Search

Objective: To investigate the prevalence of echinococcosis in Yushu Prefecture of Qinghai Province in 2012., Methods: Two to three towns were selected in each of Chengduo, Nangqian, Qu malai, Yushu, Zaduo and Zhiduo Counties from June to August in 2012. Ultrasound examination was conducted for residents aged over 1 year, and ELISA was performed to detect serum antibody against Echinococcus. Visceral dissection was performed to detect hydatid infection in rodents and livestock. ELISA was used to detect Echinococcus antigen in collected dog feces., Results: A total of 7 025 residents received ultrasound examination, of whom 319 showed hydatid cysts with a morbidity rate of 4.54%. ELISA showed a serum antibody positive rate of 16.38% （457/2 790）. The mobidity of hydatid disease was highest in Chengduo County （7.41%, 181/2 444）, and the rate of serum antibody was highest in Yushu County （23.18%, 127/548）. The morbidity and serum antibody in males were 3.91% （118/3 018） and 13.93% （172/1 235） respectively, and those in females were 5.02% （201/4 007） and 18.33% （285/1 555）. In terms of age distribution, the morbidity was relatively higher in residents of 60- （8.39%, 38/453） and 40- years （6.61%, 67/1 014）; and the rate of serum antibody was highest in residents over 70 years （33.93%, 19/56）. In terms of occupation, the morbidity was relatively higher in herdsmen （5.28%, 252/4 777）, Herdsmen-peasants （6.52%, 24/368）, and religious workers（3.37%, 11/326）, while the rate of serum antibody was relatively higher in children（24%, 6/25）, religious workers （18.79%, 31/165） and herdsmen（18.34%, 328/1 788）. In terms of education level, the morbidity and the rate of serum antibody were both highest in the uneducated（5.04%, 41/4 779; 18.34%, 359/1 958, respectively）. In terms of residential pattern, the morbidity and the rate of serum antibody were both highest in those who were settled in winter and nomadic in summer （8.25%, 227/2 753; 19.48%, 158/811, respectively）. There were significant differences in the morbidity and the rate of serum antibody in aspects of residential region, sex, age, occupation, education level and residential pattern (P<0.05 or P<0.01). In 872 rodents detected, the Echinococcus hydatid rate was 0.46% （4/872）, while in 809 cattle and sheep detected, the Echinococcus hydatid rate was 10.14% （82/809）. The fecal antigen positive rate in 838 samples of dog feces was 10.74%（90/838）., Conclusion: It shows a high morbidity of hydatid diesease and serum antibody positive rate in residents, a high Echinococcus hydatid rate in cattle and sheep, and a high fecal antigen positive rate in dogs in Yushu Prefecture.

Objective: To investigate the prevalence of Capillaria hepatica in rodents from Anning Prefecture, Yunnan, and observe the susceptibility of C. hepatica to SD rats and KM mice., Methods: Rodents were trapped in a cultivated filed of Wenquan Town, Annning from March 2010 to March 2012. The species of rodents were identified. The liver was examined and a microscopic examination of tissue was performed by the tissue press technique for the presence of the typical bipolar eggs, adults or larval stages. The prevalence of C. hepatica in rodents was calculated. C. hepatica eggs were collected and cultured in vitro. Each SD rat or KM mouse was orally infected with approximately 1 000 C. hepatica eggs. The control groups with 4 SD rats or 4 KM mice received only normal saline. The experimental animals were euthanized at the 30th and 80th day post infection. Collected liver samples were processed for gross pathological and histological section examination., Results: A total of 115 rodents were captured and examined. C. hepatica eggs were found in 26 (22.6%) rodents. There was no significant difference in the prevalence between female (22.5%, 18/80) and males (22.9%, 26/115) (P > 0.05). The highest prevalence was found in Rattus norvegicus (10/11). Pathologi cal findings showed numerous white-yellow small nodules ranged from 0.1-0.2 cm in diameter. Under light microscope, C. hepatica eggs were ovoid [(50-65) microm x (25-30) microm]. At the 30th day post-infection, there were several adult worms and their eggs delimited by a fibrous capsule, and septal fibrosis formations occurred in the liver of SD rat. No worm or eggs were found in the mouse liver, but the liver presented inflammatory cell infiltration. At the 80th day post-infection, live worms disappeared from the focal lesions in the liver of SD rat, being replaced by partially calcified worm debris. Mature worms and eggs were seen in the KM mouse liver, however, septal fibrosis was absent., Conclusion: This study has documented a high prevalence of C. hepaticum in R. norvegicus from Anning Prefecture. SD rat and KM mouse are the susceptible hosts of C. hepatica.

