Malaria is still one of the most prevalent diseases in the world with a major impact on developing tropical countries. Over 2 billion people live in malarious areas of the world and over 200 million are infected each year. Malaria is caused by protozoan parasites of the genus Plasmodium. Four species of the parasite commonly infect man, the most important being Plasmodium falciparum which is responsible for approximately 3 million deaths per year.
The Cellabs malaria range of products were developed for a range of applications in clinical and research. The Pan Malaria Antibody CELISA is for the detection of antibodies to all species of malaria, used in hospitals, reference clinics, laboratories and research. For antigen detection, Cellabs offers three antigen detection ELISA kits: the first commercially available antigen test, Malaria Ag CELISA (Product Code: KM2) which was recommended by WHO in the 1990s for the detection of HRP2; Quantimal™ Ultra-sensitive PfHRP2 CELISA (Product Code: KM8), a newly developed kit based on the the Malaria Ag CELISA, with improved ultra-sensitivity up to twenty times; and the Quantimal™ Ultrasensitive pLDH Malaria Ag CELISA (Product Code: KM7) for the detection of Plasmodium lactate dehydrogenase (pLDH), an enzyme common to all species of malaria.
Malaria and Blood Banking
Transfusion-induced malaria is an ever present risk in endemic areas. In the developed world, transfusion-induced malaria is relatively rare, however, blood is excluded from potential donors who have visited malaria-endemic countries resulting in reduction of the available blood pool. The use of a product such as the Cellabs Pan Malaria Antibody CELISA ensures that individuals who have had malaria in the past, and are exposed to the disease are excluded from the donation process. This screening method is critical for preventing malaria from contaminating blood supplies. Cellabs Pan Malaria Antibody CELISA
has unique specificity which recognises all four species of malaria, including Plasmodium knowlesi.
The highly specific and sensitive assay is the first product of its kind to use a cocktail of recombinant antigen that specifically targets the parasite at different stages of its life-cycle.
Malaria Drug Sensitivity Testing
Cellabs produces a special product for Malaria drug sensitivity studies based on the standard Malaria Ag CELISA
kit. The Malaria Ag CELISA Bulk (Catalogue number KM2BP) is a specialised product which contains reagents for 960 tests (10 plates). Following a protocol used by Dr Harald Noedl, the kit contains enough reagents for approximately 120 patient studies per individual antimalarial drug. This product is reserved for bona fide
medical research laboratories conducting drug sensitivity testing on patient samples and sold exclusively by Cellabs directly to the customer in order to minimise end-user costs.
The modified Cellabs product has been extensively evaluated and validated in Malaria endemic regions by organisation such as the US Center for Disease Control (CDC), USAMC-AFRIMS unit in Bangkok, Thailand and by Dr Harald Noedl (University of Vienna). The method using Cellabs kits originally published by Dr Noedl contained samples from Thailand, Myanmar and Bangladesh. Reference: Noedl H., Wensdorfer W.H., Miller R.S. and Wongsirichanalai C. (2002). Histidine Rich Protein II: a novel approach to malaria drug sensitivity testing. Antimicrobial Agents and Chemotherapy, June 2002, p. 1658-1664
Quantitative and Ultra-sensitivity Assays
The Quantimal™ Cellabs range of product is a trademark of Cellabs Pty Ltd, denoting assays developed and optimised using a well-defined positive control that can be used for quantification. The Quantimal Ultra-sensitive PfHRP2 CELISA comes with a calibrated positive control with a determined PfHRP2 concentration that is diluted two-fold to give a standard curve to which unknown sample concentrations are extrapolated. The Quantimal™ pLDH CELISA uses the same positive control calibrated against a pLDH recombinant antigen to give a determined concentration for a standard curve.
There is an increasing demand for highly-sensitive detection tests for malaria due to the recent discovery of low-level malaria after an increased and effective effort in malaria elimination initiatives. The Quantimal™ Ultra-sensitive PfHRP2 CELISA was developed to detect PfHRP2 concentrations as low as 10 picograms/millilitre.
Advantages of HRP2 method
The Cellabs Malaria range of ELISA kits for drug sensitivity studies presents the following advantages:
- Eliminates the use of radioactive isotopes and the associated costs of its use.
- Sensitvity equivalent to WHO Schizont maturation test (approximately 0.01% initial parasite density).
- Quality controlled product from Cellabs, manufactured to strict ISO13485 standards. This ensures consistency of results and no need to calibrate the assay extensively, as would be required for an in-house assay.
- No expert technical skills or expensive equipment needed. Can be run in a basic laboratory equipped with an ELISA plate reader (450/620nm or 450nm filter).
- Significantly less laborious than the DELI assay.
- Sold directly by Cellabs to Malaria research centres. Elimination of intermediaries in order to minimise end-user cost per test.
- Stable during transit up to 30 days and can be delivered ANYWHERE in the world by air freight.
Noedl H., Wongsrichanalai C., and Wernsdorfer W.H. (2003) Malaria Drug Sensitivity Testing: new assays, new perspectives. Trends in Parasitology, Vol 19 (4): p175-181
Malaria Consortium http://www.malariaconsortium.org
Multilateral Initiative on Malaria http://mim.nih.gov/english/partnerships/index.html