Pakistan J. Zool. Suppl. Ser., No.9, pp. 639-643, 2009. An Evaluation for Bacterial Contamination of Vaccines for Buffaloes Used in Pakistan Asghar Ali Kamboh*, Jameel Ahmed Gandahi, Atta Hussain Shah, Wei-Yun Zhu, Moolchand Malhi, Rahmatullah Rind and Masroor Ellahi Babar Department of Veterinary Microbiology, Sindh Agriculture University Tando Jam, Pakistan (AAK), Department of Anatomy and Histology, Sindh Agriculture University Tando Jam, Pakistan (JAG, MM), Department of Animal Product Technologies, Sindh Agriculture University Tando Jam, Pakistan (AHS), Laboratory of Gastrointestinal Microbiology, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China (WYZ), Department of Veterinary Microbiology, Sindh Agriculture University Tando Jam, Pakistan (RR) and Department of Molecular Biology and Biotechnology, University of Veterinary and Animal Sciences Lahore, Pakistan (MEB) Abstract.- A study was conducted for the evaluation of bacterial contamination in vaccines used by the buffalo farmers in Pakistan. Vaccine samples (both locally produced and imported) were collected from market. A total of 32 (20 local & 12 imported) buffalo vaccines available in Pakistan for Hemorrhagic Septicaemia (HS), Anthrax, Black Quarter (BQ) and Foot and Mouth disease (FMD) were tested for bacterial contaminants. Four different bacterial species were identified from three different local vaccine samples, while imported vaccines found free from bacterial contaminants. The species found were Escherichia coli, Pasteurella multocida, Bacillus cereus and B. subtilis. Among the local vaccines, one of the total eight Haemorrhagic septicaemia (H.S.) vaccines examined was found contaminated with E. coli and P. multocida, whereas one of the four anthrax vaccines examined was positive for B. cereus and the other for B. subtilis. None of the black quarter (n=4) and foot and mouth disease (n=4) vaccines were contaminated with bacteria. All the 12 imported vaccines (n=3 for each HS, anthrax, BQ and FMD) were free of bacterial contamination. Results of this study warrant immediate attention of the local vaccine manufacturers of Pakistan to improve quality of their vaccines. Such studies need to be continued on periodical basis. Key words: Buffalo, vaccines, bacterial contamination. INTRODUCTION Vaccines are the biological products designed to prevent infections of various kinds by promoting an immune response termed as “active immunity”. Typically vaccines work by enhancing the immune system of the body (Levinson and Jawad, 2000). Vaccination is basically the introduction of a specific biological substance (antigen) into the organism to stimulate the formation of a resistance or immunity to a particular disease (MSUES, 2006). This leads to the production of memory cells within the host, so that on a second encounter with the microbe the immune system can generate a rapid antibody response thereby preventing infection. Vaccination reduces the incidence of the organism in the environment. It also has proved to be a useful way of protecting the __________________________________ * Corresponding author: drasgharkamboh@yahoo.com individual, and the population, from a number of bacterial diseases (Nicklin et al., 1999). There are several types of vaccines, which are used in veterinary practice like, Attenuated whole-agent vaccines that contains, live but attenuated (weakened) microbes; inactivated whole-agent vaccines that contain whole killed (usually by formalin or phenol) microbes; Toxoid vaccines, which contain inactivated bacterial toxins; Subunit vaccines, contain antigenic fragments of a microorganism; conjugated vaccines; and nucleic acid vaccines or DNA vaccines (Tortora et al., 2009). Dead vaccines have very little risk of ‘alive’ contamination while live vaccines always run the risk of contamination with unwanted organisms; for instance, out breaks of reticuloendotheliosis in chickens in Japan and Australia have been traced to contaminated Marek’s disease vaccine (Tizard, 2009). The avian leucosis virus may contaminate distemper vaccine and would represent a risk to