193 resultados para experimental sandfly infection


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The aim of this study was to experimentally evaluate infection in Gallus gallus domesticus with Neospora caninum tachyzoites of the NC-1 strain. Experimental infection was conducted in 90-day-old chickens, embryonated eggs and bioassays in dogs. In the first experiment, poults were randomly divided into four groups. Groups I and II were provided feed with coccidiostat, whereas groups III and IV received feed without coccidiostat. When the poults from groups I and III reached 90 days of age, they received a subcutaneous inoculation of N. caninum. Once the hens entered their egg-laying period, during the following 30 days, the eggs were collected, identified, weighed and placed in an incubator. On the 70th day after inoculation, all animals, including the chicks, were euthanized. Tissue samples from the adult poultry and chicks were collected for histopathology, immunohistochemistry (IHC) and PCR. Brain tissue and pectoral muscle samples from infected birds were fed to two dogs. Notably, the average weight of the group III eggs was lower than that of the group IV eggs (p <0.05). No changes consistent with infection in adult poultry or chicks were detected by histopathology or IHC; moreover, no amplified parasite DNA was detected in the birds'tissues or dogs'feces. No dog eliminated oocysts. In the second experiment, the embryonated chicken eggs were inoculated with 1 x 10(2) N. caninum tachyzoites, on the 10th day of incubation, and chicks born from these eggs were housed in boxes suitable for the species and received commercial feed and distilled water ad libitum. On the 30th day after infection (DAI), the poultry were euthanized, and their organs were processed as described in experiment I. The amplification of parasite DNA was observed in the spleen and pectoral muscles of one of the birds. The ingestion of bird tissues by dogs did not result in oocyst elimination. These results indicate that the parasite may have been eliminated by the host and that the use of tachyzoites to induce chronic disease might be a poor source for hens. (C) 2014 Elsevier B.V. All rights reserved.

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There are no studies investigating the role of nutritional status and immunity associated with Jorge Lobo's disease. The objective of this study was to evaluate the effects of protein-calorie malnutrition on the immune response of BALB/c mice inoculated with Lacazia loboi. In this study,the animals were divided into four groups: G1: inoculated with restricted diet, G2: not inoculated with restricted diet, G3: inoculated with regular diet, G4: not inoculated with regular diet. The animals of groups G1 and G2 were submitted to malnutrition for 20 days and once installed the animals were inoculated intradermally into the footpad. After 4 months, they were euthanised for the isolation of peritoneal lavage cells and removal of the footpad. The production of IL-2, IL-4, IL-10, IL-12, IFN-γ, TNF-α, H2 O2 and nitric oxide (NO) was evaluated in the peritoneal lavage cells. The footpad was evaluated regarding the size of macroscopic lesions, number of fungi and viability index. The results showed that the infection did not exert great influence on the body weight of the mice and previous malnutrition was an unfavourable factor for viability index, number of fungi, macroscopic lesion size in the footpad and production of H2 O2 , NO, IL-12, IL-10 and IFN-γ, suggesting that malnutrition significantly altered fungal activity and peritoneal cells. The results suggest considerable interaction between nutrition and immunity in Jorge Lobo's disease.

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In this study, we evaluated the interactions between Candida albicans, Candida krusei and Candida glabrata in mixed infections. Initially, these interactions were studied in biofilms formed in vitro. CFU/mL values of C. albicans were lower in mixed biofilms when compared to the single biofilms, verifying 77% and 89% of C. albicans reduction when this species was associated with C. glabrata and C. krusei, respectively. After that, we expanded this study for in vivo host models of experimental candidiasis. G. mellonella larvae were inoculated with monotypic and heterotypic Candida suspensions for analysis of survival rate and quantification of fungal cells in the haemolymph. In the groups with single infections, 100% of the larvae died within 18 h after infection with C. albicans. However, interaction groups achieved 100% mortality after 72 h of infection by C. albicans-C. glabrata and 96 h of infection by C. albicans-C. krusei. C. albicans CFU/mL values from larvae hemolymph were lower in the interacting groups compared with the monoespecies group after 12 h of infection. In addition, immunosuppressed mice were also inoculated with monotypic and heterotypic microbial suspensions to induce oral candidiasis. C. albicans CFU/mL values recovered from oral cavity of mice were higher in the group with single infection by C. albicans than the groups with mixed infections by C. albicans-C. glabrata and C. albicans-C. krusei. Moreover, the group with single infection by C. albicans had a higher degree of hyphae and epithelial changes in the tongue dorsum than the groups with mixed infections. We concluded that single infections by C. albicans were more harmful for animal models than mixed infections with non-albicans species, suggesting that C. albicans establish competitive interactions with C. krusei and C. glabrata during biofilm formation and development of experimental candidiasis.

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The treatment of schistosomiasis depends on a single drug: praziquantel (PZQ). However, this treatment presents limitations such as low and/or erratic bioavailability that can contribute to cases of tolerance. Improvements to the available drug are urgently needed and studies with a controlled system of drug release, like liposomes, have been gaining prominence. The present study evaluated the activity and synergy between liposomal-praziquantel (lip.PZQ) and hyperbaric oxygen therapy (HBO). Mice received doses of 60 or 100mg/kg PZQ or lip.PZQ, 50 days post-infection, and after the treatment, were exposed to HBO (3 atmosphere absolute - ATA) for 1h. The viability of adult worms and oviposition were analyzed, by necropsy and Kato-Katz examination performed after 15 days of treatment. A concentration of 100mg/kg of lip.PZQ+HBO was more effective (48.0% reduction of worms, 83.3% reduction of eggs/gram of feces) and 100% of the mice had altered of oograms (indicating interruption of oviposition) compared to other treatments and to the Control group (infected and untreated). It is known that PZQ requires participation of the host immune system to complete its antischistosomal activity and that HBO is able to stimulate the immune system. The drug became more available in the body when incorporated into liposomes and, used with HBO, the HBO worked as an adjuvant. This explains the decreases of oviposition and worms recovered form hepatic portal system.

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