Frogs were caught from 4 towns in Huaxi of Guiyang and dissected. The collected spargana were used to infect young dogs for species identification. Results showed that the wild frogs were identified as Rana nigromaculata, and the infection rate was 16% (131/818) with an average intensity infection of 3.44 per frog, The tapeworm obtained from an infected dog was specified as Spirometra mansoni.

Objective: To study the life span of Trichinella spiralis male adult and its effect on female fertility., Methods: 22 Kunming mice were divided into three groups. Group A was orally inoculated by encysted larvae, dissected at day 5, 10, 20, and 30 post infection, adult worms were then collected and counted. Group B was fed with 5-day adults (70 females + 30 males/mouse). Group C was fed with 5-day females (70/mouse) only. Groups B and C were sacrificed 30 days post inoculation, larvae were collected to calculate reproductive capacity index (RCI). Male worms of day 5, 10, 20 and 30 were fixed in glutaraldehyde for scanning electron microscopy (SEM) and transmission electron microscopy (TEM)., Results: 20 days after infection, there were more males than females in the intestines of group A mice (female: male = 1:1.3), but much more males than females on the 30th day after infection (female: male =1:8.5). Mice of groups B and C were infected by 5-day adults successfully with a RCI of 154.90 +/- 2.62 and 13.77 +/- 1.67 respectively (t=111.26, P<0.01). SEM revealed the copulatory bell of 5-day male adult, alae erected, and genital pore uncovered; while alae of 20-day male collapsed, genital pore was covered. Under TEM, there were large number of mature sperms within spermaductus of 5-day and 10-day males, but only a few immature sperms in the testis of 20-day and 30-day males., Conclusion: Male adults can survive longer than one month in host. 5-day female and male adults and 5-day females can infect mice orally, with a significantly higher fertility in the former.

69 crabs were collected from Daxing, Gekui and Niukong townships of Lvchun county, Yunnan Province in 2006 and excysted metacercariae were only obtained from crabs of Niukong. The infection rate was 27.6% (8/29) with an average metacercaria number of 2.25 each crab. No encysted metacercariae were found. The excysted metacercariae were morphologically identified as Paragonimus proliferus.

Objective: To identify the species of Paragonimus proliferus with scanning electron microscopy (SEM) based on the surface structure of excysted metacercariae, adult worms and eggs., Methods: Crabs were collected from the endemic area of P. proliferus and excysted metacercariae were separated. Adult worms at different ages and eggs were obtained from the experimentally infected rats. After being fixed by 2.5% glutardialdehyde and 1% osmic acid, alcohol dehydration, gilded by ion spatter, the specimens were observed under SEM by STEREOSCAN-100., Results: The cuticular spines of excysted metacercariae distributed in single pattern, bayonet-shaped or scale-shaped. There were 6 dome-shape papillae around the rim of the ventral sucker symmetrically arranged. The cuticular spines of different age adult worms distributed in group pattern, relatively denser and more regularly arranged in the anterior part than the posterior part of the worm body. The shape and arrangement of the cuticular spines on adult worms at different ages were basically uniform. The surface of eggshell including the operculum was generally smooth. The shell rim joining the operculum was thick and prominent. A knot-like prominence was observed at the aboperculum end., Conclusion: The cuticular spines of both excysted metacercariae and adult worms of P. proliferus show its own characteristics, but the size and shape of the cuticular spines among individuals or different parts of the same specimen show certain differences.