Acta Tropica 145 (2015) 88–92 Contents lists available at ScienceDirect Acta Tropica journal homepage: www.elsevier.com/locate/actatropica Schistosomiasis in a migrating population in the lake region of China and its potential impact on control operation Chun-li Cao a,∗∗, Zi-ping Bao a, Shi-zhu Li a, Wang-yuan Wei b, Ping Yi b, Qing Yu a, Hong-qing Zhu a, Jing Xu a, Jia-gang Guo a, Zheng Feng a,∗ a National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, WHO Collaborating Center for Malaria, Schistosomiasis and Filariasis, The Key laboratory of Parasite and Vector Biology, Ministry of Health, China, 207 Rui Jin Er Road, Shanghai 200025, People’s Republic of China b Hunan Institute of Schistosomiasis Control, Hunan, People’s Republic of China article info abstract Article history: Coverage of migrating people in schistosomiasis control program is a growing concern in China. Schis- Received 17 March 2014 tosomiasis caused by Schistosoma japonicum is still one of the major infectious diseases of public health Received in revised form 2 February 2015 importance in China though tremendous efforts have been made to control the transmission over the past Accepted 8 February 2015 decades. Along with the rapid social-economic development, migrant population has been remarkably Available online 18 February 2015 increasing across the country. The infected migrants may introduce a new souse of infection to endemic areas or the areas where the transmission had been controlled or interrupted but the intermediate host Keywords: Oncomelania snail is still present. Preliminary studies for surveillance on schistosomiasis prevalence in Schistosomiasis japonica Migrant population migrants were reported, but there is little basic information provided. We carried out an investigation on Knowledge of schistosomiasis the prevalence in immigrants, emigrants and permanent residents in three villages of Hunan province Impact factor located in the main endemic area of lake region, and analyzed the potential impact of migration on control China practice. In the study villages, the migrant population accounts for 53.6% of the total. Schistosoma infec- tion was detected by modified Kato-Katz method and miracidium hatching test. Questionnaire survey was conducted comprising knowledge of disease and its transmission, water contact, personal protective measures, and whether examined and treated after water contact. The survey indicated that the migrants and permanent residents had similar life style, and the majority of them experienced water contact in agricultural work or routine life activities. However, the infection rate in immigrants was significantly higher than that in permanent residents. It was also found that the migrants had significantly less knowl- edge about the disease than the permanent residents, and took no personal protective measures. This is due to that the control program could not cover the migrants when they were absent at the time the program being implemented. The present study suggested that the surveillance and intervention for migrants, immigrants in particular, should be included and strengthened in schistosomiasis control program and a feasible scheme be developed. © 2015 The Author. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 1. Introduction where interruption of transmission has proven difficult (Zhou et al., 2007a,b; Gray et al., 2008). Schistosomiasis japonica, a zoonotic parasitic disease caused Along with the social-economic development, migrant popu- by Schistosoma japonicum, remains a public health problem and lation has been in continuous increase in the country (Guo and is listed among the top infectious diseases prioritized for control Yu, 2005). According to the nationwide census sampling survey in and elimination in China, despite tremendous efforts have been China in 2005, there were 147 million migrating population, among made over the past decades (Wang et al., 2008; Ross et al., 2013). them 61.3% were from rural areas, and 84.4% migrating from rural More than 82% of infected persons lived in lake and marshland to urban areas (Duan and Yang, 2009). About 30 million people regions (Dongting Lake and Poyang Lake) along the Yangtze River, moved from schistosomiasis endemic areas to cities and developed regions in the country (Zheng, 2003). During the migration, people may carry the parasite and/or snail vector to the new settlement ∗ introducing a risk of transmission (Gautret et al., 2012; Ostroff and Corresponding author. Tel.: +86 21 54653507; fax: +86 21 54653512. ∗∗ Co-corresponding author. Tel.: +86 21 54650863; fax: +86 21 54650863. Kozarsky, 1998; Bella et al., 1980). Importantly, the schistosomiasis E-mail addresses: [email protected] (C.-l. Cao), [email protected] (Z. Feng). patients among the migrants may miss treatment after left home http://dx.doi.org/10.1016/j.actatropica.2015.02.009 0001-706X/© 2015 The Author. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). C.-l. Cao et al. / Acta Tropica 145 (2015) 88–92 89 and become a new source of infection in the endemic areas or the The infected individuals among the immigrants and permanent areas where snails are present (Zhou et al., 2011; Chen et al., 2011). residents were treated by the local anti-schistosomiasis station Currently, studies were reported on the surveillance of schistoso- with praziquantel in October when the local intervention took miasis in migrant population in the areas where the transmission place. The infected emigrants were treated in January–February was controlled or interrupted (Zhou et al., 2007a,b; Huang et al., 2010, before outgoing for work again. The treatment was delivered 2008; Cai et al., 2007), but there is little basic information on the as described in the national manual (Bureau of Disease Control, prevalence in migrating population and its implication in control Ministry of Health, China, 2000). practice (Guo and Yu, 2005; Cao and Guo, 2006). To provide essen- tial information for optimizing control strategy covering migrants, 2.4. Questionnaire survey we investigated the schistosomiasis prevalence status in migrant population and its potential impact on the control operation in the The questionnaire survey was conducted for cognition of sch- lake region of schistosomiasis endemic area of China in September istosomiasis knowledge and personal behavior as described (Cao 2009–February 2010. et al., 2008; Chen et al., 2008). Three sets of questions were designed for the participants: (1) basic demographic informa- 2. Method tion including the gender, age, education (illiterate, elementary school, middle school or higher) and occupation (farmer, fishery 2.1. Migrating and permanent residents and aquatic work, business and others), and the current staying status in the village for defining the groups of immigrant, emi- In this study, the villagers who have administratively registered grant and permanent residents; (2) knowledge of schistosomiasis and possessed house property in the study villages for more than comprising whether knowing: how people contract the disease 10 years are defined as the permanent residents, while the native (infection route), harm of the disease, and the transmission through villagers temporally left home for work in other places for more feces of infected people and livestock, the snail is the mediate than 3 months as the emigrants. host, the best way to prevent from infection is to avoid contact- The immigrants are those have migrated from other places into ing infested water, and the drug for treatment; (3) water contact the study villages for work for 6 months or longer. According to the pertaining weather experiencing water contact during the trans- administrative rule, one person can only register at one permanent mission season (April–October) for agricultural work or routine home residence, and the migrants only need to have a local record life, taking personal protective measure, and receiving examination in the new places where they temporally stay for a period of time. and treatment after water contact. The proportion of knowledge cognition and personal protection in the three defined groups 2.2. Study subjects and sites of participants were estimated and compared. The investigators were trained for the survey protocol before the questionnaire Three villages were selected in the endemic area in Yueyang commenced. City, Dongting lake region, Hunan Province of China. The selected villages were Jinshan village/Yueyang county, Changjiang vil- 2.5. Data analysis lage/Junshan district and Pulao village/Yueyanglou district, where >30% of the total population were migrants, and the ecological envi- The participants were grouped as immigrant, emigrant and per- ronment were similar. manent residents, and the data were processed accordingly. On a village base, all migrants and permanent residents, who All survey data were input using Excel (2007) and analyzed with were present at the time of project survey, at age 6–65, were SPSS 13.0. For the group comparison, the chi-square test was used enrolled, of them 808 migrants and 699 permanent residents and the significance at P < 0.05 was estimated. participated in the project, excluding those were sick, failed in collecting fecal sample or absent. The resident enrollment was car- ried out based on the administrative information and