Low-pathogenic avian influenza (LPAI) H9N2 virus is endemic in Bangladesh, causing huge economic ... more Low-pathogenic avian influenza (LPAI) H9N2 virus is endemic in Bangladesh, causing huge economic losses in the poultry industry. Although a considerable number of Bangladeshi LPAI H9N2 viruses have been molecularly characterized, there is inadequate information on the pathogenicity of H9N2 viruses in commercial poultry. In this study, circulating LPAI H9N2 viruses from recent field outbreaks were characterized, and their pathogenicity in commercial Sonali (crossbred) and broiler chickens was assessed. Phylogenetic analysis of currently circulating field viruses based on the hemagglutinin (HA) and neuraminidase (NA) gene sequences revealed continuous circulation of G1 lineages containing the tri-basic hemagglutinin cleavage site (HACS) motif (PAKSKR*GLF) at the HA protein. Both the LPAI susceptible Sonali and broiler chickens were infected with selected H9N2 isolates A/chicken/Bangladesh/2458-LT2/2020 or A/chicken/Bangladesh/2465-LT56/2021 using intranasal (100 µL) and intraocular (1...
For rapid and sensitive pathogen screening from field outbreaks, molecular techniques such as qPC... more For rapid and sensitive pathogen screening from field outbreaks, molecular techniques such as qPCR-based simultaneous detections are efficient. Respiratory diseases are the most detrimental diseases to the poultry industry and need to be addressed because of their major economic losses. In the current study, we have applied two different detection assays: one for simultaneous detection of avian influenza virus (AIV; M gene) and subtyping (H5, N1, H9, N2) using TaqMan probe chemistry (TaqMan multitarget) and another for simultaneous detection of Newcastle disease virus (NDV), infectious bronchitis virus (IBV), and infectious laryngotracheitis virus (ILTV) using SYBR Green chemistry (SYBR Green multitarget). Two individual qPCRs were conducted for the detection of four pathogens. Surveillance of tissue (n = 158) and oropharyngeal swab (206) samples from multiple poultry flocks during the years April 2020–July 2022 applying the TaqMan and SYBR Green multitarget qPCRs revealed that 48.9...
The Journal of Infection in Developing Countries, 2022
Introduction: Peste des petits ruminants (PPR) is an important transboundary animal disease of sm... more Introduction: Peste des petits ruminants (PPR) is an important transboundary animal disease of small ruminants which causes serious damage to the livelihood and food security of millions of small-scale farmers. PPR is endemic in goats in Bangladesh since 1993. The aim of this study was to determine the seroprevalence of PPR in sheep, cattle, and buffaloes in Bangladesh. Methodology: A total of 434 blood samples from sheep (n = 100), cattle (n = 190) and buffalo (n = 144) were collected aseptically. Sera were separated and antibody titer was determined using a commercially available c-ELISA kit. Results: The overall seroprevalence was 16% and 3.68% in sheep and cattle, respectively, while buffaloes had a considerably higher seroprevalence of 42.36%. The study suggests that buffaloes are more prone to the PPR virus (PPRV) infection and cattle. Conclusions: This study provides serological evidence of PPRV infection in cattle and buffaloes. These results may warrant further studies to f...
