Distribution and clinical features of Paragonimiasis skrjabini in Three Gorges Reservoir Region

Paragonimiasis has previously been reported in the Southwest Provinces of China, including Chongqing and Sichuan. The construction of Three Gorges Dam, which was begun in 1994, has resulted in substantial changes to the depth and the flow pattern of the Yangtze River. To investigate epidemiology of the paragonimiasis, 724 people aged 2-49 years were selected and examined for Paragonimus infection by intradermal test (IDT), and enzyme-linked immunosorbent assay (ELISA). A survey of eating habits was conducted face-to-face in 5 endemic counties. Freshwater crabs were collected from seven sites in the 5 counties to determine the rate of infection with Paragonimus metacercariae. Additionally, we analyzed 213 case reports from the region dated 2006 to 2009. According to the survey results, the prevalence of Paragonimus skrjabini infection in freshwater crab was 39.65%, and the human infection rates detected by IDT and ELISA were 14.36% (104/724) and 7.46% (54/724), respectively. These results show that the Three Gorges Reservoir is still an area of high paragonimiasis endemicity. The water level of the Yangtze River has risen to 175 m, and the area of water coverage in the region has increased to 1084 km2. These conditions will favor the growth and expansion of the freshwater crab population.

The first author is Xi-lin Zhang (Corresponding author), who is from the Department of Pathogenic Biology, Third Military Medical University, Chongqing, China. The other authors are from this Department and from the Department of Pathogenic Biology, Luzhou Medical College, which is in Sichuan, China. Our specialities are Helminthology and Epidemiology and we have a particular interest in the epidemiology of parasitic disease in the Three-Gorges Reservoir Areas in Chongqing and Sichuan, China.Highlights► Freshwater crabs were collected to determine the Paragonimus infection rate. ► Questionnaire and immunodiagnosis were carried out among 724 people aged 2-49 years. ► We collected 213 case reports from the region and analyzed their clinical types. ► The Three Gorges Reservoir is still an area of high paragonimiasis endemicity.