Malaria and Widal reaction

Widal reaction was studied in 52 patients having malaria parasites in the peripheral blood smear. Twenty had Plasmodium vivax, 26 had Plasmodium falciparum and the rest had mixed (both vivax and falciparum) infections. Widal test for both O and H antigens of Salmonella typhi was positive in high titres in 3 falciparum, 3 vivax and 2 cases of mixed infection. Of these 8 cases, one had been treated for typhoid fever 3 months back and again one month back for relapse. Blood culture for Salmonella typhi was negative in all. All were cured after antimalarial therapy. The positive Widal reaction may be false.

[The immunoenzymatic assay (ELISA) in the serodiagnosis of Plasmodium vivax]

ELISA was evaluated for the serodiagnosis of Plasmodium vivax using homologous antigen. This was a crude fraction obtained after detergent (NP-40) lysis of human parasitized red blood cells. Antibodies of the classes IgM, IgG, IgA were determined in a pool of eleven sera from patients with P. vivax malaria. The protein A was introduced as secondary probe to screen P. vivax antibodies in 30 sera of patients harbouring a first episode of P. vivax malaria. There was a correlation of 93% with the parasitological diagnosis and the test resulted specific and reproducible.