Mycoplasma gallisepticum is considered to be the most important pathogenic Mycoplasma sp. and occ... more Mycoplasma gallisepticum is considered to be the most important pathogenic Mycoplasma sp. and occurs world-wide. For effective control of mycoplasmosis, early diagnosis is the cornerstone, but the cultural method is laborious, expensive and timeconsuming, whereas agglutination test is easy to perform in field conditions and cheaper. Mycoplasma gallisepticum was isolated and two types of stained antigen produced. The antigen produced distinct tiny clumps with positive antisera of Mycoplasma spp. The slide agglutination system was sensitive, reliable and cheap. This method may be used to screen Mycoplasma infections in poultry farms.DOI: http://dx.doi.org/10.3329/bvet.v28i2.10688Bangl. vet. 2011. Vol. 28, No. 2, 80 84
Egg Drop Syndrome-76 (EDS-76), a viral disease caused by EDS-76 virus or Duck adenovirus A, is a ... more Egg Drop Syndrome-76 (EDS-76), a viral disease caused by EDS-76 virus or Duck adenovirus A, is a major cause of drop in egg production in breeder and layer flocks with severe economic losses. Poultry farms in Bangladesh occasionally experience outbreaks of EDS-76. For adoption of a polymerase chain reaction (PCR) for detection of EDS -76 virus, a local isolate of the virus was propagated in 10 days old embryonated duck eggs after inoculation through allantoic route. The presence of EDS-76 virus in the allantoic fluid was reconfirmed by hemagglutination (HA) and hemagglutination inhibition (HI) test using chicken red blood cells and hyperimmune anti-EDS-76 virus antiserum. Then a PCR was successfully applied to amplify 238 bp fragments from the EDS-76 virus genome. The PCR product was sequenced. Blast search in the GenBank revealed that the PCR product represents a genome fragment that lies in the non-coding region between the 100K protein and pVIII genes of EDS-76 virus.
Dhaka Zoo with 2000 animal heads of 184 species from significant genetic diversity and five milli... more Dhaka Zoo with 2000 animal heads of 184 species from significant genetic diversity and five million visitors influx round the year is placing it a public health important spot. This study was conducted to investigate blastomycosis in animals at Dhaka Zoo to ascertain animal health, welfare and public health safety standard. One hundred and two necropsied tissue samples preserved in 10% neutral buffered formalin at necropsy from 36 animals of 25 different species were collected from Dhaka Zoo. Twenty five out of 36 study animals were suffering from granulomatous diseases. Among them three animals were found suffering from blastomycosis. Clinical history, nodular lesions from necropsy findings, granulomatous reactions with fungal spores on histopathology and spherical yeast cells with double contoured wall and broad base budding on special staining were used for the confirmation of blastomycosis in spotted deer (Cervus axis/Axis axis), nilgai (Boselaphustragocamelus) and horse (Equus...
Newcastle disease (ND) is endemic in Bangladesh. Locally produced or imported live Newcastle dise... more Newcastle disease (ND) is endemic in Bangladesh. Locally produced or imported live Newcastle disease virus (NDV) vaccines based on lentogenic virus strains, locally produced live vaccines of the mesogenic Mukteswar strain, as well as imported inactivated vaccines of lentogenic strains, are being used in Bangladesh under different vaccination regimens. Despite these vaccinations, frequent outbreaks of ND are being reported in Bangladesh. Here we compared the efficacy of booster immunization with three different vaccines in chickens that had been primed with two doses of live LaSota vaccine. A total of 30 birds (Group A) were primed with two doses of live LaSota virus (genotype II) vaccine at days 7 and 28, while 20 birds (Group B) remained unvaccinated. At day 60, birds of Group A were divided into three sub-groups, which received booster immunizations with three different vaccines; A1: live LaSota vaccine, A2: inactivated LaSota vaccine, and A3: inactivated genotype XIII.2 vaccine (...
Genetic characterization may provide useful insights into severe acute respiratory coronavirus 2 ... more Genetic characterization may provide useful insights into severe acute respiratory coronavirus 2 (SARS CoV 2) circulating in Bangladesh. Here we analyzed the SARS Cov 2 positive 41 nasopharyngeal samples collected in lysis buffer obtained at different regional national laboratories of Bangladesh during July – December 2020. Full length spike gene was amplified and SARS CoV 2 was confirmed upon Sanger sequencing. Multiple ClustalW alignment and phylogenetic study of 15 strains showed that genetically diverse SARS CoV 2 is circulating in the country where 80 documented and 55 novel substitutions have been observed in different regions of spike glycoprotein. Major mutations and/or deletions was identified at conserved amino acid positions that are functionally linked to host transition, antigenic drift, host surface receptor binding or antibody recognition sites, and viral oligomerization interfaces that may have significant effects on pathogenic capacity and epidemiological signatures.
