Preservation of blood fed Aedes albopictus from field to laboratory and its incidence on host species identification

Abstract

Aedes albopictus is the major vector of Chikungunya virus in Thailand and Southeast Asian countries. Blood meal characterizations are necessary to determine its natural feeding behaviour and on which host the females are feeding. This research determined the best laboratory preservation method for blood source detection of field mosquitoes. Female Ae. albopictus were fed with human blood and harvested at 0, 24, 48, 72 and 96 hours afterward. Then, females were either: (1) preserved at – 20°C, (2) air-dried, (3) dried by lantern, (4) immersed in absolute ethanol, (5) placed in Carnoy’s solution or (6) their abdomen were crushed on filter paper. After 24 hours, every sample was stocked at -20°C. The blood meal was detectable up to 24 hours post-feeding with ELISA tests. The optimal preservation method for ELISA test was ethanol. All the preservation methods were positive with PCR techniques up to 48 hours, except the Carnoy’s solution method which was less efficient. We propose the use of the filter paper or ethanol as most convenient and efficient methods to preserve field mosquitoes until laboratory analysis either by ELISA or PCR.