Elimination is not the end: experience in handling the last residual filariasis focus in China.

BACKGROUND

A residual focus of bancroftian filariasis was found in Fuchuan County, Guangxi Zhuang Autonomous Region, China in 2007, and the response measures were implemented with participation and guidance from the National Institute of Parasitic Diseases at the Chinese Center for Disease Control and Prevention (China CDC). This study aims to assess the infection sources and summarize the management processes of the residual focus to fill the gap of the re-emergence of focus after elimination as a public health problem.

METHODS

The assessment of the infection sources in the residual filariasis focus was conducted by on-site investigation and review of the database that was created and maintained by the China CDC. Historical records that were created by the China/Fuchuan CDC and maintained by the China CDC were retrospectively reviewed to summarize the experience of the handling process for filariasis. Statistical tests and logistic regression were performed to analyse the epidemic characteristics of the residual filariasis focus.

RESULTS

A total of 7308 test records were reviewed, of which 919 were from the focus's natural village while 6389 were from other affected populations. Age and sex significantly affect filariasis infection, and the high-risk population was the 50-69 y age group and males in this focus. The on-site evaluation result and database monitoring showed that the focus did not spread locally or to neighbouring places and thus did not pose a public health threat. The emergency response process (ERP) for residual filariasis focus was developed and the rapid report and survey of the first case serves as the pre-trigger signal for ERP. Implementation of the ERP should account for local technical resource availability, representing the optimal approach under capacity-constrained conditions.

CONCLUSIONS

Maintenance of a sensitive and effective surveillance system and stockpiling of technologies and medicines are key to consolidating the elimination of filariasis and preventing its re-emergence. The disposal process is a systematic and scientific action that must follow epidemiological and medical principles according to local conditions.