eggs treated with Metarhizium anisopliae or water only was tested for up to a six months exposure at 25ºC. Survival of larvae inside eggs was clearly affected by the lowest humidity (43%) tested, and eclosion diminished at all humidities after increasing periods of exposure. M. anisopliae showed to have a strong ovicidal activity only at humidity close to saturation. No difference of activity was found between conidia and hyphal bodies tested. This fungus affected larvae inside eggs and has potential as a control agent of this important vector in breeding sites with high moisture.
Comparative descriptions of eggs from three species of Rhodnius (Hemiptera: Reduviidae: Triatominae)
Resumo:
The authors describe and compare the morphological and ultrastructural characteristics of eggs from the three most recent described species of the genus Rhodnius Stål, 1859, which have not previously been studied. These species are Rhodnius colombiensis (Mejia, Galvão & Jurberg 1999), Rhodnius milesi (Carcavallo, Rocha, Galvão & Jurberg 2001) and Rhodnius stali (Lent, Jurberg & Galvão 1993). The results revealed that there are similarities in the exochorial architecture of optical microscopy and scanning electron microscopy; these include the predominance of hexagonal cells that are common to all Rhodnius species and variable degrees of lateral flattening, which is common not only to species of this genus, but also to the Rhodniini tribe. Differences in overall colour, the presence of a collar in R. milesi, a longitudinal bevel in R. stali and the precise length of R. colombiensis can be useful distinguishing features. As a result of this study, the key for egg identification proposed by Barata in 1981 can be updated.
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Eggs and nymphs of Triatoma dimidiata were described using both light and scanning electron microscopy. The egg body and operculum have an exochorion formed by irregular juxtaposed polygonal cells; these cells are without sculpture and the majority of them are hexagonal in shape. The five instars of T. dimidiatacan be distinguished from each other by characteristics of the pre, meso and metanotum. The number of setiferous tubercles increases progressively among instars. The sulcus stridulatorium of 1st instar nymphs is amorphous, showing median parallel grooves; from the 2nd instar on the sulcus is, progressively, elongate, deep and posteriorly pointed with stretched parallel grooves. All instars have a trichobothrium on the apical 1/3 of segment II of the antenna. The opening of the Brindley's gland is on the mesopleura. Fifth instar nymphs have an apical ctenidium on the ventral surface of the fore tibia. Dorsal glabrous patches are found on the lateral 1/3 of abdomen. Bright oval patches are found on the ventral median line of the abdomen, from segment IV-VI; 1st instar nymphs lack these patches. Abdominal dorsal plates are present from the 1st-5th instars; the 1st instar also contains a rectangular plate in segment IX. From the 2nd instar on, variably-shaped plates are present on segments VII to IX. Morphometric data were also obtained and proved to be useful for distinguishing T. dimidiata instars.
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Abdominal angiostrongyliasis is a potentially fatal zoonotic disease with a broad geographical distribution throughout Central and South America. This study assessed the performance of Angiostrongylus costaricensis eggs as the antigen in an indirect immunofluorescence assay for the determination of parasite-specific IgG and IgG1 antibodies. For prevalence studies, an IgG antibody titre > 16 was identified as the diagnostic threshold with the best performance, providing 93.7% sensitivity and 84.6% specificity. Cross reactivity was evaluated with 65 additional samples from patients with other known parasitic infections. Cross reactivity was observed only in samples from individuals infected with Strongyloides stercoralis. For clinical diagnosis, we recommend the determination of IgG only as a screening test. IgG1 determination may be used to increase the specificity of the results for patients with a positive screening test.
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The effect of multiple immersions on Haemagogus janthinomys , Haemagogus leucocelaenus , Aedes albopictus and Ochlerotatus terrens eggs was studied. Eggs were collected in April, June, October and December of 2011 in Minas Gerais, Brazil. Most of the Aedes and Ochlerotatus eggs hatched upon the first immersion, while Haemagogus eggs showed a varied instalment hatching response. The number of immersions required for hatching increased for eggs collected closer to the dry winter season.
