Potential risk zones and climatic factors influencing the occurrence and persistence of avian influenza viruses in the environment of live bird markets in Bangladesh

Live bird markets (LBMs) are critical for poultry trade in many developing countries that are regarded as hotspots for the prevalence and contamination of avian influenza viruses (AIV). Therefore, we conducted weekly longitudinal environmental surveillance in LBMs to determine annual cyclic patterns of AIV subtypes, environmental risk zones, and the role of climatic factors on the AIV presence and persistence in the environment of LBM in Bangladesh. From January 2018 to March 2020, we collected weekly fecal and offal swab samples from each LBM and tested using rRT-PCR for the M gene and subtyped for H5, H7, and H9. We used Generalized Estimating Equations (GEE) approaches to account for repeated observations over time to correlate the AIV prevalence and potential risk factors and the negative binomial and Poisson model to investigate the role of climatic factors on environmental contamination of AIV at the LBM. Over the study period, 37.8% of samples tested AIV positive, 18.8% for A/H5, and A/H9 was, for 15.4%. We found the circulation of H5, H9, and co-circulation of H5 and H9 in the environmental surfaces year-round. The Generalized Estimating Equations (GEE) model reveals a distinct seasonal pattern in transmitting AIV and H5. Specifically, certain summer months exhibited a substantial reduction of risk up to 70-90% and 93-94% for AIV and H5 contamination, respectively. The slaughtering zone showed a significantly higher risk of contamination with H5, with a three-fold increase in risk compared to bird-holding zones. From the negative binomial model, we found that climatic factors like temperature and relative humidity were also significantly associated with weekly AIV circulation. An increase in temperature and relative humidity decreases the risk of AIV circulation. Our study underscores the significance of longitudinal environmental surveillance for identifying potential risk zones to detect H5 and H9 virus co-circulation and seasonal transmission, as well as the imperative for immediate interventions to reduce AIV at LBMs in Bangladesh. We recommend adopting a One Health approach to integrated AIV surveillance across animal, human, and environmental interfaces in order to prevent the epidemic and pandemic of AIV.

Annual trading patterns and risk factors of avian influenza A/H5 and A/H9 virus circulation in turkey birds (Meleagris gallopavo) at live bird markets in Dhaka city, Bangladesh

The impacts of the avian influenza virus (AIV) on farmed poultry and wild birds affect human health, livelihoods, food security, and international trade. The movement patterns of turkey birds from farms to live bird markets (LBMs) and infection of AIV are poorly understood in Bangladesh. Thus, we conducted weekly longitudinal surveillance in LBMs to understand the trading patterns, temporal trends, and risk factors of AIV circulation in turkey birds. We sampled a total of 423 turkeys from two LBMs in Dhaka between May 2018 and September 2019. We tested the swab samples for the AIV matrix gene (M-gene) followed by H5, H7, and H9 subtypes using real-time reverse transcriptase-polymerase chain reaction (rRT-PCR). We used exploratory analysis to investigate trading patterns, annual cyclic trends of AIV and its subtypes, and a generalized estimating equation (GEE) logistic model to determine the factors that influence the infection of H5 and H9 in turkeys. Furthermore, we conducted an observational study and informal interviews with traders and vendors to record turkey trading patterns, demand, and supply and turkey handling practices in LBM. We found that all trade routes of turkey birds to northern Dhaka are unidirectional and originate from the northwestern and southern regions of Bangladesh. The number of trades from the source district to Dhaka depends on the turkey density. The median distance that turkey was traded from its source district to Dhaka was 188 km (Q1 = 165, Q3 = 210, IQR = 45.5). We observed seasonal variation in the median and average distance of turkey. The qualitative findings revealed that turkey farming initially became reasonably profitable in 2018 and at the beginning of 2019. However, the fall in demand and production in the middle of 2019 may be related to unstable market pricing, high feed costs, a shortfall of adequate marketing facilities, poor consumer knowledge, and a lack of advertising. The overall prevalence of AIV, H5, and H9 subtypes in turkeys was 31% (95% CI: 26.6-35.4), 16.3% (95% CI: 12.8-19.8), and 10.2% (95% CI: 7.3-13.1) respectively. None of the samples were positive for H7. The circulation of AIV and H9 across the annual cycle showed no seasonality, whereas the circulation of H5 showed significant seasonality. The GEE revealed that detection of AIV increases in retail vendor business (OR: 1.71; 95% CI: 1.12-2.62) and the bird's health status is sick (OR: 10.77; 95% CI: 4.31-26.94) or dead (OR: 11.33; 95% CI: 4.30-29.89). We also observed that winter season (OR: 5.83; 95% CI: 2.80-12.14) than summer season, dead birds (OR: 61.71; 95% CI: 25.78-147.75) and sick birds (OR 8.33; 95% CI: 3.36-20.64) compared to healthy birds has a higher risk of H5 infection in turkeys. This study revealed that the turkeys movements vary by time and season from the farm to the LBM. This surveillance indicated year-round circulation of AIV with H5 and H9 subtypes in turkey birds in LBMs. The seasonality and health condition of birds influence H5 infection in birds. The trading pattern of turkey may play a role in the transmission of AIV viruses in the birds. The selling of sick turkeys infected with H5 and H9 highlights the possibility of virus transmission to other species of birds sold at LBMs and to people.

