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Molecular epidemiology of Plasmodium vivax and Plasmodium falciparum malaria among Duffy-positive and Duffy-negative populations in Ethiopia.

Lo E, Yewhalaw D, Zhong D, Zemene E, Degefa T, Tushune K, Ha M, Lee MC, James AA, Yan G - Malar. J. (2015)

Bottom Line: Parasite gene copy number was measured by quantitative real-time PCR and compared between symptomatic and asymptomatic samples, as well as between children/adolescents and adults from the local community.The prevalence of P. vivax and P. falciparum malaria is the highest in children compared to adolescents and adults.Samples from asymptomatic individuals show a significantly lower parasite gene copy number than those from symptomatic infections for P. vivax and P. falciparum.

View Article: PubMed Central - PubMed

Affiliation: Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA. eugenia.loyy@gmail.com.

ABSTRACT

Background: Malaria is the most prevalent communicable disease in Ethiopia, with 75% of the country's landmass classified as endemic for malaria. Accurate information on the distribution and clinical prevalence of Plasmodium vivax and Plasmodium falciparum malaria in endemic areas, as well as in Duffy-negative populations, is essential to develop integrated control strategies.

Methods: A total of 390 and 416 community and clinical samples, respectively, representing different localities and age groups across Ethiopia were examined. Malaria prevalence was estimated using nested PCR of the 18S rRNA region. Parasite gene copy number was measured by quantitative real-time PCR and compared between symptomatic and asymptomatic samples, as well as between children/adolescents and adults from the local community. An approximately 500-bp segment of the human DARC gene was amplified and sequenced to identify Duffy genotype at the -33rd nucleotide position for all the clinical and community samples.

Results: Plasmodium vivax prevalence was higher in the south while P. falciparum was higher in the north. The prevalence of P. vivax and P. falciparum malaria is the highest in children compared to adolescents and adults. Four P. vivax infections were detected among the Duffy-negative samples. Samples from asymptomatic individuals show a significantly lower parasite gene copy number than those from symptomatic infections for P. vivax and P. falciparum.

Conclusions: Geographical and age differences influence the distribution of P. vivax and P. falciparum malaria in Ethiopia. These findings offer evidence-based guidelines in targeting malaria control efforts in the country.

No MeSH data available.


Related in: MedlinePlus

Box plot of the log-transformed parasite gene copy number ofPlasmodium vivaxandPlasmodium falciparummeasured by qPCR in asymptomatic and symptomatic samples from Asendabo (community) and Jimma (hospital), respectively. The central box represents the interquartile range and the vertical lines represent the first and fourth quartiles of the data. The median is shown as a line through the centre of the box. Outlier samples are represented by open circles. The gene copy number of P. vivax detected in the four Duffy-negative individuals are indicated by crosses in red. Numbers (top) indicate the number of individuals included. P-values (below) are provided for the comparison of gene copy number between asymptomatic and symptomatic samples with respect to P. vivax and P. falciparum.
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Fig3: Box plot of the log-transformed parasite gene copy number ofPlasmodium vivaxandPlasmodium falciparummeasured by qPCR in asymptomatic and symptomatic samples from Asendabo (community) and Jimma (hospital), respectively. The central box represents the interquartile range and the vertical lines represent the first and fourth quartiles of the data. The median is shown as a line through the centre of the box. Outlier samples are represented by open circles. The gene copy number of P. vivax detected in the four Duffy-negative individuals are indicated by crosses in red. Numbers (top) indicate the number of individuals included. P-values (below) are provided for the comparison of gene copy number between asymptomatic and symptomatic samples with respect to P. vivax and P. falciparum.

Mentions: qPCR analyses revealed a significant difference in the parasite GCN among the asymptomatic (community) and symptomatic (hospital) infections for both P. vivax and P. falciparum (Figure 3). Symptomatic P. vivax infections showed a mean GCN of 3.45 ± 0.69/μl, which was significantly higher than that observed in the asymptomatic P. vivax infections (mean GCN of 1.30 ± 0.82/μl; Figure 3). Similarly, symptomatic P. falciparum infections showed a mean GCN of 2.48 ± 1.29/μl, which was higher than that in the asymptomatic P. falciparum infections (mean GCN 1.13 ± 0.41/μl; Figure 3). No significant differences were detected for the P. vivax and P. falciparum GCNs in the symptomatic samples derived from the six sites across Ethiopia (Additional file 2).Figure 3


Molecular epidemiology of Plasmodium vivax and Plasmodium falciparum malaria among Duffy-positive and Duffy-negative populations in Ethiopia.

