Banca de DEFESA: KEITHY WENNY PLASTER LIMA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : KEITHY WENNY PLASTER LIMA
DATE: 29/10/2024
TIME: 09:00
LOCAL: Sala Virtual Remota (Microsoft Teams) https://bit.ly/DefMSc_KeithyLima_PGBIOEXP
TITLE:

.

KEY WORDS:

Plasmodium; malaria diagnosis; Rapid Diagnostic Test (RDT); pfhrp2;
pfhrp3.

PAGES: 141
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

INTRODUÇÃO: 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 - 1786399 - DHELIO BATISTA PEREIRA
Externa à Instituição - SIMONE DA SILVA SANTOS