Review of Risk Factors for Human Echinococcosis Prevalence on the Qinghai-Tibet Plateau, China: a Prospective for Control Options
Total Page:16
File Type:pdf, Size:1020Kb
Review of risk factors for human echinococcosis prevalence on the Qinghai-Tibet Plateau, China: a prospective for control options. Qian Wang, Yan Huang, Liang Huang, Wenjie Yu, Wei He, Bo Zhong, Wei Li, Xiangman Zeng, Dominique A Vuitton, Patrick Giraudoux, et al. To cite this version: Qian Wang, Yan Huang, Liang Huang, Wenjie Yu, Wei He, et al.. Review of risk factors for human echinococcosis prevalence on the Qinghai-Tibet Plateau, China: a prospective for control options.. Infect Dis Poverty, 2014, 3 (1), pp.3. 10.1186/2049-9957-3-3. hal-00943685 HAL Id: hal-00943685 https://hal.archives-ouvertes.fr/hal-00943685 Submitted on 28 May 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Wang et al. Infectious Diseases of Poverty 2014, 3:3 http://www.idpjournal.com/content/3/1/3 SCOPING REVIEW Open Access Review of risk factors for human echinococcosis prevalence on the Qinghai-Tibet Plateau, China: a prospective for control options Qian Wang1*, Yan Huang1, Liang Huang1, Wenjie Yu1, Wei He1, Bo Zhong1*, Wei Li2*, Xiangman Zeng3, Dominique A Vuitton4, Patrick Giraudoux5, Philip S Craig6 and Weiping Wu3* Abstract Objective: Echinococcosis is a major parasitic zoonosis of public health importance in western China. In 2004, the Chinese Ministry of Health estimated that 380,000 people had the disease in the region. The Qinghai-Tibet Plateau is highly co-endemic with both alveolar echinococcosis (AE) and cystic echinococcosis (CE). In the past years, the Chinese government has been increasing the financial support to control the diseases in this region. Therefore, it is very important to identify the significant risk factors of the diseases by reviewing studies done in the region in the past decade to help policymakers design appropriate control strategies. Review: Selection criteria for which literature to review were firstly defined. Medline, CNKI (China National Knowledge Infrastructure), and Google Scholar were systematically searched for literature published between January 2000 and July 2011. Significant risk factors found by single factor and/or multiple factors analysis were listed, counted, and summarized. Literature was examined to check the comparability of the data; age and sex specific prevalence with same data structures were merged and used for further analysis. A variety of assumed social, economical, behavioral, and ecological risk factors were studied on the Plateau. Those most at risk were Tibetan herdsmen, the old and female in particular. By analyzing merged comparable data, it was found that females had a significant higher prevalence, and a positive linearity relationship existed between echinococcosis prevalence and increasing age. In terms of behavioral risk factors, playing with dogs was mostly correlated with CE and/or AE prevalence. In terms of hygiene, employing ground water as the drinking water source was significantly correlated with CE and AE prevalence. For definitive hosts, dog related factors were most frequently identified with prevalence of CE or/and AE; fox was a potential risk factor for AE prevalence only. Overgrazing and deforestation were significant for AE prevalence only. (Continued on next page) * Correspondence: [email protected]; [email protected]; [email protected]; [email protected] 1Sichuan Provincial Center for Diseases Control and Prevention, Chengdu, Sichuan, China 2Ganzi Prefecture Center for Diseases Control and Prevention, Kangding, Sichuan, China 3Institute of Parasitic Diseases, China Center for Diseases Control and Prevention, Shanghai, China Full list of author information is available at the end of the article © 2014 Wang et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Wang et al. Infectious Diseases of Poverty 2014, 3:3 Page 2 of 8 http://www.idpjournal.com/content/3/1/3 (Continued from previous page) Conclusion: Tibetan herdsmen communities were at the highest risk of echinococcosis prevalence and should be the focus of echinococcosis control. Deworming both owned and stray dogs should be a major measure for controlling echinococcosis; treatment of wild definitive hosts should also be considered for AE endemic areas. Health education activities should be in concert with the local people’s education backgrounds and languages in order to be able to improve behaviors. Further researches are needed to clarify the importance of wild hosts for AE/CE prevalence, the extent and range of the impacts of ecologic changes (overgrazing and deforestation) on