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Prevalence of pfhrp2 and pfhrp3 gene deletions in Puerto Lempira, Honduras.

Abdallah JF, Okoth SA, Fontecha GA, Torres RE, Banegas EI, Matute ML, Bucheli ST, Goldman IF, de Oliveira AM, Barnwell JW, Udhayakumar V - Malar. J. (2015)

Bottom Line: It was found that all samples were positive for pfhrp2 and its flanking genes on chromosome 8.It was also determined that a greater proportion of parasites with pfhrp3-(and flanking gene) deletions belonged to one cluster compared to the other.The findings indicate that the P. falciparum parasite population in the municipality of Puerto Lempira maintains the pfhrp2 gene and that PfHRP2-based RDTs could be considered for use in this region; however continued monitoring of parasite population will be useful to detect any parasites with deletions of pfhrp2.

View Article: PubMed Central - PubMed

Affiliation: Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, 1600 Clifton Road, MS D-67, Atlanta 30333, GA, USA. vxu0@cdc.gov.

ABSTRACT

Background: Recent studies have demonstrated the deletion of the histidine-rich protein 2 (PfHRP2) gene (pfhrp2) in field isolates of Plasmodium falciparum, which could result in false negative test results when PfHRP2-based rapid diagnostic tests (RDTs) are used for malaria diagnosis. Although primary diagnosis of malaria in Honduras is determined based on microscopy, RDTs may be useful in remote areas. In this study, it was investigated whether there are deletions of the pfhrp2, pfhrp3 and their respective flanking genes in 68 P. falciparum parasite isolates collected from the city of Puerto Lempira, Honduras. In addition, further investigation considered the possible correlation between parasite population structure and the distribution of these gene deletions by genotyping seven neutral microsatellites.

Methods: Sixty-eight samples used in this study, which were obtained from a previous chloroquine efficacy study, were utilized in the analysis. All samples were genotyped for pfhrp2, pfhrp3 and flanking genes by PCR. The samples were then genotyped for seven neutral microsatellites in order to determine the parasite population structure in Puerto Lempira at the time of sample collection.

Results: It was found that all samples were positive for pfhrp2 and its flanking genes on chromosome 8. However, only 50% of the samples were positive for pfhrp3 and its neighboring genes while the rest were either pfhrp3-negative only or had deleted a combination of pfhrp3 and its neighbouring genes on chromosome 13. Population structure analysis predicted that there are at least two distinct parasite population clusters in this sample population. It was also determined that a greater proportion of parasites with pfhrp3-(and flanking gene) deletions belonged to one cluster compared to the other.

Conclusion: The findings indicate that the P. falciparum parasite population in the municipality of Puerto Lempira maintains the pfhrp2 gene and that PfHRP2-based RDTs could be considered for use in this region; however continued monitoring of parasite population will be useful to detect any parasites with deletions of pfhrp2.

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Related in: MedlinePlus

Bayesian cluster analysis ofP. falciparumsingly-infected samples collected from Puerto Lempira, Honduras (N = 65). The predicted number of likely clusters (K) for the samples was K = 2. Each color corresponds to a population cluster as classified by Structure v2.3.3, and each individual isolate is represented by a vertical bar. The Y axis represents the estimated proportion of membership of an individual to each population.
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Fig3: Bayesian cluster analysis ofP. falciparumsingly-infected samples collected from Puerto Lempira, Honduras (N = 65). The predicted number of likely clusters (K) for the samples was K = 2. Each color corresponds to a population cluster as classified by Structure v2.3.3, and each individual isolate is represented by a vertical bar. The Y axis represents the estimated proportion of membership of an individual to each population.

Mentions: We performed neutral microsatellite genotyping and cluster analysis to determine if the population structure correlated with pfhrp3-deleted parasites. Structure analysis predicted the presence of at least two clusters of parasites (K = 2; Figure 3). Twenty-seven samples belonged to the first cluster (designated Cluster 1) while 37 were assigned to Cluster 2 (Figure 3). One isolate belonging to Cluster 1 was MAL13P1.475-negative (3.7%), six were MAL13P1.475/pfhrp3-negative (22.2%) and one had deleted all three genes (3.7%) (Table 2). Among the samples assigned to Cluster 2, two were MAL13P1.475-negative (5.3%), twelve isolates were MAL13P1.475/pfhrp3-negative (32.4%) while eight were MAL13P1.475/pfhrp3/MAL13P1.485 triple-negative (21.6%) (Table 2). In order to assess genetic differentiation due to population substructure, pair-wise Fst values were calculated, and found that Clusters 1 and 2 presented moderate genetic differentiation (0.12146; p-value < 0.05).Figure 3


Prevalence of pfhrp2 and pfhrp3 gene deletions in Puerto Lempira, Honduras.

