An algorithm for the clinical differentiation of malaria and typhoid: a preliminary communication.

The objective of this study was to determine which clinical features of typhoid and malaria are most helpful in distinguishing the two diseases among Papua New Guinean highlanders. In a study of 35 patients with culture-positive typhoid and 49 with blood-slide-positive malaria (Group 1), the odds of typhoid were increased most in patients with altered bowel habit, an illness of more than 2 week's duration, tremor or the presence of typhoid facies. The odds of typhoid were lowest in patients with pallor or jaundice. These findings were used to derive a clinical diagnostic algorithm, which was then evaluated in a further group of 34 typhoid patients and 41 malaria patients (Group 2). The sensitivity of the algorithm in diagnosing malaria was 91% in Group 1 and 71% in Group 2, with specificities of 85% and 79% respectively. For typhoid, the sensitivity of the algorithm was 85% and 79% for Groups 1 and 2, respectively, and the specificities were 91% and 71%. We conclude that the algorithm merits further evaluation in a primary health care setting and may prove useful in making an earlier diagnosis of typhoid.