Virus evolution and mutation analyses are crucial for tracing virus transmission, the potential v... more Virus evolution and mutation analyses are crucial for tracing virus transmission, the potential variants, and other pathogenic determinants. Despite continuing circulation of the SARS-CoV-2, very limited studies have been conducted on genetic evolutionary analysis of the virus in Bangladesh. In this study, a total of 791 complete genome sequences of SARS-CoV-2 from Bangladesh deposited in the GISAID database during March 2020 to January 2021 were analyzed. Phylogenetic analysis revealed circulation of seven GISAID clades G, GH, GR, GRY, L, O, and S or five Nextstrain clades 20A, 20B, 20C, 19A, and 19B in the country during the study period. The GISAID clade GR or the Nextstrain clade 20B or lineage B.1.1.25 is predominant in Bangladesh and closely related to the sequences from India, USA, Canada, UK, and Italy. The GR clade or B.1.1.25 lineage is likely to be responsible for the widespread community transmission of SARS-CoV-2 in the country during the first wave of infection. Signif...
Avian influenza virus (AIV) remains a huge challenge for poultry production with negative repercu... more Avian influenza virus (AIV) remains a huge challenge for poultry production with negative repercussions for micro- and macro-economy and public health in Bangladesh. High (HP) H5N1 and low pathogenicity (LP) H9N2 AIV are currently endemic in poultry, and both have been reported to infect humans sporadically. Multiple virus introductions of different clades of HPAIV H5N1, reassorted genotypes, and on-going diversification of LPAIV H9N2 create a highly volatile virological environment which potentially implicates increased virulence, adaptation to new host species, and subsequent zoonotic transmission. Allotropy of poultry rearing systems and supply chains further increase the risk of virus spreading, which leads to human exposure and fosters the emergence of new potentially pre-pandemic virus strains. Here, we review the epidemiology, focusing on (i) risk factors for virus spreading, (ii) viral genetic evolution, and (iii) options for AIV control in Bangladesh. It is concluded that i...
Newcastle disease (ND) is endemic in poultry in Bangladesh. We performed genotypic and pathotypic... more Newcastle disease (ND) is endemic in poultry in Bangladesh. We performed genotypic and pathotypic characterization of four ND virus (NDV) isolates from recent outbreaks in broiler chickens in Bangladesh during the period of 2020–2021. Phylogenetic analysis based on the complete fusion protein gene coding sequences classified the viruses into NDV class II genotype VII.2 together with viruses from Indonesia isolated between 2014 and 2021 and a single 2020 Indian isolate. Pathogenicity testing using the intracerebral pathogenicity index in day-old chickens and mean embryo death time in embryonating chicken eggs revealed that the Bangladeshi isolates are velogenic. Inoculation of 35-day-old chickens with two NDV isolates (LT67 and N5) resulted in 100% morbidity by 3 days post inoculation (DPI), and all birds succumbed to infection by 7 DPI. Massive hemorrhages, congestion and necrotic lesions were observed in different visceral organs, which were typical for infection with a velogenic v...
Lumpy skin disease (LSD) emerged in Bangladesh in mid-2019, leading to great economic losses for ... more Lumpy skin disease (LSD) emerged in Bangladesh in mid-2019, leading to great economic losses for cattle farmers. This study describes the recent occurrence of the LSDV in Bangladesh and examines the clinical manifestation of the disease in local cattle breeds, characteristic epidemiological features, and pathological findings in affected animals. In addition, a full-genome sequencing of two local LSDV isolates was carried out. A total of 565 animals from 88 households were investigated, and 165 samples (skin lesions, saliva, nasal discharge, feces, and milk) were collected for virus detection. Pathology and immunohistochemistry were performed on nodule biopsies. Fever, nodular skin lesions, and swelling of the joints were the most common clinical manifestations. Skin lesions had a higher concentration of viral DNA compared to other sample types and were therefore selected for virus isolation and characterization. Pathology of the LSD skin nodules comprised a granulomatous reaction i...
