Most humans are in contact with animals in a way or another. A zoonotic disease is a disease or infection that can be transmitted naturally from vertebrate animals to humans or from humans to vertebrate animals. More than 60% of human pathogens are zoonotic in origin. This includes a wide variety of bacteria, viruses, fungi, protozoa, parasites, and other pathogens. Factors such as climate change, urbanization, animal migration and trade, travel and tourism, vector biology, anthropogenic factors, and natural factors have greatly influenced the emergence, re-emergence, distribution, and patterns of zoonoses. As time goes on, there are more emerging and re-emerging zoonotic diseases. In this review, we reviewed the etiology of major zoonotic diseases, their impact on human health, and control measures for better management. We also highlighted COVID-19, a newly emerging zoonotic disease of likely bat origin that has affected millions of humans along with devastating global consequences. The implementation of One Health measures is highly recommended for the effective prevention and control of possible zoonosis.

Diseases caused by Escherichia coli (E. coli) and Salmonella spp. can negatively impact turkey farming. The aim of this study was to isolate and characterize multidrug-resistant (MDR) E. coli and Salmonella spp. in healthy and diseased turkeys. A total of 30 fecal samples from healthy turkeys and 25 intestinal samples from diseased turkeys that died of enteritis were collected. Bacterial isolation and identification were based on biochemical properties and polymerase chain reaction (PCR). Antibiogram profiles were determined by disk diffusion. The tetracycline-resistance gene tetA was detected by PCR. All samples were positive for E. coli. Only 11 samples (11/30; 36.67%) were positive for Salmonella spp. from healthy turkeys, whereas 16 (16/25; 64%) samples were positive for Salmonella spp. from diseased turkeys. E. coli isolated from diseased turkeys showed higher resistance to levofloxacin, gentamicin, chloramphenicol, ciprofloxacin, streptomycin, and tetracycline. Salmonella spp. isolated from healthy turkeys exhibited higher resistance to gentamicin, chloramphenicol, ciprofloxacin, streptomycin, imipenem, and meropenem. All E. coli and Salmonella spp. from both healthy and diseased turkeys were resistant to erythromycin. Salmonella spp. from both healthy and diseased turkeys were resistant to tetracycline. Multidrug resistance was observed in both E. coli and Salmonella spp. from diseased turkeys. Finally, the tetA gene was detected in 93.1% of the E. coli isolates and in 92.59% of the Salmonella spp. isolates. To the best of our knowledge, this is the first study to isolate and characterize tetA-gene-containing MDR E. coli and Salmonella spp. from healthy and diseased turkeys in Bangladesh. Both microorganisms are of zoonotic significance and represent a significant public health challenge.

Virulent and multi drug resistant (MDR) Salmonellaenterica is a foremost cause of foodborne diseases and had serious public health concern globally. The present study was undertaken to identify the pathogenicity and antimicrobial resistance (AMR) profiles of Salmonellaenterica serovars recovered from chicken at wet markets in Dhaka, Bangladesh. A total of 870 cecal contents of broiler, sonali, and native chickens were collected from 29 wet markets. The overall prevalence of S. Typhimurium, S. Enteritidis, and untyped Salmonella spp., were found to be 3.67%, 0.57%, and 1.95% respectively. All isolates were screened by polymerase chain reaction (PCR) for eight virulence genes, namely invA, agfA, IpfA, hilA, sivH, sefA, sopE, and spvC. S. Enteritidis isolates carried all virulence genes whilst S. Typhimurium isolates carried six virulence genes except sefA and spvC. A diverse phenotypic and genotypic AMR pattern was found. Harmonic descending trends of resistance patterns were observed among the broiler, sonali, and native chickens. Interestingly, virulent and MDR Salmonella enterica serovars were found in native chicken, although antimicrobials were not used in their production cycle. The research findings anticipate that virulent and MDR Salmonella enterica are roaming in the wet markets which can easily anchor to the vendor, consumers, and in the food chain.

The aim of the present study was to detect the pathogenic Escherichia coli (E. coli) through pathological study of the colibacillosis affected birds. These isolated E. coli were further confirmed by PCR using specific primer. For this purpose, a total of 20 swabs (10 from lung and 10 from intestine of 10 dead birds) were collected in sterile nutrient broth. The histopathological samples were collected in 10% buffered neutral formalin. The used methods were histopathology, isolation and identification of E. coli by conventional methods and as well as by PCR method. A total of 10 isolates of E. coli from 20 swabs of lung and intestine was characterized by conventional routine methods of bacteriology. Gross pathological lesions of all lungs in the present investigation were congested and consolidated. Duodenum showed congestion and hemorrhages with excess mucus in the luminal surface of it. Microscopically, all the lungs showed severe congestion, infiltration of heterophils, macrophages and lymphocytes in the wall of bronchus as well as in the peribronchial alveoli. E. coli infected all the duodenum showed severe infiltration of leukocytes mainly heterophils, lymphocytes and macrophages in the submucosa of the duodenal wall. In this study, DNA of 8 isolates out of 10 isolated E. coli organisms was amplified by PCR using ECO-f and ECO-r primer targeting 16S ribosomal DNA and found 585 bp amplicon which is specific for E. coli with enteroinvasive type confirmed by histopathological lesions in duodenum. Further investigation should be focused on serotyping and detection of genes of E. coli which are responsible for pathogenicity of the organism.DOI = http://dx.doi.org/10.3329/bjvm.v9i1.11205Bangl. J. Vet. Med. (2011). 9(1): 17-25

