7.1 Basic Situation

The monitoring scale and items in 2003 were the same as that in 2002, including Chongqing, Wanzhou District , Fengdu County of Chongqing and Yichang of Hubei Province. The total number of people monitored was 490,632. The gender ratio of male and female was 1.02:1.

In 2003, there were altogether 314 medical institutions at various levels in the monitoring points, 60 less than that in 2002, mainly caused by the emigration of people from the Three Gorges reservoir area. The total number of public health workers of various types at different levels was 4,307, 97 less than that in 2002. There were 3,716 hospital beds in the medical institutions, 370 more than that in 2002.

7.2 Statistics of Lives

7.2.1 Birth and death

In 2003, 3,766 people were born within the monitoring range, among which 1,971 were males and 1,795 were females. The birth rate was 7.68‰, a light increase compared with 2002. 2,918 people died with a mortality rate of 594.74/100 thousand. Among them 1,603 were males with a mortality rate of 647.80/100 thousand and 1,315 were females with a mortality rate of 541.78/100 thousand. 54 babies including 28 male babies and 26 female babies died. The mortality rate of babies was 14.34‰, decreased by 1.51‰ compared with 2002, close to the baby mortality rate in the whole country.

7.2.2 Analysis of death cause

According to the classification standard for ICD-9 diseases, the first five diseases causing people's death were ranked as follows: the circulatory system diseases (28.8%), malignant tumor (22.8%), respiratory system diseases (20.2%), damnification and poisoning (12.3%) and digestive system diseases (3.2%). The death cases caused by the above five types of diseases accounted for 87.2% of the total deaths, indicating that these five types of diseases were the major causes for the death of people in the Three Gorges reservoir area. Among the top ten causes of death, the percentages of death causes of circulatory system diseases, damnification and poisoning, unidentified diseases and urinary diseases decreased a little, while those of malignant tumor, respiratory system diseases, digestive system diseases, endocrine system diseases, nervous system diseases and baby diseases increased a little.

7.3 Monitoring of Diseases

7.3.1 Monitoring of infectious diseases

In 2003, 2,890 cases of infectious diseases were reported from different monitoring points with 1 death case. The total morbidity rate was 589.04/100 thousand with mortality rate at 0.2/100 thousand and fatality rate at 0.035%. Among them, 1,802 cases in 12 types of category B infectious disease were reported with 1 death case. The morbidity rate was 367.28/100 thousand with mortality rate at 0.2/100 thousand and fatality rate at 0.055%. There was no report of category A infectious disease. 1,088 cases in 5 types of category C were reported with morbidity rate at 221.75/100 thousand. Morbidity rates of infectious disease in Categories A and B decreased by 9.2%, while that in category C increased by 25.2%.

In 2003, morbidity of the first five infectious diseases in category B was basically the same as in 2002. The order of them was: pulmonary tuberculosis (145.73/100 thousand), virus hepatitis (100.28/100thousand), dysentery (60.33/100 thousand), gonorrhea (37.50/100 thousand) and measles (14.88/100 thousand).

In 2003, there were reports of incidence of infectious diseases every month from the monitoring sites. 168-201 cases of category B infectious diseases were found each month from April to October. The peak morbidity rate was in August, but no so obvious, indicating that the incidence of infectious diseases was scattered and there was no outbreak of epidemics. Two peak periods for incidence of category C infectious diseases appeared in May and September. The major cause was the outbreak of urticaria and conjunctivitis epidemics in these two months.

7.3.2 Monitoring of endemic diseases

In 2003, the monitoring points in Chongqing, Wanzhou and Yichang conducted sampling inspection of endemic diseases and monitoring of iodine salt among junior and middle school students according to the requirements of the Iodine-Deficient Disease Monitoring Program of the Ministry of Public Health. The results of the monitoring conducted at the monitoring points in Chongqing urban area and Wanzhou showed that the rate of iodine-deficient goiter among children at the age of 8-10 were 11.9% and 7.5% respectively. Compared with the situation of 2002, morbidity of children goiter was kept at a lower level. At monitoring points, the average coverage of iodine salt was 97.0%, the acceptance rate of iodine salt was 98.6% and the edible rate of iodine salt was 95.7%. Compared with normal years, all the above three indexes were raised, indicating that the interference measures on iodine salt popularization were well performed.

7.4 Monitoring of Biological Media

In 2003, the deratization campaign carried out for the cleanup of the reservoir made the density of indoor and outdoor mice dropped to 1.3% and 3.4% respectively before water storage of the reservoir started in April, obviously lower than those of 2002. By September after water storage, the density of indoor mice dropped further to 1.0%, while that of the outdoor mice rose up to 3.7%. This situation should be given further attention.

In indoor areas, the brown mice were the superior kind, accounting for 57.1%. The small mice ranked the second, accounting for 34.7%. Besides there were also the small insectivora occasionally invading from outdoors. In the field, the small insectivora (mostly short-tail shrews) were the dominant kind, accounting for 66.7%. The black strip rats and the brown mice ranked as the second, accounting for 14.6% and 13.0% respectively. Small mice and Rattus flavipectus were at a lower rate, less than 5% of the total. As the host animals for epidemic hemorrhagic fever and leptospirosis, the percentage of black strip rats remained at a low level though a little higher than 2002.

In 2003, all monitoring points collected kidney and lung samples of rat-type animals according to provisions to monitor infection of epidemic hemorrhagic fever and leptospirosis. Leptospirosis tests were made on 242 kidney samples. The results showed that only one sample tested at Yichang monitoring point was positive and all the others were negative. The positive rate was 0.4%. The epidemic hemorrhagic fever test on 14 rat lung samples all showed negative response.

In 2003, the results of monitoring on mosquitoes were similar to those of 2002. The density of mosquito in the livestock sty was higher than that in human living room. The density of mosquito in the livestock sty was 148.11/room.manhour in 2003, higherthan 135.77/room.manhour in 2002. This was mainly because of the obvious increase of the total density of mosquito at Yichang monitoring point. The density of mosquito in human living room was 43.09/ room.manhour, a little higher than 41.98/ room.manhour in 2002.

The peak period for the density of mosquito in human living room was the first ten days of June in Chongqing urban area and the first ten days of July in Fengdu, Wanzhou and Yichang. The peak period for the density of mosquito in livestock sty was the first ten days of June in Chongqing urban area and the first ten days of July in Fengdu and Wanzhou too.

According to analysis on species of the mosquitoes, the armiger's subalbatus were the dominant kind both in human living room and in the livestock sty, accounting for 55.3% and 56.4% respectively. The culicine mosquitoes ranked the second in human living room, accounting for 23.9%, the same level of 2002; Anopheles hyrcanus ranked the second in livestock sty, accounting for 15.0%.