Padronização da técnica de imunocitoquímica no diagnóstico da leishmaniose visceral canina

Abstract

Leishmaniasis are diseases caused for protozoa of the genus Leishmania, a parasite that infects and multiplies in cells of the monocytic phagocytic system of several animal species. They are diseases framed as neglected by the World Health Organization (WHO) and affecting populations in several countries. In Brazil they are already present in all the regions, causing damages to the public health and wages with treatments and prevention. Previously associated with rural areas, leishmaniasis today also affect urban populations and dogs are considered the main LV reservoirs in these environments. The transmission of the parasite occurs when the phlebotomine insect ingests infectious forms of leishmania when performing blood ingestion in infected animals, being able to transmit these parasites in new ingestion. For the diagnosis of VL, the Rapid Immunochromatographic Test (TRI) for screening and the Enzyme Linked Immunosorbent Assay (ELISA) or Immunoenzymatic Assay (EIE) and the Direct Immunofluorescence Reaction (IFR) tests, in addition to the Polymerase Chain Reaction (PCR) and direct examination as confirmatory. Direct examination, with the observation of the parasite in biological samples, is considered gold standard test, but requires personnel trained in the ide ntification of the protozoan in the sample. Methods such as immunocytochemistry may increase the accuracy of this observation. The present work compared 4 techniques for the preparation of cytological samples (cellblock, 10% formaldehyde, methanol and paraformaldehyde / PBS) extracted from bone marrow, skin and lymph node of 20 dogs seropositive to Leishmania sp., Submitted to an immunocytochemistry protocol (ICQ) . With the ICQ protocol, a 15% positive increase in bone marrow ICQ was observed in relation to cytopathological examination, 30% in lymph node analysis and 5% in skin when compared to cytopathological tests, thus increasing the efficiency of the diagnosis. The techniques of fixation of the biological material presented satisfactory immunostaining with better results obtained by the agarose cellblock technique followed by fixation in 10% formaldehyde and paraffin embedding, fixation in alcohol methanol and lastly the fixation technique in paraformaldehyde / PBS.