Epidemiological assessment of clinical poultry cases through the government veterinary hospital-based passive surveillance system in Bangladesh: a case study

Epidemiological investigation of poultry infectious in Kazakhstan (2021-2024)

Introduction

This study examines the epidemiological dynamics and genetic diversity of major avian infectious diseases in Kazakhstan, including highly pathogenic avian influenza (HPAI), Newcastle disease virus (NDV), and others. Using official data, laboratory diagnostics, and surveys, we identified high prevalence rates and virulent strains, exposing gaps in vaccination coverage and biosecurity practices. Continuous monitoring, improved vaccination strategies, and robust biosecurity measures are essential to reduce disease impact and ensure sustainable poultry farming.

Methods

A cross-sectional study was conducted to assess the prevalence and genetic diversity of major avian infectious diseases in Kazakhstan. Data sources included official reports, laboratory diagnostics (RT-PCR, ELISA, and sequencing), and a survey of veterinary specialists. Serum samples were analyzed to evaluate antibody responses and vaccine efficacy. Genetic and phylogenetic analyses were conducted for key pathogens, while a questionnaire provided insights into farm-level disease control practices.

Results

Analysis of official data recorded 27 outbreaks of avian diseases in Kazakhstan from 2005 to 2023, primarily involving HPAI and NDV. Our research further identified virulent strains such as NDV genotype VII and infectious bursal disease virus (IBDV) variants linked to global lineages. Serological studies revealed widespread exposure to pathogens, including Mycoplasma gallisepticum (MG), Mycoplasma synoviae (MS), chicken anemia virus (CAV), Ornithobacterium rhinotracheale (ORT), and low-pathogenic avian influenza (LPAI) H9, underscoring deficiencies in vaccination coverage. Farm surveys also identified weaknesses in biosecurity measures and inconsistencies in vaccination protocols.

Discussion

The findings underscore the urgent need for enhanced biosecurity measures, standardized vaccination programs, and routine monitoring to mitigate the impact of avian infectious diseases. This integrated approach offers valuable insights to support evidence-based decision-making for effective poultry health management in Kazakhstan.

Knowledge, attitude and practice towards antibiotic use and resistance among the veterinarians in Bangladesh

BACKGROUND

The emergence of antimicrobial resistance is a growing human and animal health concern around the world. When a number of studies have emphasized the Knowledge, Attitude and Practice (KAP) regarding antibiotic use and resistance in humans, little attention has been paid to the veterinary sector. The aim of this study was to understand the KAP towards antibiotic use and resistance among veterinarians in Bangladesh.

METHODS

A cross-sectional online based questionnaire survey was conducted from August to September 2020 among the registered veterinary practitioners. A self-administered Google form questionnaire consisting of 45 questions on knowledge, attitude and practice regarding antibiotic use and resistance was used. For statistical significance test we used Chi-square or Fisher's Exact test and logistic regression for factor analysis.

RESULTS

A total of 208 registered veterinarians participated in this study. The study involved a majority of male participants, constituting 85.1%, while 54.8% of the participants held a Masters degree. Around 52% of the veterinarians were poultry practitioners. All respondents were familiar with antimicrobials. The participants (91.4%) knew that antibiotics cannot cure viral infections, while 97.6% believed that frequent antibiotic prescriptions rendered them less effective. Participants claimed that only they were eligible to prescribe drugs for the treatment of animals, and around 80% disagreed with adding antibiotics with feed/water as a growth promoter in livestock. Of the total participants, 87% believed that a local antimicrobial guideline would be more effective than an international one. A multivariable analysis revealed that male veterinarians have 2.37 times higher knowledge regarding antimicrobial use (AMU) and antimicrobial resistance (AMR) (OR = 2.37, CI = 1.01-5.59, p = 0.05). Veterinarians engaged in government services demonstrated a 2.59 times more favorable attitude towards AMU and AMR (OR = 2.59, CI = 0.99-6.73, p = 0.05). Additionally, respondents aged 31-35 were 0.45 times more likely to exhibit good practices (OR = 0.45, CI = 0.2-1.00, p = 0.05). However, gaps in practices were highlighted in our study, suggesting training deficiencies.

CONCLUSION

The present study, for the first time conducted in Bangladesh, dictates that future interventions like academic courses, workshops, and seminars on antibiotic usage and resistance are needed to facilitate the knowledge, behavior and practice of veterinarians with regard to the rational use of antibiotics.

First Evidence of Fowl Adenovirus Induced Inclusion Body Hepatitis in Chicken in Bangladesh

Background

The livestock sector contributes 1.90% to the GDP in Bangladesh during 2021-22. Poultry is one of the important subsectors struggling with diseases. Fowl adenoviruses (FAdVs) cause numerous diseases resulting in economic losses to the poultry industry worldwide. Several FAdV serotypes cause inclusion body hepatitis in chicken. Although FAdV infection was suspected, there was no confirmatory report from Bangladesh. The study was conducted to investigate the FAdV infection and antibodies in chicken.

