Plasmodium knowlesi from archival blood films: Further evidence that human infections are widely distributed and not newly emergent in Malaysian Borneo
Human infections with Plasmodium knowlesi have been misdiagnosed by microscopy as Plasmodium malariae due to their morphological similarities. Although microscopy-identified P. malariae cases have been reported in the state of Sarawak (Malaysian Borno) as early as 1952, recent epidemiological stud...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier Ltd.
2009
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| Subjects: | |
| Online Access: | http://ir.unimas.my/id/eprint/15813/ http://ir.unimas.my/id/eprint/15813/1/Plasmodium.pdf |
| Summary: | Human infections with Plasmodium knowlesi have been misdiagnosed by microscopy as Plasmodium malariae
due to their morphological similarities. Although microscopy-identified P. malariae cases have been
reported in the state of Sarawak (Malaysian Borno) as early as 1952, recent epidemiological studies suggest
the absence of indigenous P. malariae infections. The present study aimed to determine the past incidence
and distribution of P. knowlesi infections in the state of Sarawak based on archival blood films from
patients diagnosed by microscopy as having P. malariae infections. Nested PCR assays were used to identify
Plasmodium species in DNA extracted from 47 thick blood films collected in 1996 from patients in
seven different divisions throughout the state of Sarawak. Plasmodium knowlesi DNA was detected in
35 (97.2%) of 36 blood films that were positive for Plasmodium DNA, with patients originating from all
seven divisions. Only one sample was positive for P. malariae DNA. This study provides further evidence
of the widespread distribution of human infections with P. knowlesi in Sarawak and its past occurrence.
Taken together with data from previous studies, our findings suggest that P. knowlesi malaria is not a
newly emergent disease in humans. |
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