[Detection effect of an automatic identification system of Schistosoma japonicum miracidia].

OBJECTIVE: To evaluate the effect of an automatic identification system of Schistosoma japonicum miracidia, and compare it with the traditional eye detection method in the simulation field. METHODS: A total of 260 fecal samples were collected from schistosomiasis non-endemic areas, and the test sample bottles containing schistosome miracidia were prepared according to different experimental needs. Thirty fecal samples for the sensitivity test were separately added with five fresh miracidia per sample, and then the mixed samples were detected by two experienced technicians (with more than 15 years' traditional test experience) or the automatic system. The positive detection rates were compared between the two methods. Thirty fecal samples for repetition test were separately added with ten fresh miracidia per sample, and then the mixed samples were detected separately with the automatic identification system by two experienced technicians. The results were compared between two persons. The two methods including the automatic identification system and the traditional eye detection method were carried out blindly with totally 200 samples in the simulation field. There were three groups (each with 30 samples) : Group 1 with more than 21 fresh miracidia, Group 2 with 6 to 20 fresh miracidia, and Group 3 with 1 to 5 fresh miracidia. The other 110 samples were as a negative group. The detection time, accuracy, missed detection rate, and false detection rate of the two methods were statistically compared. RESULTS: The positive detection rates of the 30 positive samples were 43.33% and 33.33% by the two technicians with the traditional eye detection method, respectively, while the detection rate was 80.00% by the automatic identification system, and the difference was statistically significant (χ2 = 7.05, χ2 = 12.97, both P < 0.01). Thirty positive samples were detected by the two technicians using the same automatic identification system, and the positive detection rates of the two were 96.67% and 86.67%, respectively, with no significant difference (χ2 = 0.27, P > 0.05). The experiments showed that the correct detection rate of the positive samples was 98.00% by the automatic identification system, which was higher than 79.75% by the traditional eye detection method. The detection time of the automatic identification system was shortened by half compared with that of the traditional eye detection method. The missed detection rate, and false detection rate of the automatic identification system were 2.22% and 1.82%, respectively, which were much lower than 35.56% and 7.73% of the traditional eye detection method. CONCLUSIONS: Compared with the traditional eye detection method, the automatic identification system of S. japonicum miracidia has the advantages of high sensitivity, good repeatability, short detection time, high accuracy, low missed detection rate, and low false detection rate. It can be used in the field and clinical detection in replacement of the traditional eye detection method.

[Investigation of Toxoplasma gondii infection among special populations in Nanjing City, Jiangsu Province].

OBJECTIVE: To understand the prevalence of Toxoplasma gondii infection among special populations in Nanjing City, so as to provide the reference for formulating the interventions for the prevention and control of T. gondii infections in this population. METHODS: The HIV/AIDS patients, tumor patients, pregnant women, and people with livestock and poultry breeding or processing works were selected as the study subjects from September to November 2015. The venous blood samples were collected from each participant for detecting IgG and IgM antibodies against T. gondii by ELISA. RESULTS: The overall prevalence of T. gondii infection was 10.2% in the study subjects in Nanjing City. The T. gondii infection rates were 12.2%, 11.3%, 4.0%, and 13.0% among the HIV/AIDS patients, tumor patients, pregnant women, and people with livestock and poultry breeding or processing works, respectively, and there was no statistically significant difference among the four groups (χ2 = 5.668, P = 0.130). The prevalence of T. gondii infection was higher in men than in women (15.3% vs. 5.8%; χ2 = 10.213, P = 0.001), and there were significant differences in the prevalence of T. gondii infection in terms of gender (χ2 = 9.501, P = 0.023), education levels (χ2 = 9.850, P = 0.043) or occupations (χ2 = 8.983, P = 0.062). CONCLUSIONS: The infection rate of T. gondii among the special population in Nanjing City is high. Therefore, the health education intervention should be strengthened in the follow-up work for the special population.

[Cryptosporidium infection in Nanjing City from 2015 to 2016].

