Improved method for distinguishing the human source of mosquito blood meals between close family members

We have developed a simpl.e and relatively cheap method to distinguish the origin of mosquito blood meals between close family members, effective for both laboratory and field samples. Each blood meal was squashed on to filte r paper and eluted overnight with 0(.)5 mt phosphate-buffered saline. Deoxy ribonucleic acid (DNA) was extracted using a chemical matrix (Insta-gene(TM )) which bound to everything from the blood meal except DNA, which remained in the supernatant. Following extractions, reference DNA samples taken dir ectly from finger-prick blood of human subjects and those from blood meals of unknown origin were amplified with human microsatellite markers using a thermal cycler. Polymerase chain reaction products were then run on an ABI( TM) gel (Automated Biosystems) to obtain a genotype for each sample. The DN A from each mosquito blood meal was then matched to an individual host. Wit h laboratory samples, human DNA which had been extracted from mosquito bloo d meals up to 12 h after feeding could be used. One important application o f this method will be to identify which members of a community are most at risk from vector-borne diseases. It also has numerous potential application s in studies of insect biting behaviour in both human and veterinary scienc e.