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Open Access Research article

Comparative efficacy of two poeciliid fish in indoor cement tanks against chikungunya vector Aedes aegypti in villages in Karnataka, India

Susanta K Ghosh2*, Preethi Chakaravarthy2, Sandhya R Panch2, Pushpalatha Krishnappa2, Satyanarayan Tiwari1, Vijay P Ojha1, Manjushree R3 and Aditya P Dash4

Author Affiliations

1 National Institute of Malaria Research (ICMR), Poojanahalli, Kannamangala Post, Devanahalli, Bangalore-562110, Karnataka, India

2 Bangalore Medical College and Research Institute, Bangalore-560002, Karnataka, India

3 Office of the District Health and Family Welfare Services, District Tumkur 572101, Karnataka, India

4 World Health Organization, South East Asia Regional Office, Indra Prastha Marg, New Delhi-110002, India

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BMC Public Health 2011, 11:599  doi:10.1186/1471-2458-11-599

Published: 28 July 2011

Abstract

Background

In 2006, severe outbreaks of Aedes aegypti-transmitted chikungunya occurred in villages in Karnataka, South India. We evaluated the effectiveness of combined information, education and communication (IEC) campaigns using two potential poeciliid larvivorous fish guppy (Poecilia reticulata) and mosquitofish (Gambusia affinis), in indoor cement tanks for Aedes larval control.

Methods

Trials were conducted in two villages (Domatmari and Srinivaspura) in Tumkur District from March to May 2006 for Poecilia and one village (Balmanda) in Kolar District from July to October 2006 for Gambusia. A survey on knowledge, attitude and practice (KAP) on chikungunya was initially conducted and IEC campaigns were performed before and after fish release in Domatmari (IEC alone, followed by IEC + Poecilia) and Balmanda (IEC + Gambusia). In Srinivaspura, IEC was not conducted. Larval surveys were conducted at the baseline followed by one-week and one-month post-intervention periods. The impact of fish on Aedes larvae and disease was assessed based on baseline and post-intervention observations.

Results

Only 18% of respondents knew of the role of mosquitoes in fever outbreaks, while almost all (n = 50 each) gained new knowledge from the IEC campaigns. In Domatmari, IEC alone was not effective (OR 0.54; p = 0.067). Indoor cement tanks were the most preferred Ae. aegypti breeding habitat (86.9%), and had a significant impact on Aedes breeding (Breteau Index) in all villages in the one-week period (p < 0.001). In the one-month period, the impact was most sustained in Domatmari (OR 1.58, p < 0.001) then Srinivaspura (OR 0.45, p = 0.063) and Balmanda (OR 0.51, p = 0.067). After fish introductions, chikungunya cases were reduced by 99.87% in Domatmari, 65.48% in Srinivaspura and 68.51% in Balmanda.

Conclusions

Poecilia exhibited greater survival rates than Gambusia (86.04 vs.16.03%) in cement tanks. Neither IEC nor Poecilia alone was effective against Aedes (p > 0.05). We conclude that Poecilia + IEC is an effective intervention strategy. The operational cost was 0.50 (US$ 0.011, 1 US$= 47) per capita per application. Proper water storage practices, focused IEC with Poecilia introductions and vector sanitation involving the local administration and community, is suggested as the best strategy for Aedes control.