Shifting to Plasmodium Vivax Dominance At Highlands of Ethiopia Following the Countrywide Intensive Use of Artemether-Lumefantrine throughout Endemic Areas Since 2005: Can We Neglect the Role of Climate and Relapse Cases?

A shifting to Plasmodium vivax dominance was found at highlands of South-Central Ethiopia after intensive malaria interventions:  Can we neglect the role of climate and relapses?

Adugna Woyessa^{1, 2*}, Wakgari Deressa², Ahmed Ali² and Bernt Lindtjørn³

Background: Plasmodium falciparum has been the major causes of severe epidemics accounting 60-70% compared to P. vivax (30-40%) in Ethiopia. Since 2005 artemether-lumefantrine (AL) has been the first line drug for the treatment of falciparum malaria and widely applied using RDTs. Despite the persistent decline of malaria still there is scarce information at highlands with low transmission. With the objective of measuring malaria prevalence and identifying risk factors at community level the present study was conducted at highlands of Ethiopia.

Method: Multi-stage sampling technique was used to sample 750 households from six kebeles located at altitudes 1800-2300 m. Blood films were seasonally collected from all consenting family members for two consecutive years. Malaria case review was also collected from two health facilities for the period September 2004 to August 2010.

Results: A total of 19,207 (94.4%) blood slides were analyzed from 3,780 people recruited from 738 households. Of those 178 (0.93%) had malaria infection, with Plasmodium vivax accounting 87.1% (155178) and P. falciparum 12.9% (23/178) of them. Shifting of species distribution showed variation at different locations and years. Overall, health facility record review showed the dominance of P. vivax mainly at high altitude from 2005 to 2010. Plasmodium vivax accounted 73.1% (5413/7406) at Butajira Health Centre (>2000m), while 48.7% (4695/9648) at Inseno Health Centre (<2000m). Plasmodium vivax high transmissibility, key malaria interventions mainly targeted to P. falciparum and warming climate might have facilitated dominance of P. vivax.

Conclusion: Very low malaria prevalence with significant variation at different altitudes identified. P. vivax found predominant species at highlands of Ethiopia.

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