Multidrug-resistant non-typhoidal Salmonella of public health significance recovered from migratory birds in Bangladesh

Non-typhoidal Salmonella provides an exemplar for the One Health approach as it encompasses public and animal health, food safety, and environmental considerations. The contribution of environmental aspects is currently less well-defined. The purpose of this study was to determine the carriage occurrence of non-typhoidal Salmonella in migratory birds in Bangladesh and assess the potential significance to public and animal health. Cloacal swabs (N = 453) were collected in the years 2018-2020 from Tanguar and Hakaluki Haors, important wetland ecosystems in Northeastern Bangladesh. The prevalence of Salmonella was 13.5% (61 positive swabs). Classical serotyping identified six serovars: Salmonella enterica subsp. enterica serovars Perth, Kentucky, Albany, Infantis, Weltevreden, and Brancaster. Resistance towards 14 antimicrobials was assessed by broth microdilution minimum inhibitory concentration determination and the antimicrobial resistance (AMR) genotype established by whole-genome sequencing. S. Perth and S. Weltevreden isolates were susceptible and harbored no acquired AMR genes. Isolates from the remaining serovars were multidrug resistant, commonly possessing resistance to tetracycline, ampicillin, chloramphenicol, sulfamethoxazole, trimethoprim, and ciprofloxacin. Salmonella resistant to ciprofloxacin meets WHO criteria for priority pathogens. There was excellent concordance between resistance phenotype and the presence of corresponding AMR genes, many of which reside on Salmonella Genomic Islands. High-level ciprofloxacin resistance correlated with the presence of mutations in the chromosomal gyrB and/or parC genes. The S. Kentucky isolates were ST198, a widely distributed multidrug-resistant lineage reported in humans and animals, and constituting an ongoing risk to public health worldwide. We have demonstrated that multidrug-resistant non-typhoidal Salmonella of public health significance can be recovered from migratory birds. A potential for risk can manifest through direct interaction, transmission to food-producing livestock on farms, and dissemination via the long range migratory movements of birds. Risks can be mitigated by measures including continued surveillance and implementation of good farm biosecurity practices.

H9N2 avian influenza virus dispersal along Bangladeshi poultry trading networks

Avian influenza virus subtype H9N2 is endemic in Bangladesh's poultry population. The subtype affects poultry production and poses a potential zoonotic risk. Insufficient understanding of how the poultry trading network shapes the dissemination of avian influenza viruses has hindered the design of targeted interventions to reduce their spread. Here, we use phylodynamic analyses of haemagglutinin sequences to investigate the spatial spread and dispersal patterns of H9N2 viruses in Bangladesh's poultry population, focusing on its two largest cities (Dhaka and Chattogram) and their poultry production and distribution networks. Our analyses suggest that H9N2 subtype avian influenza virus lineage movement occurs relatively less frequently between Bangladesh's two largest cities than within each city. H9N2 viruses detected in single markets are often more closely related to viruses from other markets in the same city than to each other, consistent with close epidemiological connectivity between markets. Our analyses also suggest that H9N2 viruses may spread more frequently between chickens of the three most commonly sold types (sunali-a cross-bred of Fayoumi hen and Rhode Island Red cock, deshi-local indigenous, and exotic broiler) in Dhaka than in Chattogram. Overall, this study improves our understanding of how Bangladesh's poultry trading system impacts avian influenza virus spread and should contribute to the design of tailored surveillance that accommodates local heterogeneity in virus dispersal patterns.

Characterization and epidemiology of antimicrobial resistance patterns of Salmonella spp. and Staphylococcus spp. in free-ranging rhesus macaque (Macaca mulatta) at high-risk interfaces with people and livestock in Bangladesh

Introduction

Antimicrobial resistance (AMR) is a growing global health threat for humans and animals. Environmental contamination of antimicrobials from human and domestic animal feces has been linked to AMR in wildlife populations, including rhesus macaques. This study aimed to describe the eco-epidemiology of AMR within Salmonella and Staphylococcus species isolated from rhesus macaques.

Methods

We followed macaque groups for 4 h per day (2 days) to observe the direct and indirect contact rate and type between macaques and people and livestock. We collected 399 freshly defecated, non-invasive fecal samples from macaques at seven sites in Bangladesh in January-June 2017. Bacterial isolation and identification were conducted using culture, biochemical characteristics, and polymerase chain reaction (PCR). An antimicrobial susceptibility test (AST) for 12 antimicrobials for each organism was conducted using the Kirby-Bauer disc diffusion method.

Results

The overall prevalence of Salmonella spp. and Staphylococcus spp. in rhesus macaques was 5% (n = 18; 95% CI: 3-7%) and 16% (n = 64; 95% CI: 13-20%), respectively. All the isolated Salmonella spp. and most of the Staphylococcus spp. (95%; 61/64; 95% CI: 86.9-99%) were resistant to at least one antimicrobial. The odds of a fecal sample having antimicrobial-resistant Salmonella spp (OR = 6.6; CI: 0.9-45.8, P = 0.05) and Staphylococcus spp. (OR = 5.6; CI: 1.2-26, P = 0.02) were significantly higher in samples collected at peri-urban sites than those collected at rural and urban sites. Salmonella spp. were most frequently resistant to tetracycline (89%), azithromycin (83%), sulfamethoxazole-trimethoprim (50%), and nalidixic acid (44%). Staphylococcus spp. were found to be highly resistant to ampicillin (93%), methicillin (31%), clindamycin (26%), and rifampicin (18%). Both bacterial species produced colonies with multidrug resistance to up to seven antimicrobials. Direct and indirect contact rates (within 20 m for at least 15 min) and resource sharing between macaques and people were higher in urban sites, while macaque-livestock contact rates were higher in rural sites.

Discussion

The study shows that resistant microorganisms are circulating in rhesus macaque, and direct and indirect contact with humans and livestock might expand the resistant organisms.

Prevalence and risk factors for avian influenza virus (H5 and H9) contamination in peri-urban and rural live bird markets in Bangladesh

