Spatiotemporal Changes in Plasmodium vivax msp142 Haplotypes in Southern Mexico: From the Control to the Pre-Elimination Phase.

Alejandro Flores-Alanis,Cecilia Ximenez,Marco A Sandoval-Bautista,Rene Cerritos,Frida Santillán-Valenzuela,Lilia González-Cerón

doi:10.3390/microorganisms10010186

Alejandro Flores-Alanis, Cecilia Ximenez + Show 4 more

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https://doi.org/10.3390/microorganisms10010186

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Abstract

For 20 years, Plasmodium vivax has been the only prevalent malaria species in Mexico, and cases have declined significantly and continuously. Spatiotemporal genetic studies can be helpful for understanding parasite dynamics and developing strategies to weaken malaria transmission, thus facilitating the elimination of the parasite. The aim of the current contribution was to analyze P. vivax-infected blood samples from patients in southern Mexico during the control (1993–2007) and pre-elimination phases (2008–2011). Nucleotide and haplotype changes in the pvmsp142 fragment were evaluated over time. The majority of multiple genotype infections occurred in the 1990s, when the 198 single nucleotide sequences exhibited 57 segregating sites, 64 mutations, and 17 haplotypes. Nucleotide and genetic diversity parameters showed subtle fluctuations from across time, in contrast to the reduced haplotype diversity and the increase in the R2 index and Tajima’s D value from 2008 to 2011. The haplotype network consisted of four haplogroups, the geographical distribution of which varied slightly over time. Haplogroup-specific B-cell epitopes were predicted. Since only high-frequency and divergent haplotypes persisted, there was a contraction of the parasite population. Given that 84% of haplotypes were exclusive to Mesoamerica, P. vivax flow is likely circumscribed to this region, representing important information for parasite surveillance.

Highlights

Introduction published maps and institutional affilThere are approximately 241 million malaria cases per year worldwide and 627,000 related deaths, according to the estimates of the World Health Organization (WHO) [1].In Mexico, the number of cases fluctuated between 20,000 and 130,000 per year in the 1980s.In the following decade, the anti-malaria measures of the intensified control programs caused a gradual decrease in cases.Anti-malarial control measures are implemented when the burden of malaria infection becomes an important public health problem and the slide positivity rate of fever cases is above 5%
The moderate level of nucleotide haplodiversity allowed for the evaluation of of transmission dynamics type diversity allowed for the evaluation transmission dynamicsduring duringthe thecontrol control and pre-elimination phases (2002–2011)
There were only subtle variations in the nucleotide and genetic diversity for pvmsp142, the haplotype diversity diminished and the R2 index of linkage disequilibrium (LD) increased in samples from the pre-elimination period

Summary

Introduction

In Mexico, the number of cases fluctuated between 20,000 and 130,000 per year in the 1980s. Anti-malarial control measures are implemented when the burden of malaria infection becomes an important public health problem and the slide positivity rate of fever cases is above 5%. The latter rate is a method for analyzing changes in malaria incidence; if it drops below 5% and certain other requirements are met, a country may enter the pre-elimination phase, which consists of the evaluation and reorientation of anti-malaria policies and strategies with the aim of continually reducing the number of cases [2]. Mexico has remained in the pre-elimination phase since 2007

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