Fig 1.
Blood smears tested with Plasmodium genus FISH assay.
Blood smears from different Plasmodium species P. falciparum, P. vivax, P. knowlesi, P. ovale and P. malariae were analyzed using Plasmodium genus FISH assay. (1) All the processed smears were read with a 100X objective in a fluorescence microscope. (2) P. falciparum. P. vivax, P. knowlesi and negative control smears were read with a 100X objective on a regular microscope with a LED unit. Green fluorescence indicates the presence of Plasmodium ribosomal RNA (rRNA). (A) P. falciparum including crescent shaped gametocytes (B) P. vivax; (C) P. knowlesi; (D) P. ovale; (E) P. malariae; and (N) Negative Control; (A1) P. falciparum;. (B1) P. vivax; (C1) P. knowlesi; and (N1) Negative Control.
Fig 2.
Blood smears tested with P. falciparum FISH assay.
Malaria positive patient blood samples from two collection sites, Peru (A), and Kenya (B) were analyzed using PF-FISH assay. (A) Patient blood positive for P. falciparum. (B) Patient blood positive for P. malariae [1] and P. falciparum gametocyte [2]. (C) Patient blood positive for P. ovale. (D) Patient blood positive for P. vivax. Green fluorescence is due to the P. falciparum specific probe and red fluorescence due to the Plasmodium genus probe.
Fig 3.
Blood smears tested with P. vivax FISH assay.
Malaria positive patient blood samples from two collection sites, Peru (A), India (B) and Kenya (C-E) were analyzed using PV-FISH assay. (A) Patient blood positive for P. vivax. (B) Patient blood positive for P. vivax. (C) Patient blood positive for P. ovale. (D) Patient blood positive for P. malariae. (E) Patient blood positive for P. falciparum. Green fluorescence is due to reactivity with the P. vivax specific probe and red fluorescence is due to reactivity with the Plasmodium genus probe.
Table 1.
Lowest number of parasites detected per μl blood by Giemsa and FISH.
N/A—not applicable.
Fig 4.
FISH assay only detects live Plasmodium parasites.
Blood smears prepared from P. falciparum positive patient before (0 Hrs) and after 24 hours (24Hrs) drug treatment were analyzed by Plasmodium Genus FISH assay. The disappearance of the Plasmodium Genus fluorescence signal at 24 hours suggests that FISH assay only detects live Plasmodium parasites.
Fig 5.
P. falciparum positive patient’s finger-prick capillary blood smear tested with Plasmodium genus FISH assay.
Smear prepared from finger-prick capillary blood without anticoagulant. Green fluorescence indicates the presence of Plasmodium ribosomal RNA (rRNA) due to reaction with Plasmodium genus FISH.
Table 2.
Summary of Clinical Study Results.
Giemsa negative, PCR and FISH Positive samples a = 17; b = 5; c = 14. (Note: 150 samples from US are excluded)
Table 3.
Sensitivity of Plasmodium FISH tests and RDTs as compared to Giemsa.
After discrepant analysis: Including FISH and PCR positive but Giemsa negative samples as true positives.” P-Genus FISH -17; PF-FISH– 5; and PV-FISH– 14. CI—confidence interval.
Table 4.
Specificity of Plasmodium FISH tests and RDTs as compared to Giemsa.
After discrepant analysis: Including FISH and PCR positive but Giemsa negative samples as true positives”. P-Genus FISH -17; PF-FISH– 5; and PV-FISH– 14. CI—confidence interval.