Dados do Trabalho

Título

Evaluation of parasite distribution at Leishmania braziliensis ulcerated lesion in golden hamster (Mesocricetus auratus).

Introdução

Cutaneous leishmaniasis (CL) is an infectious disease, transmitted by sandflies, caused by protozoa of the genus Leishmania and the main clinical manifestation are unique, rounded and painless ulcerated lesions. The distribution of parasites in the ulcerated lesion is not uniform and determining the region of the lesion with the highest parasite density and, consequently, the most appropriate place for collecting the clinical specimen, can define the success of the laboratory diagnosis. There are few studies in the literature describing the best region of the ulcerated lesion to collect samples for diagnostic.

Objetivo (s)

In this context the aim of our study was to evaluate the parasite load and viability, and also carry out a histopathological evaluation of the ulcer and external border to better understand parasite distribution in the ulcerated lesion.

Material e Métodos

Thirty-eight animals were infected with Leishmania braziliensis and observed until the development of an ulcerated lesion. The ulcer and outer edge of the ulcerated lesion were collected with a 2mm puncture. The samples were sectioned and conditioned in 10% formaldehyde 10% and RNAlater®. We used qPCR in order to determine the parasite load of Leishmania with primers directed to the kinetoplast DNA of the minicircle. Parasite viability was evaluated using RT-qPCR with primers targeting the 7SRLNA gene transcript. Histopathological examination was performed to evaluate the cellular profile, tissue alterations and semi-quantitative evaluation of amastigotes. Immunohistochemistry was used to quantify parasites as well.

Resultados e Conclusão

We found a higher parasite load in the ulcer by qPCR (P<0.0001). Likewise, a greater parasite load was found on ulcer by immunohistochemistry as well (P=0.0025). On the other hand, we found greater parasite activity in the outer edge of the lesion, expressed by the measurement of 7SLRNA transcripts, which correlates with the presence of live parasites. Regarding the histopathological evaluation, we found a greater parasite load in the ulcer. Predominantly poorly organized granulomas were found in the two regions of the ulcerated lesion.
These results suggest that the ulcer of the lesion is a viable site for collecting samples for the purposes of molecular and histopathologic diagnostic.

Palavras-chave

Leishmaniasis, parasite load, qPCR, Histopathology

Agradecimentos

Agradecemos o projeto Inova Fiocruz, pelo apoio financeiro adicional