RESUMO
Objective To explore the spatio-temporal characteristics of Oncomelania hupensis snails along the Danyang section of the Beijing-Hangzhou Grand Canal and the Danyang-Jintan-Liyang Canal, so as to provide scientific evidence for the dynamic assessment of the risk of snail spread in this region. Methods O. hupensis snail status was collected in the plain regions with waterway networks in the study area from 2012 to 2017. The spatio-temporal variations of snail distribution were investigated along the Danyang section of the Beijing-Hangzhou Grand Canal and the Danyang-Jintan-Liyang Canal using buffer zone analysis, spatial autocorrelation, hotspot analysis and standard deviational ellipse with the geographical information system (GIS) tools. Results The number of snail habitats showed a tendency towards a rise in the study area from 2012 to 2017, and snail habitats were predominantly distributed in the 1 000 m long buffer zone of the Danyang-Jintan-Liyang Canal, notably along the Jiuqu River at the junction between the Beijing-Hangzhou Grand Canal and the Danyang-Jintan-Liyang Canal. The distribution of snail habitats appeared spatial autocorrelations in 2014, 2016 and 2017, and the hotspot areas were mainly identified at the junction between the Danyang-Jintan-Liyang Canal and the Beijing-Hangzhou Grand Canal. In addition, the overall distribution of snail habitats was located in the northeastern-southwestern part of the study aera, and gradually shifted to the southern and northern parts with the time. Conclusions The spatial distribution of O. hupensis snails is complex along the Danyang section of the Beijing-Hangzhou Grand Canal and the Danyang-Jintan-Liyang Canal, and there is a risk of snail spread from the upper reaches to the lower reaches, where snail control needs to be intensified.
RESUMO
OBJECTIVE: To understand the prevalence of Toxoplasma gondii infection and related factors among special population in Changzhou City, so as to provide the evidence for formulating toxoplasmosis prevention measures. METHODS: The venous blood was collected from participants in Changzhou City for detecting IgG and IgM antibodies against T. gondii by ELISA; and an epidemiological questionnaire investigation was also conducted. RESULTS: Among the total 400 respondents detected, the prevalence of T. gondii infection was 15.0% and the positive rates of IgG and IgM were 15.0% and 0.8%, respectively. The T. gondii infection rates of pregnant women, HIV/AIDS patients, patients with neoplasia, and livestock and poultry breeding and processing workers were 11.0%, 11.0%, 24.0% and 14.0%, respectively. As the age increased, the infection rate of T. gondii showed an upward trend, with the highest infection rate (21.6%) among the group of respondents aged above 50 years. The infection rates of groups with different education levels were statistically different (χ2 = 11.443, P < 0.05), and there was a trend that the infection rate decreased with the increase of education level. The prevalence of T. gondii infection in pregnant women was not significantly associated with the number of pregnancies and gestational age. The infection rate of T. gondii in the live-stock and poultry breeding and processing workers increased with the length of their working years. CONCLUSIONS: The prevalence of T. gondii infection among the special population in Changzhou City is high. Therefore, it is necessary to enhance the health education on the knowledge and information of prevention and control of toxoplasmosis, and to improve the awareness of personal protection, the hygiene practices and diet habits. In addition, more attention should be paid to T. gondii monitoring in the special population.
