Poultry waste management practices in Bangladesh: Farmer's perceptions, and food and environmental hazards.

Objective: The poultry industry plays a key role in developing socio-economic and health sectors in Bangladesh. Poultry waste is a potential environmental threat as untreated poultry waste is used in vegetable gardens. The study aimed to investigate the current situation of small-scale poultry farms and their waste management practices in selected areas of Bangladesh and detect Escherichia coli and Salmonella in vegetables from farms using untreated poultry waste as fertilizer. Materials and Methods: A structured questionnaire-based survey was conducted in 86 small-scale poultry farms from different upazilas of Mymensingh and Khulna districts. 104 samples, including vegetables, poultry litter, water, and soil, were collected from vegetable gardens, ponds, fields, and wet markets in Mymensingh district to detect microbial contamination. Bacteria were identified based on their growth and colony morphology on selective media and motility tests. The presence of E. coli and Salmonella was confirmed by polymerase chain reaction (PCR) using a commercial PCR kit. Results: The survey revealed that mostly middle-aged males were involved in poultry farming. Most of the farmers had primary education and engaged in farming for about 5 years without training. In the study area, 37% of farmers collected droppings daily in the morning and used them as organic fertilizer. About 58% of farmers did not know the hygienic handlings of droppings and faced health problems. In PCR, either E. coli or Salmonella or both were confirmed in vegetables, litter, soil, and pond water. Conclusion: Appropriate poultry waste management practices can reduce the possible contamination of microbial agents in the human food chain.

A Booster with a Genotype-Matched Inactivated Newcastle Disease Virus (NDV) Vaccine Candidate Provides Better Protection against a Virulent Genotype XIII.2 Virus.

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 (BD-C161/2010 strain from Bangladesh). Two weeks after booster vaccination (at day 74), all vaccinated birds (A1-A3) and half of the unvaccinated birds (B1) were challenged with a genotype XIII.2 virulent NDV (BD-C161/2010). A moderate antibody response was observed after the primary vaccination, which substantially increased after the booster vaccination in all groups. The mean HI titers induced by the inactivated LaSota vaccine (8.0 log2/5.0 log2 with LaSota/BD-C161/2010 HI antigen) and the inactivated BD-C161/2010 vaccine (6.7 log2/6.2 log2 with LaSota/BD-C161/2010 HI antigen) were significantly higher than those induced by the LaSota live booster vaccine (3.6 log2/2.6 log2 with LaSota/BD-C161/2010 HI antigen). Despite the differences in the antibody titers, all chickens (A1-A3) survived the virulent NDV challenge, while all the unvaccinated challenged birds died. Among the vaccinated groups, however, 50% of the chickens in Group A1 (live LaSota booster immunization) shed virus at 5- and 7-days post challenge (dpc), while 20% and 10% of the chickens in Group A2 (inactivated LaSota booster immunization) shed virus at 3 and 5 dpc, respectively, and only one chicken (10%) in Group A3 shed virus at 5 dpc. In conclusion, the genotype-matched inactivated NDV booster vaccine offers complete clinical protection and a significant reduction in virus shedding.

Comparative pathogenicity of a genotype XXI.1.2 pigeon Newcastle disease virus isolate in pigeons and chickens.