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Trichogramma atopovirilia Oatman & Platner is an egg parasitoid of the corn earworm Helicoverpa zea (Boddie) (Lepidoptera, Noctuidae), and has recently been collected from eggs of Anticarsia gemmatalis Hübner on soybeans. In order to evaluate the suitability of A. gemmatalis eggs as hosts of T. atopovirilia, field surveys were conducted in 1999 and 2000 on corn and soybeans, and a colony of the parasitoid was established in laboratory. At 25 ºC, development from oviposition to emergence lasted nine days and a sex-ratio of 0.58 (females:males) was obtained. Females lived significantly longer (11.4 days) when kept in ovipositional activity, than in the absence of host eggs (6.6 days). Total fecundity averaged 104.5 parasitized eggs, resulting in the emergence of 138.3 descendents. Mean daily fecundity was highest (30 eggs/female) on the first day. Oviposition continued until one day before the death of the females, however 70% of the eggs were laid during the first four days after emergence. A female-biased progeny was produced during the first three days of oviposition, whereas further ovipositions were male-biased. Females lived significantly longer when exposed to host eggs in comparison to females deprived of eggs. The results show that eggs of A. gemmatalis are suitable for the development of T. atopovirilia, and this parasitoid should be considered in future programs of biological control of the velvetbean caterpillar.
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The parasitism behavior of Trichogramma atopovirilia and T. pretiosum in Spodoptera frugiperda eggs was evaluated focusing on the features related to the associative learning (alpha conditioning) and recognition of the egg parasitized by the female after the first oviposition experience. Females of both species were observed to recognize the parasitized egg, which takes place after the female drills into the host egg. Following oviposition, 43.59% and 67.53 of females began to feed with an average feeding time of 73.26 ± 11.57 and 64.04 ± 7.05 seconds for T. atopovirilia and T. pretiosum, respectively. The time elapsed in each step of the parasitism behavior significantly decreased after the first oviposition experience, with a trend to stabilize after the 2nd or 3rd egg parasitized, indicating associative learning in these Trichogramma species.
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Life table analyses have been developed to understanding the impact of various sources of intrinsic and extrinsic mortalities on the rate of population growth. The understanding of the population increase of the parasitoids related to their hosts is important in biological control programs. This work had as objective to evaluate the survival and fertility of the parasitoid Lysiphlebus testaceipes (Cresson, 1880) on Schizaphis graminum (Rondani, 1852) as a host under fertility life table. The experiment were carried out in a climatic chamber at 25 ± 1ºC, RH 60 ± 10% and 10h photophase. To determine the immature mortality, the development time and the sex ratio of the parasitoid, 12 females of the parasitoid (less than one day old) and 240 nymphs of S. graminum (3 days old) were used. To evaluate the longevity and fertility of L. testaceipes, 15 females (less than one day old) were used. Nymphs of S. graminum (3 days old) were offered for each parasitoid female daily, until the female died, being in the 1st day - 300 nymphs; 2nd day - 250 nymphs; 3rd day - 200 nymphs; 4th day - 150 and in the other days a number of 50 nymphs. L. testaceipes had an immature mortality of 22,2%, and a development time of males and females of 9.0 and 9.1 days, respectively. The females of L. testaceipes laid, in it first life day, 257.8 eggs, and they survived up until seven days. The net reproduction rate (Ro) and the intrinsic rate of increase (r m) were respectively, 301.9 and 0.513. The finite rate of increase (l) was 1.67 females per day, the mean length of a generation (T) was 11.13 days and the time to duplicate the population (TD) was 1.35 weeks. The parasitoid L. testaceipes have a high potential of population growth on S. graminum as a host under the analyzed conditions.
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Egg ultrastructure of two morphologicaly similar species of the Arribalzagia Series, Anopheles (A.) costai Fonseca & Ramos, 1939 and A. (A.) mediopunctatus (Lutz, 1903) are described and illustrated using scanning electron micrographs. Although similar in the adult stage, male genitalia structures and larval and pupal stages, the eggs of these species are distinct. The eggs of A. costai and A. mediopunctatus are compared with that of A. forattinii Wilkerson & Sallum, 1999. Incomplete illustration of egg of A. forattinii is provided for comparison.