Avian influenza viruses (AIV) have been frequently detected in live bird markets (LBMs) around the world, primarily in urban areas, and have the ability to spillover to other species, including humans. Despite frequent detection of AIV in urban LBMs, the contamination of AIV on environmental surfaces in rural and peri-urban LBMs in Bangladesh is poorly documented. Therefore, we conducted this study to determine the prevalence of AIV subtypes within a subset of peri-urban and rural LBMs in Bangladesh and to further identify associated risk factors. Between 2017 and 2018, we collected faecal and offal samples from 200 stalls in 63 LBMs across four sub-districts. We tested the samples for the AIV matrix gene (M-gene) followed by H5, H7, and H9 subtypes using real-time reverse transcriptase-polymerase chain reaction (rRT-PCR). We performed a descriptive analysis of market cleanliness and sanitation practices in order to further elucidate the relationship between LBM biosecurity and AIV subtypes by species, sample types, and landscape. Subsequently, we conducted a univariate analysis and a generalized linear mixed model (GLMM) to determine the risk factors associated with AIV contamination at individual stalls within LBMs. Our findings indicate that practices related to hygiene and the circulation of AIV significantly differed between rural and peri-urban live bird markets. 42.5% (95% CI: 35.56-49.67) of stalls were positive for AIV. A/H5, A/H9, and A HA/Untyped were detected in 10.5% (95% CI: 6.62-15.60), 9% (95% CI: 5.42-13.85), and 24.0% (95% CI: 18.26-30.53) of stalls respectively, with no detection of A/H7. Significantly higher levels of AIV were found in the Sonali chicken strain compared to the exotic broiler, and in offal samples compared to fecal samples. In the GLMM analysis, we identified several significant risk factors associated with AIV contamination in LBMs at the stall level. These include: landscape (AOR: 3.02; 95% CI: 1.18-7.72), the number of chicken breeds present (AOR: 2.4; 95% CI: 1.01-5.67), source of birds (AOR: 2.35; 95% CI: 1.0-5.53), separation of sick birds (AOR: 3.04; 95% CI: 1.34-6.92), disposal of waste/dead birds (AOR: 3.16; 95% CI: 1.41-7.05), cleaning agent (AOR: 5.99; 95% CI: 2.26-15.82), access of dogs (AOR: 2.52; 95% CI: 1.12-5.7), wild birds observed on site (AOR: 2.31; 95% CI: 1.01-5.3). The study further revealed a substantial prevalence of AIV with H5 and H9 subtypes in peri-urban and rural LBMs. The inadequate biosecurity measures at poultry stalls in Bangladesh increase the risk of AIV transmission from poultry to humans. To prevent the spread of AIV to humans and wild birds, we suggest implementing regular surveillance at live bird markets and enhancing biosecurity practices in peri-urban and rural areas in Bangladesh.

Patterns and risk factors of avian influenza A(H5) and A(H9) virus infection in pigeons and quail at live bird markets in Bangladesh, 2017-2021

The avian influenza virus (AIV) impacts poultry production, food security, livelihoods, and the risk of transmission to humans. Poultry, like pigeons and quail farming, is a growing sector in Bangladesh. However, the role of pigeons and quails in AIV transmission is not fully understood. Hence, we conducted this study to investigate the prevalence and risk factors of AIV subtypes in pigeons and quails at live bird markets (LBMs) in Bangladesh. We collected oropharyngeal and cloacal swab samples from 626 birds in 8 districts of Bangladesh from 2017 to 2021. We tested the swab samples for the matrix gene (M gene) followed by H5, H7, and H9 subtypes using real-time reverse transcriptase-polymerase chain reaction (rRT-PCR). We then used exploratory analysis to investigate the seasonal and temporal patterns of AIV and a mixed effect logistic model to identify the variable that influences the presence of AIV in pigeons and quails. The overall prevalence of AIV was 25.56%. We found that the prevalence of AIV in pigeons is 17.36%, and in quail is 38.75%. The prevalence of A/H5, A/H9, and A/H5/H9 in quail is 4.17, 17.92, and 1.67%, respectively. Furthermore, the prevalence of A/H5, A/H9, and A/H5/H9 in pigeons is 2.85, 2.59, and 0.26%. We also found that the prevalence of AIV was higher in the dry season than in the wet season in both pigeons and quail. In pigeons, the prevalence of A/untyped (40%) increased considerably in 2020. In quail, however, the prevalence of A/H9 (56%) significantly increased in 2020. The mixed-effect logistic regression model showed that the vendors having waterfowl (AOR: 2.13; 95% CI: 1.04-4.33), purchasing birds from the wholesale market (AOR: 2.96; 95% CI: 1.48-5.92) instead of farms, mixing sick birds with the healthy ones (AOR: 1.60; 95% CI: 1.04-2.45) and mingling unsold birds with new birds (AOR: 3.07; 95% CI: 2.01-4.70) were significantly more likely to be positive for AIV compared with vendors that did not have these characteristics. We also found that the odds of AIV were more than twice as high in quail (AOR: 2.57; 95% CI: 1.61-4.11) as in pigeons. Furthermore, the likelihood of AIV detection was 4.19 times higher in sick and dead birds (95% CI: 2.38-7.35) than in healthy birds. Our study revealed that proper hygienic practices at the vendors in LBM are not maintained. We recommend improving biosecurity practices at the vendor level in LBM to limit the risk of AIV infection in pigeons and quail in Bangladesh.

Assessment of poultry rearing practices and risk factors of H5N1 and H9N2 virus circulating among backyard chickens and ducks in rural communities

Background

The avian influenza virus (AIV) causes significant economic losses by infecting poultry and occasional spillover to humans. Backyard farms are vulnerable to AIV epidemics due to poor health management and biosecurity practices, threatening rural households’ economic stability and nutrition. We have limited information about the risk factors associated with AIV infection in backyard poultry in Bangladesh. Hence, we conducted a cross-sectional survey comprising epidemiological and anthropological investigations to understand the poultry rearing practices and risk factors of AIV circulation among backyard poultry in selected rural communities.

Methods

We sampled 120 poultry from backyard farms (n = 30) of the three selected communities between February 2017 and January 2018. We tested swab samples for the matrix gene (M gene) followed by H5, H7, and H9 subtypes using real-time reverse transcriptase-polymerase chain reaction (rRT-PCR). We applied multivariable logistic regression for risk factor analysis. Furthermore, we conducted an observational study (42 hours) and informal interviews (n = 30) with backyard farmers to record poultry-raising activities in rural communities.