Here, we performed molecular and pathogenic characterization of a Newcastle disease virus (NDV) isolate from pigeons in Bangladesh. Molecular phylogenetic analysis based on the complete fusion gene sequences classified the three study isolates into genotype XXI (sub-genotype XXI.1.2) together with recent NDV isolates obtained from pigeons in Pakistan (2014-2018). The Bayesian Markov Chain Monte Carlo analysis revealed that the ancestor of Bangladeshi pigeon NDVs and the viruses from sub-genotype XXI.1.2 existed in the late 1990s. Pathogenicity testing using mean embryo death time pathotyped the viruses as mesogenic, while all isolates carried multiple basic amino acid residues at the fusion protein cleavage site. Experimental infection of chickens and pigeons revealed no or minimum clinical signs in chickens, while a relatively high morbidity (70%) and mortality (60%) were observed in pigeons. The infected pigeons showed extensive and systemic lesions including hemorrhagic and/or vascular changes in the conjunctiva, respiratory and digestive system and brain, and atrophy in the spleen, while only mild congestion in the lungs was noticed in the inoculated chickens. Histologically, consolidation in the lungs with collapsed alveoli and edema around the blood vessels, hemorrhages in the trachea, severe hemorrhages and congestion, focal aggregation of mononuclear cells, and single hepatocellular necrosis in the liver, severe congestion, multifocal tubular degeneration, and necrosis, as well as mononuclear cell infiltration in the renal parenchyma, encephalomalacia with severe neuronal necrosis with neuronophagia were noticed in the brain in infected pigeons. In contrast, only slight congestion was found in lungs of the infected chickens. qRT-PCR revealed the replication of the virus in both pigeons and chickens; however, higher viral RNA loads were observed in oropharyngeal and cloacal swabs, respiratory tissues, and spleen of infected pigeons than the chickens. In conclusion, genotype XXI.1.2 NDVs are circulating in the pigeon population of Bangladesh since 1990s, produce high mortality in pigeons with pneumonia, hepatocellular necrosis, renal tubular degeneration, and neuronal necrosis in pigeons, and may infect chickens without overt signs of clinical disease and are likely to shed viruses via the oral or cloacal routes.

Experimental Pathogenicity of H9N2 Avian Influenza Viruses Harboring a Tri-Basic Hemagglutinin Cleavage Site in Sonali and Broiler Chickens.

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 (100 µL) routes with a dose of 106 EID50/mL. Infected groups (LT_2-So1 and LT_56-So2; LT_2-Br1 and LT_56-Br2) revealed no mortality or clinical signs. However, at gross and histopathological investigation, the trachea, lungs, and intestine of the LT_2-So1 and LT_56-So2 groups displayed mild to moderate hemorrhages, congestion, and inflammation at different dpi. The LT 2-Br1 and LT 56-Br2 broiler groups showed nearly identical changes in the trachea, lungs, and intestine at various dpi, indicating no influence on pathogenicity in the two commercial bird species under study. Overall, the prominent lesions were observed up to 7 dpi and started to disappear at 10 dpi. The H9N2 viruses predominantly replicated in the respiratory tract, and higher titers of virus were shed through the oropharyngeal route than the cloacal route. Finally, this study demonstrated the continuous evolution of tri-basic HACS containing H9N2 viruses in Bangladesh with a low-pathogenic phenotype causing mild to moderate tracheitis, pneumonia, and enteritis in Sonali and commercial broiler chickens.

The First Report of a Virulent Newcastle Disease Virus of Genotype VII.2 Causing Outbreaks in Chickens in Bangladesh.

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 viscerotropic pathotype of NDV. At microscopic examination, tracheitis, severe pneumonia, focal proventriculitis, transmural enteritis, focal myocarditis, severe congestion and necrosis in kidneys, and lymphoid depletion in lymphoid tissues were found. Our study reports the first outbreak of the panzootic genotype VII.2 NDV in poultry in Bangladesh and documents a possible recent re-introduction of this NDV genotype from Southeast or East Asia. This study further provides viral distribution and epidemiological data that can facilitate the effective control of NDV.

Investigation of respiratory disease outbreaks of poultry in Bangladesh using two real-time PCR-based simultaneous detection assays.

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% of samples were positive for respiratory infections, of which 17.2% were positive for NDV, 25.5% were positive for AIV, 9.9% were positive for IBV, and only a single positive (0.3%) for ILTV. Among the AIV, 35% were highly pathogenic subtype H5N1 and 65% were low pathogenic subtype H9N2. Co-infections of 2-3 respiratory viruses were also accurately detected. Respiratory viral pathogens are quite common in Bangladeshi poultry and can be successfully detected using multitarget simultaneous real-time quantitative polymerase chain reaction (RT-qPCR) assays like those adopted in the current study. Increased mass surveillance, along with the molecular characterization of the circulating respiratory viruses, is crucial to control the epidemic and subsequently save the Bangladeshi poultry industry.

Clinical Epidemiology, Pathology, and Molecular Investigation of Lumpy Skin Disease Outbreaks in Bangladesh during 2020-2021 Indicate the Re-Emergence of an Old African Strain.

