1. Laboratorio Lema & Bandin; C./Lepanto, 5, bajo 36201 Vigo Spain
2. Servicio de Otorrinolaringoligía; Hospital Xeral-Cies; C./Pizarro 36203 Vigo Spain
3. Departamento de Medicina Preventiva y Salud Pública; Hospital Clínico Universitario; A Choupana 15706 Santiago de Composela Spain
4. Departamento de Patología Animal I; Facultad de Veterinaria; Universidad Complutense; Avenida Puerta de Hierra s/n 28040 Madrid Spain
5. Laboratory of Public Health Entomology; Department of Immunology and Infectious Diseases; Harvard School of Public Health; 665 Huntington Avenue Boston Massachusetts 02115 USA