Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2014 Sep 13:13:360.
doi: 10.1186/1475-2875-13-360.

Increased malaria transmission around irrigation schemes in Ethiopia and the potential of canal water management for malaria vector control

Solomon Kibret  1 , G Glenn Wilson, Habte Tekie, Beyene Petros
Affiliations

Increased malaria transmission around irrigation schemes in Ethiopia and the potential of canal water management for malaria vector control

Solomon Kibret et al. Malar J. .

Abstract

Background: Irrigation schemes have been blamed for the increase in malaria in many parts of sub-Saharan Africa. However, proper water management could help mitigate malaria around irrigation schemes in this region. This study investigates the link between irrigation and malaria in Central Ethiopia.

Methods: Larval and adult mosquitoes were collected fortnightly between November 2009 and October 2010 from two irrigated and two non-irrigated (control) villages in the Ziway area, Central Ethiopia. Daily canal water releases were recorded during the study period and bi-weekly correlation analysis was done to determine relationships between canal water releases and larval/adult vector densities. Blood meal sources (bovine vs human) and malaria sporozoite infection were tested using enzyme-linked immunosorbent assay (ELISA). Monthly malaria data were also collected from central health centre of the study villages.

Results: Monthly malaria incidence was over six-fold higher in the irrigated villages than the non-irrigated villages. The number of anopheline breeding habitats was 3.6 times higher in the irrigated villages than the non-irrigated villages and the most common Anopheles mosquito breeding habitats were waterlogged field puddles, leakage pools from irrigation canals and poorly functioning irrigation canals. Larval and adult anopheline densities were seven- and nine-fold higher in the irrigated villages than in the non-irrigated villages, respectively, during the study period. Anopheles arabiensis was the predominant species in the study area. Plasmodium falciparum sporozoite rates of An. arabiensis and Anopheles pharoensis were significantly higher in the irrigated villages than the non-irrigated villages. The annual entomological inoculation rate (EIR) calculated for the irrigated and non-irrigated villages were 34.8 and 0.25 P. falciparum infective bites per person per year, respectively. A strong positive correlation was found between bi-weekly anopheline larval density and canal water releases. Similarly, there was a strong positive correlation between bi-weekly vector density and canal water releases lagged by two weeks. Furthermore, monthly malaria incidence was strongly correlated with monthly vector density lagged by a month in the irrigated villages.

Conclusion: The present study revealed that the irrigation schemes resulted in intensified malaria transmission due to poor canal water management. Proper canal water management could reduce vector abundance and malaria transmission in the irrigated villages.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Monthly malaria incidence (cases per 1,000 population) in the irrigated and non-irrigated villages in the Ziway area, Ethiopia, in 2010.
Figure 2
Figure 2
Monthly trend of anopheline larval density (no. larvae per sq m) in the irrigated and non-irrigated villages in the Ziway area, Ethiopia, between November 2009 and October 2010.
Figure 3
Figure 3
Monthly malaria vector density (mean no. of adult anopheline per light trap per night) in the irrigated and non-irrigated villages in the Ziway area, Ethiopia, between November 2009 and October 2010.
Figure 4
Figure 4
Scatter graph showing a strong positive correlation between mean bi-weekly anopheline larval density and mean bi-weekly canal water release in the irrigated villages in the Ziway area, Ethiopia, between November 2009 and October 2010.
Figure 5
Figure 5
Scatter graph showing a potential positive correlation between bi-weekly adult anopheline density and mean bi-weekly canal water release lagged by 2 weeks in the irrigated villages in the Ziway area, Ethiopia, between November 2009 and October 2010.
Figure 6
Figure 6
Scatter diagram showing a potential positive correlation between mean bi-weekly larval anopheline density and mean bi-weekly adult anopheline density lagged by 2 weeks in the irrigated villages in the Ziway area, Ethiopia, between November 2009 and October 2010.
Figure 7
Figure 7
Scatter graph showing a positive correlation between monthly malaria incidence and monthly vector density lagged by one month in the irrigated villages in the Ziway area, Ethiopia, between November 2009 and October 2010.
See this image and copyright information in PMC

References

    1. Bank W. The water resources sector strategy: An overview. Washington DC: The World Bank; 2004.
    1. Rosegrant MW, Perez ND. Water resources development in Africa: a review and synthesis of issues, potentials, and strategies for the future. Washington DC: International Food Policy Research Institute; 1997. EPTD Discussion Paper No. 28.
    1. Hunter JM, Rey L, Chu KY, Adekolu-John EO, Mott KE. Parasitic diseases in water resources development: the need for intersectoral negotiation. Geneva: World Health Organization; 1993.
    1. WHO . World Malaria Report 2011. Geneva: World Health Organization; 2012.
    1. Boelee E, Konradsen F, vander Hoek W, editors. Malaria in irrigated agriculture: papers and abstracts for the SIMA special seminar at the ICID 18th International congress on irrigation and drainage, Montreal. Colombo: International Water Management Institute; IWMI Working Paper 47; 2002.

Publication types