Md. Liakot Hossen

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.

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.