Multidrug resistant (MDR) Salmonella are a leading cause of foodborne diseases and serious human health concerns worldwide. In this study we detected MDR Salmonella in broiler chicken along with the resistance genes and class 1 integron gene intl1. A total of 100 samples were collected from broiler farms comprising 50 cloacal swabs, 35 litter and 15 feed samples. Overall prevalence of Salmonella was 35% with the highest detected in cloacal swabs. Among the Salmonella, 30 isolates were confirmed as S. enterica serovar Typhimurium using molecular methods of PCR. Disk diffusion susceptibility test revealed that all the Salmonella were classified as MDR with the highest resistance to tetracycline (97.14%), chloramphenicol (94.28%), ampicillin (82.85%) and streptomycin (77.14%). The most prevalent resistance genotypes were tetA (97.14%), floR (94.28%), blaTEM-1 (82.85%) and aadA1 (77.14%). In addition, among the MDR Salmonella, 20% were positive for class 1 integron gene (intl1). As far as we know, this is the first study describing the molecular basis of antibiotic resistance in MDR Salmonella from broiler farms in Bangladesh. In addition to tetA, floR, blaTEM-1, aadA1 and intl1 were also detected in the isolated MDR Salmonella. The detection of MDR Salmonella in broiler chicken carrying intl1 is of serious public health concern because of their zoonotic nature and possibilities to enter into the food chain.

This study was conducted to evaluate the zoonotic gastrointestinal parasitic infections in cattle at Sirajganj district of Bangladesh during the period from February, 2016 to November, 2016 by coproscopy examination. A total of 150 fecal samples of cattle were collected from the study areas, which examined and found 41 (27.33%) were positive for gastrointestinal parasitic infections that has zoonotic importance. The prevalence of parasitic infection was significantly higher in female (33.7%) than in males (19. 4%). The prevalence of parasite was recorded higher in cross breed than in indigenous cattle which are statistically significant (p≤0.05). In case of age groups, the highest rate of infection was observed in adult of >1 years (28.5%) and the lowest in calves aged ≤1 year (25.4%). Moreover, the prevalence of gastrointestinal parasites were higher in poor body conditioned cattle (36.3%) than that of malnourished (34%) and healthy cattle (22.4%). In case of management system, the prevalence of parasitic infections was higher in cattle reared in free range (40.0%) than cattle reared in semi-intensive (28.5%) and intensive system (25.5%). Furthermore, parasitic infections were higher in summer (36.5%) followed by winter season (25.5%) and rainy season (15.7%). A significant correlation (P=0.00) has been found between diarrheic non-diarrhea cattle. Finally, prevalence was significantly (P=0.02) higher in cattle with no previous history of anthelmintic use. From this study, it is concluded that gastrointestinal parasitic infection is a major threat to cattle health and production at Sirajganj district irrespective of age, sex, management system, breed, season, diarrheic and anthelmintic usage.

Drug residues in poultry and poultry products are becoming an alarming or burning concern for public health because of improper use of drugs/feed additive, or failure to observe drug withdrawal period, non-existence of restrictive legislation and lack of consumer awareness in the poultry industry. The declared withdrawal periods and safe level/tolerance level of any antibiotics will be stay in same points. The aim of the study was to validate the declared withdrawal periods and to see whether there is any alteration of these declared withdrawal periods that farmers are practicing in in-situ and ex-situ condition in Bangladesh context. For this, a total of 2100 broilers and 2100 eggs were collected from different markets of poultry rich area in seven divisions of Bangladesh. Seven different drugs such as Enrofloxacin, Oxytetracycline, Ciprofloxacin, Sulfonamide, Cloramphenical, Gentamycin, Furazolidone were used as Maximum Residue Limit (MRL). In case of Enrofloxacin, Ciprofloxacin and Sulfonamides residues persist in broiler meat after the declared withdrawal periods, on the other hand Oxytetracycline, Cloramphenical and Gentamycin maintains the withdrawal period as per stated but the Furazolidone disappears for broiler meat before the declared withdrawal periods. It was found that 55% poultry samples remain above MRL during 1-3 interval period's in the validation of withdrawal period indicates not safe for human health. It can be concluded that lack of observation of withdrawal period might be a common practice given the high level of antibiotics in the poultry farm of Bangladesh.

