240 resultados para Parasitism.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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This study evaluated the potential of congenital transmission in goats experimentally infected and reinfected with Toxoplasma gondii, in three gestational stages (initial, intermediate and final). Of the 25 non-pregnant females negative for T. gondii, 20 were orally inoculated with 2.5 x 103 T. gondii ME49 oocysts. Of these, 15 pregnant females chronically infected were reinoculated, via oral, with 2.5 x 103 T. gondii VEG oocysts. Five experimental groups were formed (n=5): I, II and III (reinoculations in the initial, intermediate and final gestational stage, respectively), IV (inoculation) and V (no inoculation). Clinical and serological exams (IgG IFAT [indirect immunofluorescence antibody test]) in different days of evaluation, and bioassay and PCR were performed in all goats. In the infected goats with T. gondii a peak of 40.2°C (IV) at nine, seroconversion (IgG≥64) at 21 and stabilization (IgG<1024) at 119 days postinoculation were observed. In the reinfected goats with T. gondii occurred an increase in IgG titers (≥1,024) at 28 (I), 7 (II) and 3 (III) days post-reinoculation. During kidding were observed only in the reinfected groups: dystocia, malformation body, stillbirth and weakness, and IgG anti-Toxoplasma were detected in all and in some offsprings of the reinfected and infected goats, respectively. Tissue parasitism by T. gondii was diagnosed by bioassay and PCR in infected and reinfected goats and in their offspring. The congenital toxoplasmosis was possible in goats chronically infected and reinfected with T. gondii. The primary infection with T. gondii did not protect the pregnant goats against congenital disease resulting from toxoplasmic reinfection, in different gestational stages (initial, intermediate and final).
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Pós-graduação em Ciências Biológicas (Zoologia) - IBRC
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Background: Buteo magnirostris, popularly known as roadside hawk belongs to the family Accipitridae, Ciconiiformes. The specimen is common throughout Brazil inhabiting open areas, tolerating disturbed areas very well, but avoiding dense forests. The trematodes are common parasites in the intestines of birds of prey, with scant notice of pathogenic infections. However, severe infections of trematodes Strigeidae family have been previously reported as a cause of anemia, diarrhea, enteritis, weight loss and death. This paper aims to report the occurrence of infection in S. Falconis in B. magnirostris diagnosed by post mortem examination. Case: The specimen of B. magnirostris, male, young was sent for necropsy at the Laboratory of Veterinary Pathology, Federal Rural University of Semi-Arid (UFERSA), Mossoró-RN, Brazil. With a history of apathy, anorexia, diarrhea and death in one course of 24 h. The free bird life and even puppy had been captured for training and practice of falconry shortly before the clinical manifestation of infection (time of captivity uninformed). On physical examination ruffled feathers, cachexia and pallor of skeletal muscle was observed. At necropsy there was severe enteritis with petechiae and accumulation of liquid contents into the duodenum. Fifty-two trematodes were found set in duodenal mucosa. The other organs and structures showed no changes. Fragments of all organs were harvested, fixed in 10% formalin buffered, routinely processed for histopathology and stained with hematoxylin and eosin (HE). Parasites were carefully collected, washed in saline, fixed, processed and identified according to the morphology and taxonomy. Histologically, the lesions were restricted to the duodenum and were characterized by melting, severe atrophy and necrosis of the epithelial cells of the intestinal villi; inflammatory infiltrate (consisting of lymphocytes, plasma cells and eosinophils) in the lamina propria, in addition to trematodes infiltrated the mucosa and lamina propria. These were 60-80 mm in diameter, consisted of parenchymal body enclosed by the integument. In some cross sections of the parasite was possible to observe the presence of cecum, testis and uterus, with some variations between sections; there were also yellowish eggs and coated with a delicate membrane. The trematodes contain approximately 1 mm in length and used as morphology and taxonomy has been identified as S. Falconis. Discussion: S. Falconis is a trematode intestinal parasite of birds of prey, with reports of its occurrence in Europe, North America and Central. In neotropical regions is described the occurrence of the subspecies S. Falconis brasiliana. Although the absence of clinical signs is a common pattern, parasitism by trematodes may become evident, common to captivity stress conditions, and thus infections, even for low pathogenic parasites can cause diarrhea, anorexia, weight loss and death, as reported in this paper. A factor that possibly contributed to the scant notice is its small size, which makes the observation of this parasite in analysis of necropsy in non-pathological conditions and also not familiar with the technical laboratories in the morphological shape of the eggs, which creates difficulty in finding the parasite in parasitological analysis in captive animals. Despite being considered poorly pathogenic trematodes, epidemiologically, the presence of the parasite should be considered a health risk to free-living predators, newly captive in parks, zoos, veterinary hospitals, triage center for wildlife and creators, as they may express pathogenicity in immunosuppressed animals. This work contributes to recording the presence S. falconis parasitizing the duodenal mucosa of B. magnirostris in Brazil.