An in-depth knowledge of the molecular evolution of the peste des petits ruminants virus (PPRV) i... more An in-depth knowledge of the molecular evolution of the peste des petits ruminants virus (PPRV) is critical for the success of the current global eradication program. For this reason, a molecular evolutionary analysis of PPRVs circulating in Bangladesh over a decade (2008-2020) was performed. The complete genome sequencing of three PPRV isolates from 2008 (BD2), 2015 (BD12) and 2017 (BD17) as well as full length nucleocapsid (N), matrix (M) and fusion (F) gene sequencing of seven more samples from 2015 to 2020 was performed. Phylogenetic analysis classified all ten PPRVs from Bangladesh as members of lineage IV and showed that they were closely related to PPRV strains detected in China and Tibet during 2007-2008, and India during 2014-2018. Time scale Bayesian Maximum Clade Credibility (MCC) phylogenetic analysis of the three complete genomes revealed a mean Time to Most Recent Common Ancestor (TMRCA) of 2000. Comparative deduced amino acid residue analysis at various functional motifs of PPRVs related to virus structure and function, virulence and host adaptation, receptor binding sites and polymerase activity revealed conserved residues among the PPRVs from Bangladesh. In total sixteen epitopes were predicted from four immunogenic proteins i.e. N, M, F and haemagglutinin (H). Interestingly, the predicted epitopes from the N and M proteins shared conserved epitopes with two vaccine strains currently being used, indicating that the strains from Bangladesh could be potentially used as alternative local vaccines.
Background: Specialized freeze-drying process is being used in the field for different thermostab... more Background: Specialized freeze-drying process is being used in the field for different thermostable vaccine preparation worldwide. The thermostability remains only in undiluted conditions. If dilution is made at the morning and used for the whole day, the vaccine efficacy is compromised at high ambient temperature. In this study, trehalose based specialized vaccine diluent was used to improve the stability of Peste des Petits Ruminants (PPR) vaccine in diluted condition. Methods: The available PPR vaccine was reconstituted with conventional diluent and with trehalose based test diluent. The diluted vaccine was kept at ambient temperature without maintaining any cool chain. Stability of diluted vaccine virus was further assessed in vivo and in vitro at different temperatures. Goats were vaccinated and Vero cells were infected with reconstituted vaccines and were assessed at 0, 3, 6, 9 and 24 hours post dilution. Antibody titer was measured and virus infectivity titer was determined i...
A total of 15 dead or sick birds from 13 clinical outbreaks of avian influenza in ducks, geese, c... more A total of 15 dead or sick birds from 13 clinical outbreaks of avian influenza in ducks, geese, chickens and turkeys in 2017 in Bangladesh were examined. The presence of H5N1 influenza A virus in the affected birds was detected by RT-PCR. Phylogenetic analysis based on full-length gene sequences of all eight gene segments revealed that these recent outbreaks were caused by a new reassortant of clade 2.3.2.1a H5N1 virus, which had been detected earlier in 2015 during surveillance in live bird markets (LBMs) and wet lands. This reassortant virus acquired PB2, PB1, PA, NP and NS genes from low pathogenic avian influenza viruses mostly of non-H9N2 subtypes but retained HA, NA and M genes of the old clade 2.3.2.1a viruses. Nevertheless, the HA gene of these new viruses was 2.7% divergent from that of the old clade 2.3.2.1a viruses circulated in Bangladesh. Interestingly, similar reassortment events could be traced back in four 2.3.2.1a virus isolates of 2013 from backyard ducks. It suggests that this reassortant virus emerged in 2013, which took two years to be detected at a broader scale (i.e. in LBMs), another two years until it became widely spread in poultry and fully replaced the old viruses. Several mutations were detected in the recent Bangladeshi isolates, which are likely to influence possible phenotypic alterations such as increased mammalian adaptation, reduced susceptibility to antiviral agents and reduced host antiviral response.
