U. B. USMAN

Division of Veterinary Services, Ministry of Animal Health and Fisheries Development, Sokoto, Nigeria

J. K. P. KWAGA

Department of Veterinary Public Health and Preventive Medicine, Faculty of veterinary medicine, Ahmadu Bello University, Zaria, Nigeria

J. KABIR

Department of Veterinary Public Health and Preventive Medicine, Faculty of veterinary medicine, Ahmadu Bello University, Zaria, Nigeria

O. S. OLONITOLA

Department of Microbiology, faculty of Science, Ahmadu Bello University, Zaria, Nigeria