| 1. |
- Aydin-Schmidt, Berit, et al.
(författare)
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Carolus Linnaeus, the ash, worm-wood and other anti-malarial plants
- 2010
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 42:11-12, s. 941-942
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Tidskriftsartikel (refereegranskat)abstract
- In 1735 Carolus Linnaeus wrote that quinine was the preferred treatment for malaria but that the bark of the ash (Fraxinus excelsior) and worm-wood (Artemisia absinthium) also had effects on the disease. We here report that lipo- and hydrophilic extracts of the bark of the ash inhibit the in vitro growth of the asexual stages of P. falciparum. The data suggests that the knowledge of the treatment of malaria was already available in Europe some 300 years ago.
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| 2. |
- Aydin-Schmidt, Berit, et al.
(författare)
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Loop mediated isothermal amplification (LAMP) accurately detects malaria DNA from filter paper blood samples of low density parasitaemias
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:8, s. e103905-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:Loop mediated isothermal amplification (LAMP) provides an opportunity for improved, field-friendly detection of malaria infections in endemic areas. However data on the diagnostic accuracy of LAMP for active case detection, particularly low-density parasitaemias, are lacking. We therefore evaluated the performance of a new LAMP kit compared with PCR using DNA from filter paper blood spots.METHODS AND FINDINGS:Samples from 865 fever patients and 465 asymptomatic individuals collected in Zanzibar were analysed for Pan (all species) and Pf (P. falciparum) DNA with the Loopamp MALARIA Pan/Pf kit. Samples were amplified at 65°C for 40 minutes in a real-time turbidimeter and results were compared with nested PCR. Samples with discordant results between LAMP and nested PCR were analysed with real-time PCR. The real-time PCR corrected nested PCR result was defined as gold standard. Among the 117 (13.5%) PCR detected P. falciparum infections from fever patients (mean parasite density 7491/µL, range 6-782,400) 115, 115 and 111 were positive by Pan-LAMP, Pf-LAMP and nested PCR, respectively. The sensitivities were 98.3% (95%CI 94-99.8) for both Pan and Pf-LAMP. Among the 54 (11.6%) PCR positive samples from asymptomatic individuals (mean parasite density 10/µL, range 0-4972) Pf-LAMP had a sensitivity of 92.7% (95%CI 80.1-98.5) for detection of the 41 P. falciparum infections. Pan-LAMP had sensitivities of 97% (95%CI 84.2-99.9) and 76.9% (95%CI 46.2-95) for detection of P. falciparum and P. malariae, respectively. The specificities for both Pan and Pf-LAMP were 100% (95%CI 99.1-100) in both study groups.CONCLUSION:Both components of the Loopamp MALARIA Pan/Pf detection kit revealed high diagnostic accuracy for parasite detection among fever patients and importantly also among asymptomatic individuals of low parasite densities from minute blood volumes preserved on filter paper. These data support LAMPs potential role for improved detection of low-density malaria infections in pre-elimination settings.
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| 3. |
- Aydin Schmidt, Berit
(författare)
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New diagnostic tools for malaria-challenges and opportunities
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Nearly half of the world’s population is at risk for malaria and over 600,000 die from the disease every year. Access to prompt and correct parasite based diagnosis in order to target treatment to those with a confirmed malaria infection and improved malaria surveillance are cornerstones in malaria control. The availability of modern diagnostic tools such as rapid diagnostic test (RDT), polymerase chain reaction (PCR) and loop mediated isothermal amplification (LAMP) represent new opportunities besides microscopy for improved sensitive and accurate parasite-based diagnosis. However, there are different demands on diagnostic tools for different health care settings and endemic contexts. The performance of RDT was compared to blood smear microscopy and PCR among febrile patients in a low endemic/pre elimination area (Zanzibar). Although the sensitivity of RDT was found to be relatively low (76.5%) the health care workers were highly adherent to test results in prescribing antimalarial drugs. Parasite clearance and detection of recurrent infections was assessed by different diagnostic methods after malaria treatment in febrile children in a relatively high endemic area of mainland Tanzania. Median clearance time was two days for PCR and microscopy whereas the clearance times were seven and 28 days for the pLDH and HRP2 based RDTs, respectively. pLDH based RDT was a better tool than HRP2 based for treatment follow up and detection of recurrent infection. The usefulness of RDT as a source of parasite DNA was evaluated through different parasite DNA extraction methods. DNA extraction efficacy varied with test device and extraction method. There was no difference in PCR detection rates between RDT and filter paper samples collected from the field. This confirms the usefulness of RDTs stored under field conditions as a modern tool for molecular malaria surveillance and RDT quality control. A LAMP kit was compared to conventional PCR methods for detection of parasite DNA from dried blood spots collected among both fever patients and asymptomatic individuals in Zanzibar. The LAMP kit had a sensitivity of 98% for detection of Plasmodium(P) falciparum among fever patients and a sensitivity of > 92% and 77% for detection of P. falciparum and P. malariae among asymptomatic individuals. The high diagnostic accuracy of the LAMP kit for detection of low density parasitaemias from minute blood volumes preserved on filter papers supports its role for improved case detection in areas of low density malaria infections. The results in this thesis provide important data on the usefulness of new diagnostic tools for improved case detection and surveillance of malaria in different endemic contexts.
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| 4. |
- Aydin-Schmidt, Berit, et al.
(författare)
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Usefulness of Plasmodium falciparum-specific rapid diagnostic tests for assessment of parasite clearance and detection of recurrent infections after artemisinin-based combination therapy.
- 2013
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Ingår i: Malaria journal. - : Springer Science and Business Media LLC. - 1475-2875. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Rapid diagnostic test (RDT) is an important tool for parasite-based malaria diagnosis. High specificity of RDTs to distinguish an active Plasmodium falciparum infection from residual antigens from a previous infection is crucial in endemic areas where residents are repeatedly exposed to malaria. The efficiency of two RDTs based on histidine-rich protein 2 (HRP2) and lactate dehydrogenase (LDH) antigens were studied and compared with two microscopy techniques (Giemsa and acridine orange-stained blood smears) and real-time polymerase chain reaction (PCR) for assessment of initial clearance and detection of recurrent P. falciparum infections after artemisinin-based combination therapy (ACT) in a moderately high endemic area of rural Tanzania.
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| 5. |
- Morris, Ulrika, et al.
(författare)
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Rapid diagnostic tests for molecular surveillance of Plasmodium falciparum malaria -assessment of DNA extraction methods and field applicability.
- 2013
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Ingår i: Malaria journal. - : Springer Science and Business Media LLC. - 1475-2875. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- The need for new malaria surveillance tools and strategies is critical, given improved global malaria control and regional elimination efforts. High quality Plasmodium falciparum DNA can reliably be extracted from malaria rapid diagnostic tests (RDTs). Together with highly sensitive molecular assays, wide scale collection of used RDTs may serve as a modern tool for improved malaria case detection and drug resistance surveillance. However, comparative studies of DNA extraction efficiency from RDTs and the field applicability are lacking. The aim of this study was to compare and evaluate different methods of DNA extraction from RDTs and to test the field applicability for the purpose of molecular epidemiological investigations.
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