Abstract:
Background: Plasmodium vivax accounts for about 44 % of all malaria infection in Ethiopia. Chloroquine (CQ) is the
first-line treatment for vivax malaria in Ethiopia. Chloroquine-resistant (CQR) P. vivax has been emerging in different parts of the world to compromise the efficacy of the drug and pose both health and economic impact in the
developing world. The current study was aimed at assessing the therapeutic efficacy of CQ for the treatment of vivax
malaria among outpatients at Hossana Health Care Centre, southern Ethiopia.
Methods: A one-arm, 28-day follow-up, in vivo therapeutic efficacy study was conducted from 5 April to 25 June,
2014. Sixty-three patients aged between four and 59 years were enrolled with microscopically confirmed P. vivax
infection. All patients were treated with CQ 25 mg/kg for 3 days. Recurrence of parasitaemia and clinical conditions of
patients were assessed on days 1, 2, 3, 7, 14, 21, and 28 during the 28-day follow-up period. Haemoglobin (Hb) level
was determined on day 0, day 28 and on day of recurrence of parasitaemia by using portable spectrophotometer.
Results: Of the total 63 patients included in the study, 60 (95.2 %) completed their 28-day follow-up; three patients
were excluded from the study: one patient due to vomiting of the second dose of drug, one patient due to Plasmodium falciparum infection and one patient lost to follow-up during the study. During enrolment, 35 (53.3 %) had a history of fever and 28 (46.7 %) had documented fever. The geometric mean of parasite density on day of enrolment was
3472 parasites/μl. Among these, two patients had recurrent parasitaemia within the 28-day follow-up. CQ was found
to be efficacious in 96.7 % of the study participants except two treatment failures detected. The failure might be due
to late parasitological failure among these two patients who had recurrent parasitaemia within the 28-day follow-up.
Conclusion: The current study revealed that CQ showed a high rate of efficacy (96.7 %) among the study participants
even though some reports from previous studies elsewhere in Ethiopia showed an increase in CQR P. vivax. Thus, CQR
molecular markers and regular monitoring of the pattern of resistance to CQ is needed for rapid and effective control
measures of possible spread of drug resistance in the study area.