Milk is highly vulnerable to microbial contamination and consequently is easily perishable. The aim of the present study was microbial analysis of raw and pasteurized milk. For this, a total of 32 milk samples (12 from raw milk and 20 from pasteurized milk) were collected from 8 sources. Among them three were raw (R1 to R3) sources and rest five were pasteurized milk (P1 to P5) sources. Each of the collected samples was investigated during the period from May to December, 2012. All milk samples were subjected to total viable count (TVC), total coliform count (TCC), Total Staphylococcus count (TSC) and Gram’s staining to determine the loads of microbes in raw and pasteurized milk. Total viable counts (TVC) range of 12 raw milk samples (R, R2 and R3) were 1.3 x106 to 7.4 x105 cfu/ml. The presence of Escherichia coli in the raw milk samples were from 2.3 x102 to 9.4 x102 cfu/ml, but the presence of Staphylococcus were from 5.9 x102 to 7.9 x102 cfu/ml. Whereas, the range of TVC for five brands of pasteurized milk (P1, P2, P3, P4, and P5) were from 1.8 x104 to 9.8 x104 cfu/ml, TSC were from 2.8 x10 to 8.6 x102 cfu/ml and TCC from 1.01 x102 to 9.1 x10 cfu/ml. Therefore, it can be concluded that high counts of bacteria were found in raw milk and pasteurized milk. The government therefore should conduct frequent inspection of the marketed milks to check whether they meet the minimum legal standards and should monitor the overall hygienic condition surrounding the production and handling of milk. Realistic standards for the raw milks need to be devised and appropriate training should be given to the raw milk producers in hygienic handling of milk.Asian J. Med. Biol. Res. June 2015, 1(2): 292-296

Mutations in the hepatitis B virus (HBV) genome can potentially lead to vaccination failure, diagnostic escape, and disease progression. However, there are no reports on viral gene expression and large hepatitis B surface antigen (HBsAg) antigenicity alterations due to mutations in HBV isolated from a Bangladeshi population. Here, we sequenced the full genome of the HBV isolated from a clinically infected patient in Bangladesh. The open reading frames (ORFs) (P, S, C, and X) of the isolated HBV strain were successfully amplified and cloned into a mammalian expression vector. The HBV isolate was identified as genotype C (sub-genotype C2), serotype adr, and evolutionarily related to strains isolated in Indonesia, Malaysia, and China. Clinically significant mutations, such as preS1 C2964A, reverse transcriptase domain I91L, and small HBsAg N3S, were identified. The viral P, S, C, and X genes were expressed in HEK-293T and HepG2 cells by transient transfection with a native subcellular distribution pattern analyzed by immunofluorescence assay. Western blotting of large HBsAg using preS1 antibody showed no staining, and preS1 ELISA showed a significant reduction in reactivity due to amino acid mutations. This mutated preS1 sequence has been identified in several Asian countries. To our knowledge, this is the first report investigating changes in large HBsAg antigenicity due to preS1 mutations.

Fasciolosis is an economically important parasitic disease of cattle in Bangladesh. The aim of the study was to determine the prevalence of fasciolosis in cattle and identifying the potential risk factors associated with the disease. A cross-sectional survey was carried out from November 2012 to October 2013 on bovine fasciolosis in and around Shahjadpur upazila of Bangladesh. For this, a total of 762 fecal samples were collected from crossed breed cattle and all samples were subjected to standard sedimentation test at Animal Health Laboratory of BLRI regional station, Shahjadpur, Bangladesh. The overall prevalence of bovine fasciolosis was found to be 66.14% from 504 positive samples. From the various risk factor analysed, age categories of cattle, sex and seasonal influence were found to be significantly associated (p<0.01) with the prevalence of bovine fasciolosis. When considered the relationship with sex, it was observed that female (70.3%) cattle had significantly (p<0.01) higher than male (55.23%). As regards to age, bovine fasciolosis was significantly (p<0.01) higher in old cattle (76.43%) compared to adult (68.69%) and young (48.62%). The seasonal influence of outbreak of this disease was significantly (p<0.01) higher in summer season (72.44%) followed by winter (67.75%) and rainy season (58.55%). It can be concluded that these risk factors need to be taken in consideration when designing effective fasciolosis control management system for cattle in Bangladesh.

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A cell-culture-adapted reverse genetics strain of very virulent infectious bursal disease virus (IBDV) of chickens, designated as BD-3tcC, having four amino acid substitutions (Gln253His, Asp279Asn, Ala284Thr and Ser330Arg) in the capsid protein VP2 was tested for its genetic stability during serial passage in chickens and chicken embryo fibroblast (CEF) cell culture. Results of in vitro and in vivo experiments demonstrated that all four introduced mutations in BD-3tcC remained stable during serial passage in CEF cell culture, but during passage in chickens, amino acid residues at position 253 and 284 reverted from histidine to glutamine and threonine to alanine, respectively. In a parallel experiment, the same substitutions also occurred in a conventionally attenuated vaccine strain D-78 on serial passage in chickens. However, no reversion or substitution took place at positions 279 and 330 during in vivo passage of the mutant virus BD-3tcC or vaccine virus D-78. The findings provide conclusive evidence that while IBDV requires histidine and threonine at positions 253 and 284 for cell culture adaptation, glutamine and alanine at these positions are selected preferentially during in vivo replication.