Low-pathogenic avian influenza (LPAI) H9N2 virus is endemic in Bangladesh, causing huge economic ... more Low-pathogenic avian influenza (LPAI) H9N2 virus is endemic in Bangladesh, causing huge economic losses in the poultry industry. Although a considerable number of Bangladeshi LPAI H9N2 viruses have been molecularly characterized, there is inadequate information on the pathogenicity of H9N2 viruses in commercial poultry. In this study, circulating LPAI H9N2 viruses from recent field outbreaks were characterized, and their pathogenicity in commercial Sonali (crossbred) and broiler chickens was assessed. Phylogenetic analysis of currently circulating field viruses based on the hemagglutinin (HA) and neuraminidase (NA) gene sequences revealed continuous circulation of G1 lineages containing the tri-basic hemagglutinin cleavage site (HACS) motif (PAKSKR*GLF) at the HA protein. Both the LPAI susceptible Sonali and broiler chickens were infected with selected H9N2 isolates A/chicken/Bangladesh/2458-LT2/2020 or A/chicken/Bangladesh/2465-LT56/2021 using intranasal (100 µL) and intraocular (1...
For rapid and sensitive pathogen screening from field outbreaks, molecular techniques such as qPC... more For rapid and sensitive pathogen screening from field outbreaks, molecular techniques such as qPCR-based simultaneous detections are efficient. Respiratory diseases are the most detrimental diseases to the poultry industry and need to be addressed because of their major economic losses. In the current study, we have applied two different detection assays: one for simultaneous detection of avian influenza virus (AIV; M gene) and subtyping (H5, N1, H9, N2) using TaqMan probe chemistry (TaqMan multitarget) and another for simultaneous detection of Newcastle disease virus (NDV), infectious bronchitis virus (IBV), and infectious laryngotracheitis virus (ILTV) using SYBR Green chemistry (SYBR Green multitarget). Two individual qPCRs were conducted for the detection of four pathogens. Surveillance of tissue (n = 158) and oropharyngeal swab (206) samples from multiple poultry flocks during the years April 2020–July 2022 applying the TaqMan and SYBR Green multitarget qPCRs revealed that 48.9...
The Journal of Infection in Developing Countries, 2022
Introduction: Peste des petits ruminants (PPR) is an important transboundary animal disease of sm... more Introduction: Peste des petits ruminants (PPR) is an important transboundary animal disease of small ruminants which causes serious damage to the livelihood and food security of millions of small-scale farmers. PPR is endemic in goats in Bangladesh since 1993. The aim of this study was to determine the seroprevalence of PPR in sheep, cattle, and buffaloes in Bangladesh. Methodology: A total of 434 blood samples from sheep (n = 100), cattle (n = 190) and buffalo (n = 144) were collected aseptically. Sera were separated and antibody titer was determined using a commercially available c-ELISA kit. Results: The overall seroprevalence was 16% and 3.68% in sheep and cattle, respectively, while buffaloes had a considerably higher seroprevalence of 42.36%. The study suggests that buffaloes are more prone to the PPR virus (PPRV) infection and cattle. Conclusions: This study provides serological evidence of PPRV infection in cattle and buffaloes. These results may warrant further studies to f...
