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Leishmaniasis, a zoonosis of worldwide distribution, presents a significant impact on immunosupressed patients. This study aimed to evaluate Leishmania chagasi infection in BALB/c mice immunosuppressed with dexamethasone. Spleen cells stimulated or not with L. chagasi were cultured for cytokine quantification (IFN-γ, IL-2, IL-4 and IL-10) by sandwich ELISA. Parasite loads in the spleen and liver were determined by means of culture microtitration. Immunosuppressed groups showed statistically lower spleen weight and CD4-cell percentage in blood on the day of infection and produced Th1 and Th2 cytokines on other days of the study. The other infected groups, weather immunosupressed or not, also produced Th1 and Th2 cytokines. Parasite loads in the spleen and liver were not statistically different among the groups. It was concluded that L. chagasi infection was not affected by dexamethasone-induced immunosuppression, probably due the reversible effect of the treatment.

Canine visceral leishmaniasis (CVL) is endemic in numerous Brazilian regions. The greatest difficulty in controlling the disease is the diagnostic limitation. In the present study, the most common tests employed for visceral leishmaniasis diagnosis were compared: immunofluorescence antibody test (IFAT), immunoenzymatic assay (ELISA), direct parasitological examination and polymerase chain reaction (PCR). Samples of lymph node aspirates and blood were collected from 100 dogs that lived in an endemic area (Bauru city, São Paulo state) and from 100 negative controls from a non-endemic area (Botucatu city, São Paulo state). Specificity of both IFAT and PCR was 100% whereas ELISA was 99%. Sensitivities were 97.77, 93.33 and 91.11% respectively for IFAT, ELISA and PCR.

The immune response in leishmaniasis may result in a polarization of the T lymphocyte subpopulation, altering cell phenotype and resulting in immune protection or disease exacerbation. Leishmania may persist in the body either during asymptomatic infections or after treatment, which represents high risk under immunosuppression. The objective of this study was to evaluate the effect of infection with immunosuppression by dexamethasone associated with pentoxifylline on animal weight, spleen weight, spleen and hepatic parasitic load and immunopathology, as well as the IFN-γ and IL-10 production in spleen cell culture of Balb/c mice infected with Leishmania chagasi. The infection did not cause body weight gain in animals, but both the weight and size of the spleen were increased. The immunosuppression using dexamethasone associated with pentoxifylline affected body weight gain and spleen weight and size in both infected and non-infected animals. The immunosuppression did not significantly alter the course of the splenic or hepatic parasite burden. Dexamethasone and pentoxifylline significantly affected cytokine production, but did not influence the Th1/Th2 ratio in infected animals.

The extent of genomic variability of clones of Schistosoma mansoni obtained from field isolates was compared with that of strains that have been laboratory maintained. Analysis was undertaken using randomly amplified polymorphic dNAs (RAPDs) generated with three primers. Phenograms showing the similarity among the clones were constructed. The data showed that while the laboratory strain is highly homogeneous the clones derived from the field populations were highly variable with 43% of RAPDs exhibiting polymorphisms among 23 clones. Clones isolated from the same infected individual were always more closely grouped than clones from different individuals. The data clearly demonstrated that earlier analyses of the genomic variability in S. mansoni have underestimated this phenomenon due to the failure to examine field isolates

Index code	Element
ti	article title
au	author
kw	article keywords
subject	subject (title words, abstract and keywords)
ab	abstract
ta	journal short title (e.g. Cad. Saúde Pública)
journal_title	journal full title (e.g. Cadernos de Saúde Pública)
la	publication language code (e.g. pt - Portuguese, es - Spanish)
type	document type
pid	publication identifier
publication_year	publication year of publication
sponsor	sponsor
aff_country	country code of the author's affiliation
aff_institution	author affiliation institution
volume	article volume
issue	article issue
elocation	elocation
doi	DOI number
issn	journal ISSN
in	SciELO colection code (e.g. scl - Brasil, col - Colômbia)
use_license	article usage license code

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