1 LeAF, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands E-mail: miriam.vaneekert@wur.nl.
2 Bear Valley Ventures, Utkinton Lane, Tarporley, Cheshire CW6 0JH, United Kingdom.
3 Environmental Health Group, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom.
4 Ifakara Health Institute, Off Mlabani Passage, P.O. Box 53, Ifakara, Tanzania.