1. Department of Medical Parasitology and Entomology, Kilimanjaro Christian Medical University College, Moshi 255, Tanzania
2. Pan African Malaria Vector Research Consortium, Moshi 255, Tanzania
3. Department of Disease Control, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
4. Country Office, World Health Organization, Dar es Salaam 255, Tanzania