[Molluscicidal effects of different formulations of niclosamide ethanolamine salt in marshlands].

OBJECTIVE: To evaluate the molluscicidal effects of different formulations of niclosamide ethanolamine salt in marshlands. METHODS: The molluscicidal effects of spraying with 25% suspension concentrate of niclosamide ethanolamine salt (25% SCN) and 50% wettable powder formulation of niclosamide ethanolamine salt (50% WPN), and dusting with 4% niclosamide ethanolamine salt dustable powder (4% DP) for controlling Oncomelania hupensis snails were investigated and compared in the fields, and the cost-effectiveness was analyzed. RESULTS: The corrected mortalities and the reduced rates of density of snails were 54.37%, 91.70%, 92.76%, 79.50%, and 59.55%, 95.93%, 97.63%, 94.15%, respectively, on 3, 7, 15, 30 d after spaying with 25% SCN, those on 3, 7, 15, 30 d after dusting with 4% DP were 59.10%, 91.83%, 95.56%, 93.34% and 65.03%, 94.93%, 97.61%, 97.28%, respectively; and those on 3, 7, 15, 30 d after spraying with 50% WPN were 76.29%, 91.68%, 93.12%, 81.59% and 81.24%, 97.02%, 97.84%, 95.27%, respectively. The cost of spraying with 25% SCN was 0.21 Yuan/m2, that of dusting with 4% DP was 0.39 Yuan/m2, and that of spraying with 50% WPN was 0.23 Yuan/m2 for snail control in the marshland. The cost of reduced one percentage of the corrected mortalities and the density of snails in controlling snails by 25% SCN, 4% DP and 50% WPN on 15 d were 22.68, 40.63, 25.17 Yuan and 21.54, 39.78, 23.95 Yuan, respectively. CONCLUSIONS: The three different formulations of niclosamide are reliable and effective for snail control in marshlands. There are some differences among the different molluscicides in start time, pharmacodynamic characteristics, spraying methods in the field, cost of snail control, and influencing factors. Therefore, we need reasonably select the suitable molluscicides according to the environmental characteristics and working condition.

[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.

[Molluscicidal effect of niclosamide ethanolamine salt powder - granula against Oncomelania hupensis].

OBJECTIVE: To evaluate the molluscicidal effect of niclosamide ethanolamine salt powder-granula (PG) against Oncomelania hupensis. METHODS: The molluscicidal experiment was carried out by the dusting method with niclosamide ethanolamine salt 4% PG. The experiments were respectively done in the laboratory and the tidal flats wetlands. At the same time, the niclosamide ethanolamine salt 4% dustable powder (DP) was as the control group. The single blind method was used for the quality control. The corrected mortality and the median lethal concentration (LC50) were compared between PG and DP in the molluscicidal experiment of the laboratory. The corrected mortality and the reduced rate of snails'density were compared between PG and DP in the tidal flats wetlands. RESULTS: The mortality rates of the snails were 96.67% and 100% respectively on 1 d after dusting 4.0 g/m2 of 4% PG and 2.0 g/m2 of 4% DP in the laboratory. The results showed that the mortality rates of the snails were higher with 4% DP than 4% PG in each dosage (t1 d = 3.60, P < 0.01). The LC50 (s) of 1d, 3 d, 7 d after dusting the molluscicide also showed that the molluscicidal effects of DP were better than PG. The corrected mortality rates were 91.71%, 92.91%, 90.57%, 85.33% and 71.09%, 90.11%, 90.13%, 85.26% on 3 d, 7 d, 15 d, 30 d after dusting with 4% PG and 4% DP, respectively, in the fields. Statistics showed that the mortality rates of snails were higher on 3 d, 7 d after dusting with PG than DP (χ23 d = 731.57, χ27 d = 25.90, P < 0.01), but there were no significant differences between PG and DP on 15d, 30d after dusting (χ215 d = 0.53, χ230 d = 0.01, P > 0.05). CONCLUSIONS: 4% PG has both the adsorption of powder and the penetrability of the granules. The molluscicidal effects of 4% PG and 4% DP are almost the same. However, the drift of the powder was still not effectively controlled. This problem need to be further studied.