A retrospective study on 4693 patients with epidemic fever/epidemic haemorrhagic fever during 1990-1999 in Thanh Hãa province to find and identify the epidemic haemorrhagic fever, viral isolation, serological diagnosis in 5 coast line districts, 9 district in the delta region and 1 mountain district. The results have demonstrated that the average morbidity rate of the haemorrhagic fever in Thanh Hãa during 1990-1999 was 24.5/100.000; the average mortality rate of haemorrhagic fever was 0.04/100.000. Some epidemics had high morbidity rate included HËu Léc (1573.7/1in 1991) and SÇm S¬n (1978.7/1in 1998). Both were under the country's spread epidemics. There was significant difference of morbidity and mortality rate from the geographic region to another. The disease occurred all ages
Fever ; epidemiology

There were 104 cases of new emerged den-4 serotype hemorrhagic dengue in 2 communes comprising of 81.7% of grade I and 18.3% of grade II. No cases of shock and death were reported. Under 15 years old children account for 26.9%. Differential diagnosis was established late, but active measures such as the elimination of vectorial larvae by larvivorous fishes were well applicated to prevent the spread of the epidemic.
Dengue ; Disease Outbreaks