Malaria situation and related factors in a Central Border Areas of Laos and Vietnam
Pongvongsa Tiengkham（ラオス保健省サワナケット県マラリアセンター所長、地球研招へい外国人研究員）
-
要 旨：
-
In Savannakhet of Laos and Quang Tri of Vietnam, most malaria cases are indeed found in their border areas that are mountainous, forested and populated with ethnic minority groups. Despite substantial control activities by the local governments, malaria is still an important health problem. The objective of this study was to have better understanding of the border malaria situation for further cross border collaboration between the two countries. Fourteen villages in Savannakhet and 22 villages in Quang Tri were representatively chosen within 5 km from the border where malaria blood survey (n = 1256 and n = 1803, respectively), interview survey with household heads (n = 400 both sides), entomological survey were conducted between August and September 2010. Data were analyzed and forest densities were computed in Research Institute for Humanity and Nature between 2011 May and August with the support of the Ecohealth Project. Malaria prevalence was significantly higher in Laos (5.2 %) than in Vietnam (1.8%) (p<0.001). P.vivax was predominantly found in Laos (50.8%), while in Vietnam P.faciparum was higher than any other species (54.5%). Bed net coverage was high on both Laos and Vietnam (99.7%, 2.3 persons/net and 92.9%, 2.6 persons/net, respectively). Anopheles mosquitoes were more abundant in Laos than in Vietnam (2.56/light trap/night in Laos and 1.25/light trap/night in Vietnam). Although Anopheles minimus was present in the both sides, An. dirus was only found in Laos. The forest density was higher in Laos than Vietnam. This study suggests that the presence of An.dirus, which is known to be the most efficient malaria vector, could lead to higher malaria prevalence in Laos where the higher forest density supports this vector in dominating. Vector and environmental differences need to be taken into account to make border the malaria control effectively.