1 Introduction
Echinococcosis (hydatid disease) is a severe zoonotic parasitic disease caused by larval forms of Echinococcus in animals and humans.[1] [2] E. granulosus and E. multilocularis , respectively. The treatment of echinococcosis requires continuous chemotherapy for many years, or even for the whole life.[1] [2–8] [9]
CE is highly endemic in pastoral areas, especially in regions of South America, Eastern Europe, the Middle East, East Africa, China, and Russia. AE is strictly distributed in Europe, the Near East, Russia, and China. CE and AE have aroused wide public health concerns.[10] [11] [12] [9] [9,11–13] [4,14,15] risk factors to help policymakers develop effective control and prevention strategies.
2 Materials and methods
2.1 Settings and eligibility criteria
This cross-sectional study was undertaken at the People's Hospital of Ganzi County, which is located in the Ganzi Tibetan Autonomous Prefecture in the western Sichuan Province of southwestern China. The mean elevation of Ganzi County is 3390 m above sea level, and the annual mean temperature is 5.6°C. By the end of 2010, the total population of Ganzi County was 72,000, and the Tibetan population accounted for over 95%. Their primary economic income is from livestock production and herding. Their lifestyle is nomadic or seminomadic. In addition, this area has many domestic dogs, stray dogs, and wild canids, such as foxes. Ganzi County had already been confirmed to have a focus of human echinococcosis cases, estimating human echinococcosis prevalence of 1.86%.[16]
The Diagnostic Criteria for Echinococcosis (WS257–2006)[17]
2.2 Questionnaire
The questionnaire was developed based on the Program of National Epidemiological Survey on Echinococcosis released by the Chinese Centers for Disease Control and Prevention in 2011. It included information on demographics, animal ownership, sources of drinking water, hygiene-related behaviors, lifestyle practices, and knowledge of echinococcosis prevention and control.
The following demographic data were collected in the questionnaire: age, gender, nationality, religion, occupation, educational qualification, and living styles (nomadic, seminomadic, or settled). The numbers of owned livestock and species (cattle, sheep, camel, and pig) were documented. The surrounding environment evaluated in this study focused on dog care, the presence of stray dogs in the community, sources of drinking water, and accessible medical resources in villages. Additionally, health knowledge about human echinococcosis prevention and control were collected to find the relationship between educational level and health literacy.
2.3 Procedures
From January to November 2018, we screened 13,097 residents from 1 town and 22 villages in Ganzi County through abdominal ultrasound; 509 were diagnosed with hepatic echinococcosis in the People's Hospital of Ganzi County. Prior to the survey, information about the survey, provision of free treatment to patients diagnosed with hepatic echinococcosis were clearly explained. They could choose to participate by their own will and withdraw their participation without any disadvantage. A total of 195 participants provided oral consent and were finally enrolled. Full-time investigators interviewed all participants. Each participant completed the questionnaire during the interview. All the analyzed data were anonymized. The investigators only explained the questions of the questionnaire and avoided using inductive language to ensure the results were objective and accurate. Furthermore, all patients received a chest CT and a head CT to detect cerebral and pulmonary echinococcosis.
2.4 Statistical analysis
All data were coded and analyzed using SPSS version 18.0 (IBM). The missing data were not included in the analysis. The qualitative data were described by the number of cases and the percentage. The quantitative data were displayed by showing means and standard deviations. A Chi–Squared test (χ) was performed to assess the between-group differences. P -values (α) of less than .05 were considered significant.
3 Results
3.1 Demographics of the participants
During the analysis of questionnaire information and responses, all participants were computed for each question. The demographics of the 195 participants are presented in Table 1 . Analysis of demographics for all participants indicated that females were at a higher risk of infection in comparison to males, with 120 females and 75 males included in this study. The age of individuals ranged from 7 to 75 years, with an average age of 39.95 ± 15.68 years. The highest prevalence by age group was in the 41- to 50-year-old group (28.21%), followed by the 31- to 40- and 51- to 60-year-old groups (18.97% and 15.38%, respectively). There was a positive association with involvement in herding and farming compared to other occupations (61.03% and 26.15%, respectively). Herdsmen were at the highest risk of echinococcosis infection compared to other occupations (61.03%). The second high-risk occupational group was farmers, accounting for 26.15%. All were Tibetans, and their religion was Buddhism. In terms of educational qualification, most of them (86.67%) were illiterate, and 62.56% lived in settlements.
Table 1: Assessed hepatic echinococcosis patients’ demographic characteristics (n = 195).
3.2 Raising livestock
Categories and numbers of livestock raised in each participant's household were investigated. The results showed that the average numbers of sheep and cattle raised per household were 0.03 and 9.80, respectively. The number of cattle raised per household was significantly higher than the number of sheep raised. The proportion of households raising cattle was 37.10%, and the proportion of households raising sheep was 1.08% (Table 2 ).
Table 2: Raising livestock investigation of 186 households.
3.3 Living environment and medical resources
Among the 195 patients with hepatic echinococcosis, 41.03% reported stray dogs near their habitations. Sixty percent of the participants said their neighbors raised dogs, and 48.21% of participants chose tap water as their drinking water source. Additionally, 24.61% of them said they did not have a doctor or did not know if there were doctors in their village. Relevant information is shown in Table 3 .
Table 3: The surrounding environment and medical resources.