Results

We detected that 25.2% of the backyard poultry tested positive for AIV, whereas 5% tested positive for H5N1 and 10.8% tested positive for H9N2. Results showed that scavenging in both household garden and other crop fields has higher odds of AIV than scavenging in the household garden (AOR: 24.811; 95% CI: 2.11–292.28), and keeping a cage inside the house has higher odds (AOR:14.5; 95% CI: 1.06–198.51) than keeping it in the veranda, cleaning the cage twice a week or weekly has a higher risk than cleaning daily (AOR: 34.45; 95% CI: 1.04–1139.65), dumping litter or droppings (AOR: 82.80; 95% CI: 3.91–1754.59) and dead birds or wastage (AOR: 109.92, 95% CI: 4.34–2785.29) near water bodies and bushes have a higher risk than burring in the ground, slaughtering and consuming sick birds also had a higher odd of AIV (AOR: 73.45, 95% CI: 1.56–3457.73) than treating the birds. The anthropological investigation revealed that household members had direct contact with the poultry in different ways, including touching, feeding, slaughtering, and contacting poultry feces. Poultry is usually kept inside the house, sick poultry are traditionally slaughtered and eaten, and most poultry raisers do not know that diseases can transmit from backyard poultry to humans.

Conclusions

This study showed the circulation of H5N1 and H9N2 virus in backyard poultry in rural communities; associated with species, scavenging area of the poultry, location of the poultry cage, the practice of litter, wastage, droppings, and dead bird disposal, and practice of handling sick poultry. We suggest improving biosecurity practices in backyard poultry and mass awareness campaigns to reduce incidences of AIV in household-level poultry farms in rural communities in Bangladesh.

Measures, Gaps, and Mitigation Strategies in Bangladesh's COVID-19 Response

The Coronavirus Disease 2019 (COVID-19) spread rapidly from China to most other countries around the world in early 2020 killing millions of people. To prevent virus spread, world governments implemented a variety of response measures. This paper's objectives were to discuss the country's adopted measures to combat the virus through June 2020, identify gaps in the measures' effectiveness, and offer possible mitigations to those gaps. The measures taken included screening device deployment across international air and land ports, flight suspensions and closures from COVID-19 affected countries, and declaration and extension of a national public holiday (equivalent to lockdowns in other countries). Identified gaps were test kit, PPE, ICU beds, and ventilator shortages, limited public awareness, and insufficient coordination and collaboration among national and international partners. Proper and timely risk mapping, preparedness, communication, coordination, and collaboration among governments and organizations, and public awareness and engagement would have provided sufficient COVID-19 mitigation in Bangladesh.

Mapping the Antimicrobial Supply Chain in Bangladesh: A Scoping-Review-Based Ecological Assessment Approach

A standardized method for evaluating antimicrobial supply chains in the context of access and use could be a useful tool in assessing national capacity to implement programs that address antimicrobial resistance. We present both a novel ecological approach comprising mapping and the use of indicators that can be used to characterize national antimicrobial supply chains as well as benchmark countries and, for the first time, a country-level assessment of Bangladesh.

Introduction:

Maintaining access to antimicrobials while preventing misuse is essential to combating the threat of antimicrobial resistance (AMR). The study objectives are to propose a framework of 16 indicators that can be used at the national level to assess the capacity to ensure access and curtail inappropriate use and to profile the antimicrobial supply chain for Bangladesh.

Methods:

Using a framework based on a rational construct, we assessed the antimicrobial supply chain of Bangladesh, with a focus on key players and products using a scoping review to obtain and describe information on 16 indicators. With players, we mapped linkages, manufacturers’ production capacity, and ownership, among others, and demand point characteristics—pharmacy and pharmacist density, pharmacy/medicine outlets dispersion, veterinary clinic/hospitals, veterinarians’ density, product quality, and regulation. We assessed product characteristics including listing on the World Health Organization (WHO) Model Essential Medicines List (EML) and WHO Access, Watch, and Reserve (AWaRe) classification of the major (top 10) antibiotics for human use; the proportion of medically important antimicrobials (MIAs) in veterinary use; and pricing. Production capacity and price controls were used to assess access and listing on the WHO EML, AWaRe/MIA classification, and a calculated pharmacy-to-pharmacist ratio to assess use.

Results:

Bangladesh has a high (98%) local antibiotic production capacity with pricing controls indicating the ability to ensure access. The presence of a high proportion of medicine outlets not under the control of pharmacists (4:1) and the high percentages of WHO Watch (54%) and MIAs (90%) of the major antibiotics are indicators of possible misuse.

Discussion:

Most of the data used in the framework were publicly available. Bangladesh has the capacity to ensure access but needs to strengthen its ability to regulate the quality of antimicrobials and prevent their inappropriate use through antimicrobial stewardship at the community (medicine outlet) levels to check AMR. There may also be a need for more regulations on licensing of MIAs.

Risk Areas for Influenza A(H5) Environmental Contamination in Live Bird Markets, Dhaka, Bangladesh

We evaluated the presence of influenza A(H5) virus environmental contamination in live bird markets (LBMs) in Dhaka, Bangladesh. By using Bernoulli generalized linear models and multinomial logistic regression models, we quantified LBM-level factors associated with market work zone–specific influenza A(H5) virus contamination patterns. Results showed higher environmental contamination in LBMs that have wholesale and retail operations compared with retail-only markets (relative risk 0.69, 95% 0.51–0.93; p = 0.012) and in March compared with January (relative risk 2.07, 95% CI 1.44–2.96; p<0.001). Influenza A(H5) environmental contamination remains a public health problem in most LBMs in Dhaka, which underscores the need to implement enhanced biosecurity interventions in LBMs in Bangladesh.

