Prevalence of submicroscopic malaria in low transmission state of Punjab: A potential threat to malaria elimination.
India
Punjab
malaria
prevalence
submicroscopic
Journal
Journal of vector borne diseases
ISSN: 0972-9062
Titre abrégé: J Vector Borne Dis
Pays: India
ID NLM: 101212761
Informations de publication
Date de publication:
Historique:
entrez:
10
5
2019
pubmed:
10
5
2019
medline:
7
8
2019
Statut:
ppublish
Résumé
Submicroscopic malaria infections with low parasite density serve as a silent reservoir for maintaining residual transmission in the population. These infections should be identified and targeted to be eliminated for sustained malaria control. The conventional methods of diagnosis such as light microscopy and rapid diagnostic kits often fail to detect low density infections. Therefore, the more sensitive molecular techniques should be employed to detect low density infections. The objectives of the study was to explore the prevalence of sub-microscopic infections in low transmission areas of Punjab using highly sensitive molecular tool. A total of 1114 finger prick blood samples were collected through active surveillance and tested for malaria diagnosis using light microscopy, RDT and PCR. Nested PCR amplification was performed using a pair of Plasmodium genus-specific primers from the 18S rRNA small subunit gene (18S rRNA). The amplified PCR products were analysed using a 2% agarose gel, stained with ethidium bromide and observed under transilluminator. Test positive rate (TPR) by microscopy, RDT and PCR was 4.4, 3.95 and 5.75%, respectively. Microscopy and RDT failed to detect mixed infections whereas 0.26% cases were found to be mixed infection in PCR. Compared to LM and RDT, PCR has detected 1.3% additional positive cases. However, of the total positive cases detected by PCR, 23.4% infections were found to be submicroscopic, which could not be detected by conventional methods of diagnosis. The molecular study revealed the existence of submicroscopic malaria cases in the study population which would have remained undetected by conventional methods of diagnosis. This is particularly important because Punjab state is in malaria elimination phase and targeted to achieve elimination in 2021. However, such undetected parasite positive cases may pose bigger problem any time due to continued transmission. Therefore, application of more sensitive diagnostic tools like PCR and LAMP with conventional methods may be much more useful in case detection particularly in low transmission settings for malaria elimination.
Sections du résumé
BACKGROUND & OBJECTIVES
OBJECTIVE
Submicroscopic malaria infections with low parasite density serve as a silent reservoir for maintaining residual transmission in the population. These infections should be identified and targeted to be eliminated for sustained malaria control. The conventional methods of diagnosis such as light microscopy and rapid diagnostic kits often fail to detect low density infections. Therefore, the more sensitive molecular techniques should be employed to detect low density infections. The objectives of the study was to explore the prevalence of sub-microscopic infections in low transmission areas of Punjab using highly sensitive molecular tool.
METHODS
METHODS
A total of 1114 finger prick blood samples were collected through active surveillance and tested for malaria diagnosis using light microscopy, RDT and PCR. Nested PCR amplification was performed using a pair of Plasmodium genus-specific primers from the 18S rRNA small subunit gene (18S rRNA). The amplified PCR products were analysed using a 2% agarose gel, stained with ethidium bromide and observed under transilluminator.
RESULTS
RESULTS
Test positive rate (TPR) by microscopy, RDT and PCR was 4.4, 3.95 and 5.75%, respectively. Microscopy and RDT failed to detect mixed infections whereas 0.26% cases were found to be mixed infection in PCR. Compared to LM and RDT, PCR has detected 1.3% additional positive cases. However, of the total positive cases detected by PCR, 23.4% infections were found to be submicroscopic, which could not be detected by conventional methods of diagnosis.
INTERPRETATION & CONCLUSIONS
CONCLUSIONS
The molecular study revealed the existence of submicroscopic malaria cases in the study population which would have remained undetected by conventional methods of diagnosis. This is particularly important because Punjab state is in malaria elimination phase and targeted to achieve elimination in 2021. However, such undetected parasite positive cases may pose bigger problem any time due to continued transmission. Therefore, application of more sensitive diagnostic tools like PCR and LAMP with conventional methods may be much more useful in case detection particularly in low transmission settings for malaria elimination.
Identifiants
pubmed: 31070171
pii: JVectorBorneDis_2019_56_1_78_257780
doi: 10.4103/0972-9062.257780
doi:
Substances chimiques
RNA, Ribosomal, 18S
0
Types de publication
Journal Article
Langues
eng
Pagination
78-84Déclaration de conflit d'intérêts
None