[Surveillance on Japanese encephalitis in Henan province, 2006 - 2010].

OBJECTIVE

To analyze the epidemiological characteristics and risk factors of Japanese encephalitis (JE) in Henan province.

METHODS

Epidemiological characteristics and related factors of JE cases in Henan province from 2006 to 2010 were analyzed with descriptive epidemiological method and JE IgM antibodies of the serum or cerebrospinal fluid of the cases were detected by ELISA.

RESULTS

3099 cases were reported in Henan province from 2006 to 2010. The incidence fluctuated from 0.39/100 000 to 1.08/100 000, and the incidence rate was decreasing. Patients were concentrated mainly in Xinyang, Nanyang and Luoyang cities, which accounted for 60.12% of the total. The peak season was in July-September, accounted for 93.26% of all the cases. Most cases were in 0 - 14 year old (83.61%) in the whole province. However, in Luoyang city, number of cases in the ≥ 15 year old group, had an obvious increase (57.63%). Compared with the provincial data, significant difference was found between the two ≥ 15 year old groups (χ(2) = 330.0341, P < 0.05) statistically. 20.23% of the JE cases were vaccinated but 75.54% of them did not complete the whole course. 79.77% of the cases were not sure if they had received the vaccination. 42.98% of the JE cases were confirmed through laboratory tests but other 45.95% of them were clinically diagnosed, with the rest 11.07% were suspected cases.

CONCLUSION

The distribution of JE cases showed seasonal, regional characteristics and crowd differences in Henan province. Basic immunization and the program on strengthening immunization of JE should be further standardized. The laboratory diagnosis rate of JE cases should be further improved.