the AE prevalence, and risk factors in Tibet. Keywords: Echinococcosis, Risk factors, Qinghai-Tibet Plateau, Control options Multilingual abstract and the Qinghai Province, as well as part of the Sichuan Please see Additional file 1 for translations of the ab- Province, the Gansu Province, the Xinjiang Uygur stract into the six official working languages of the Autonomous Region, and the Yunnan Province. A part United Nations. of the Plateau is bordered to the south by the Himalayan range, to the north by the Kunlun range, to the northeast by the Qilian range, to the east by the Hengduan Mountains, Background and to the west by the Pamir Mountains. There are some Human cystic echinococcosis (CE) and alveolar echino- 155 counties/cities located in the Plateau, and some 61 coccosis (AE) are caused by the larval stage of E. granu- counties/cities at the edge of the Plateau. The estimated losus and E. multilocularis, respectively. Transmission of population was 1,204 million [8]. CE and AE to humans is by unintentional consumption Two forms of echinococcosis, CE and AE, are highly of parasite eggs excreted in the feces of the definitive endemic on the Qinghai-Tibet Plateau [7]. The domestic hosts such as dogs and foxes. Geographically, CE has a lifecycle and sylvatic lifecycle were assumed for E. gran- universal distribution, while AE is confined to the north- ulosus and E. multilocularis [9] respectively, and indi- ern hemisphere. In humans, infection results in a meta- cated that the risk factors could be very complicated cestode in the liver mostly. Chemotherapy is required and diversified. To curb the transmission of the disease, continuously for many years, or even for the entire life- the Chinese government is increasing the financial sup- time. In the absence of treatment, the disease is fatal. AE port for the control of echinococcosis. The resources al- mortality could reach 94% and above if untreated within location will largely depend on the control options 10 years [1,2]. It has been acknowledged as one of the decided on by keeping the significant risk factors in world’s most lethal parasitic zoonoses [3]. mind. Therefore, it is high time to review and identify The World Health Organization (WHO) listed echino- the risk factors for echinococcosis on the Qinghai-Tibet coccosis, including both CE and AE, as a neglected trop- Plateau, where the transmission AE and/or CE is very dy- ical disease in 2010 [4]. The estimated worldwide human namic [7,10-13]. The findings could help policymakers de- burden of CE is 285,407 (95% confidence interval [CI], sign more targeted control strategies. 218,515–366,133) DALYs [5], and the figure for AE is 666,434 DALYs (CIs 331,000–1.3 million) [6]. China is responsible for 40% of the global CE DALYs [5] and 91% Review of global AE DALYs [6]. In western China, 380,000 pa- Methods tients were estimated by a nationwide sampling survey Selection criteria conducted from 2001 to 2004 [7]. The figure indicates Literature with the following characteristics was included: that western China is a highly-endemic area of echino- 1. Diagnosis of human echinococcosis for community- coccosis worldwide. The survey estimated that the prev- based studies was based on positive findings by abdominal alences of echinococcosis in Tibet, Tibetan communities ultrasound examinations and complemented by confirma- in Sichuan, and Qinghai Province were 2.76%, 2.33%, tory serological tests, as WHO suggested [14]; diagnosis and 1.91%, respectively. These figures were the top three for hospital-based studies were dependent on abdominal in the nation, and indicated Qinghai-Tibet Plateau to be ultrasounds, X-rays, computed tomography examinations, the most endemic area in China (see Figure 1). and complemented by confirmatory serological tests. 2. The Qinghai-Tibet Plateau is located at 26°00′12″N~ Risk factors were linked to human prevalence. 3. Litera- 39°46′50″Nand73°18′52″E ~ 104°46′59″Einwestern ture had to refer to an actual study rather than be a review China. It covers most of the Tibet Autonomous Region of a study/studies. Wang et al. Infectious Diseases of Poverty 2014, 3:3 Page 3 of 8 http://www.idpjournal.com/content/3/1/3 Figure 1 Human echinococcosis prevalence on the Qinghai-Tibet Plateau. Note: within the legend, the right blue bar indicates 3.4% of CE prevalence. References: 7, 10–13, 15–39. Search strategy Data analysis Medline, CNKI, and Google Scholar were searched for Significant risk factors found by single factor and/or literature which was published between January 2000 multiple factors analysis were listed, counted, and sum- and July 2011.