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 in the dermis and hypodermis that extended to the surrounding tissues. Development of the skin lesions started with swelling of keratinocytes with cytoplasmic vacuolation, vasculitis, panniculitis, thrombosis, and infarction. Altogether, the LSDV produced transmural, hemorrhagic, necrotizing, proliferative and ulcerative dermatitis. The LSD viral antigen was detected occasionally in the macrophages, epithelial cells, and vascular smooth muscle cells. The complete genome sequence analysis revealed that the two Bangladeshi field strains (BD-V392.1 and BD-V395.1) were distinct from the contemporary field strains and were closely related to the ancestral African Neethling strain. The findings of this study will improve the diagnosis, monitoring, and control of LSD in Bangladesh.

Peste des petits ruminants virus antibodies in domestic large ruminants in Bangladesh.

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 find out the role of large ruminants in transmitting PPRV infection to small ruminants and vice versa and inclusion of all domestic and wild ruminants for regular surveillance program.

Molecular insights into peste des petits ruminants virus identified in Bangladesh between 2008 and 2020.

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.

Circulation of three genotypes and identification of unique mutations in neutralizing epitopes of infectious bronchitis virus in chickens in Bangladesh.

Infectious bronchitis (IB) is a highly contagious respiratory disease caused by a gammacoronavirus that has been circulating for many years in chickens in Bangladesh, resulting in significant economic losses. The aim of this study was to detect and characterize infectious bronchitis virus (IBV) from clinical outbreaks and surveillance samples. Real-time RT-PCR was used to detect IBV in pooled lung and tracheal tissue samples (n = 78), oropharyngeal swabs (n = 19), and pooled fecal samples (n = 13) from live-bird markets. Both respiratory and nephropathogenic forms of IB were suspected at necropsy (n = 7) from clinical outbreaks. Sequencing of hypervariable regions (HVR1-2 and HVR3) of the region of the spike gene (S) encoding the S1 subunit of five isolates revealed circulation of the Mass-like, QX-like, and 4/91-like genotypes of IBV in Bangladesh. Each genotype was extremely variable, as shown by separate clustering of the viruses in a phylogenetic tree and high nucleotide (nt) sequence divergence (38.8-41.2% and 25.7-37.4% in the HVR1-2 and HVR3 sequence, respectively). The unique mutation G65E was observed in each Mass-like isolate, and Y328S was observed in each 4/91-like Bangladeshi isolate. Three neutralizing epitope sites were predicted within the HVRs that differed significantly among the three genotypes. In addition, one Bangladeshi isolate carried fixed mutations at 294F and 306Y, like other pathogenic QX-like IBVs, which could affect epitopes involved in neutralization, facilitating virus circulation among vaccinated flocks. Therefore, continuous screening and genotype characterization will be necessary to track the epidemiology of IBV and control IB infection in Bangladesh.

Molecular Analysis of SARS-CoV-2 Circulating in Bangladesh during 2020 Revealed Lineage Diversity and Potential Mutations.

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. Significant amino acid diversity was observed among Bangladeshi SARS-CoV-2 isolates, where a total of 1023 mutations were detected. In particular, the D614G mutation in the spike protein (S_D614G) was found in 97% of the sequences. However, the introduction of lineage B.1.1.7 (UK variant/S_N501Y) and S_E484K mutation in lineage B.1.1.25 in a few sequences reported in late December 2020 is of particular concern. The wide genomic diversity indicated multiple introductions of SARS-CoV-2 into Bangladesh through various routes. Therefore, a continuous and extensive genome sequence analysis would be necessary to understand the genomic epidemiology of SARS-CoV-2 in Bangladesh.

Controlling Avian Influenza Virus in Bangladesh: Challenges and Recommendations.

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 improved control strategies would profit from the integration of various intervention tools, including effective vaccination, enhanced biosecurity practice, and improved awareness of producers and traders, although widespread household poultry rearing significantly interferes with any such strategies. Nevertheless, continuous surveillance associated with rapid diagnosis and thorough virus characterization is the basis of such strategies.

Co-subsistence of avian influenza virus subtypes of low and high pathogenicity in Bangladesh: Challenges for diagnosis, risk assessment and control.