SUBCLINICAL MASTITIS IN LACTATING COWS: COMPARISON OF FOUR SCREENING TESTS AND EFFECT OF ANIMAL FACTORS ON ITS OCCURRENCE

A total of 444 quarter milk samples from 111 crossbred dairy cows were subjected to California mastitis test (CMT), somatic cell count (SCC) test, white side test (WST) and surf field mastitis (SFMT) test to quantify their efficacy in detecting sub clinical mastitis in dairy cows of Bangladesh during the period from 2010 to 2011.Milk samples positive by CMT, SCC, WST and SFMT were 265,230, 225 and 222 respectively. All samples were subjected to cultural isolation (gold standard test for comparison of indirect mastitis tests). Of these, 261 samples were positive by cultural isolation. The sensitivity of the CMT, SCC, WST and SFMT were 80.08%, 86.60%, 60.54% and 57.47%; specificity 69.40%, 97.81%, 63.38% and 60.66%; percentage accuracy 75.68%,91.22%, 61.71%  and 58.78%; positive predictive value 78.87%, 98.26%, 70.22% and 67.57%; and negative predictive value 70.95%, 83.64%, 52.97% and 50%respectively. Quarter-wise sub clinical mastitis (SCM) was detected in 59.68%, 51.80%, 50.68% and 50% samples by CMT, SCC, WST and SFMT, respectively, while animal-wise SCM was recorded in 72.07%, 66.67%, 64.86% and 61.26% samples by CMT, SCC, WST and SFMT, respectively. The right hind quarters were most significantly (p<0.001) susceptible to SCM than other quarters. Cows with 3rd and 4th parity and at their early lactation stage had significantly higher (p<0.001) SCM than others. Kappa value of SCC was higher than that of CMT. CMT was concluded to be the most accurate test after cultural isolation and SCC. Unlike laboratory tests as cultural isolation and SCC that require adequate laboratory facilities and skilled personnel, CMT is a reliable diagnostic method in field conditions.

Surveillance of avian influenza virus type A in semi-scavenging ducks in Bangladesh

Background

Ducks are the natural reservoir of influenza A virus and the central host for highly pathogenic avian influenza (H5N1), while domestic ducks rearing in semi-scavenging system could serve as re-assortment vessels for re-emerging new subtypes of influenza viruses between birds to human. Avian influenza virus (AIV) surveillance in Bangladesh has been passive, relying on poultry farmers to report suspected outbreaks of highly pathogenic H5N1 influenza. Here, the results of an active surveillance effort focusing on the semi-scavenging ducks are presented.

Result

A total of 2100 cloacal swabs and 2100 sera were collected from semi-scavenging ducks from three wintering-sites of Bangladesh during three successive winter seasons, December through February in the years between 2009 and 2012. Virus isolation and identification were carried out from the cloacal swabs by virus propagation in embryonated hen eggs followed by amplification of viral RNA using Avian influenza virus (AIV) specific RT-PCR. The overall prevalence of avian influenza type A was 22.05% for swab samples and 39.76% ducks were sero-positive for avian influenza type A antibody. Extremely low sero-prevalence (0.09%) of AIV H5N1 was detected.

Conclusions

Based on our surveillance results, we conclude that semi-scavenging ducks in Bangladesh might play important role in transmitting Avian Influenza virus (AIV) type A. However, the current risk of infection for humans from domestic ducks in Bangladesh is negligible. We believe that this relatively large dataset over three winters in Bangladesh might create a strong foundation for future studies of AIV prevalence, evolution, and ecology in wintering sites around the globe.

PUBLIC HEALTH THREAT CAUSED BY ZOONOTIC DISEASES IN BANGLADESH

Diseases and infections shared between animals and humans are mainly called zoonotic diseases which may be categorized as emerging, reemerging and neglected. All types of these diseases occur t  hroughout the world including Bangladesh. The results on the prevalence and effects of zoonotic diseases in humans and animals of Bangladesh are analyzed from the published literatures and presented in this report. It appears from the literature that there are about 1415 human pathogens of which 61% are zoonotic and nearly half of all human pathogens can be classified as emerging, of which 75% of these are caused by zoonotic pathogens. The major zoonotic bacterial diseases recorded in Bangladesh are Anthrax, Tuberculosis, Brucellosis, Salmonellosis, Campylobacteriosis and Leptospirosis, of which only Anthrax has been reported as clinical outbreaks form in both the humans and cattle. During the period 2009 to 2012, anthrax caused death of hundreds of cattle and more than 650 cases of cutaneous anthrax in humans including fatalities in two humans associated with anthrax. The major reported viral zoonotic diseases in Bangladesh include Avian influenza, Rabies, Nipah virus infection, Japanese encephalitis, Rotavirus and Dengue fever. Avian influenza caused by highly pathogenic H5N1 in humans and poultry in Bangladesh and about six humans affected with H5N1 but all of them have recovered. Since 27 March 2007 when Avian influenza was reported to have occurred for the first time in Bangladesh, this virus spread in 51 out of 64 districts with more than 480 outbreaks, culled more than two million poultry birds and cost Tk. 55 billion (US $ 757.9 million) in Bangladesh. Rabies is considered as a priority zoonosis in Bangladesh and it is mainly transmitted to humans and food animals mainly through dog bite nearly 100,000 people and at least 2000 died of rabies in 2009 in Bangladesh. Nipah virus infection is an important emerging infectious disease has been recognized since 2001 in Bangladesh and up to February 2011, 173 humans cases have been identified, of which 110 (63.58%) died. Japanese encephalitis (JE) is a vector borne zoonotic disease, first recognized in Bangladesh since an outbreak in 1977 and 12.38% encephalitis patients had JE virus infection which was associated with mortality, physical disability and cognitive difficulties. Rotavirus is a worldwide distributed zoonotic disease affecting mammals and birds and it has been reported from Bangladesh in humans (23.75%), animals (12 to 43.78%) and broiler birds (13.15%) associated with diarrheic syndrome. Dengue fever was first reported in Bangladesh in 1964 and outbreak that began in 2000 predominantly caused by DENV-3 in which 5551 cases recovered and 93 Dengue related deaths were reported. The dermatomycosis has been reported in 9.3% cattle, 18.6% goats and 25.2% in contact humans. The major zoonotic parasites recorded in cats in Bangladesh include Paragonimus westermani (9.09%), Ancyclostoma tubaeforme (36.36%), Dirofilaria immitis (9.09%), Toxocara cati (45.45%) and Toxoplasma gondii (9.09%), in dogs include Diphyllobothrium latum (13.3%), Diphylidium caninum (16.69%), Echinococcus granulosus (9.17%), Ancylostomum caninum (9-100%), Gnathostoma spingerum (40.0%), Toxocara canis (23.3%), Trichuris vulpis (13.8%) and in pigs include Entaemebea histolytica (17.24%) and Balantidium coli (60.34%). The prevalence of zoonotic protozoan diseases recorded in humans in Bangladesh include amebiasis (E. histolytica 4.71% & E. dispar 12.6%), giardiasis (21% in children & 51% in malnourished children), cryptosporidiasis (1.4 to 3.5% in diarrheic patients) and visceral leishmaniasis (kala-azar) which was first reported in Jassore in 1824 but still sporadic outbreaks are occurring in the different districts in Bangladesh. Sero-surveillance studies showed 16 to 17% cattle, 17.65 to 53.6% sheep, 12.09 to 35.4% goats and 15.89% women had T. gondii antibodies in Bangladesh. It appears from these results that all types of emerging, reemerging and neglected zoonotic diseases are widely prevalent and pose a great threat to human health in Bangladesh. Neglected Veterinary medical profession and its extension services, poor people without any knowledge of zoonotic diseases who are in close contact with livestock and their products, and unhygienic processing, maintaining and marketing the livestock and livestock products have made the situation graver in Bangladesh.DOI: http://dx.doi.org/10.3329/bjvm.v9i2.13451

