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.