Paracoccidioides lutzii, formerly known as 'Pb01-like' strains in the P. brasiliensis complex, is proposed as a new species based on phylogenetic and comparative genomics data, recombination analysis, and morphological characteristics. Conidia of P. lutzii are elongated, different from those of P. brasiliensis. P. lutzii occurs in the central and northern regions of Brazil. Studies comparing P. brasiliensis and P. lutzii may have significant clinical consequences for the diagnosis and treatment of paracoccidioidomycosis.

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Strongyloides venezuelensis is a parasitic nematode that has been used as a model to study human and animal strongyloidiasis. In this study, we compared the sensitivity between traditional methodologies and PCR assay to characterize the dynamics of S. venezuelensis infection and its migration route in Lewis rats subcutaneously infected with 4000 L3. The dynamics of the infection was determined by counting the number of eggs and by detecting parasite deoxyribonucleic acid in faeces samples. Both techniques similarly detected the infection at day 6 after larvae inoculation. However, PCR performed with the genus primer showed higher sensitivity during the recovery phase. Histological analysis and PCR assay were then used to follow parasite tissue migration. S. venezuelensis migration route included the muscular fibers below the skin, the pulmonary alveoli and the small intestine vilosities. The sensitivity of these two techniques to detect parasite's presence in these tissues was statistically similar.

We aimed to evaluate whether the occurrence of cryptic species of Paracoccidioides brasiliensis, S1, PS2, PS3 and Paracoccidioides lutzii, has implications in the immunodiagnosis of paracoccidioidomycosis (PCM). Small quantities of the antigen gp43 were found in culture filtrates of P. lutzii strains and this molecule appeared to be more variable within P. lutzii because the synonymous-nonsynonymous mutation rate was lower, indicating an evolutionary process different from that of the remaining genotypes. The production of gp43 also varied between isolates belonging to the same species, indicating that speciation events are important, but not sufficient to fully explain the diversity in the production of this antigen. The culture filtrate antigen AgEpm83, which was obtained from a PS3 isolate, showed large quantities of gp43 and reactivity by immunodiffusion assays, similar to the standard antigen (AgB-339) from an S1 isolate. Furthermore, AgEpm83 was capable of serologically differentiating five serum samples from patients from the Botucatu and Jundiaí regions. These patients had confirmed PCM but, were non-reactive to the standard antigen, thus demonstrating an alternative for serological diagnosis in regions in which S1 and PS2 occur. We also emphasise that it is not advisable to use a single antigen preparation to diagnose PCM, a disease that is caused by highly diverse pathogens.

Protease/anti-protease imbalance is the main pathogenic mechanism of emphysema and protease inhibitors have been recognized as potential molecules to treat the disease conditions. In this work the rBmTI-6 first domain (rBmTI-6-D1), a recombinant Kunitz-type serine proteinase inhibitor, was used to verify its effect in prevention or minimization of PPE-induced emphysema in mice. C57BL/6 mice were submitted to a PPE-induced emphysema model and treated with rBmTI-6-D1 before the emphysema development. We showed that the rBmTI-6-D1 treatment was sufficient to avoid the loss of elastic recoil, an effective decrease in alveolar enlargement and in the number of macrophages and lymphocytes in bronchoalveolar lavage fluid. Proteolytic analysis showed a significant increase in elastase activity in PPE-VE (induced emphysema) group that is controlled by rBmTI-6-D1. Kallikrein activity was decreased in the PPE-rBmTI6 (induced emphysema and inhibitor treated) group when compared to PPE-VE group. Although rBmTI-6-D1, did not present a neutrophil elastase (NE) inhibitory activity, the results show that the inhibitor interfered in the pathway of NE secretion in PPE-emphysema mice model. The role of rBmTI-6-D1 in the prevention of emphysema development in the mice model, apparently, is related with a control of inflammatory response due the trypsin/kallikrein inhibitory activity of rBmTI-6-D1.