Chloroquine and mefloquine resistance profiles are not related to the circumsporozoite protein (CSP) VK210 subtypes in field isolates of Plasmodium vivax from Manaus, Brazilian Amazon

• Main Authors: Lilian Rose Pratt-Riccio, Bárbara de Oliveira Baptista, Vanessa Rodrigues Torres, Cesare Bianco-Junior, Daiana de Souza Perce-Da-Silva, Evelyn Kety Pratt Riccio, Josué da Costa Lima-Junior, Paulo Renato Rivas Totino, Gustavo Capatti Cassiano, Luciane Moreno Storti-Melo, Ricardo Luiz Dantas Machado, Joseli de Oliveira-Ferreira, Dalma Maria Banic, Leonardo José de Moura Carvalho, Cláudio Tadeu Daniel-Ribeiro
• Format: Article
• Language: English
• Published: Instituto Oswaldo Cruz, Ministério da Saúde
• Series: Memórias do Instituto Oswaldo Cruz.
• Subjects: malaria; Plasmodium vivax; circumsporozoite protein; chemoresistance
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0074-02762019000100340&lng=en&tlng=en

BACKGROUND The central repetitive region (CRR) of the Plasmodium vivax circumsporozoite surface protein (CSP) is composed of a repetitive sequence that is characterised by three variants: VK210, VK247 and P. vivax-like. The most important challenge in the treatment of P. vivax infection is the possibility of differential response based on the parasite genotype. OBJECTIVES To characterise the CSP variants in P. vivax isolates from individuals residing in a malaria-endemic region in Brazil and to profile these variants based on sensitivity to chloroquine and mefloquine. METHODS The CSP variants were determined by sequencing and the sensitivity of the P. vivax isolates to chloroquine and mefloquine was determined by Deli-test. FINDINGS Although five different allele sizes were amplified, the sequencing results showed that all of the isolates belonged to the VK210 variant. However, we observed substantial genetic diversity in the CRR, resulting in the identification of 10 different VK210 subtypes. The frequency of isolates that were resistant to chloroquine and mefloquine was 11.8 and 23.8%, respectively. However, we did not observe any difference in the frequency of the resistant isolates belonging to the VK210 subtypes. MAIN CONCLUSION The VK210 variant is the most frequently observed in the studied region and there is significant genetic variability in the CRR of the P. vivax CSP. Moreover, the antimalarial drug sensitivity profiles of the isolates does not seem to be related to the VK210 subtypes.