Mycoplasma gallisepticum is considered to be the most important pathogenic Mycoplasma sp. and occ... more Mycoplasma gallisepticum is considered to be the most important pathogenic Mycoplasma sp. and occurs world-wide. For effective control of mycoplasmosis, early diagnosis is the cornerstone, but the cultural method is laborious, expensive and timeconsuming, whereas agglutination test is easy to perform in field conditions and cheaper. Mycoplasma gallisepticum was isolated and two types of stained antigen produced. The antigen produced distinct tiny clumps with positive antisera of Mycoplasma spp. The slide agglutination system was sensitive, reliable and cheap. This method may be used to screen Mycoplasma infections in poultry farms.DOI: http://dx.doi.org/10.3329/bvet.v28i2.10688Bangl. vet. 2011. Vol. 28, No. 2, 80 84
Egg Drop Syndrome-76 (EDS-76), a viral disease caused by EDS-76 virus or Duck adenovirus A, is a ... more Egg Drop Syndrome-76 (EDS-76), a viral disease caused by EDS-76 virus or Duck adenovirus A, is a major cause of drop in egg production in breeder and layer flocks with severe economic losses. Poultry farms in Bangladesh occasionally experience outbreaks of EDS-76. For adoption of a polymerase chain reaction (PCR) for detection of EDS -76 virus, a local isolate of the virus was propagated in 10 days old embryonated duck eggs after inoculation through allantoic route. The presence of EDS-76 virus in the allantoic fluid was reconfirmed by hemagglutination (HA) and hemagglutination inhibition (HI) test using chicken red blood cells and hyperimmune anti-EDS-76 virus antiserum. Then a PCR was successfully applied to amplify 238 bp fragments from the EDS-76 virus genome. The PCR product was sequenced. Blast search in the GenBank revealed that the PCR product represents a genome fragment that lies in the non-coding region between the 100K protein and pVIII genes of EDS-76 virus.
Dhaka Zoo with 2000 animal heads of 184 species from significant genetic diversity and five milli... more Dhaka Zoo with 2000 animal heads of 184 species from significant genetic diversity and five million visitors influx round the year is placing it a public health important spot. This study was conducted to investigate blastomycosis in animals at Dhaka Zoo to ascertain animal health, welfare and public health safety standard. One hundred and two necropsied tissue samples preserved in 10% neutral buffered formalin at necropsy from 36 animals of 25 different species were collected from Dhaka Zoo. Twenty five out of 36 study animals were suffering from granulomatous diseases. Among them three animals were found suffering from blastomycosis. Clinical history, nodular lesions from necropsy findings, granulomatous reactions with fungal spores on histopathology and spherical yeast cells with double contoured wall and broad base budding on special staining were used for the confirmation of blastomycosis in spotted deer (Cervus axis/Axis axis), nilgai (Boselaphustragocamelus) and horse (Equus...
Newcastle disease (ND) is endemic in Bangladesh. Locally produced or imported live Newcastle dise... more Newcastle disease (ND) is endemic in Bangladesh. Locally produced or imported live Newcastle disease virus (NDV) vaccines based on lentogenic virus strains, locally produced live vaccines of the mesogenic Mukteswar strain, as well as imported inactivated vaccines of lentogenic strains, are being used in Bangladesh under different vaccination regimens. Despite these vaccinations, frequent outbreaks of ND are being reported in Bangladesh. Here we compared the efficacy of booster immunization with three different vaccines in chickens that had been primed with two doses of live LaSota vaccine. A total of 30 birds (Group A) were primed with two doses of live LaSota virus (genotype II) vaccine at days 7 and 28, while 20 birds (Group B) remained unvaccinated. At day 60, birds of Group A were divided into three sub-groups, which received booster immunizations with three different vaccines; A1: live LaSota vaccine, A2: inactivated LaSota vaccine, and A3: inactivated genotype XIII.2 vaccine (...
Genetic characterization may provide useful insights into severe acute respiratory coronavirus 2 ... more Genetic characterization may provide useful insights into severe acute respiratory coronavirus 2 (SARS CoV 2) circulating in Bangladesh. Here we analyzed the SARS Cov 2 positive 41 nasopharyngeal samples collected in lysis buffer obtained at different regional national laboratories of Bangladesh during July – December 2020. Full length spike gene was amplified and SARS CoV 2 was confirmed upon Sanger sequencing. Multiple ClustalW alignment and phylogenetic study of 15 strains showed that genetically diverse SARS CoV 2 is circulating in the country where 80 documented and 55 novel substitutions have been observed in different regions of spike glycoprotein. Major mutations and/or deletions was identified at conserved amino acid positions that are functionally linked to host transition, antigenic drift, host surface receptor binding or antibody recognition sites, and viral oligomerization interfaces that may have significant effects on pathogenic capacity and epidemiological signatures.
