Malaria in Venezuela: changes in the complexity of infection reflects the increment in transmission intensity.

Autor: Pacheco MA; Biology Department/Institute of Genomics and Evolutionary Medicine (iGEM), Temple University, Philadelphia, PA, USA., Forero-Peña DA; Escuela de Ciencias de la Salud, Universidad de Oriente, Núcleo Bolívar, Ciudad Bolívar, Venezuela.; Departamento de Medicina Interna, Complejo Hospitalario Universitario 'Ruíz y Páez', Ciudad Bolívar, Venezuela.; Biomedical Research and Therapeutic Vaccines Institute, Ciudad Bolívar, Venezuela., Schneider KA; Department CB, University of Applied Sciences Mittweida, Mittweida, Germany., Chavero M; Escuela de Ciencias de la Salud, Universidad de Oriente, Núcleo Bolívar, Ciudad Bolívar, Venezuela.; Departamento de Medicina Interna, Complejo Hospitalario Universitario 'Ruíz y Páez', Ciudad Bolívar, Venezuela.; Biomedical Research and Therapeutic Vaccines Institute, Ciudad Bolívar, Venezuela., Gamardo A; Biomedical Research and Therapeutic Vaccines Institute, Ciudad Bolívar, Venezuela., Figuera L; Departamento de Medicina Interna, Complejo Hospitalario Universitario 'Ruíz y Páez', Ciudad Bolívar, Venezuela.; Biomedical Research and Therapeutic Vaccines Institute, Ciudad Bolívar, Venezuela., Kadakia ER; Biology Department/Institute of Genomics and Evolutionary Medicine (iGEM), Temple University, Philadelphia, PA, USA., Grillet ME; Instituto de Zoología y Ecología Tropical, Universidad Central de Venezuela, Caracas, Venezuela., Oliveira-Ferreira J; Institute Oswaldo Cruz, Oswaldo Cruz Foundation, Fiocruz, Rio de Janeiro, Brazil., Escalante AA; Biology Department/Institute of Genomics and Evolutionary Medicine (iGEM), Temple University, Philadelphia, PA, USA. Ananias.Escalante@temple.edu.
Jazyk: angličtina
Zdroj: Malaria journal [Malar J] 2020 May 07; Vol. 19 (1), pp. 176. Date of Electronic Publication: 2020 May 07.
DOI: 10.1186/s12936-020-03247-z
Abstrakt: Background: Malaria incidence has reached staggering numbers in Venezuela. Commonly, Bolívar State accounted for approximately 70% of the country cases every year. Most cases cluster in the Sifontes municipality, a region characterized by an extractive economy, including gold mining. An increase in migration to Sifontes, driven by gold mining, fueled a malaria spillover to the rest of the country and the region. Here samples collected in 2018 were compared with a previous study of 2003/2004 to describe changes in the parasites population structures and the frequency of point mutations linked to anti-malarial drugs.
Methods: A total of 88 Plasmodium falciparum and 94 Plasmodium vivax isolates were collected in 2018 and compared with samples from 2003/2004 (106 P. falciparum and 104 P. vivax). For P. falciparum, mutations linked to drug resistance (Pfdhfr, Pfdhps, and Pfcrt) and the Pfk13 gene associated with artemisinin delayed parasite clearance, were analysed. To estimate the multiplicity of infection (MOI), and perform P. falciparum and P. vivax population genetic analyses, the parasites were genotyped by using eight standardized microsatellite loci.
Results: The P. falciparum parasites are still harbouring drug-resistant mutations in Pfdhfr, Pfdhps, and Pfcrt. However, there was a decrease in the frequency of highly resistant Pfdhps alleles. Mutations associated with artemisinin delayed parasite clearance in the Pfk13 gene were not found. Consistent with the increase in transmission, polyclonal infections raised from 1.9% in 2003/2004 to 39% in 2018 in P. falciparum and from 16.3 to 68% in P. vivax. There is also a decrease in linkage disequilibrium. Bayesian clustering yields two populations linked to the time of sampling, showing that the parasite populations temporarily changed. However, the samples from 2003/2004 and 2018 have several alleles per locus in common without sharing multi-locus genotypes.
Conclusions: The frequency of mutations linked with drug resistance in P. falciparum shows only changes in Pfdhps. Observations presented here are consistent with an increase in transmission from the previously circulating parasites. Following populations longitudinally, using molecular surveillance, provides valuable information in cases such as Venezuela with a fluid malaria situation that is affecting the regional goals toward elimination.
Databáze: MEDLINE
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