To dynamic monitor drinking-water-borne fluorosis in Huzhu County and water improvement projects, to know the trend of the disease, and to evaluate the effect of prevention and control measures.

Seven townships in Huzhu County including 60 history drinking-water-borne fluorosis villages were selected as investigation sites in 2017, and demographic data were collected. In the villages of the diseased areas where the water had been changed, the operation of the water improvement project was investigated, and 1 tap water sample was collected to determine the fluorine content; for the villages in the diseased areas where the water had not been changed, one water sample was collected from the drinking water source in accordance with the five directions of east, west, south, north and middle to determine the fluorine content. More than 90% of the children aged 8 - 12 years old in the surveyed villages were examined and judged for dental fluorosis. According to historical data, 1 village with severe illness of children was selected, 50 people were selected who were over 25 years old and lived in the villages for more than 5 years. Clinical and X-ray examinations of skeletal fluorosis were performed. Urine samples from adults surveyed were collected for urinary fluoride detection.

Six of the 60 villages in the 7 townships had been relocated. By 2017, a total of 54 villages in drinking-water-borne fluorosis areas had changed their water. A total of 16 water improvement project were surveyed, among them, there were small water improvement project 6, accounting for 37.50%, large water improvement project 10, accounting for 62.50%; normal operated project 16, accounting for 100.00%; water fluoride content of qualified project 16, the qualified rate was 100.00%, the water fluoride content ranged 0.10 - 0.66 mg/L, covering a population of about 160 thousand and 846 people. A total of 2 399 children aged 8 - 12 were examined, 117 cases of dental fluorosis were detected, the detection rate of dental fluorosis was 4.88%, dental fluorosis index was 0.13. Among them, 89 cases were extremely mild, accounting for 3.71% of all the children examined, 21 cases were mild, accounting for 0.88% of all the children examined, 7 cases were moderate, accounting for 0.29% of all the children examined, and no severe cases were found. A total of 68 adults over 25 years old were examined for skeletal fluorosis. Twelve patients were found to have clinical skeletal fluorosis. The detection rate was 17.65%. X-ray radiography was used to examine 46 people, and 1 case was detected, the detection rate was 2.17%. Clinical and X ray examinations showed no more than moderate patients. Fifty samples of adult urine were tested, the level of urine fluorine was 0.72 mg/L.

Water improvement project is working well in Huzhu County, and no serious children with dental fluorosis and adult skeletal fluorosis are detected. The prevention and control measures of drinking-water-borne fluorosis has achieved remarkable results in Huzhu County. We will continue to strengthen water improvement project and disease monitoring, and thoroughly control the prevalence of drinking water fluorosis.

Fluorosis, dental; Water; Result evaluation