Dogs as a favored host choice of Anopheles gambiae sensu stricto (Diptera : Culicidae) of Sao Tome, west Africa

The host source and human blood index (HBI) of an exophilic population of t he "forest" cytoform of Anopheles gambiae Giles sensu stricto, from a peri- urban area of the island of Sao Tome, were assessed. Blood meals of 434 An. gambiae females from all-night indoor light-trap collections, 193 from ind oor and 422 from outdoor resting collections, were determined by ELISA. Sig nificant differences were found in the HBI estimates from insects collected indoors (0.93) and outdoors (0.27). Blood-fed insects collected resting ou tdoors provided the most representative sample for host determination. Dogs were the predominant hosts, followed by humans and pigs. Of all human feed s, it was estimated that 81.5% were taken inside houses. The low HBI of 0.2 7 for the An. gambiae population explains the low sporozoite rate and the m eso-endemicity of malaria in the island.