The present study reports the duration of immunity and protective efficacy of Peste des Petits Ruminants (PPR) vaccine (Nigerian strain 75/1) in sheep and goats. A total of 105 sheep and goats were divided into three groups A, B and C. Group A received normal recommended dose (1.0 ml) of PPR vaccine, group B received half dose (0.5 ml) of PPR vaccine and group C was kept as unvaccinated control group in contact with vaccinated animals. The post vaccination dynamics of antibodies against PPR virus was studied. It was found that significant antibody titres persisted for 3 years post vaccination in sheep and goats vaccinated with either full dose or half dose of PPR vaccine. The challenge protection studies were carried out in experimental animals at 24 and 36 month post vaccination. The vaccinates withstood challenge and were found completely resistant clinically and virologically to virulent PPR virus for 24 and 36 months post vaccination. The unvaccinated control animals developed typical clinical signs of PPR and the challenged virus was detected in ocular, nasal and oral secretions of these animals. This study demonstrated that a single immunization with PPR vaccine conferred solid protection in sheep and goats for 3 years.
 Gibbs, E., Taylor, W., Lawman, M. and Bryant, J. (1979) Classification of Peste des Petits Ruminants Virus as the Fourth Member of the Genus Morbillivirus. Intervirology, 11, 268-274. http://dx.doi.org/10.1159/000149044
 Amjad, H., Forsyth, M., Barrett, T. and Rossiter, P. (1996) Peste des Petits Ruminants in Goats in Pakistan. Veterinary Record, 139, 118-119. http://dx.doi.org/10.1136/vr.139.5.118
 Zahur, A., Irshad, H., Hussain, M., Ullah, A., Jahangir, M., Khan, M.Q. and Farooq, M.S. (2008) The Epidemiology of Peste des Petits Ruminants in Pakistan. Rev Sci Tech (International Office of Epizootics), 27, 877-884.
 Zahur, A., Ullah, A., Hussain, M., Irshad, H., Hameed, A., Jahangir, M. and Farooq, M. (2011) Sero-Epidemiology of Peste des Petits Ruminants (PPR) in Pakistan. Preventive Veterinary Medicine, 102, 87-92. http://dx.doi.org/10.1016/j.prevetmed.2011.06.011
 Anderson, J. and McKay, J.A. (1994) The Detection of Anti-bodies Against Peste des Petits Ruminants Virus in Cattle, Sheep and Goats and the Possible Implications to Rinderpest Control Programmes. Epidemiology & Infection, 112, 225-231. http://dx.doi.org/10.1017/S0950268800057599
 Libeau, G., Prehaud, C., Lancelot, R., Colas, F., Guerre, L., Bishop, D. and Diallo, A. (1995) Development of a Competitive ELISA for Detecting Antibodies to the Peste des Petits Ruminants Virus Using a Recombinant Nucleoprotein. Research in Veterinary Science, 58, 50-55. http://dx.doi.org/10.1016/0034-5288(95)90088-8
 Forsyth, M. and Barrett, T. (1995) Evaluation of Polymerase Chain Reaction for the Detection and Characterization of Rinderpest and Peste de Petit Ruminant’s Viruses for Epide-miological Studies. Virus Research, 39, 151-163. http://dx.doi.org/10.1016/0168-1702(95)00076-3
 Diallo, A., Minet, C., Le Goff C., Berhe, G., Albina, E., Libeau, G. and Barrett T. (2007) The Threat of Peste des Petits Ruminants: Progress in Vaccine Development for Disease Control. Vaccine, 25, 5591-5597. http://dx.doi.org/10.1016/j.vaccine.2007.02.013
 Adu, F. and Nawathe D. (1981) Safety of Tissue Culture Rin-derpest Vaccine in Pregnant goats. Tropical Animal Health and Production, 13, 166-166. http://dx.doi.org/10.1007/BF02237916
 Taylor, W. (1984) The Distribution and Epidemiology of Peste des Petits Ruminants. Preventive Veterinary Medicine, 2, 157-166. http://dx.doi.org/10.1016/0167-5877(84)90059-X
 Diallo, A., Taylor, W.P., Lefevre, P.C. and Provost, A. (1989) Attenuation D'une Ouche De Virus De La Peste des Petits Ru-minants: Candidat Pour un Vaccin Homologue Vivant. Rev Elev Med Vet Pay, 42, 311-319.
 Awa, DN., Ngagnou, A., Tefiang, E., Yaya, D, and Njoya, A. (2002) Post Vaccination and Colostral Peste des Petits Ruminants Antibody Dynamics in Research Flocks of Kirdi Goats and Foulbe Sheep of North Cameroon. Preventive Veterinary Medicine, 55, 265-271. http://dx.doi.org/10.1016/S0167-5877(02)00013-2
 Intizar, M., Ahmad, M., Anjum, A, and Hanif, A. (2009) Comparative Efficacy of Peste des Petits Ruminants (PPR) Vaccines Available in Pakistan in Sheep and Goats. Pakistan Veterinary Journal, 29.
 Siddique, M., Rahman, M., Chowdhury, S., Kafi, M. and Alam, M. (2006) Determination of Efficacy of Thermostable PPR Live Homologous Vaccine Incubated at Room Temperature for 14 Days. BangladeshJVetMed, 4, 43-46.
 Plowright, W. (1984) The Duration of Immunity in Cattle following Inoculation of Rinderpest Cell Culture Vaccine. Journal of Hygiene-Cambridge, 92, 285-296. http://dx.doi.org/10.1017/S0022172400064524
 Martrenchar, A., Bouchel, D., Zoyem, N., Thiaucourt, F. and Lambert, M. (1997) Risk Factors Responsible for the Appearance of Individual Clinical Signs in Small Ruminants in Northern Cameroon. Small Ruminant Research, 26, 45-52. http://dx.doi.org/10.1016/S0921-4488(96)00975-3
 Singh, R., Saravanan, P., Sreenivasa, B., Singh, R. and Ban-dyopadhyay, S. (2004) Prevalence and Distribution of Peste des Petits Ruminants Virus Infection in Small Ruminants in India. Rev Sci Tech (International Office of Epizootics), 23, 807-819.
 Roeder, P.L. and Obi, T.U. (1999) Recognizing Peste des Petits Ruminants: A Field Manual. In: Food and Agriculture Organization of the United Nations. Rome. ftp://ftp.fao.org/docrep/FAO/003/X1703E/X1703E00.PDF.
 Abubakar, M., Ali, Q. and Khan, H.A. (2008)Prevalence and Mortality Rate of Peste des Petitis Ruminant (PPR): Possible Association with Abortion in Goat. Tropical Animal Health and Production, 40, 317-321. http://dx.doi.org/10.1007/s11250-007-9105-2
 Cosby, S.L., Kai, C. and Yamanouchi, K. (2005) Immunology of Rin-derpest—An Immunosuppression but a Lifelong Vaccine Protection. In: Barrett, T., Paul-Pierre, P. and Taylor, W., Eds. Rinderpest and Peste des Petits Ruminants: Virus Plagues of Large and Small Ruminants. Pirbright, United Kingdom, 196.