Molecular epidemiology of circulating highly pathogenic avian influenza (H5N1) virus in chickens, in Bangladesh, 2007-2010

Bangladesh has been severely hit by highly pathogenic avian influenza H5N1 (HPAI-H5N1). However, little is known about the genetic diversity and the evolution of the circulating viruses in Bangladesh. In the present study, we analyzed the hemagglutinin gene of 30 Bangladeshi chicken isolates from 2007 through 2010. We analyzed the polybasic amino acid sequence motif of the cleavage site and amino acid substitution pattern. Phylogenetic history was reconstructed using neighbor-joining and Bayesian time-scaled methods. In addition, we used Mantel correlation tests to analyze the relation between genetic relatedness and spatial and temporal distances. Neighbor-joining phylogeography revealed that virus circulating in Bangladesh from 2007 through 2010 belonged to clade 2.2. The results suggest that clade 2.2 viruses are firmly entrenched and have probably become endemic in Bangladesh. We detected several amino acid substitutions, but they are not indicative of adaptation toward human infection. The Mantel correlation test confirmed significant correlation between genetic distances and temporal distances between the viruses. The Bayesian tree shows that isolates from waves 3 and 4 derived from a subgroup of isolates from the previous waves grouping with a high posterior probability (pp=1.0). This indicates the possibility of formation of local subclades. One surprising finding of spatio-temporal analysis was that genetically identical virus caused independent outbreaks over a distance of more than 200 km and within 14 days of each other. This might indicate long distance dispersal through vectors such as migratory birds and vehicles, and challenges the effectiveness of movement restriction around 10 km radius of an outbreak. The study indicates possible endemicity of the clade 2.2 HPAI-H5N1 virus in Bangladesh. Furthermore, the formation of a subclade capable of transmission to humans cannot be ruled out. The findings of this study might provide valuable information for future surveillance, prevention and control programme.

IMPORTANT VIRAL DISEASES ASSOCIATED WITH MORTALITY OF LAYER CHICKENS IN COMMERCIAL POULTRY FARMS IN BANGLADESH

Disease profile investigation on 1751 dead chickens supplied from about 100 commercial large or small scale poultry farms of Gazipur district and surrounding area in Bangladesh during one year period from January to December 2002 at the BRAC Poultry Disease Diagnostic Centre, Nagapara, Gazipur showed that 22.73% (n = 398) cases with five different viral diseases, of which infectious bursal disease (IBD) (n = 196) and Newcastle disease (ND) (n = 181) showed significantly (p < 0.01) higher rate of occurrence than infectious bronchitis (IB) (n = 6), avian leukosis (AL) (n = 6) and fowl pox (FP) (n = 4). Age-wise occurrence of IBD showed highest infection rate in growing stage (82.65%) in comparison to brooding (3.06%), pullet (6.12%) and adult layer (8.16%) chickens. Although more or less all age groups of chickens were affected by ND (1.66% to 50.83%) but it was found significantly (p < 0.01) highest in adult (50.83%) chickens. Infectious bronchitis was recorded only in adult chickens. Avian leukosis was found higher in pullet (66.67%) than the adult (33.33%) layer birds. Fowl pox also recorded only in pullet stage of chickens. Seasonal influence showed significantly (p < 0.01) highest occurrence of IBD during summer (44.39%) in comparison to rainy (30.61%) and winter (25.00%) seasons. Similarly ND was recorded more or less uniformly in all the three seasons of the year with significantly (p < 0.01) higher rate during summer (41.99%) season. Infectious bronchitis was recorded significantly (p < 0.01) higher in summer (63.66%) season while avian leukosis was recorded in winter (66.67%). Fowl pox was found equally in winter and summer seasons (50%). Although IBD was found with other concurrent infection e.g., dual (23.98%) and triple (2.55%) types of infection but highest occurrence was recorded as a single type (73.47%) of infection. ND was found with dual (44.75%), triple (7.18%) and fourth (1.10%) types of infection but specially single infection (46.96%) were associated with high mortality. IB was recorded highest in single infection (54.55%) in comparison to dual (9.09%), triple (18.18%) and fourth types (18.18%) of infection. Avian leukosis was recorded higher as a single infection (83.33%) than dual (16.67%) type of infection. Fowl pox was recorded equally (50%) as single and triple types of infection. It may be concluded that both the single and concurrent infection of viral diseases, greatly influenced by season and age associated with high mortality, should be considered during vaccination programme, diagnosis, prevention and control.

