Marzia Rahman

Surveillance, epidemiological, and virological detection of highly pathogenic H5N1 avian influenza viruses in duck and poultry from Bangladesh.

Avian influenza viruses (AIVs) continue to pose a global threat. Waterfowl are the main reservoir and are responsible for the spillover of AIVs to other hosts. This study was conducted as part of routine surveillance activities in Bangladesh and it reports on the serological and molecular detection of H5N1 AIV subtype. A total of 2169 cloacal and 2191 oropharyngeal swabs as well as 1725 sera samples were collected from live birds including duck and chicken in different locations in Bangladesh between the years of 2013 and 2014. Samples were tested using virus isolation, serological tests and molecular methods of RT-PCR. Influenza A viruses were detected using reverse transcription PCR targeting the virus matrix (M) gene in 41/4360 (0.94%) samples including both cloacal and oropharyngeal swab samples, 31 of which were subtyped as H5N1 using subtype-specific primers. Twenty-one live H5N1 virus isolates were recovered from those 31 samples. Screening of 1,868 blood samples collected from the same birds using H5-specific ELISA identified 545/1603 (34%) positive samples. Disconcertingly, an analysis of 221 serum samples collected from vaccinated layer chicken in four districts revealed that only 18 samples (8.1%) were seropositive for anti H5 antibodies, compared to unvaccinated birds (n=105), where 8 samples (7.6%) were seropositive. Our result indicates that the vaccination program as currently implemented should be reviewed and updated. In addition, surveillance programs are crucial for monitoring the efficacy of the current poultry vaccinations programs, and to monitor the circulating AIV strains and emergence of AIV subtypes in Bangladesh.

Prevalence and characterization of multi-drug resistant Salmonella Enterica serovar Gallinarum biovar Pullorum and Gallinarum from chicken

Aim: Salmonella is an important zoonotic pathogen responsible for animal and human diseases. The aim of the present study was to determine the prevalence and stereotyping of Salmonella isolates isolated from apparently healthy poultry. Furthermore, the clonal relatedness among the isolated Salmonella serovars was assessed. Materials and Methods: A total of 150 cloacal swab samples from apparently healthy chickens were collected, and were subjected for the isolation and identification of associated Salmonella organisms. The isolated colonies were identified and characterized on the basis of morphology, cultural characters, biochemical tests, slide agglutination test, polymerase chain reaction, and pulsed-field gel electrophoresis (PFGE). Antibiotic sensitivity patterns were also investigated using commonly used antibiotics. Results: Of the 150 samples, 11 (7.33%) produced characteristics pink colony with black center on XLD agar medium, and all were culturally and biochemically confirmed to be Salmonella. All possessed serovar-specific gene SpeF and reacted uniformly with group D antisera, suggesting that all of the isolates were Salmonella Enterica serovar Gallinarum, biovar Pullorum and/or Gallinarum. Antimicrobial susceptibility testing revealed that 54.54% of the isolated Salmonella Enterica serovars were highly sensitive to ciprofloxacin, whereas the 81.81% isolates were resistant to amoxycillin, doxycycline, kanamycin, gentamycin, and tetracycline. Pulsed-field gel electrophoresis of the XbaI-digested genomic DNA exhibited identical banding patterns, suggesting that the multidrug resistant Salmonella Enterica serovars occurring in commercial layers are highly clonal in Bangladesh. Conclusion: The present study was conducted to find out the prevalence of poultry Salmonella in layer chicken and to find out the clonal relationship among them. The data in this study suggest the prevalence of Salmonella Enterica, which is multidrug resistant and highly clonal for commercial layers of Bangladesh.

Preparation of Inactivated Trivalent FMD Vaccine and Determination of Antibody Titre in Vaccinated Cattle

Aims: This research work was conducted for isolation and molecular detection of Foot and Mouth Disease (FMD) virus from the field samples, development of inactivated trivalent FMD vaccine, and determination of antibody titer in vaccinated cattle. Methodology: A total of 10 samples (tongue epithelium) were collected from FMD affected cattle from Gazipur, Mymensingh, and Pabna districts of Bangladesh during May 2014. Inoculum was prepared from the sample and the associated FMDV was propagated in BHK-21 cell lines. Besides, viral RNA was extracted for molecular detection (RT-PCR) of the serotypes involved. The isolated serotypes were used as seed virus in preparation of binary ethyleneimine (BEI) inactivated trivalent FMD vaccine using saponin and oil adjuvants. For the determination of antibody production in Original Research Article Chowdhury et al.; IJTDH, 16(2): 1-8, 2016; Article no.IJTDH.25870 2 response to our trivalent FMD vaccine, a total of 25 cattle aging 11-22 months were used. Sera of vaccinated cattle were collected on day 0, 21, 35, 49, 63. The sera were subjected for the determination of antibody level using enzyme-linked immunosorbent assay (ELISA). The titer values were statistically analyzed using one-way ANOVA to see immune response against the serotypes. Results: Three serotypes of FMDV were detected; these were FMD serotype-O, A and Asia-1, of which serotype-O was mostly prevalent, followed by serotype-A and Asia-1. The highest mean antibody titer was found on day 63 in all serotypes. Sixteen cattle (80%) out of 20 vaccinated cattle obtained protective antibody titer. The titer values of the vaccinated cattle were statistically significant against O, A and Asia-1 serotypes. Conclusion: FMD serotype-O, A, and Aisa-1 are prevailing in Bangladesh. A trivalent inactivated FMD vaccine has been prepared successfully using circulating virus of Bangladesh. The vaccine can be used to combat FMD in Bangladesh.

Molecular detection of Pasteurella multocida type B causing haemorrhagic septicemia in cattle and buffaloes in Bangladesh

Haemorrhagic septicaemia (HS) is an acute and highly fatal septicemic disease of cattle and buffaloes caused by Pasteurella multocida. The disease has a high morbidity and mortality in cattle, particularly in buffaloes. P. multocida are classified into several serotypes based on their capsular and somatic antigens. According to the capsular polysaccharides P. multocida according are classified into five serotypes designated A, B, D, E and F, while according to the cell wall lipopolysaccharides typing they are classified into 16 somatic serotypes (Cartet, GR., 1955; Carter and Alwis, 1989). The general and biochemical properties of the various strains are very similar, and from this point of view these organisms all belong to the single species, but different serotypes show different pathogenicity when tested in various hosts. The etiology of HS is P. multocida serotype B: 2 and E: 2 (Annas et al., 2014; Chung et al., 2015; Marza et al., 2015).