3.4 Echinococcosis prevention knowledge and hygienic practices
Among the 195 participants, 8.21% of them knew or partially knew the route of transmission of echinococcosis. There was a significant difference in the percentage knowing the transmission route among the different groups (χ2
= 12.534, P
< .05), and the student group had the highest proportion (44.4%). In terms of hygienic practices, 5.64% of the participants often washed their hands, 56.41% sometimes washed their hands, and 37.95% rarely washed their hands. Patients with different educational qualifications and living styles showed significant differences in handwashing before eating (P < .05). Approximately 99.49% of the participants were willing to deworm dogs if it was free of charge (Table 4 and Table 5 ).
Table 4: Knowledge of echinococcosis prevention and control and hygiene practices.
Table 5: Analysis of the factors affecting the knowledge of echinococcosis prevention and control and the status quo of health behaviors.
3.5 Detection of echinococcosis outside the abdominal cavity
Among the 195 patients with hepatic echinococcosis, 4 patients were found to have cerebral echinococcosis, and the detection rate was 2.05%. One patient was found to have pulmonary echinococcosis for a detection rate of 0.51% (Table 6 ).
Table 6: The detection rate of echinococcosis outside the abdominal cavity in 195 patients with hepatic echinococcosis.
4 Discussion
Sichuan Province is one of the most widespread epidemic areas for human echinococcosis in China.[18] [4,18,19] [20,21] [16] [22]
The results of this survey showed that of 195 patients with evidence of hepatic echinococcosis, 120 were female and 75 were male. Females had a higher risk of getting infected with echinococcosis than males. Similar results were also demonstrated in a cross-sectional survey of the epidemiological prevalence of echinococcosis in Sichuan Province in 2012.[16] [18]
The age of the infected participants ranged from 7 to 75 years, with an average age of 39.95 ± 15.68. Cases of echinococcosis were found in different age groups: the 40- to 49-year-old group had the highest prevalence, followed by the 30- to 39-year-old group (18.97%) and the 50- to 59-year-old group (15.38%). The possible reason was that adults, as the primary labor force of the family, had a higher probability of contact with the contaminated environment or infected animals. Thus, they were more easily infected.
Among the different occupational groups, the infection prevalence in herders was significantly higher than that in other occupational groups, accounting for 61.03%. The main activities of herdsmen included hazing, which increased the possible risk of exposure to sheep and dogs. Some other behaviors, such as allowing dogs to sleep indoors at night[18]
Approximately 41% of the participants said that there were often wild animals in their residence, and 60.00% of the participants said they had dogs, or their neighbors kept dogs. The presence of stray dogs was another significant risk factor impacting the prevalence of human echinococcosis. Qian et al[23] E. multilocularis prevalence in owned dogs was significantly associated with the number of stray dogs.[16] [18] [18,24,25] [24]
Regarding the surrounding environment and medical resources, only 48.21% of the 195 participants used tap water for drinking. Other water resources were significantly correlated with echinococcosis prevalence, for example, ditch or river water. Approximately 25% of the participants did not know if there were doctors in the village or not. Thus, there is an urgent need to provide tap water resources and increase the number of medical staff in epidemic areas.
According to the survey, only 8.21% of the participants knew or partially knew the route of transmission of echinococcosis. There were significant differences in the awareness rate among different occupational groups, with students having the highest awareness rate (44%). In terms of hygiene practices, 5.64% often washed hands, 56.41% sometimes washed their hands, and 37.95% rarely washed their hands. Patients with higher educational qualifications performed better handwashing self-discipline. Patients with lower education qualifications had fewer opportunities to access knowledge and understanding of echinococcosis prevention and control, which might inhibit the implementation of effective behaviors for echinococcosis prevention and control. In addition, most of the Tibetan population lives in remote areas, where living conditions are poor and health literacy is generally inadequate, which might be the reason for the high frequency of echinococcosis in the Tibetan population. Therefore, a health education program aligned with the population's educational background and local culture is necessary to effectively disseminate knowledge and improve hygienic practices.
Echinococcosis outside the abdominal cavity (cerebral echinococcosis and pulmonary echinococcosis) was also detected. According to the sampling survey of the epidemiological status of echinococcosis in Sichuan Province in 2012,[16] [9,12]
The first limitation of this study is the sampling method, which might introduce potential unknown bias. This limitability might jeopardize the representativeness of the sample and generalizability of the results. Another limitation is the small sample size. Although we diagnosed 509 patients with hepatic echinococcosis, 195 patients agreed to participate in our study and share their information. We could not present all the data of all screened local people. Based on the data of enrolled participants, we still can realize the objectives of this study, which is to identify the possible risk factors for human echinococcosis.
5 Conclusions
Possible high-risk factors for echinococcosis identified by this study were being female, herding population, in the 20 to 60 age group, having stray dogs around habitations, having activities with dogs and livestock, having poor health literacy, having low educational qualifications, and not using tap water as a drinking water source. Effective preventive strategies should be implemented, such as deworming both owned and stray dogs, providing tap water drinking resources, disposing of infected animals and viscera, holding health education activities, and increasing the number of medical staff in epidemic areas. The detection rate for brain echinococcosis in patients with hepatic echinococcosis was high (2.05%). Therefore, head CT scans should be applied for early detection of cerebral echinococcosis to carry out the treatment.
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