Accuracy of the health information system on malaria surveillance in Vietnam.

The health information system (HIS) is a key component of control programs and its accuracy is necessary for the assessment of disease risks, the formulation of priorities and the evaluation of the cost-effectiveness of different interventions. In order to assess the quality of the HIS in estimating malaria morbidity in Vietnam, we compared data obtained by a 2-year active (ACD) and passive case detection (PCD) study with those routinely collected at the local commune health centres (CHC) at three sites having different malaria epidemiology. The majority of malaria cases (80-95%) detected by ACD were missed by the HIS. Similarly, most malaria cases (50-90%) detected by PCD were also missed by the HIS, and this was proportional to the number of active private practitioners. Reasons for this low sensitivity are low CHC attendance, high attendance at private health facilities, widespread self-medication and attendance at central health facilities. In conclusion, although malaria has sharply decreased in Vietnam over the past 10 years, the current HIS greatly underestimates the malaria burden. Involvement of the private sector and the establishment of sentinel sites might improve the quality of data and the relevance of HIS in malaria control.

Treatment of falciparum malaria in Vietnamese children: the need for combination therapy and optimized dosage regimens.

To assess the in vivo sensitivity of Plasmodium falciparum to mefloquine and artesunate in a hyperendemic area of southern Viet Nam, we studied 41 children and 21 adults from a remote commune who had uncomplicated falciparum malaria without previous treatment. Patients were randomly allocated to artesunate (4 mg/kg on day 0 and 2 mg/kg on days 1-4) or mefloquine (10 mg/kg followed by 5 mg/kg at 6 h). Serial assessments were performed over 28 days. Of 31 patients allocated artesunate, nine (29%) redeveloped parasitaemia during follow-up compared with 23% (seven of 30) who received mefloquine. Of the 41 children, 15 (37%) had recrudescence/re-infection compared with only one of 20 adults (5%; p < 0.001). Significantly more children than adults failed on mefloquine treatment (37% vs 0%; p = 0.021) and one case showed RIII resistance. There was no significant difference in the case of artesunate. In regression analysis, parasitaemia was an independent predictor of recrudescence/re-infection after mefloquine (p = 0.02). These data support the use of combination therapy such as artesunate plus mefloquine for falciparum malaria in a hyperendemic area of Viet Nam. Primarily because of their greater parasite densities, children should be given higher doses of mefloquine (e.g. 25 mg/kg).