Banca de QUALIFICAÇÃO: KEITHY WENNY PLASTER LIMA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : KEITHY WENNY PLASTER LIMA
DATE: 27/02/2024
TIME: 08:30
LOCAL: Sala Virtual Remora
TITLE:

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KEY WORDS:

Plasmodium; malaria diagnosis; Rapid Diagnostic Test (RDT); PfHRP2.

PAGES: 119
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

Malaria is an infectious disease caused by the parasite of the genus
Plasmodium. In Brazil, the species that infect humans are P. vivax, P. falciparum, and
P. malariae, with Plasmodium falciparum being the most lethal species. Despite
efforts to control the disease, 128,076 cases were recorded in the country in 2022.
Diagnostic techniques include routine microscopy, rapid diagnostic tests (RDTs) for
the detection of antigens from PfHRP2/3 genes, and Polymerase Chain Reaction
(PCR). Discrepancies between RDT and other techniques point to genetic variations
in Plasmodium, which can affect the diagnosis, control, and monitoring of malaria.
Despite the World Health Organization's recommendation for monitoring deletions in
PfHRP2/3 genes, such data are scarce in Brazil. OBJETIVO: Analyze the prevalence
of malaria through microscopy, immunochromatography, and molecular approaches,
including the study of genetic variations in P. falciparum. METODOLOGIA: This
study is approved by the CEP/CONEP system. Socio-epidemiological data and
venous blood samples from 995 patients were used for population characterization
and Plasmodium detection through thick blood smear microscopy, RDTs, and
molecular tests by qPCR. Additionally, for genetic diversity analyses, all positive
cases for P. falciparum underwent amplification of PfHRP2 and PfHRP3 genes
followed by Sanger sequencing. RESULTS AND CONCLUSION: The positive
diagnosis for malaria by microscopy was 40% of participants (394/995), while in
RDTs it was observed to be 41% (405/995), and by qPCR, it was 46% (457/995).
Through qPCR, it was also possible to detect the presence of one sample positive for
P. malariae and two samples with co-infection of P. vivax and P. falciparum. The
majority prevalence of Plasmodium vivax was observed in over 90% of cases.
Additionally, 18% (82/457) showed discordance in the identification of Plasmodium
species between microscopy and qPCR techniques, and 12% (57/457) were
discordant between RDTs and qPCR. Furthermore, evidence of deletions in PfHRP2
and PfHRP3 was identified for 8 cases positive by microscopy for Plasmodium
falciparum and negative by RDTs, as well as 4 cases positive by qPCR and negative
by RDTs. The presence of deletions observed in this study highlights the genetic
variability of Plasmodium falciparum in the population, with a high frequency of
deletion in PfHRP3 (94%; 48/51) and a significant frequency for PfHRP2 (18%; 9/51),
unlike what has been reported in previous studies. These findings are further
supported by the presence of significant amino acid substitutions and/or
deletions/insertions not previously described in the literature, with potential clinical
implications for diagnosis and treatment. Thus, the data from this study emphasize
the importance of epidemiological surveillance of malaria cases in the region.

COMMITTEE MEMBERS:
Externa à Instituição - ANNA CAROLINE CAMPOS AGUIAR - UNIFESP
Presidente - ***.429.088-** - CAROLINA BIONI GARCIA TELES - FIOCRUZ
Externa à Instituição - SIMONE DA SILVA SANTOS