Methods

A total of 50 samples, each composed of liver and spleen, were collected from different chickens of Gazipur, Dinajpur, and Panchagarh district. Each location belongs to A, B, and C poultry zones of Bangladesh, respectively. Viruses were detected by real-time PCR and conventional PCR. Blood samples (n = 303) were collected at the beginning and after the recovery from infection and tested by indirect ELISA. Sequencing of PCR products was done for serotyping and phylogenetic analysis.

Results

Clinical signs were observed including anorexia, drowsiness, ruffled feathers, reduced body weight, lack of uniformity, and high mortality (15-25%). Enlarged friable liver with yellow to tan color mottled with the focal soft area, fluid in pericardial sac, swollen and hemorrhagic kidneys, enlarged congested spleen and pancreas, etc. were found on postmortem examination. FAdVs were detected in 90% of the flocks except commercial layer flock from Dinajpur. Three serotypes, namely, 8b (70%), 11 (10%), and 5 (10%) were detected. Anti-FAdV antibody was detected in 80% flocks at the beginning of infection and in 90% of the flocks after recovery from infection. The antibody titer increases significantly (p < 0.05) after recovery from infection. Phylogenetic analysis revealed that the Bangladeshi FAdVs have close identity with viruses from Asia, Europe, and South and North America.

Conclusions

These findings suggested that several introductions of FAdVs were taken place in Bangladesh. To combat the disease, vaccination along with maintenance of biosecurity is essential.

Determinants of Newcastle disease in commercial layer chicken farms in two districts of Bangladesh: A case-control study

Newcastle disease (ND) is a real threat for commercial layer chicken farms in Bangladesh. However, only few studies have focused on exploring the epidemiology of this disease. A case-control study was conducted to identify determinants of Newcastle disease in commercial layer chicken farms in Kishoreganj and Gazipur district of Bangladesh between September 2019 and February 2020. Farms with birds diagnosed as ND positive based on clinical history, clinical signs and postmortem findings were considered as case and farms that did not have such ND positive chickens were the control for this study. Farmers of 56 case farms and 56 control farms were interviewed face to face using a structured questionnaire. The association between Farms’ ND status and determinants was assessed by multivariable logistic regression with backward elimination. In the final model, six variables were found to be associated with the risk for ND outbreak: age of the farmers (Odds Ratio [OR] 0.94; 95% Confidence Interval [CI] 0.87–0.99), distance from the nearest poultry farms (OR = 3.23, 95% CI 1.27–8.39), number of houses in the farms (OR = 3.06, 95% CI 1.06–8.83), surrounding environments (OR = 5.27, 95% CI 1.96–14.20), rearing different aged bird together (OR = 4.76, 95% CI 1.25–18.19), and no isolation of sick birds (OR = 2.85, 95% CI 1.07–7.55). Alteration of these determinants should reduce the ND burden in commercial layer chicken farms.

A Cross-Sectional Seroepidemiological Study on Infectious Bursal Disease in Backyard Chickens in the Mymensingh District of Bangladesh

Infectious bursal disease (IBD) is a highly contagious disease that causes significant economic loss in chickens. A cross-sectional study was conducted in the Mymensingh district of Bangladesh to determine the seroprevalence of IBD virus (IBDV) antibodies in backyard chickens and their association with different epidemiological risk factors. A total of 460 serum samples were randomly collected from backyard chickens that had not been previously vaccinated against IBDV. The collected sera were examined using an enzyme-linked immunosorbent assay (ELISA). Data on epidemiological risk factors were collected through face-to-face interviews with owners and subjected to both uni- and multivariable risk analyses to determine their association with IBDV infection. Using ELISA, the overall seroprevalence of IBDV antibodies in backyard chickens was 83.4% (95% confidence interval: 79.8%-86.6%), among which, a significantly higher seroprevalence was recorded in females (83.4%, 345/350), 4-6 weeks age group (95.3%, 244/256), and unhealthy (95.0%, 57/60) backyard chickens than those of males, other age groups, and healthy chickens, respectively. Furthermore, chickens reared in free-ranging housing systems (93.3%, 280/300) and poor-conditioned houses (98.0%, 147/150) showed a significantly higher seropositivity of IBDV antibodies than those reared in separated housing systems and other hygienic-conditioned houses, respectively. Moreover, compared with their counterparts, a higher but nonsignificant seroprevalence of IBDV antibodies was observed in backyard chickens that were selected from Fulbaria Upazila (88.8%; 80/90) and which were brought from the marketplace (85.7%, 60/70). A higher seropositivity of IBDV antibodies was shown to be statistically associated with various critical epidemiological risk factors, indicating that field strains of IBDV were exposed in backyard chickens and could be readily transferred horizontally. Proper prevention and control methods, villagers' awareness of IBD, and the rapid and widespread use of seroepidemiological investigations could help to reduce the spread of IBDV infection in backyard chickens.