Lo E, Yewhalaw D, Zhong D, Zemene E, Degefa T, Tushune K, Ha M, Lee MC, James AA, Yan G - Malar. J. (2015)

Box plot of the log-transformed parasite gene copy number ofPlasmodium vivaxandPlasmodium falciparummeasured by qPCR in asymptomatic and symptomatic samples from Asendabo (community) and Jimma (hospital), respectively. The central box represents the interquartile range and the vertical lines represent the first and fourth quartiles of the data. The median is shown as a line through the centre of the box. Outlier samples are represented by open circles. The gene copy number of P. vivax detected in the four Duffy-negative individuals are indicated by crosses in red. Numbers (top) indicate the number of individuals included. P-values (below) are provided for the comparison of gene copy number between asymptomatic and symptomatic samples with respect to P. vivax and P. falciparum.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4340780&req=5

Fig3: Box plot of the log-transformed parasite gene copy number ofPlasmodium vivaxandPlasmodium falciparummeasured by qPCR in asymptomatic and symptomatic samples from Asendabo (community) and Jimma (hospital), respectively. The central box represents the interquartile range and the vertical lines represent the first and fourth quartiles of the data. The median is shown as a line through the centre of the box. Outlier samples are represented by open circles. The gene copy number of P. vivax detected in the four Duffy-negative individuals are indicated by crosses in red. Numbers (top) indicate the number of individuals included. P-values (below) are provided for the comparison of gene copy number between asymptomatic and symptomatic samples with respect to P. vivax and P. falciparum.
Mentions: qPCR analyses revealed a significant difference in the parasite GCN among the asymptomatic (community) and symptomatic (hospital) infections for both P. vivax and P. falciparum (Figure 3). Symptomatic P. vivax infections showed a mean GCN of 3.45 ± 0.69/μl, which was significantly higher than that observed in the asymptomatic P. vivax infections (mean GCN of 1.30 ± 0.82/μl; Figure 3). Similarly, symptomatic P. falciparum infections showed a mean GCN of 2.48 ± 1.29/μl, which was higher than that in the asymptomatic P. falciparum infections (mean GCN 1.13 ± 0.41/μl; Figure 3). No significant differences were detected for the P. vivax and P. falciparum GCNs in the symptomatic samples derived from the six sites across Ethiopia (Additional file 2).Figure 3

Bottom Line: Parasite gene copy number was measured by quantitative real-time PCR and compared between symptomatic and asymptomatic samples, as well as between children/adolescents and adults from the local community.The prevalence of P. vivax and P. falciparum malaria is the highest in children compared to adolescents and adults.Samples from asymptomatic individuals show a significantly lower parasite gene copy number than those from symptomatic infections for P. vivax and P. falciparum.

View Article: PubMed Central - PubMed

Affiliation: Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA. eugenia.loyy@gmail.com.

ABSTRACT

Background: Malaria is the most prevalent communicable disease in Ethiopia, with 75% of the country's landmass classified as endemic for malaria. Accurate information on the distribution and clinical prevalence of Plasmodium vivax and Plasmodium falciparum malaria in endemic areas, as well as in Duffy-negative populations, is essential to develop integrated control strategies.

Methods: A total of 390 and 416 community and clinical samples, respectively, representing different localities and age groups across Ethiopia were examined. Malaria prevalence was estimated using nested PCR of the 18S rRNA region. Parasite gene copy number was measured by quantitative real-time PCR and compared between symptomatic and asymptomatic samples, as well as between children/adolescents and adults from the local community. An approximately 500-bp segment of the human DARC gene was amplified and sequenced to identify Duffy genotype at the -33rd nucleotide position for all the clinical and community samples.

Results: Plasmodium vivax prevalence was higher in the south while P. falciparum was higher in the north. The prevalence of P. vivax and P. falciparum malaria is the highest in children compared to adolescents and adults. Four P. vivax infections were detected among the Duffy-negative samples. Samples from asymptomatic individuals show a significantly lower parasite gene copy number than those from symptomatic infections for P. vivax and P. falciparum.

Conclusions: Geographical and age differences influence the distribution of P. vivax and P. falciparum malaria in Ethiopia. These findings offer evidence-based guidelines in targeting malaria control efforts in the country.

No MeSH data available.


Related in: MedlinePlus