Ovitrap Surveillance and Mixed Infestation of Aedes aegypti (Linnaeus) and Aedes albopictus (Skuse) in Northern Region and Southern Region of Malaysia

An ovitrap surveillance was conducted to provide recent baseline information on the existence and distribution of Aedes larvae in four dengue prone areas located in Penang, Kedah, Johor and Melaka of Peninsula Malaysia. Among these areas, the highest ovitrap index (OI) for both indoors and outdoors were recorded from Sungai Ara, Penang with 62% and 75%, respectively. There was no significant difference for indoor populations of Ae. aegypti and outdoor populations of Ae. albopictus between all study areas selected (P>0.05), whereas the outdoor populations of Ae. aegypti and the indoor populations of Ae. albopictus in Sungai Ara, Penang were significantly higher than other study areas by 1.91 - 2.61 folds and 1.66 - 3.01 folds, respectively (P<0.05). Different population ratios of Ae. aegypti to Ae. albopictus larvae for both indoors and outdoors were observed in all study areas, respectively. Furthermore, mixed infestation was found in both indoor and outdoor populations in all study areas ranging from 11.36% to 29.03% of the total positive ovitraps. The sensitivity and reliability of ovitrap as a surveillance tool in detecting the presence of more than one mosquito species especially Aedes populations were also re-confirmed.