E. coli is one of the major significant pathogens causing mastitis, the most complex and costly diseases in the dairy industry worldwide. Present study was undertaken to isolate, detect the virulence factors, phylogroup, antimicrobial susceptibility and antimicrobial resistance genes in E. coli from cows with clinical mastitis. A total of 68 milk samples comprising 53 from clinical mastitis and 15 from apparently healthy cattle were collected from four different established dairy farms in Bangladesh. E. coli was isolated from the milk samples and identified by PCR targeting malB gene and sequencing of 16S rRNA gene. E. coli isolates were screened by PCR for the detection of major virulence genes ( stx , eae and cdt ) of diarrheagenic E. coli followed by phylogenetic grouping. Antimicrobial susceptibility of the E. coli isolates was determined by disk diffusion test and E. coli showing resistance was further screened for the presence of antimicrobial resistance genes. E. coli was isolated from 35.8% of the mastitis milk samples but none from the apparently healthy cattle milk. All the E. coli isolates were negative for stx , eae and cdt genes and belonged to the phylogenetic groups A and B1 which comprising of commensal E. coli . Antibiotic sensitivity testing revealed 84.2% (16/19) of the isolates as multidrug resistant. Highest resistance was observed against amoxicillin (94.5%) followed by ampicillin (89.5%) and tetracycline (89.5%). E. coli were found resistant against all the classes of antimicrobials used at the farm level. Tetracycline resistance gene ( tetA ) was detected in 100% of the tetracycline resistant E. coli and bla TEM-1 was present in 38.9% of the E. coli isolates. Findings of this study indicate a potential threat of developing antimicrobial resistance in commensal E. coli and their association with clinical mastitis. Occurrence of multidrug resistant E. coli might be responsible for the failure of antibiotic therapies in clinical mastitis as well as pose potential threat of transmitting and development of antibiotic resistance in human.

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The prevalence of gastrointestinal helminth parasites and the gross pathological lesions produced by them in different types of poultry were studied from March 2005 to March 2006, in the Department of Parasitology, Bangladesh Agricultural University, Mymensingh. In this study, 240 viscera of three types of poultry such as broiler, layer and backyard indigenous chickens were collected from local markets of Mymensingh district. During routine examination, total six species of helminth parasites were recorded, of which three species were nematodes such as Ascaridia galli, Heterakis gallinarum and Capillaria annulata; two species were cestodes such as Raillietina tetragona and Amoebotaenia sphenoides and only one species was belonged to trematode such as Catatropis verrucosa. Prevalence of different species of gastrointestinal helminths was highest in backyard poultry (100%) followed by layer (48.75%) and broiler (3.75%) which was statistically significant (p < 0.01). Backyard poultry was significantly (p < 0.05) 168.21 and 4106.67 times more susceptible to helminth infection than layer and broiler respectively. But layer was 24.41 times more susceptible to helminth infection than broiler. In backyard poultry, all six species of helminth parasites were found. A statistically significant (p < 0.05) variation in the prevalence of the recovered parasites from backyard poultry were observed such as the prevalence of R. tetragona (100%) was the highest followed by that of A. galli (87.50%) and H. gallinarum (80%). From the odds ratio of the recovered parasites, it was observed that chance of developing R. tetragona (odds ratio 189.73) in backyard poultry was the highest followed by A. galli (odds ratio 7.51) and H. gallinarum (odds ratio 4.04). In case of layer, only A. galli and R. tetragona were recorded, of which, prevalence of A. galli was the highest (43.75%). In broiler, only A. galli (3.75%) was found. Gross pathological lesions were found only in backyard poultry. Pathological changes were detected in case of A. sphenoides and H. gallinarum infection. In A. sphenoides infection petechial hemorrhages were observed in the mucosa of the duodenum. On the other hand, tiny, white, circumscribed nodules of about 2-3 mm of diameter were found in the caecal mucosa in case of H. gallinarum infection.Results of the present study suggest that the backyard poultry is at the high risk of helminth infection. However, layers are also vulnerable to parasitic infection. So regular deworming is essential both in backyard poultry and layer birds to obtain better production from them.

The study was conducted to isolate and identify E. coli from apparently healthy broilers and layers from different poultry farms adjacent to the Bangladesh Agricultural University, Mymensingh, Bangladesh, during the period of January to May 2006 and characterize their ability to produce enterotoxin and also the antibiogram of the isolates. A total of 110 fecal samples were collected from broiler (n=55) and layer (n=55) chickens. E. coli were isolated and identified by cultural, biochemical, motility test and the heat-stable toxins were determined by Infant Mouse Assay (IMA). In case of broilers, 35 (63.6%) samples were found positive while 31 (56.4%) from layers. The overall prevalence of E. coli was 60%. Among the isolates of E. coli, 22.86% isolates from broiler and 38.71% isolates from layer were found positive for their ability to produce enterotoxin based on mice inoculation test. The antibiotic sensitivity pattern showed that the isolates were highly sensitive to chloramphenicol, ciprofloxacin, kenamycin and cephalexin and an increasing trend of resistance was recorded in both broiler and layer isolates. It may be concluded from the results of this study that the high resistance of E. coli to antibiotics constitutes a threat to poultry industry in Bangladesh.