Virus evolution and mutation analyses are crucial for tracing virus transmission, the potential v... more Virus evolution and mutation analyses are crucial for tracing virus transmission, the potential variants, and other pathogenic determinants. Despite continuing circulation of the SARS-CoV-2, very limited studies have been conducted on genetic evolutionary analysis of the virus in Bangladesh. In this study, a total of 791 complete genome sequences of SARS-CoV-2 from Bangladesh deposited in the GISAID database during March 2020 to January 2021 were analyzed. Phylogenetic analysis revealed circulation of seven GISAID clades G, GH, GR, GRY, L, O, and S or five Nextstrain clades 20A, 20B, 20C, 19A, and 19B in the country during the study period. The GISAID clade GR or the Nextstrain clade 20B or lineage B.1.1.25 is predominant in Bangladesh and closely related to the sequences from India, USA, Canada, UK, and Italy. The GR clade or B.1.1.25 lineage is likely to be responsible for the widespread community transmission of SARS-CoV-2 in the country during the first wave of infection. Signif...
Avian influenza virus (AIV) remains a huge challenge for poultry production with negative repercu... more Avian influenza virus (AIV) remains a huge challenge for poultry production with negative repercussions for micro- and macro-economy and public health in Bangladesh. High (HP) H5N1 and low pathogenicity (LP) H9N2 AIV are currently endemic in poultry, and both have been reported to infect humans sporadically. Multiple virus introductions of different clades of HPAIV H5N1, reassorted genotypes, and on-going diversification of LPAIV H9N2 create a highly volatile virological environment which potentially implicates increased virulence, adaptation to new host species, and subsequent zoonotic transmission. Allotropy of poultry rearing systems and supply chains further increase the risk of virus spreading, which leads to human exposure and fosters the emergence of new potentially pre-pandemic virus strains. Here, we review the epidemiology, focusing on (i) risk factors for virus spreading, (ii) viral genetic evolution, and (iii) options for AIV control in Bangladesh. It is concluded that i...
Newcastle disease (ND) is endemic in poultry in Bangladesh. We performed genotypic and pathotypic... more Newcastle disease (ND) is endemic in poultry in Bangladesh. We performed genotypic and pathotypic characterization of four ND virus (NDV) isolates from recent outbreaks in broiler chickens in Bangladesh during the period of 2020–2021. Phylogenetic analysis based on the complete fusion protein gene coding sequences classified the viruses into NDV class II genotype VII.2 together with viruses from Indonesia isolated between 2014 and 2021 and a single 2020 Indian isolate. Pathogenicity testing using the intracerebral pathogenicity index in day-old chickens and mean embryo death time in embryonating chicken eggs revealed that the Bangladeshi isolates are velogenic. Inoculation of 35-day-old chickens with two NDV isolates (LT67 and N5) resulted in 100% morbidity by 3 days post inoculation (DPI), and all birds succumbed to infection by 7 DPI. Massive hemorrhages, congestion and necrotic lesions were observed in different visceral organs, which were typical for infection with a velogenic v...
Lumpy skin disease (LSD) emerged in Bangladesh in mid-2019, leading to great economic losses for ... more Lumpy skin disease (LSD) emerged in Bangladesh in mid-2019, leading to great economic losses for cattle farmers. This study describes the recent occurrence of the LSDV in Bangladesh and examines the clinical manifestation of the disease in local cattle breeds, characteristic epidemiological features, and pathological findings in affected animals. In addition, a full-genome sequencing of two local LSDV isolates was carried out. A total of 565 animals from 88 households were investigated, and 165 samples (skin lesions, saliva, nasal discharge, feces, and milk) were collected for virus detection. Pathology and immunohistochemistry were performed on nodule biopsies. Fever, nodular skin lesions, and swelling of the joints were the most common clinical manifestations. Skin lesions had a higher concentration of viral DNA compared to other sample types and were therefore selected for virus isolation and characterization. Pathology of the LSD skin nodules comprised a granulomatous reaction i...