OBJECTIVE: To investigate the status of Cryptosporidium infection in the population in Nanjing City so as to provide the evidence for the prevention and control of cryptosporidiosis. METHODS: A total of 100 fecal samples were collected from each of three districts (Liuhe, Qixia and Gaochun) and one hospital (Nanjing Zhongda Hospital) in 2015 and 2016 respectively. The fecal samples were detected for Cryptosporidium with microscopy (by using the gold amine phenol-modified acid-fast staining) and the positive samples were detected again for the molecular biology confirming by using the fluorescence quantitative PCR. RESULTS: During the two years, 581 cases of normal population who lived in the city were surveyed and no Cryptosporidium infection was found. Among 202 cases of outpatients with chronic diarrhea, there were 9 Cryptosporidium positive cases with the microscope scanning method (4.46%), and among the 9 cases, 7 cases showed obvious logarithmic amplification curves showing positive Cryptosporidium nucleic acid, but 2 cases without the obvious logarithmic amplification curves, and the Cryptosporidium nucleic acid positive rate was 3.47%. CONCLUSIONS: Cryptosporidium infection is not found in the normal population of Nanjing City, but the Cryptosporidium infection is found in the chronic diarrhea patients. The results imply that we should strengthen the detection of Cryptosporidium in the chronic diarrhea patients, so as to provide the evidence for improving the diagnosis and treatment of cryptosporidiosis.

[Comparison of Schistosoma japonicum development between single sexual infection and double sexual infection in mice and rabbits].

OBJECTIVE: To observe the development of Schistosoma japonicum after single sexual infection and double sexual infection respectively. METHODS: A single Oncomelania hupensis snail was infected by a single schistosome miracidium. The larva were induced and released from the snail after 60-day incubation at 26 ℃. The mice were infected by the larva (single sexual infection) and dissected 40 days after the infection. All the worms were collected and the sex of the larvae was determined by the sex of the adult worms. Then, the mice and rabbits were infected by single sex of larvae (single sexual infection) and double sex of larvae (double sexual infection) respectively. The mice and the rabbits were dissected 40 days after the infection. All the worms were collected and measured under a microscope. RESULTS: All the male or female worms were collected from the mice and rabbits after single sexual infection. There were three main forms of worms after dissection of double sexual infection of mice and rabbits: folded mature male and female, male or female. Few folded male and immature female were found. Only the double sexual larva infected mice or rabbits had schistosome eggs in the liver and the liver had typical schistosome egg nodules. The single sexual larva infected mice or rabbits had no schistosome eggs or schistosome egg nodules in the liver tissues. The single male larva could develop to worms with the testis, and with a little smaller size compared to the mature folded male, while the single sexual infection female worm could not develop to the mature stage with much thinner and smaller compared to the mature folded female. CONCLUSIONS: The male or female worms from single sexual infection are smaller than those from double sexual infection (mature worms - folded male and female). So it is necessary to check single sex worms in vessels of intestinal mucosa thoroughly in the sentinel mice when no schistosome eggs were found in the liver.

Molecular epidemiology of genogroup II noroviruses infection in outpatients with acute gastroenteritis in Nanjing, China (2010-2013).

OBJECTIVE: Human noroviruses (NoVs) of genogroup II are the most common strains detected in sporadic cases of acute nonbacterial gastroenteritis in outpatients in Nanjing. To gain insight into the molecular epidemiology of GII strains, we analyzed 75 positive NoV cases from 2010 to 2013. METHODS: The sporadic cases were detected by real-time PCR with specific primers and probes to human NoVs of genogroup I or II, human sapovirus, human rotavirus, human astrovirus, and human enteric adenovirus. Human NoVs of genogroup II were further studied by VP1 amplification (RT- PCR), cloning, sequencing, and phylogenetic analysis. RESULTS: Rotavirus and human NoVs were more frequently detected in all the cases from 2010 to 2013. Human NoVs infection was more frequent since 2011 and more frequent than rotavirus infection after 2012. Out of the 75 NoV cases of genogroup II, there were 5 GII.6, 11 GII.3, and 59 GII.4. Of the 59 GII.4, 27 cases were previous GII.4.2006b strains that circulated between 2010 and 2012; while 32 cases were the newly emerging GII.4 strains GII.4.2012 from 2011 to 2013. CONCLUSION: Our data confirm other studies on the rapid emergence and displacement of highly virulent GII.4 strains.