PREVALENCE OF CLINICAL DISEASES OF PET DOGS AND RISK PERCEPTION OF ZOONOTIC INFECTION BY DOG OWNERS IN BANGLADESH

A case control study was conducted to ascertain the prevalence of clinical diseases and/or clinical conditions of 3670 sick pet dogs presented to the Central Veterinary Hospital (CVH), Dhaka during the one year period from January to December 2009. A total of 57 types of diseases and conditions in 17 categories were recorded in these pet dogs and their variation in prevalence were analyzed on the basis of age, gender, season and breeds of dogs. The prevalent diseases and/or conditions from low to high rates included glaucoma (0.05%), babesiosis ( 0.08%), sinusitis (0.08%), tetanus (0.08%), spaying (0.14%), nail injury (0.19%), nephritis (0.19%), cataract (0.25%), metritis (0.25%), poisoning (0.33%), orchitis (0.35%), rabies (0.35%), pus in antrum (0.41%), purulent cough (0.46%), alopecia (0.52%), pharyngitis (0.52%), transmissible venereal tumor (0.54%), cystitis (0.52%) phimosis (0.52%), paraphimosis (0.60%), stomatitis (0.63%), pneumonia (0.63%), mastitis (0.71%), otitis (0.73%), taeniasis (0.74%), abscess (0.82%), anal gland disease (0.82%), dystocia (0.84%), conjunctivitis (0.90%), lice infestation (0.90%), lameness (0.95%), ottorrhea (1.06%), uterine prolapse (1.31%), posthitis (1.31%), dental disorders (1.34%), metabolic diseases (1.36%), protrusion of eye ball (1.44%), canine distemper (1.61%), liver disease (1.72%), nutritional deficiency diseases (1.77%), infertility (1.80%), coccidiosis (1.93%), toxocariasis (1.93%), urinary tract infection (2.10%), accidental wounds (2.32%), haematuria (2.34%), bronchitis (2.81%), arthritis (2.94%), dermatomycosis (3.30%), aspiration pneumonia (3.32%), mange (3.76%), echinococcosis (3.92%), dermatitis (4.99%), diarrhea (5.21%), ancylolostomiasis (6.20%), flea infestation (9.84%) and tick infestation (11.88%). Age-wise overall prevalence of clinical diseases revealed significantly (p <0.05) highest in age group above 36 months (48.12%) compared to that in 7 to 36 months (34.33%) and up to 6 months (17.55%) age groups of pet dogs. The significantly (p <0.05) highest prevalence of diseases and/or clinical conditions was recorded in local (33.35%) and German shepherd (22.53%) breeds of pet dogs in comparison to that in their counterpart breeds of Lhasa-Apso (7.57%), Greyhound (7.11%), Doberman (6.34%), Samoyed (6.23%), Dachshunds (5.20%), Spaniel (3.37%), Spitz (3.07%) and Poodle (3.18%). Results from season-wise analysis of overall prevalence of diseases and/or clinical conditions in pet dogs did not differ significantly (p >0.05) among spring (21.53%), summer (25.80%), autumn (22.83%) and winter (29.84%). The highest prevalence of arthropode infestation (22.62%), followed by intestinal parasitic diseases (14.80%) and diarrhea (5.20%) suggest a poor husbandry of these pets in Dhaka. Results of this study indicate that the risk of zoonotic infection by canine intestinal parasite may be high in Bangladesh.DOI = http://dx.doi.org/10.3329/bjvm.v8i2.11201 Bangl. J. Vet. Med. (2010). 8 (2) : 163-174 

New introduction of clade 2.3.2.1 avian influenza virus (H5N1) into Bangladesh

Since the first outbreak of highly pathogenic H5N1 avian inafluenza (HPAI) in Bangladesh in February 2007, a total of 519 disease events have been reported till 22 October 2011. Partial HA gene sequences of 11 selected H5N1 HPAI isolates of 2007 to 2011 were determined and subjected to phylogenetic analysis. The study revealed a recent introduction of clade 2.3.2 and 2.3.4 viruses into Bangladesh in 2011 in addition to clade 2.2 viruses that had been in circulation since 2007. Clade 2.3.2 virus isolates from Bangladesh are phylogenetically related to the newly designated clade 2.3.2.1 viruses, reported recently from Asia and Eastern Europe.

Noise level in different places of Dhaka Metropolitan City (DMC) and noise-induced hearing loss (NIHL) in Dhaka City dwellers

A cross sectional, exploratory study was designed at "National Center for Hearing and Speech for Children" (NCHSC), Dhaka, Bangladesh, from May 2001 to June 2002, with a view to determine the average noise level in different places of Dhaka Metropolitan City (DMC), and also aiming at evaluating the extent of Noise-induced Hearing Loss (NIHL) in different groups of city dwellers and finally a base line information. A total of 32 places in DMC were selected randomly. The highest noise level recorded 104 dB at Sayedabad bus terminal and the lowest 68 dB in Banani and Baridhara residential area. In silent zone of DMC, average noise level was 79 dB, in residential zone 72 dB, in commercial zone 90 dB, and in mixed zone average noise level was recorded at 91 dB. Measured noise levels were more than acceptable and permissible levels in all places of DMC. A total of 312 persons aged between 15-45 years (mean age- 24.64 years) were enrolled for the study as per inclusion criteria. Gender-wise male were 211(67.62%) and female were 101(32.57%). Profession-wise Automobile drivers were 57(18.26 %), Garment workers 58(18.55 %), City dwellers 72(23.07%), Students 72(23.07%), Traffic polices 12(3.85%), Hawkers and Road side shopkeepers were 41(13.1%). Definite noise notch (>25dB) at 4KHz observed in 33(10.58%) audiogram of persons under study. Automobile drivers, Traffic polices, Road side hawkers and Shop keepers, Garment workers are mostly affected were 17.54%, 16.4%, 12.09% and 12.06% respectively. A total of 201 persons (64.42%) were not aware of their hearing impairment, 244(78%) of the person had poor level of knowledge regarding bad effects of noise on health and about protective means available. Amongst persons (33) found to have NIHL did not use any protective device.

Sero-epidemiological studies on Toxoplasma gondii infection in man and animals in Bangladesh

Sera from randomly selected 49 professional blood donors, 617 pregnant women, 14 butchers, 528 slaughtered goats and 24 domestic cats in the district of Mymensingh were tested for the presence of T. gondii antibodies using a Latex agglutination test (LAT). Overall 12.4% blood donors, 11.18% pregnant women, 50.00% butchers, 12.88% slaughtered goats and 33.33% cats had diagnostically significant antibody titers (> or = 1:64) to T. gondii. Epidemiological studies on T. gondii infection with LAT were conducted in 25 family members with sero-positive cats and 9 family members with 2 sero-positive women without cats in the family. Significantly (p < 0.01) higher sero-positivity rate was recorded in the family members (24.00%) with positive cats in comparison to family members (11.11%) without cats. The epidemiologic study indicates that infected cats and goat meat might be significant sources of T. gondii infection for humans in Bangladesh.

