A major epidemic of DF/DHF occurred at Ha Noi in 1998, and 3348 cases of have been reported. Serological surveillance confirmed that the epidemic of dengue fever was caused by dengue 3 and dengue 1 virus types 32/37 positive samples were dengue 3 (86.48%). Dengue virus type 3 was isolated in 6 districts of Ha Noi
Dengue Virus ; Dengue ; epidemiology

Dengue; Dengue haemorrhagic fever investigation on 1000 households in Quang Ngai province showed that Ae.aegypti was the main vector, although Ae. Albopictus had been seen. Among mosquito larvae containing water tanks was the highest rate (40,36%). Mesocyclops had discovered in water tank community's awarness on Dengue haemorrhagic fever vector prevention had been increased, however propaganda on vector, mosquito and prevention measures are also needed.
Dengue ; epidemiology

DF/DHF re-emerged in Vientiame in 1994 onwards, after a period of absence about 6 years. The disease now has expanded to rural districts of Vientiane, whereas before 1994, only urban districts were affected by dengue. Dengue cases occurred in rainy season and parallely increased with the amount of rainfall. Rainy season started from May to October. In 1997 the highest morbidity rate was found in Xaysetha - an urban district of Vientiane. By now dengue is an increasing public health problem in Vientiane. The present strategy on DF/DHF prevention should be revised with community participation and use of virological and serological controls in epidemic.
Dengue ; epidemiology

Outbreaks of DHF occured every 3-5 years in Thua Thien - Hue province. Before 1986 cases were observed essentially in urban areas. During the period of 1982-1986 the incidence was estimated 127.8 per 100.000. Afterwards the incidence in Hue city decreased gradually to 5.2 and the incidence in rural areas increased to 55.8 (1992-1996). Outbreaks usually occurred from April-May, the highest peak was seen in June-July, and a second peak in September-October, the highest morbidity rate was seen in children under 15 years of age
Epidemiology, dengue

A K.A.P. survey on dengue heamorrhagis fever (DHF) was carried out in 6 sentinel provinces (An Giang, Kien Giang, Ca Mau, HCM city, Dong Nai, Can Tho) of program for control of DHF of Southern region at the end of the year 1998. One district was selected in each province. 30 random clusters with sample size of 2000 households were applied for each district. The results: most of households heads (91%) have heard about DHF, by T.V. (62%). Continuous high fever for 2 days was a common symptom of DHF. The first health facilities for seeking DHF treatment were communal health stations (32%), and private clinic (25%). 74% of subjects understood that DHF was transmitted by mosquito. Larval habitant were considered as clean water container without cover (60%) and solid waste containers (used tires, tin, can…) by 15%. Subject prefer to cover water containers (34%), to clean water containers (25%), to destroy waster containers (14%), to put larvicid fishes into water containers (11%), to spray (50%).
Dengue ; epidemiology

The virologic surveillance offered knowledge of epidemic stereotypes of dengue viruses inViet Nam during the years from 1987-2001. The activity cycle of Dengue-1 stared in 1989 and remained active until 1996. The Dengue-2 activity cycle began in 1987 and continued through 1997. While Dengue-3 first appeared in 1995 and presently continue to be active. Genomic structure of the Dengue-2/Viet Nam/1987 is somewhat different in comparision with several topotypes of the world, but closely related to the Dengue-2 topotype of Jamaica. Another sles relationship has been demonstrated between the Dengue-3/Viet Nam and the Dengue-3/ThaiLand/1987. In Southern Viet Nam, cases of dengue haemorrhagic fever are confirmed through virologic and serologic surveillance in the first quarter of each year
Dengue ; epidemiology

Result of the research showed that dengue fever/dengue hemorrhagic fever (DF/DHF) was endemic disease in Nam Hµ province with following characteristics: low incidence (16.3/100,000 persons), sporadicalness, persistence and unpredictable. All four types of dengue virus were isolated and they were pathogens of DF/DHF endemic in this province. Two species of mosquito vector were collected, and Aedes aegypti was a major vector in transmitting dengue virus. Breeding sites of Aedes aegypti were investigated with up to seven different kinds of water body. It was determined that the key breeding places of the vector for both urban and rural area were concrete tanks, jars, wells and discarded objects. It was in first time documented the breeding site of Aedes aegypti and added into checklist for Aedes larvae in Northern part of Vietnam
Dengue ; epidemiology

DF/DHF is endemic disease in Nam Ha province with the following characteristics: low incidence, sporadicalness, persistence and unprediction. All four type of dengue virus was isolated and was the causative agents of DF/DHF epidemic in the province. Two species of mosquito vector were collected, and Aedes aegypti is major vector in transmitting dengue virus. Breeding sites of Aedes aegypti were investigated with up to seven different kind of water bodies and key breeding places of the vector for both urban and rural areas are concrete tanks, jars, wells and discarded objects. It is first time well is recognized as breeding site of Aedes aegypti and added into checking list for Aedes larvae in Northern part of Viet Nam
Dengue ; epidemiology

In 1997, a big outbreak of DF/DHF occurred in the South of Viet Nam, especially in 3 provinces: Tra Vinh, Ca Mau and Kien Giang. Morbidity and mortality of the disease is highest in these provinces. Although ULV insecticide spray was carried out several times during the year, DF/DHF situation was not improved. Result of dengue vector surveillance shows that Breteau index of Ae.aegypti was from 5 to 11 times higher than dengue transmitting risk, 83-100% houses infecting with Ae.aegypti larvae. Key breeding sites of the mosquitoes were not affected by control activities are the main reason leading to persistence of DF/DHF in the areas.
Dengue ; epidemiology

The number of haemorrhagic dengue fever hospitalized at Khanh Hoa province was high during 1989-1998. The recorded peak of outbreak in 1992, 1995 and 1998 were 2212, 5358 and 7454 cases, respectively. The number of patients was high from May to November. 67,1% were the children under 15 years old. The patients at Nha Trang consisted highly 76,1%, followed by Cam Ranh 11,1%, Dien Khanh 95%. The vector controlling indexes were high during 1995-1997, the intervention was decreased, but it quickly returned to the beginning.
Dengue ; epidemiology