Epidemiological features and risk factors of cystic echinococcosis and alveolar echinococcosis in China: analysis of a national population-based field survey | Parasites and vectors.

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Based on the national epidemic survey of echinococcosis conducted from 2012 to 2016, we analyzed the demographic and epidemiological characteristics and geographical distribution of CE and AE in China, and then identified the population at high risk for both types of echinococcosis. identified the region. In addition, we systematically and quantitatively analyzed risk factors for CE and AE, considering a more comprehensive range of risk factors than those assessed in previous studies. In addition to considering demographic risk factors, we assessed the extent to which environmental, biological, and social factors influence echinococcal infection risk. The results of this study may help researchers and policy makers improve surveillance and preventive measures aimed at reducing infectious diseases. echinococcus human infection.

We described the demographic features of echinococcosis at national and subnational levels. In general, our results showed that the prevalence of echinococcosis was significantly associated with gender, age, occupation and educational level.Similar to previous studies [18,19,20], found that being female was a potential risk factor for CE and AE. This may be because women are responsible for household chores, including feeding dogs, collecting yak dung for fuel, and milking livestock, all of which reduce the exposure of women. Increasing frequency. echinococcus egg. Furthermore, we observed that CE prevalence increased with age. This may be due to its long incubation period and gradual acquisition of the disease in the population with age, or perhaps due to the weakened immune system of the elderly. In contrast, AE prevalence has decreased in persons aged 60 years and older, which may be associated with premature death in those infected with AE. Regarding occupations, we found that pastoralists and religious workers were more likely to be infected with echinococcus than other occupations, which is consistent with previous research findings. [21, 22]. Religious workers are at risk of Echinococcus infection because they shelter and feed stray dogs, while pastoralists are at the same risk because they come into frequent contact with livestock and dogs. Furthermore, our results suggest that limited education increases the risk of echinococcal infections, which has also been reported in many previous studies. [12, 20]. One possible explanation for this is that education level may determine career choices and lifestyles to some extent. Another possible explanation is that limited education may be related to poor hygiene practices, such as drinking unboiled water, eating raw vegetables, and not washing hands before eating. There is. Therefore, individualized and precise strategies for the prevention and control of echinococcosis should be applied to specific populations, with emphasis on women, the elderly, pastoralists, religious workers and the illiterate. be.

We also mapped the spatial distribution of CEs and AEs at the city and county levels and showed that the prevalence of echinococcosis varies geographically. We observed a high degree of coexistence of both types of echinococcosis in the Tibetan Plateau region. This may be due to a combination of local environmental, biological and social conditions favorable for the transmission of echinococcosis, such as high altitude and low temperatures. , variety of animals, limited health care and education, and poverty. Furthermore, by combining county-level echinococcosis cases with a variety of environmental, biological and social factors, generalized linear models may be used to explain the regional geographic variation of the disease. We identified and quantified spatial risk factors for echinococcosis.

Precipitation, temperature, grassland and forest area, and elevation were found to have significant effects on both CE and AE.Consistent with previous studies [23, 24]Our analysis showed that both CE and AE prevalence were positively correlated with precipitation, but negatively correlated with temperature. This is probably because cold, moist environmental conditions favor the survival, development and reproduction of organisms. echinococcus eggs [25, 26]. Moreover, temperature and precipitation may affect echinococcosis more synergistically through interactions. For example, a study conducted in Ningxia Hui Autonomous Region found that the risk of AE increased by 0.60% for each mm increase in average summer precipitation, while it decreased by 10.60% for each mm increase in average winter precipitation. found. [27]. Additionally, a number of studies have suggested an association between landscape and echinococcosis risk. [28]. Girodou et al.Echinococcosis prevalence was found to be positively correlated with the grassland area ratio, but negatively correlated with the forest area ratio. [28]This is consistent with our findings. This is likely because deforestation for agriculture creates vast areas of shrubs and grasslands that benefit the growing population of intermediate hosts (such as livestock and small mammals). [29, 30]. We also observed a positive correlation between altitude and echinococcosis prevalence, which is consistent with previous findings. [23, 31, 32].

Our results suggested that biology-related factors play an important role in influencing the prevalence of echinococcosis. Specifically, we found that cattle density, cattle morbidity, dog density, dog morbidity, and number of livestock slaughtered were positively correlated with CE morbidity.These results are consistent with those of previous studies [12, 18]. Schantz et al. Livestock owners showed a three times higher risk of being diagnosed with the disease compared to non-livestock owners. [12]. On the other hand, the meta-analysis performed by Alessia et al.Domestic animal slaughter and dog ownership have been shown to be significant risk factors associated with CE [18]. Unexpectedly, we observed in our study that sheep density was negatively correlated with CE, possibly because slaughter operations shifted from households to slaughterhouses in areas with high sheep densities. This is thought to have reduced the risk of echinococcal infection to some extent. For AEs, our analysis showed that high rodent density and prevalence contributed to the high prevalence of the disease, which is consistent with the results of previous studies. I’m here. [33]. Furthermore, some researchers have revealed that contact with stray dogs and wild animals is a risk factor for AE. [19]Unexpectedly, our results showed no significant relationship between canine density and AE. This may be a result of using low-resolution data of canine densities converted from shapefiles.

In terms of social factors, we identified local economic conditions (GDP) and drinking water sources as risk factors for both CE and AE, which were also reported as risk factors in previous studies. [17,18,19]. For example, two cross-sectional studies showed that low income increased the risk of both echinococcal infections. [18, 19]. Some studies suggest that drinking stream or river water significantly increases the risk of echinococcal infection, while drinking tap or well water reduces the risk. [12, 17]. On the other hand, developing countries may have a lack of education and poor hygiene practices, resulting in increased vulnerability to echinococcosis. Drinking water sources, on the other hand, are thought to be relevant for human exposure. echinococcus egg. Rivers, springs, ditches, and ponds are particularly susceptible to egg contamination than tap water because of their role as food sources for a variety of animal hosts. Surprisingly, we found a positive relationship between AE and cognitive rate. This may be explained by the fact that most of the counties included in our study were included in the National Echinococcus Management Program initiated in 2005.

Overall, our results further indicate that control measures such as livestock management, dog deworming, improved hygiene, and health education are essential for controlling echinococcosis. Such measures have proven feasible and effective in some states. For example, from 2017 to 2019, Tibet implemented measures to strengthen source control of echinococcosis, including dog registration and management, dog population reduction, monthly dog ​​deworming, and dog infectious disease monitoring. Various measures were implemented. [34]. As a result of these measures, the infection rate in dogs declined rapidly from 7.3% in 2016 to 1.7% in 2019, and the risk of Echinococcus infection to humans decreased significantly. [34].

There are some limitations to note in this study. First, our analysis is based on retrospective data from a national echinococcosis survey conducted using portable B-ultrasonography to examine subjects. In echinococcosis, only abdominal lesions could be detected, and lesions such as lungs and brain could not be detected. Therefore, the prevalence among people reported in this study may have been underestimated. Second, some studies have demonstrated that wild animals such as foxes and wolves can be infected with the virus. E. multilocularis [35]however, detailed data on wildlife in China were not available due to the practical difficulties of field surveys. Third, some researchers consider complex interactions between environmental, biological and social factors. [31], was not discussed in this study. Therefore, further studies are proposed that focus more on the complex interactions between various risk factors.



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