Stratified sampling survey of major human parasitic diseases in Henan province / 中华流行病学杂志

Objective: To understand the prevalence of major human parasitic diseases and related factors in Henan province. Methods: This stratified sampling survey was carried out according to the requirement of national survey protocol of major human parasitic diseases, 2014-2015. The prevalence of soil-transmitted helminths infection, taeniasis and intestinal protozoiasis were surveyed in 104 sites selected from 35 counties (districts) and the prevalence of clonorchiasis was surveyed in 62 sites selected from 37 townships. In each survey spot, 250 persons were surveyed. A total of 26 866 persons and 15 893 persons were surveyed. Modified Kato-Katz thick smear was used to detect the eggs of intestinal helminthes. Tube fecal culture was used to identify the species of hookworm. The Enterobius eggs were detected in children aged 3 to 6 years by using adhesive tape. The cyst and trophozoite of intestinal protozoa were examined with physiological saline direct smear method and iodine stain method. Results: The overall infestation rate of intestinal parasites was2.02% in Henan, and the worm infection rate was higher than protozoa infection rate. Fourteen kinds of intestinal parasites were found, including nematode (5 species), trematode (2 species), and protozoan (7 species). The infection rate of Enterobius vermicularis was highest, and Qinba Mountain ecological area had the highest infestation rate of intestinal parasites in 4 ecological areas of Henan. There was no significant difference in intestinal parasite infection rate between males and females (χ(2)=3.630, P=0.057), and the differences in intestinal parasite infection rate among different age groups had significance (χ(2)=124.783, P=0.000 1). The infection rate reached the peak in age group ≤9 years and the major parasite was Enterobius vermicularis. Furthermore the overall human infection rate of parasite showed a downward trend with the increase of educational level of the people (χ(2)=70.969, P=0.000 1), the differences had significance (χ(2)=120.118, P=0.000 1). For different populations, the infection rate of intestinal parasites was highest among preschool children. The infection of intestinal helminth was mainly mild, only 2 severe cases were detected. The infection rate of Clonorchis sinensis in urban residents was only 0.006%. Logistic regression analysis showed that being preschool children (χ(2)=15.765, P=0.000 1) and drinking well water (χ(2)=45.589, P=0.000 1) were the risk factors for intestinal parasite infection, and annual income per capita of farmers was the protective factor against intestinal parasite infection. The infection rates of protozoa and intestinal parasites decreased sharply compared with the results of previous two surveys, and the rate of intestinal helminth infection also dropped sharply compared with the second survey. The numbers of protozoa, helminth and intestinal parasites detected in this survey were all less than the numbers found in the previous two surveys. Conclusions: Compared the results of three surveys in Henan, the infection rate of protozoa and intestinal parasites showed a downward trend. The prevention and treatment of Enterobius vermicularis infection in children should be the key point of parasitic disease control in the future.

Research on reform of epidemiology teaching / 中华流行病学杂志

Epidemiology is a traditional subject mainly based on principles and concepts, and its teaching method needs further improving to meet the requirement of the new trend of education reform. Lecture-based teaching, problem-based teaching, case-based teaching, and internet based teaching, such as flip class, massive open online course and micro-lecture, all have its own unique merits in the practice of epidemiology teaching. So the combination of traditional teaching and online teaching is the most promising mode. "Rain class" , a mixed mode, is an efficient tool to present the epidemiology case more actually in class. Thus, teaching design and application of "rain class" are worth research.

Automatic detection of liver tumor motion by fluoroscopy images

Background: A method to track liver tumor motion signals from fluoroscopic images without any implanted gold fiducial markers was proposed in this study to overcome the adverse effects on precise tumor irradiation caused by respiratory movement

Materials and Methods: The method was based on the following idea: [i] Before treatment, a series of fluoroscopic images corresponding to different breathing phases and tumor positions were acquired after patient set-up; [iii] The wavelet transform method and Canny edge detection algorithm were used to detect motion trajectory of the diaphragm; [iv] The motion curves of center of lipiodol in the images were obtained by mathematical morphology and median filtering algorithm. The method was evaluated using by five sequences of fluoroscopic images from TACE patients who received transcatheter arterial chemoembolization therapy

Results: The position of liver tumor was significantly affected by respiratory motion; the motion trajectories of the diaphragm and lipiodolagreed well with the manually marked locations in amplitude and period; the motion trajectories of the diaphragm and lipiodol almost had similar period and amplitude in one treatment fraction. The respiratory period and amplitude of the same patient in different fractions had no significant differences; however, the difference was obvious for different patients. The proposed lipiodol detection methods can effectively reflect the relevant rules of tumor location caused by respiratory movement

Conclusion: Direct tracking of liver tumor motion in fluoroscopic images is feasible. The automatic detection method can reflect the characteristics of respiratory and tumor motions, which can save much time and significantly improve measurement precision compared with manual measurement

Analysis of Structures, Functions, and Epitopes of Aminopeptidase from Trichinella spiralis

We have previously reported that the recombinant T. spiralis aminopeptidase (rTsAP) could induce a partial protective immunity against T. spiralis infection in mice. The aim of this study was to predict the structures and functions of TsAP protein by using the full length cDNA sequence of TsAP gene. TsAP sequence was 1515 bp length with a 1515 bp biggest ORF encoding 504-amino acid protein. The molecular weight and isoelectric point of TsAP were 54.7 kDa and 6.69, respectively. TsAP structure domains contained a Peptidase_M17_N and a Peptidase_M17 domain, which has the function of catalysis of the hydrolysis of N-terminal amino acid residues. TsAP had no signal peptide site and transmembrane domain, and located in cytoplasm. The secondary structure of TsAP contained 16 α-helix, 14 β-strand and 29 coils. The TsAP had 11 and 21 potential antigenic epitopes of T cell and B cell, respectively. Based on the phylogenetic analyses of TsAP, T. spiralis have the closest relationship with Plasmodium falciparum. TsAP was a kind of proteolytic enzyme with a variety of biological functions and its antigenic epitopes could provide important insights on the diagnostic antigens and target molecular of anti-Trichinella drugs