Abdallah JF, Okoth SA, Fontecha GA, Torres RE, Banegas EI, Matute ML, Bucheli ST, Goldman IF, de Oliveira AM, Barnwell JW, Udhayakumar V - Malar. J. (2015)

Bayesian cluster analysis ofP. falciparumsingly-infected samples collected from Puerto Lempira, Honduras (N = 65). The predicted number of likely clusters (K) for the samples was K = 2. Each color corresponds to a population cluster as classified by Structure v2.3.3, and each individual isolate is represented by a vertical bar. The Y axis represents the estimated proportion of membership of an individual to each population.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4308922&req=5

Fig3: Bayesian cluster analysis ofP. falciparumsingly-infected samples collected from Puerto Lempira, Honduras (N = 65). The predicted number of likely clusters (K) for the samples was K = 2. Each color corresponds to a population cluster as classified by Structure v2.3.3, and each individual isolate is represented by a vertical bar. The Y axis represents the estimated proportion of membership of an individual to each population.
Mentions: We performed neutral microsatellite genotyping and cluster analysis to determine if the population structure correlated with pfhrp3-deleted parasites. Structure analysis predicted the presence of at least two clusters of parasites (K = 2; Figure 3). Twenty-seven samples belonged to the first cluster (designated Cluster 1) while 37 were assigned to Cluster 2 (Figure 3). One isolate belonging to Cluster 1 was MAL13P1.475-negative (3.7%), six were MAL13P1.475/pfhrp3-negative (22.2%) and one had deleted all three genes (3.7%) (Table 2). Among the samples assigned to Cluster 2, two were MAL13P1.475-negative (5.3%), twelve isolates were MAL13P1.475/pfhrp3-negative (32.4%) while eight were MAL13P1.475/pfhrp3/MAL13P1.485 triple-negative (21.6%) (Table 2). In order to assess genetic differentiation due to population substructure, pair-wise Fst values were calculated, and found that Clusters 1 and 2 presented moderate genetic differentiation (0.12146; p-value < 0.05).Figure 3

Bottom Line: It was found that all samples were positive for pfhrp2 and its flanking genes on chromosome 8.It was also determined that a greater proportion of parasites with pfhrp3-(and flanking gene) deletions belonged to one cluster compared to the other.The findings indicate that the P. falciparum parasite population in the municipality of Puerto Lempira maintains the pfhrp2 gene and that PfHRP2-based RDTs could be considered for use in this region; however continued monitoring of parasite population will be useful to detect any parasites with deletions of pfhrp2.

View Article: PubMed Central - PubMed

Affiliation: Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, 1600 Clifton Road, MS D-67, Atlanta 30333, GA, USA. vxu0@cdc.gov.

ABSTRACT

Background: Recent studies have demonstrated the deletion of the histidine-rich protein 2 (PfHRP2) gene (pfhrp2) in field isolates of Plasmodium falciparum, which could result in false negative test results when PfHRP2-based rapid diagnostic tests (RDTs) are used for malaria diagnosis. Although primary diagnosis of malaria in Honduras is determined based on microscopy, RDTs may be useful in remote areas. In this study, it was investigated whether there are deletions of the pfhrp2, pfhrp3 and their respective flanking genes in 68 P. falciparum parasite isolates collected from the city of Puerto Lempira, Honduras. In addition, further investigation considered the possible correlation between parasite population structure and the distribution of these gene deletions by genotyping seven neutral microsatellites.

Methods: Sixty-eight samples used in this study, which were obtained from a previous chloroquine efficacy study, were utilized in the analysis. All samples were genotyped for pfhrp2, pfhrp3 and flanking genes by PCR. The samples were then genotyped for seven neutral microsatellites in order to determine the parasite population structure in Puerto Lempira at the time of sample collection.

Results: It was found that all samples were positive for pfhrp2 and its flanking genes on chromosome 8. However, only 50% of the samples were positive for pfhrp3 and its neighboring genes while the rest were either pfhrp3-negative only or had deleted a combination of pfhrp3 and its neighbouring genes on chromosome 13. Population structure analysis predicted that there are at least two distinct parasite population clusters in this sample population. It was also determined that a greater proportion of parasites with pfhrp3-(and flanking gene) deletions belonged to one cluster compared to the other.

Conclusion: The findings indicate that the P. falciparum parasite population in the municipality of Puerto Lempira maintains the pfhrp2 gene and that PfHRP2-based RDTs could be considered for use in this region; however continued monitoring of parasite population will be useful to detect any parasites with deletions of pfhrp2.

Show MeSH
Related in: MedlinePlus