[1] Agr Univ Athens, Fac Anim Sci & Aquaculture, GR-11855 Athens, Greece
[2] Univ Athens, Sch Med, Dept Basic Med Sci, Biol Lab, Athens 11527, Greece
[3] Hellen Army Biol Res Ctr, Velliou 15236, P Penteli, Greece
[4] Aristotle Univ Thessaloniki, Fac Vet Med, Lab Microbiol & Infect Dis, Thessaloniki 54124, Greece
[5] CNR ISPA, Inst Sci Food Prod, Natl Res Council Italy, Lecce, Italy
[6] Food & Environm Res Agcy, York YO41 1LZ, N Yorkshire, England