THE PALPAL RATIO METHOD COMPARED WITH PCR TO DISTINGUISH BETWEEN ANOPHELES-GAMBIAE SS AND A-MELAS FROM GUINEA-BISSAU, WEST-AFRICA

We compared the palpal ratio method with the polymerase chain reaction (PCR) to distinguish between Anopheles gambiae s.s. and A. melas. At the end of the rainy season of 1995, female mosquitoes were collected indoors in the Antula area of Bissau, Guinea Bissau. A subsample of 35 4 mosquitoes were identified first with PCR and then with the palpal r atio method (study A). Subsequently, another 195 mosquitoes were ident ified first with the palpal ratio method and then.with PCR (study B). The highest percentage (100%, n=16) of correctly identified A. melas w as obtained at the palpal ratio cut-off point of 0.83. However, at thi s point 4.0% (14/347) and 11.3% (21/186) of the A. gambiae were errone ously identified as A. melas in study A and B, respectively. This sugg ests that the palpal ratio method is not sufficiently reliable to dist inguish between A. gambiae and A. melas from the Bissau area. (C) 1998 Elsevier Science B.V. All rights reserved.