SENSITIVE DETECTION OF PLASMODIUM-VIVAX IN BLOOD BY A CELL-ELISA USING A MONOCLONAL-ANTIBODY

An IgM monoclonal antibody (7C5B71) which reacted with the blood stage s of Plasmodium vivax, but not with those of Plasmodium falciparum was used in a cell-ELISA to detect parasites in samples of peripheral blo od. Blood thin smears were probed with monoclonal antibody 7C5B71 and then reacted with a peroxidase conjugate of the appropriate specificit y and the insoluble chromogen amino-ethyl-carbazole. Infected cells wh ich appeared dark red coloured were rapidly identified under a light m icroscope using a low magnification. The conventional microscopic exam ination of thin films coloured with Giemsa was used as reference test. Under laboratory conditions the test showed a positive result in samp les with a level of parasitaemia of less than or equal to 500 parasite s/mu l of blood. In a preliminary field trial the test showed 100 % sp ecificity for the diagnosis of P. vivax malaria.