Surveillance of Vector-borne Disease in Pakphanang Basin Project (การเฝ้าระวังโรคที่นำโดยแมลงในพื้นที่โครงการลุ่มน้ำปากพนัง)

Pakphanang Basin Project is initiated by His Majesty the King for agricultural and water resources development, covering 10 districts of Nakhonsithammarat plus 1 of Songkhla and 2 of Phattalung provinces. The Project is divided into 3 phases, which has been implemented from 1995 to 2009. This study was designed to closely observe vector-borne diseases, that is, malaria, filariasis and dengue. The study found that malaria prevailed in all districts. Three districts of Nakhonsithammarat were malaria transmission areas (A case), namely, Cha-oud, Chulaporn and Lansaka. There were 187 malarial cases and 59 cases in the two periods of fiscal years 1995-1999 and 2000-2004 respectively. Malaria vectors found in Lanasaka and Ronphibun districts were An. dirus, An. maculatus, and An. minimus and posed a threat of malaria outbreak. Filariasis, caused by periodic and sub-periodic type Brugia malayi, could be found in all districts. There were 61 and 15 filariasis cases in the periods 1997-1999 and 2000- 2001. Mansonia spp, Ma. annulifera, Ma. bonneae, Ma. indiana, Ma. uniformis and Ma. dives. were the major filaria vectors. In every three years there were dengue outbreaks in the study areas. About 2,746, 4,449 and 2,677 dengue cases were reported in 1995, 1998 and 2001 respectively. Aedes aegypti and Aedes albopictus were the main dengue vectors. Pakphanang Basinus areas still harbour many important vectors ready to transmit and propagate into critical outbreaks of diseases. Therefore, disease and vector surveillance should be carried out continuously.