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The detection of cryptic Plasmodium infection among villagers in Attapeu province, Lao PDR
- Source :
- PLoS Neglected Tropical Diseases, PLoS Neglected Tropical Diseases, Vol 11, Iss 12, p e0006148 (2017)
- Publication Year :
- 2017
-
Abstract
- Background Although the malaria burden in the Lao PDR has gradually decreased, the elimination of malaria by 2030 presents many challenges. Microscopy and malaria rapid diagnostic tests (RDTs) are used to diagnose malaria in the Lao PDR; however, some studies have reported the prevalence of sub-microscopic Plasmodium infections or asymptomatic Plasmodium carriers in endemic areas. Thus, highly sensitive detection methods are needed to understand the precise malaria situation in these areas. Methodology/Principal findings A cross-sectional malaria field survey was conducted in 3 highly endemic malaria districts (Xaysetha, Sanamxay, Phouvong) in Attapeu province, Lao PDR in 2015, to investigate the precise malaria endemicity in the area; 719 volunteers from these villages participated in the survey. Microscopy, RDTs and a real-time nested PCR were used to detect Plasmodium infections and their results were compared. A questionnaire survey of all participants was also conducted to estimate risk factors of Plasmodium infection. Numbers of infections detected by the three methods were microscopy: P. falciparum (n = 1), P. vivax (n = 2); RDTs: P. falciparum (n = 2), P. vivax (n = 3); PCR: Plasmodium (n = 47; P. falciparum [n = 4], P. vivax [n = 41], mixed infection [n = 2]; 6.5%, 47/719). Using PCR as a reference, the sensitivity and specificity of microscopy were 33.3% and 100.0%, respectively, for detecting P. falciparum infection, and 7.0% and 100.0%, for detecting P. vivax infection. Among the 47 participants with parasitemia, only one had a fever (≥37.5°C) and 31 (66.0%) were adult males. Risk factors of Plasmodium infection were males and soldiers, whereas a risk factor of asymptomatic Plasmodium infection was a history of ≥3 malaria episodes. Conclusions/Significance There were many asymptomatic Plasmodium carriers in the study areas of Attapeu province in 2015. Adult males, probably soldiers, were at high risk for malaria infection. P. vivax, the dominant species, accounted for 87.2% of the Plasmodium infections among the participants. To achieve malaria elimination in the Lao PDR, highly sensitive diagnostic tests, including PCR-based diagnostic methods should be used, and plans targeting high-risk populations and elimination of P. vivax should be designed and implemented.<br />Author summary The Lao People’s Democratic Republic (Laos) is a country in the Greater Mekong Subregion. In Laos, the numbers of reported cases of malaria and deaths due to malaria have been gradually decreasing. Recently, the Lao government adopted a goal of eliminating malaria by 2030. To achieve this goal, we must understand the precise situation in each endemic area. With this background, we conducted a field survey in Attapeu, one highly endemic province, in 2015. We collected blood samples from 719 villagers, and most (98.1%, 705/719) had no fever (
- Subjects :
- Male
Plasmodium
Fevers
Artificial Gene Amplification and Extension
Parasitemia
Pathology and Laboratory Medicine
Polymerase Chain Reaction
0302 clinical medicine
Prevalence
Medicine and Health Sciences
Ethnicities
030212 general & internal medicine
Malaria, Falciparum
Child
Asymptomatic Infections
Aged, 80 and over
Protozoans
biology
Coinfection
lcsh:Public aspects of medicine
Malarial Parasites
Eukaryota
Middle Aged
Infectious Diseases
Laos
Child, Preschool
Lao People
Female
medicine.symptom
Research Article
Adult
lcsh:Arctic medicine. Tropical medicine
Adolescent
lcsh:RC955-962
030231 tropical medicine
Plasmodium falciparum
Research and Analysis Methods
Asymptomatic
03 medical and health sciences
Young Adult
Signs and Symptoms
Diagnostic Medicine
Vivax infection
parasitic diseases
Parasite Groups
medicine
Malaria, Vivax
Parasitic Diseases
Humans
Risk factor
Molecular Biology Techniques
Molecular Biology
Aged
business.industry
Public Health, Environmental and Occupational Health
Organisms
Infant
Biology and Life Sciences
lcsh:RA1-1270
biology.organism_classification
medicine.disease
Tropical Diseases
Virology
Parasitic Protozoans
Malaria
People and Places
Parasitology
Population Groupings
business
Plasmodium vivax
Nested polymerase chain reaction
Apicomplexa
Subjects
Details
- ISSN :
- 19352735
- Volume :
- 11
- Issue :
- 12
- Database :
- OpenAIRE
- Journal :
- PLoS neglected tropical diseases
- Accession number :
- edsair.doi.dedup.....ecd0f575939f614323515a62d30b8e8e