Department of Epidemiology and Veterinary Preventive Medicine, Pandit Deen Dayal Upadhayay Pashu Chikitsa Vigyan Vishvidhyalaya Ewam Go-Anusandhan Sansthan (DUVASU), Mathura-281 001 (U.P.).
* Corresponding author: Assistant Professor; e.mail - dr_amitverma@sify.com.
1Regional centre, Mathura.