Research

Rapid decrease of malaria morbidity following the introduction of community-based monitoring in a rural area of central Vietnam

Ngo Duc Thang¹ , Annette Erhart² , Le Xuan Hung¹ , Le Khanh Thuan ¹ , Nguyen Xuan Xa¹ , Nguyen Ngoc Thanh¹ , Pham Van Ky³ , Marc Coosemans² , Nico Speybroeck^2,4 and Umberto D'Alessandro²

¹  National Institute of Malariology, Parasitology and Entomology, Luong The Vinh street 245, BC 10200 Tu Liem district, Hanoi, Vietnam

²  Prince Leopold Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp, Belgium

³  Provincial Centre for Malariology, Parasitology and Entomology, 156 Ngo Gia Tu, Phan Rang, Ninh Thuan, Vietnam

⁴  Ecole de santé publique, Université Catholique de Louvain, Clos Chapelle-aux-Champs, 1200 Bruxelles, Belgium

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Malaria Journal 2009, 8:3doi:10.1186/1475-2875-8-3

Published:	5 January 2009

Abstract

Background

Despite a successful control programme, malaria has not completely disappeared in Vietnam; it remains endemic in remote areas of central Vietnam, where standard control activities seem to be less effective. The evolution of malaria prevalence and incidence over two and half years in a rural area of central Vietnam, after the introduction of community-based monitoring of malaria cases, is presented.

Methods

After a complete census, six cross-sectional surveys and passive detection of malaria cases (by village and commune health workers using rapid diagnostic tests) were carried out between March 2004 and December 2006 in Ninh-Thuan province, in a population of about 10,000 individuals. The prevalence of malaria infection and the incidence of clinical cases were estimated.

Results

Malaria prevalence significantly decreased from 13.6% (281/2,068) in December 2004 to 4.0% (80/2,019) in December 2006. Plasmodium falciparum and Plasmodium vivax were the most common infections with few Plasmodium malariae mono-infections and some mixed infections. During the study period, malaria incidence decreased by more than 50%, from 25.7/1,000 population at risk in the second half of 2004 to 12.3/1,000 in the second half of 2006. The incidence showed seasonal variations, with a yearly peak between June and December, except in 2006 when the peak observed in the previous years did not occur.

Conclusion

Over a 2.5-year follow-up period, malaria prevalence and incidence decreased by more than 70% and 50%, respectively. Possibly, this could be attributed to the setting up of a passive case detection system based on village health workers, indicating that a major impact on the malaria burden can be obtained whenever prompt diagnosis and adequate treatment are available.