Endemic co-circulation of potentially zoonotic avian influenza viruses (AIV) of subtypes H5N1 and H9N2 (G1 lineage) in poultry in Bangladesh accelerated diversifying evolution. Two clinical samples from poultry obtained in 2016 yielded five different subtypes (highly pathogenic [HP] H5N1, HP H5N2, HP H7N1, HP H7N2, H9N2) and eight genotypes of AIV by plaque purification. H5 sequences grouped with clade 2.3.2.1a viruses while N1 was related to an older, preceding clade, 2.2.2. The internal genome segments of the plaque-purified viruses originated from clade 2.2.2 of H5N1 or from G1/H9N2 viruses. H9 and N2 segments clustered with contemporary H9N2 strains. In addition, HP H7 sequences were detected for the first time in samples and linked to Pakistani HP H7N3 viruses of 2003. The unexpected findings of mixtures of reassorted HP H5N1 and G1-like H9N2 viruses, which carry genome segments of older clades in association with the detection of HP H7 HA segments calls for confirmation of these results by targeted surveillance in the area of origin of the investigated samples. Hidden niches and obscured transmission pathways may exist that retain or re-introduce genome segments of older viruses or reassortants thereof which causes additional challenges for diagnosis, risk assessment and disease control.

A new reassortant clade 2.3.2.1a H5N1 highly pathogenic avian influenza virus causing recent outbreaks in ducks, geese, chickens and turkeys in Bangladesh.

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.

Review analysis and impact of co-circulating H5N1 and H9N2 avian influenza viruses in Bangladesh.

Almost the full range of 16 haemagglutinin (HA) and nine neuraminidase subtypes of avian influenza viruses (AIVs) has been detected either in waterfowl, land-based poultry or in the environment in Bangladesh. AIV infections in Bangladesh affected a wide range of host species of terrestrial poultry. The highly pathogenic avian influenza (AI) H5N1 and low pathogenic AI H9N2 were found to co-circulate and be well entrenched in the poultry population, which has caused serious damage to the poultry industry since 2007. By reviewing the available scientific literature, the overall situation of AIVs in Bangladesh is discussed. All Bangladeshi (BD) H5N1 and H9N2 AIV sequences available at GenBank were downloaded along with other representative sequences to analyse the genetic diversity among the circulating AIVs in Bangladesh and to compare with the global situation. Three different H5N1 clades, 2.2.2, 2.3.2.1 and 2.3.4.2, have been detected in Bangladesh. Only 2.3.2.1a is still present. The BD LP H9N2 viruses mostly belonged to the H9 G1 lineage but segregated into many branches, and some of these shared internal genes with HP viruses of subtypes H7N3 and H5N1. However, these reassortment events might have taken place before introduction to Bangladesh. Currently, H9N2 viruses continue to evolve their HA cleavage, receptor binding and glycosylation sites. Multiple mutations in the HA gene associated with adaptation to mammalian hosts were also observed. Strict biosecurity at farms and gradual phasing out of live-bird markets could be the key measures to better control AIVs, whereas stamping out is not a practicable option in Bangladesh. Vaccination also could be an additional tool, which however, requires careful planning. Continuous monitoring of AIVs through systematic surveillance and genetic characterisation of the viruses remains a hallmark of AI control.

Gross anatomical study of spleenic length.

The aim of the present study was to establish the standard length of the normal spleen in Bangladeshi people. One hundred and twenty human cadavers of which eighty-seven male and thirty-three female were dissected to remove spleen with associated structures in the morgue of Forensic Medicine Department of Mymensingh Medical College. Collected specimens were tagged with specific identification number, divided into five groups according to age and height of the individual. Gross and fine dissections were carried out after fixing the specimen in 10% formol saline solution. Length of the spleen was measured by measuring tape and expressed in cm and findings of the present study were compared with the findings of national and international studies. This was a cross sectional descriptive study carried out in the Department of Anatomy of Mymensingh Medical College, Mymensingh. The mean length of spleen was maximum as 11.20 cm in male in group C (31-45 years), and as 11.80 cm in female in group B(16-30 years) and mean length of spleen was minimum as 10.06 cm in male and 9.53 cm in female in group A (upto 15 years). Difference between group A and B, A and C, A and D were statistically significant. There were no significant differences in between other groups. According to height of individual the mean length of spleen was maximum 11.42 cm in 165.01 to 180 cm height group and minimum 10.30 cm in 0-120 cm height group which indicate that length of the spleen increases with height of the individual. This was observed that length of the spleen depends on the age, sex and body height of the individual.