ABSTRACT
<p><b>OBJECTIVE</b>To evaluate the development and operation on measles surveillance system.</p><p><b>METHODS</b>To formulate surveillance program, and then establish surveillance system on measles in Hainan province before the case surveillance was conducted. Descriptive epidemiological method was used to analyze the measles cases reported through the notifiable diseases epidemic situation report system and measles surveillance system during 2004 - 2008 in Hainan province.</p><p><b>RESULTS</b>From 2004 to 2008, through surveillance system, 3040 suspected measles cases were reported which was 96.00% higher than that from the notifiable diseases epidemic situation report system. When the measles surveillance system was first established in 2004, the number of cases reported by the surveillance system was less than that from the epidemic report system, however, the sensitivity of the surveillance system had been increasing since 2005. In 2008, the number of suspected cases reported by surveillance system was 19.12 times more than from the epidemic report system. The proportion of confirmed cases in the total suspected cases was decreasing annually, from 90.34% to 4.48%, along with the increase of the sample collection rate, from 22.73% to 99.12%. The proportion of laboratory confirmed cases in the total confirmed cases increased from 7.55% to 86.97%. With suspected cases, the IgM antibody positive rate on measles and rubella were 31.57% and 34.52%, respectively. In Hainan, the epidemic pattern of measles had been sporadic, except for 2006 as there occurred several outbreaks in that year. The of disease incidence had an obvious seasonal peaks, from March to June. Measles mainly attacked children under 15 years of age, accounted for 86.68% of the age group. Children with no immunity or unknown immune history accounted for 85.67%.</p><p><b>CONCLUSION</b>The sensitivity of surveillance system had been increasing annually since it was developed and the incidence had been dropping to its lowest level. These achievements had built a solid foundation for the eventual elimination of measles.</p>
Subject(s)
Humans , China , Epidemiology , Disease Outbreaks , Incidence , Measles , Epidemiology , Population SurveillanceABSTRACT
Objective To understand the epidemiological characteristics and the influencing factors of Japanese encephalitis (Abbreviated JE) at different periods in Hainan province, and to provide evidence for JE control strategies. Methods Data on JE had been collected since 1952 and related incidence, mortality, fatality rates of JE and the rate of JE vaccination were calculated for four periods: the natural epidemic period (1952-1978), period for inactivated JE vaccine promotion (1979-1986), national immunization program period (1987-1990) and the promotion of live-attenuated JE vaccine period (1991-2007). History on the immunity of JE and data from the monitoring programs on cases and insect vectors were also analyzed. Results The average annual incidence in natural epidemic period was 7.12/100 000, which was also the highest among the 4 periods with the mortality rate as 0.89/100 000. The average annual incidence was 0.11/100 000 which was the lowest while the mortality rate was 0.01/100 000 in the period when live-attenuated JE vaccination was under promotion. Since the establishment of JE surveillance system was set up in Hainan province in 2002, the specimen collection rate of JE reported suspected cases had reached 92.8%, while the incidence of confirmed JE cases fluctuated between 0.05/100 000 and 0.2/100 000. Of the confirmed cases, 86% did not have clear history of JE vaccination. The annual average protective rate reached 95.69% in 2004-2007. The density of insect vectors was high in Hainan province. The infection rate of JE in host animal swine, kept rising from April to October, and in some surveillance points, the rate reached 99.3%. The density of insect vector plotted in trans-curve with the infection of host animals. Conclusion The application of live-attenuated JE vaccine was found to have had significant protective effect on JE in susceptible children. It helped reducing the incidence and controlling the epidemics of JE. It appears feasible to include live-attenuated JE vaccine into the expanded immunization program.