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This is the first report on the parasitoid Palmistichus elaeisis, genus Eulophidae, found in the field parasitizing pupae of defoliating eucalyptus. Lepidopterous pests occur in eucalyptus plantations in Brazil, reaching high population levels. Due to the complexity of pest control in eucalyptus forests, alternative control methods have been proposed, for instance biological control through use of parasitoids. Natural enemies play an important role in regulating host populations because their larvae feed on the eggs, larvae, pupae or adults of other insects. The parasitic Hymenoptera are important agents in biological control programs against forest pests, and may provide economic and environmental benefits. The generalist endoparasitoid Palmistichus elaeisis Delvare and LaSalle, 1993 (Hymenoptera: Eulophidae) can develop in its host’s pupae, which overcome the host’s physiology and can therefore be used for biological control of agricultural and forest pests. This study aimed to evaluate the impact of P. elaeisis as a pupal parasitoid of S. violascens in providing a potential alternative to chemical control of the pest and creation of an alternative host. The experiment was developed in the Laboratory for Biological Control of Forest Pests, Universidade Estadual Paulista "Julio Mesquita Filho”. Parasitoids used in this test were originally collected on pupae of E. eucerus. (Lepidoptera: Riodinidae) in eucalyptus plantations at Lençois Paulistas, São Paulo state, Brazil, in 2011. Thereafter, a laboratory culture has been maintained, using pupae of Spodoptera frugiperda (J. E. Smith) (Lep.: Noctuidae) as hosts. S. violascens eggs were collected in a eucalyptus clonal plantation in Sao Paulo state (Brazil). Larvae were reared under ambient conditions on Eucalyptus urophylla S.T. Blake (Myrtaceae) leaves. The following parameters were determined: parasitism level, numbers of emerged and non-emerged parasitoids and duration of egg-adult cycle. The S. violascens pupae were dissected to evaluate the non-emerged parasitoids. The parasitism level reached 100%, with a 100% emergence rate. It was verified that 113.2±0.8 parasitoids emerged per individual pupa versus only 0.7±0.1 that did not emerge. The P. elaeisis egg-adult cycle was 20.3±0.6 days in S. violascens pupae. This opens new perspectives for utilizing this parasitoid in biological control programs against caterpillars important to forestry. Sarsina violascens in Brazil.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Sclerotia of Sclerotinia sclerotiorum (Ss) can survive for long time in soil and are the main inoculum source of the white mold disease. An alternative for reducing this inoculum is the use of parasites, such as Coniothyrium minitans (Cm). We evaluated the potential of Cm isolates for the biological control of Ss in beans. The effect of the temperature on the growth of 15 isolated of Cm was evaluated in vitro. The hyperparasitism ability of Cm was evaluated in soil infested with sclerotia and conditioned in pots. The infested soil was treated with conidia suspension of the antagonists, fluazinan or sterile distilled water. After seven days at 20°C, the sclerotia were removed from soil and placed inside Petri dishes over bean leaves previously disinfested. The germination and parasitism of sclerotia were evaluated after 7 to 10 days. To evaluate the apothecia emission, soil infested with sclerotia of Ss and treated as described was maintained at 18°C and the number of emerged apothecia was counted up to 84 days after inoculation. The emergence of bean plants in soil infested with sclerotia and mycelium of the pathogen and treated as described was evaluated in greenhouse. The ideal temperature for growth of Cm isolates varied from 18 to 19°C and at 30-35°C they were complete inhibited. The isolates of Cm promoted less than 10% of reduction in viability of the sclerotia, but they significantly reduced the emission of apothecia. Two isolates increased the emergence of plants in relation to the inoculated check, but was significantly lower than the non-inoculated check. Field tests will be conduct to confirm the potential of the selected isolates to reduce the inoculum source of the pathogen.
Biological control of the bronze bug, Thaumastocoris peregrinus, in eucalyptus plantations in Brazil
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The bronze bug Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae) was detected in Brazil in 2008 and infested >180 000 ha of eucalyptus plantations in 2011. The bronze bug can cause a reduction of 10–15% in wood productivity after 2 years of heavy infestation. Although there is not an effective control method known, biological control is the main control strategy studied. An exotic egg parasitoid, Cleruchoides noackae (Hymenoptera: Mymaridae), was imported from Australia in 2012, reared in a laboratory and released in three Brazilian regions. Parasitoids were recovered at release points after 20–30 d. In 2013, preliminary evaluations demonstrated parasitoid establishment in these areas, and the parasitoid was recovered in adjacent areas after 1 year of release. Bioassays confi rmed egg parasitism of 15–20% by C. noackae. Other native natural enemies were studied. We found green lacewing Chrysoperla externa and predatory bugs Supputius cincticeps and Atopozelus opsimus preying on nymphs and/or adults of T. peregrinus. Another promising possibility is entomopathogenic fungi. Commercial formulations of Beauveria bassiana were tested with success in lab and fi eld conditions. Fusarium proliferatum and Paecilomyces cateniannulatus caused mortality of T. peregrinus in natural epizooties. After 5 years of research, it is possible to develop an integrated pest management system (IPM) for eucalyptus plantations based on biocontrol strategy for bronze bug.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)