An in-depth knowledge of the molecular evolution of the peste des petits ruminants virus (PPRV) i... more An in-depth knowledge of the molecular evolution of the peste des petits ruminants virus (PPRV) is critical for the success of the current global eradication program. For this reason, a molecular evolutionary analysis of PPRVs circulating in Bangladesh over a decade (2008-2020) was performed. The complete genome sequencing of three PPRV isolates from 2008 (BD2), 2015 (BD12) and 2017 (BD17) as well as full length nucleocapsid (N), matrix (M) and fusion (F) gene sequencing of seven more samples from 2015 to 2020 was performed. Phylogenetic analysis classified all ten PPRVs from Bangladesh as members of lineage IV and showed that they were closely related to PPRV strains detected in China and Tibet during 2007-2008, and India during 2014-2018. Time scale Bayesian Maximum Clade Credibility (MCC) phylogenetic analysis of the three complete genomes revealed a mean Time to Most Recent Common Ancestor (TMRCA) of 2000. Comparative deduced amino acid residue analysis at various functional motifs of PPRVs related to virus structure and function, virulence and host adaptation, receptor binding sites and polymerase activity revealed conserved residues among the PPRVs from Bangladesh. In total sixteen epitopes were predicted from four immunogenic proteins i.e. N, M, F and haemagglutinin (H). Interestingly, the predicted epitopes from the N and M proteins shared conserved epitopes with two vaccine strains currently being used, indicating that the strains from Bangladesh could be potentially used as alternative local vaccines.
Background: Specialized freeze-drying process is being used in the field for different thermostab... more Background: Specialized freeze-drying process is being used in the field for different thermostable vaccine preparation worldwide. The thermostability remains only in undiluted conditions. If dilution is made at the morning and used for the whole day, the vaccine efficacy is compromised at high ambient temperature. In this study, trehalose based specialized vaccine diluent was used to improve the stability of Peste des Petits Ruminants (PPR) vaccine in diluted condition. Methods: The available PPR vaccine was reconstituted with conventional diluent and with trehalose based test diluent. The diluted vaccine was kept at ambient temperature without maintaining any cool chain. Stability of diluted vaccine virus was further assessed in vivo and in vitro at different temperatures. Goats were vaccinated and Vero cells were infected with reconstituted vaccines and were assessed at 0, 3, 6, 9 and 24 hours post dilution. Antibody titer was measured and virus infectivity titer was determined i...
A total of 15 dead or sick birds from 13 clinical outbreaks of avian influenza in ducks, geese, c... more A total of 15 dead or sick birds from 13 clinical outbreaks of avian influenza in ducks, geese, chickens and turkeys in 2017 in Bangladesh were examined. The presence of H5N1 influenza A virus in the affected birds was detected by RT-PCR. Phylogenetic analysis based on full-length gene sequences of all eight gene segments revealed that these recent outbreaks were caused by a new reassortant of clade 2.3.2.1a H5N1 virus, which had been detected earlier in 2015 during surveillance in live bird markets (LBMs) and wet lands. This reassortant virus acquired PB2, PB1, PA, NP and NS genes from low pathogenic avian influenza viruses mostly of non-H9N2 subtypes but retained HA, NA and M genes of the old clade 2.3.2.1a viruses. Nevertheless, the HA gene of these new viruses was 2.7% divergent from that of the old clade 2.3.2.1a viruses circulated in Bangladesh. Interestingly, similar reassortment events could be traced back in four 2.3.2.1a virus isolates of 2013 from backyard ducks. It suggests that this reassortant virus emerged in 2013, which took two years to be detected at a broader scale (i.e. in LBMs), another two years until it became widely spread in poultry and fully replaced the old viruses. Several mutations were detected in the recent Bangladeshi isolates, which are likely to influence possible phenotypic alterations such as increased mammalian adaptation, reduced susceptibility to antiviral agents and reduced host antiviral response.
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