Original Article A. Evans, Clinvet SA Morocco, Mohammedia, Morocco Search for more papers by this author G. Bongiorno, Unit of Vector-borne Diseases, Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy Search for more papers by this author J. J. Fourie, Clinvet International (Pty) Ltd, Bloemfontein, South Africa Search for more papers by this author N. Lekouch, Clinvet SA Morocco, Mohammedia, Morocco Search for more papers by this author R.