Understanding the role of disease knowledge and risk perception in shaping preventive behavior for selected vector-borne diseases in Guyana

Background: Individual behavior, particularly choices about prevention, plays a key role in infection transmission of vector-borne diseases (VBDs). Since the actual risk of infection is often uncertain, individual behavior is influenced by the perceived risk. A low risk perception is likely to diminish the use of preventive measures (behavior). If risk perception is a good indicator of the actual risk, then it has important implications in a context of disease elimination. However, more research is needed to improve our understanding of the role of human behavior in disease transmission. The objective of this study is to explore whether preventive behavior is responsive to risk perception, taking into account the links with disease knowledge and controlling for individuals’ socioeconomic and demographic characteristics. More specifically, the study focuses on malaria, dengue fever, Zika and cutaneous leishmaniasis (CL), using primary data collected in Guyana–a key country for the control and/or elimination of VBDs, given its geographic location. Methods and findings: The data were collected between August and December 2017 in four regions of the country. Questions on disease knowledge, risk perception and self-reported use of preventive measures were asked to each participant for the four diseases. A structural equation model was estimated. It focused on data collected from private households only in order to control for individuals’ socioeconomic and demographic characteristics, which led to a sample size of 497 participants. The findings showed evidence of a bidirectional association between risk perception and behavior. A one-unit increase in risk perception translated into a 0.53 unit increase in self-reported preventive behavior for all diseases, while a one-unit increase in self-reported preventive behavior (i.e. the use of an additional measure) led to a 0.46 unit decrease in risk perception for all diseases (except CL). This study also showed that higher education significantly improves knowledge and that better knowledge increases the take up of preventive measures for malaria and dengue, without affecting risk perception. Conclusions: In trying to reach elimination, it appears crucial to promote awareness of the risks and facilitate access to preventive measures, so that lower risk perception does not translate into lower preventive behavior

Independent Emergence of the Plasmodium falciparum Kelch Propeller Domain Mutant Allele C580Y in Guyana

International audienceSuspected artemisinin resistance in Plasmodium falciparum can be explored by examining polymorphisms in the Kelch (PfK13) propeller domain. Sequencing of PfK13 and other gene resistance markers was performed on 98 samples from Guyana. Five of these samples carried the C580Y allele in the PfK13 propeller domain, with flanking microsatellite profiles different from those observed in Southeast Asia. These molecular data demonstrate independent emergence of the C580Y K13 mutant allele in Guyana, where resistance alleles to previously used drugs are fixed. Therefore, in Guyana and neighboring countries , continued molecular surveillance and periodic assessment of the therapeutic efficacy of artemisinin-based combination therapy are warranted

Variation in <i>Plasmodium falciparum</i> Histidine-Rich Protein 2 (<i>Pfhrp2</i>) and <i>Plasmodium falciparum</i> Histidine-Rich Protein 3 (<i>Pfhrp3</i>) Gene Deletions in Guyana and Suriname

<div><p>Guyana and Suriname have made important progress in reducing the burden of malaria. While both countries use microscopy as the primary tool for clinical diagnosis, malaria rapid diagnostic tests (RDTs) are useful in remote areas of the interior where laboratory support may be limited or unavailable. Recent reports indicate that histidine-rich protein 2 (PfHRP2)-based diagnostic tests specific for detection of <i>P</i>. <i>falciparum</i> may provide false negative results in some parts of South America due to the emergence of <i>P</i>. <i>falciparum</i> parasites that lack the <i>pfhrp2</i> gene, and thus produce no PfHRP2 antigen. <i>Pfhrp2</i> and <i>pfhrp3</i> genes were amplified in parasite isolates collected from Guyana and Suriname to determine if there were circulating isolates with deletions in these genes. <i>Pfhrp3</i> deletions were monitored because some monoclonal antibodies utilized in PfHRP2-based RDTs cross-react with the PfHRP3 protein. We found that all 97 isolates from Guyana that met the inclusion criteria were both <i>pfhrp2-</i> and <i>pfhrp3</i>-positive. In Suriname (N = 78), 14% of the samples tested were <i>pfhrp2</i>-negative while 4% were <i>pfhrp3</i>-negative. Furthermore, analysis of the genomic region proximal to <i>pfhrp2</i> and <i>pfhrp3</i> revealed that genomic deletions extended to the flanking genes. We also investigated the population substructure of the isolates collected to determine if the parasites that had deletions of <i>pfhrp2</i> and <i>pfhrp3</i> belonged to any genetic subtypes. Cluster analysis revealed that there was no predominant <i>P</i>. <i>falciparum</i> population substructure among the isolates from either country, an indication of genetic admixture among the parasite populations. Furthermore, the <i>pfhrp2</i>-deleted parasites from Suriname did not appear to share a single, unique genetic background.</p></div

Suspected locations where <i>P</i>. <i>falciparum</i> infections were acquired based on patient travel histories in regions with malaria transmission two weeks prior to malaria diagnosis in Guyana (Top; total N = 100), and Suriname (Bottom; total N = 78).

<p>The number of patients who reported travelling to a particular region (Guyana) or district (Suriname) is indicated in parentheses. The travel history of seven Suriname patients is unknown. Country maps reprinted from d-maps.com under a CC BY license, with permission from Daniel Dalet, original copyright 2007(<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126805#pone.0126805.s001" target="_blank">S1 Supporting Information</a>).</p

Proportion of deletions in (A) <i>pfhrp2</i>, (B) <i>pfhrp3</i> and their respective neighboring genes in <i>P</i>. <i>falciparum</i> isolates collected in Guyana (N = 97) and Suriname (N = 78).

<p>The three pie charts to the left of each figure illustrate the proportion of parasite isolates with gene deletions in Suriname samples, while the three pie charts to the right of each Fig show the proportion of isolates with gene deletions in Guyana samples. The percentages shown represent proportions of samples out of the total samples that were <i>18S RNA</i>- and <i>msp-2</i> positive.</p

Median joining network analysis of <i>P</i>. <i>falciparum</i> isolates collected in (A) Guyana (N = 97) and Suriname (N = 57) and (B) Suriname alone (N = 57).

<p>The genetic relationships among parasites were constructed using seven neutral microsatellite loci, which have been used previously to genetically characterize <i>P</i>. <i>falciparum</i> parasite populations in South America. <i>P</i>. <i>falciparum</i> parasite isolates from Guyana are shown in green while those collected in Suriname are rendered in red. Dotted circles indicate <i>pfhrp2</i>-negative isolates.</p