00329nam a2200109 a 450000500170000002000150001710000380003224500520007026000220012230000140014449000610015820251203091522.0  a924120561X  aWorld Health Organization(Geneva)  aEcology and control of vectors in Public Health  aGenevabWhoc1975  a35p, 20cm  aworld health organization technical report series no.561