Association of serum C-reactive protein (CRP) and D-dimer concentration on the severity of COVID-19 cases with or without diabetes: a systematic review and meta-analysis

INTRODUCTION

Coronavirus disease (COVID-19) is a highly contagious disease that poses major public health risks. Fewer studies link high CRP and D-dimer levels to severe COVID-19 infection. Therefore, this study investigates the association of serum CRP and D-dimer concentration with COVID-19 severity in diabetic and non-diabetic patients.

AREAS COVERED

Relevant published articles were identified using electronic search engines, such as Google Scholar, PubMed, Springer, Science Direct, and Researchgate. A total of 29 articles reporting on 15,282 patients (4,733 diabetes and 10,549 non-diabetes) were included in this systematic review and meta-analysis. RevMan V5.4, STATA V14 software, and SPSS V25 were used for the meta-analysis. Egger's regression and Begg-Mazumdar's test were used for assessing publication bias. The pooled result of all studies revealed that serum CRP (Standard mean difference (SMD) 0.41 mg/L; P < 0.0001; I2 93%) and D-dimer (SMD 0.32 mg/L; P < 0.0001; I2 83%) concentration was significantly higher in COVID-19 diabetic patients. The prevalence of COVID-19 infection was comparatively higher in male diabetic patients (OR 2.41; P < 0.00001; I2 88%). There was no publication bias. CRP and D-dimer rose with age in COVID-19 diabetic and non-diabetic patients.

EXPERT OPINION

Overall, the serum CRP and D-dimer concentration in COVID-19 diabetic patients was significantly higher than non-diabetic patients indicating severe illness.

Dietary supplementation of Bacillus-based probiotics on the growth performance, gut morphology, intestinal microbiota and immune response in low biosecurity broiler chickens

A feeding trial was conducted to evaluate the effects of Bacillus-based probiotics on growth performance, intestinal histo-morphology, gut microbial population and immune response in broilers. A total of 2000 Hubbard Classic day-old chicks were randomly enrolled in four experimental groups and 4 replicates of 500 birds in each group, and reared for 35 days under a low- level of biosecurity measures. The trial groups were assigned treatment-1 (T1): basal diet(control), treatment-2 (T2): basal diet plus Bacillus licheniformis (DSM17236), treatment-3 (T3): basal diet plus Bacillus subtilis (PB6), and treatment-4 (T4) basal diet plus 4% Flavomycin. All four groups were fed with maize-soybean based prepared feeds (starter, grower and finisher). Dietary inclusion of B. licheniformis significantly improved body weight gain and lessened FCR in T2 compared to other groups (p < 0.05). Probiotics increased the population of Bacillus spp. and decreased the population of Clostrium perfringens, Salmonella spp. and Escherichia coli in the jejunum and ileum in broiler birds on day 21 and 35 (p < 0.05). The highest antibody production was observed in B. licheniformis treated group (T2) compared to other probiotic treated group (T1). Taken together, the study findings suggest that B. licheniformis probiotics could be used as a feasible alternative to antimicrobials in the broiler production considering beneficial impacts at low biosecurity broiler farms.

Serological survey on the prevalence of chicken infectious anemia virus in broiler breeder and layer farms in some selected areas of Bangladesh

Objective:

Chicken infectious anemia virus (CIAV) is an economically important emerging infection of poultry as it causes immunosuppression and reduces egg production. Although it is worldwide distributed and first reported (single case) in Bangladesh in 2002, no epidemiological and serological investigations have been conducted. The current study aimed to conduct a serological investigation on the prevalence of CIAV infection in broiler breeder and layer farms in some selected areas of Bangladesh.

Materials and Methods:

A total number of 460 sera samples were randomly collected from unvaccinated broiler breeder and layer flocks, of which 276 were from 11 broiler breeder farms and 184 from 12 layer farms. The sera samples were subjected to a commercially available enzyme-linked immunosorbent assay kit to observe antibodies induced by CIAV.

Results:

Results demonstrated that the overall prevalence of CIAV was 83.6% among a total of 460 samples. In broiler breeder birds, the prevalence was 89.9%, whereas it was 78.3% in layer birds. A higher number of female birds was found to be seropositive than male birds. However, chickens of all age groups were found to be susceptible to the virus.

Conclusions:

These results indicate the presence of CIAV in Bangladesh, which may be the sequel of naturally occurring either vertical or horizontal infection in all bird flocks tested without clinical symptoms of the disease. A further epidemiological investigation will be required, followed by molecular isolation and characterization of the virus for suitable vaccine candidate selection and/or preparation.