Leishmania (Viannia) shawi purified antigens confer protection against murine cutaneous leishmaniasis

First Report of an Asymptomatic Leishmania (Viannia) shawi Infection Using a Nasal Swab in Amazon, Brazil

The state of Pará has recorded seven Leishmania species that cause tegumentary leishmaniasis (TL). Leishmania species induce distinct immunological responses from the host and exhibit resistance to Glucantime, the first-line drug treatment for TL in Brazil.

OBJECTIVE

Identify the etiology of TL in an Amazonian city in the state of Pará.

MATERIAL AND METHODS

Eleven patients with TL were recruited and nasal swabs, lesion swabs, and skin fragments samples were collected. In the control group (n = 6), only the nasal swabs were collected. Polymerase Chain Reaction (PCR) amplification of the gene region hsp70-234 was performed using the extracted DNA from the samples, from which nine patients with TL and five in the control group were positive. Products were sequenced, mounted in CAP3 software, aligned using MAFFT v.7.221, edited in Geneious software v.8.1.7, and compared and aligned with sequences available in GenBank using the BLAST tool.

RESULTS

For patients with TL, six molecular diagnosis at the species level (L. (Viannia) braziliensis (n = 5/9), L. (Viannia) shawi (n = 1/9)) and three at the genus level (Leishmania sp. (n = 3/9)) were obtained. In the control group, four individuals were infected with Leishmania sp. (n = 4/5) and L. (V.) shawi (n = 1/5).

CONCLUSION

This is the first report of L. (V.) shawi infection in the mucosal secretion of a healthy person in Brazil. Moreover, genetic variants were identified in the haplotypes of L. (V.) braziliensis in the gene sequence hsp70-234.

Treatment with triterpenic fraction purified from Baccharis uncinella leaves inhibits Leishmania (Leishmania) amazonensis spreading and improves Th1 immune response in infected mice

The current medications used to treat leishmaniasis have many side effects for patients; in addition, some cases of the disease are refractory to treatment. Therefore, the search for new leishmanicidal compounds is indispensable. Recently, it was demonstrated that oleanolic- and ursolic-containing fraction from Baccharis uncinella leaves eliminated the promastigote and amastigote forms of Leishmania (Leishmania) amazonensis and L. (Viannia) braziliensis without causing toxic effects for J774 macrophages. Thus, the aim of the present work was to characterize the therapeutic effect of the triterpenic fraction in L. (L.) amazonensis-infected BALB/c mice. Oleanolic- and ursolic acid-containing fraction was extracted from B. uncinella leaves using organic solvents and chromatographic procedures. L. (L.) amazonensis-infected BALB/c mice were treated intraperitoneally with triterpenic fraction during five consecutive days with 1.0 and 5.0 mg/kg of triterpenic fraction, or with 10.0 mg/kg of amphotericin B drug. Groups of mice treated with the triterpenic fraction, presented with decreased lesion size and low parasitism of the skin-both of which were associated with high amounts of interleukin-12 and interferon gamma. The curative effect of this fraction was similar to amphotericin B-treated mice; however, the final dose, required to eliminate amastigotes, was lesser than amphotericin B. Moreover, triterpenic fraction did not cause microscopic alterations in liver, spleen, heart, lung, and kidney of experimental groups. This work suggests that this fraction possesses compounds that are characterized by leishmanicidal and immunomodulatory activities. From this perspective, the triterpenic fraction can be explored as a new therapeutic agent for use against American Tegumentar Leishmaniasis.