Molluscicidal efficacies of different formulations of niclosamide: result of meta-analysis of Chinese literature.
The control efforts on Oncomelania hupensis, the intermediate snail host of Schistosoma japonicum, cannot be easily excluded from the integrated approach of schistosomiasis control in China. Application of chemical compounds, molluscicides, in snail habitats is a common method for snail control in addition to environmental modification. We conducted a systematic review and meta-analysis to assess the molluscicidal effects of the currently recommended 50% niclosamide ethanolamine salt wettable powder and a new 4% niclosamide ethanolamine salt powder developed by Chinese researchers. Literature was searched from three Chinese databases, i.e. Chinese Biomedical Database, VIP Database and Wanfang Database, on field mollusciciding trials of niclosamide in China (from January 1, 1990 to April 1, 2010). Molluscicidal effects on reduction of snail population of the 50% or 4% niclosamide formulations in field trial were evaluated 3 days, 7 days or 15 days post-application. Out of 90 publications, 20 papers were eventually selected for analysis. Publication bias and heterogeneity tests indicated that no publication bias existed but heterogeneity between studies was present. Meta-analysis in a random effect model showed that the snail mortality of 3, 7 and 15 days after spraying the 50% niclosamide ethanolamine salt wettable powder were 77% [95%CI: 0.68-0.86], 83% [95%CI: 0.77-0.89], and 88% [95%CI: 0.82-0.92], respectively. For the 4% niclosamide ethanolamine salt powder, the snail mortality after 3, 7 and 15 days were 81% [95%CI: 0.65-0.93], 90% [95%CI: 0.83-0.95] and 94% [95%CI: 0.91-0.97], respectively. Both are good enough to be used as molluscicides integrated with a schistosomiasis control programme. The 4% niclosamide ethanolamine salt powder can be applied in the field without water supply as the surrogate of the current widely used 50% niclosamide ethanolamine salt wettable powder. However, to consolidate the schistosomiasis control achievement gained, it is necessary to continuously perform mollusciciding more than twice annually in the field.
Yang
Guo-Jing
GJ
National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, 207 Rui Jin Er Road, Shanghai 200025, People's Republic of China. ipdzhouxn@sh163.net.
Li
Wei
W
Sun
Le-Ping
LP
Wu
Feng
F
Yang
Kun
K
Huang
Yi-Xin
YX
Zhou
Xiao-Nong
XN
Stat Med. 2002 Jun 15;21(11):1539-58
12111919
Am J Trop Med Hyg. 1982 Jan;31(1):92-9
7058983
Am J Trop Med Hyg. 2008 Feb;78(2):188-94
18256410
Acta Trop. 2005 Nov-Dec;96(2-3):97-105
16125655
Ann Trop Med Parasitol. 2000 Jun;94(4):333-41
10945043
Acta Trop. 2005 Nov-Dec;96(2-3):69-96
16312039
Lancet. 1958 Jan 25;1(7013):208-14
13503262
BMJ. 1997 Sep 13;315(7109):629-34
9310563
Ecology. 2006 Jun;87(6):1445-51
16869419
Parasitology. 1994 Nov;109 ( Pt 4):443-53
7800412
Parasitol Int. 2000 Sep;49(3):195-207
11426575
Trans R Soc Trop Med Hyg. 1990 Mar-Apr;84(2):257-61
2117788
Parassitologia. 2005 Mar;47(1):27-50
16044674
N Engl J Med. 2009 Jan 8;360(2):121-8
19129526
BMJ. 2003 Sep 6;327(7414):557-60
12958120
Parasitol Today. 1996 Apr;12(4):156-9
15275225
Bull World Health Organ. 2005 Jan;83(1):43-8
15682248
Trop Med Int Health. 2009 Dec;14(12):1475-83
19793080
Bull World Health Organ. 2006 Feb;84(2):139-44
16501732