Studies on Plasmodium vivax relapse pattern in Kheda district, Gujarat.

Relapse pattern in P. vivax malaria was studied in five villages of Nadiad taluka, Kheda district, Gujarat. P. vivax cases treated with 600 mg chloroquine and in combination with 50 mg pyrimethamine (adult dose) yielded 28.31 and 27.73% relapse rate respectively. While relapse rate of 5.78% was observed with five day course of 75 mg primaquine (15 mg/day) administered as radical treatment. Relapse rate in 5-10 yr of age group was comparatively more than other age groups. There was no noticeable difference in relapse rates among male and female. The short-term relapse with a lag period of 2-3 months was significantly higher in this area. The longest relapse with an interval of 17 months was found in one case treated with chloroquine along with pyrimethamine. However, primaquine regimen prevented consecutive relapses. Primaquine has been found adequate to prevent relapse in more than 90% vivax cases, while efficacy of chloroquine-pyrimethamine and chloroquine alone was almost comparable. A high proportion of relapse may be minimized, if 5-days radical treatment is given at appropriate time.