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-Ti...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. 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.展开更多
Background:Human cystic echinococcosis(CE)and alveolar echinococcosis(AE)are highly endemic in Tibetan communities of Sichuan Province.Previous research in the region indicated that domestic dog was the major source o...Background:Human cystic echinococcosis(CE)and alveolar echinococcosis(AE)are highly endemic in Tibetan communities of Sichuan Province.Previous research in the region indicated that domestic dog was the major source of human infection,and observations indicated that domestic dog could have more access to intermediate hosts of Echinococcus spp.:both domestic livestock(CE)viscera and small mammals(AE),in early winter and again in spring.We hypothesized that there would therefore be a significant increase in the risk of canine infection with Echinococcus spp.in these two seasons and conducted a reinfection study to investigate this further.Methods:Faecal samples were collected from owned dogs in seven townships in Ganze Tibetan Autonomous Prefecture(Sichuan Province,China),and Echinococcus spp.infection status was determined using copro-antigen ELISA.Dogs were sampled in April(spring),July(early summer),September/October(autumn/early winter)and December(winter)in 2009;and in April(spring)2010.Dogs were treated with praziquantel following each of the five sample collections to eliminate any tapeworms.Information on dog sex,age and body weight was also collected.The t-test,Fisher’s exact test,Poisson regression and logistic regression were used to compare means and prevalences,and to identify factors associated with infection status.Results:The proportion of female dogs was significantly lower than that of male dogs;female dogs had significantly higher(22.78%)baseline copro-ELISA prevalence than males(11.88%).Dog body weight,sex,age,county and previous infection status at any sampling point had no influence on the re-infection prevalence in general.Poisson regression did not found a significant influence on the re-infection prevalence due to different deworming/sampling time spans.Dogs exhibited significantly higher re-infection prevalences in spring and early summer of 2009 and in early winter between September/October and December of 2009,suggesting a higher infection pressure in these seasons comparing with other seasons.Conclusion:Following praziquantel treatment,dog body weight,sex,age,county,deworming time span and previous infection status at any sampling point had no influence on the re-infection prevalence in the region in general.The differences between re-infection prevalences were probably due to the seasonality in Echinoccocus spp.infection pressure in the region.Early winter,spring and early summer should be important seasons for optimal dog deworming intervention in these Tibetan communities.展开更多
文摘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. 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.
基金supported by a project grant(#2014SZ0151)the Sichuan Bureau of Science and Technologyand in part by a project grant(#094324/Z/10/Z)from the Wellcome Trust(UK).
文摘Background:Human cystic echinococcosis(CE)and alveolar echinococcosis(AE)are highly endemic in Tibetan communities of Sichuan Province.Previous research in the region indicated that domestic dog was the major source of human infection,and observations indicated that domestic dog could have more access to intermediate hosts of Echinococcus spp.:both domestic livestock(CE)viscera and small mammals(AE),in early winter and again in spring.We hypothesized that there would therefore be a significant increase in the risk of canine infection with Echinococcus spp.in these two seasons and conducted a reinfection study to investigate this further.Methods:Faecal samples were collected from owned dogs in seven townships in Ganze Tibetan Autonomous Prefecture(Sichuan Province,China),and Echinococcus spp.infection status was determined using copro-antigen ELISA.Dogs were sampled in April(spring),July(early summer),September/October(autumn/early winter)and December(winter)in 2009;and in April(spring)2010.Dogs were treated with praziquantel following each of the five sample collections to eliminate any tapeworms.Information on dog sex,age and body weight was also collected.The t-test,Fisher’s exact test,Poisson regression and logistic regression were used to compare means and prevalences,and to identify factors associated with infection status.Results:The proportion of female dogs was significantly lower than that of male dogs;female dogs had significantly higher(22.78%)baseline copro-ELISA prevalence than males(11.88%).Dog body weight,sex,age,county and previous infection status at any sampling point had no influence on the re-infection prevalence in general.Poisson regression did not found a significant influence on the re-infection prevalence due to different deworming/sampling time spans.Dogs exhibited significantly higher re-infection prevalences in spring and early summer of 2009 and in early winter between September/October and December of 2009,suggesting a higher infection pressure in these seasons comparing with other seasons.Conclusion:Following praziquantel treatment,dog body weight,sex,age,county,deworming time span and previous infection status at any sampling point had no influence on the re-infection prevalence in the region in general.The differences between re-infection prevalences were probably due to the seasonality in Echinoccocus spp.infection pressure in the region.Early winter,spring and early summer should be important seasons for optimal dog deworming intervention in these Tibetan communities.
