[1] ARS, Anim Parasit Dis Lab, Anim & Nat Resources Inst, USDA, Beltsville, MD 20705 USA
[2] Univ Maryland, Sch Med, Dept Pediat, Baltimore, MD 21201 USA
[3] Seppic, F-92800 Puteaux La Defense, France
[4] Inst Hlth & Environm, Taejon 305338, South Korea