Serological diagnosis of Toxoplasma gondii infection in women associated with gyneco-obstetric problems

The latex agglutination test (Toxoreagent) was used to detect the sero-prevalence of Toxoplasma gondii in 302 Bangladeshi women who were under treatment for various gyneco-obstetric problems at the Mymensingh Medical College during January to June 1991. The over-all sero-prevalence rate was 15.89%, of which 6.25% reacted at 1:32, 33.33% at 1:64, 16.67% at 1:128, 22.92% at 1:256, 6.25% at 1:512 and 14.58% at 1:1024. The positivity rate of 18.60% recorded in women between 31 and 40 years was insignificantly (p > 0.05) higher than that of 15.44% in women between 17 and 30 years of age. Over-all 26.49% of infections resulted in abortion, 6.62 in stillbirths and 30.79% in dystocia, of which 20.0%, 30.0% and 7.53% women had positive titers to T. gondii, respectively, whereas 17.43% women with normal live births had also positive titers to T. gondii. The over-all prevalence rate of abortion in association with T. gondii infection was 5.30% which was higher than the rates of stillbirths (1.99%) and perinatal death (0.66%). It is concluded that toxoplasmosis can cause abortion, stillbirths and perinatal death in Bangladeshi women.

Seroprevalence of Toxoplasma gondii in domestic ruminants in Bangladesh

Sera from 205 cattle, 17 sheep and 306 goats were tested for Toxoplasma gondii antibodies by using a commercial latex agglutination test. Titres considered diagnostically significant (> or = 1:64) were detected in 16.10% of cattle, 17.65% of sheep and 12.09% of goats. Results indicate that T. gondii infection in domestic ruminants in Bangladesh is widespread.

Effect of Raillietina echinobothrida infection on blood values and intestinal tissues of domestic fowls of Bangladesh

An examination of the blood profile of domestic fowls infected with Raillietina echinobothrida revealed anaemia with a significant increase of total leukocyte counts and decrease of total serum protein. The pathological changes in the intestines were characterised by villous atrophy, enteritis with cellular infiltration and formation of characteristic granulomas.

Anthrax in man and cattle in Bangladesh

The occurrence of anthrax in 62 cattle and 27 humans in Pabna milk shed areas of Bangladesh was recorded during 1980-84. There were 62 sick animals: 43 (69%) died, 14 (23%) recovered with penicillin treatment and only five (8%) were slaughtered in a moribund stage, for human consumption. All 27 people who developed malignant pustules were cured with penicillin treatment within 14 days.

T- and B-lymphoid cell population in calves immunized against Theileria annulata

Distribution of T- and B-lymphoid cells in peripheral blood, lymph node, spleen and bone marrow of normal healthy calves and valves immunized against Theileria annulata followed by challenge on Day 50 post-immunization were studied by rosette tests. Significantly increased percentages of T- and B-lymphoid cells were recorded in immunized calves.

Bacterio-pathological Studies on Salmonellosis, Colibacillosis and Pasteurellosis in Natural and Experimental Infections in Chickens

Bacterio-pathological investigation on 1751 dead chickens during one year period from January to December 2002 at the BRAC Poultry Disease Diagnostic Centre, Gazipur showed that 39.81% (n=697) cases with seven types of different bacteriological diseases of which salmonellosis (n=385), colibacillosis (n=147) and fowl cholera (n=114) were found significantly higher rate of prevalence then staphylococcosis (n=6),  gangrenous dermatitis (n=17), necrotic enteritis (n=24) and infectious coryza (n=4). Accordingly, avian salmonellosis, colibacillosis and pasteurellosis were selected for detailed investigation. Age wise prevalence of avian salmonellosis showed highest infection rate in adult layers (53.25%) in comparison to brooding (14.55%), growing (16.10%) and pullet (16.10%) chickens. The avian colibacillosis was found widely prevalent in all age groups of chickens (9.52 to 36.73%) with specially high prevalence rate in adult layer birds (36.73%). Fowl cholera was recorded in chickens more than two weeks of age with significantly (p < 0.01) highest occurrence in adult chickens. Seasonal influence showed significantly (p < 0.01) highest proportionate prevalence of salmonellosis during summer (48.05%) in comparison to rainy (28.31%) and winter (23.66%) seasons. Colibacillosis was recorded more or less uniformly in all the three seasons of the year with significantly (p < 0.01) higher rate during summer (40.82%) season. Similarly, the prevalence of fowl cholera was also found significantly (p < 0.01) highest during summer (49.12%) in comparison to rainy (26.32%) and winter (24.56%) seasons. The isolated causative agents of avian salmonellosis (Salmonella pullorum), avian colibacillosis (Escherichia coli) and avian pasteurellosis (Pasteurella multocida) were characterized by bacteriological methods which were also subjected to pathogenicity study in 52-day old broiler chickens. Pathogenicity study showed that the incubation period of these three bacterial diseases were recorded as 96 hours and clinical signs appeared on 4th day of inoculation and observed that S. pullorum, E. coli and P.  multocida resulted 100% morbidity in chickens. Key words: Characterization; pathogenicity; salmonellosis; colibacillosis; pasteurellosis; chickens doi: 10.3329/bjvm.v2i1.1926 Bangl. J. Vet. Med. (2004). 2(1) : 01-08

Pattern of Occurrence of Single and Concurrent Diseases Associated with Mortality in Commercial Chickens in Bangladesh

The high mortality rate of commercial poultry has been encountered as a major problem which discourage farmers and entrepreneurs in this industry in Bangladesh. This study was carried out to determine the role of single and concurrent infections associated with mortality in 1751 commercial chickens during one year period from January to December 2002. Diagnosis of diseases was made on the basis of history, necropsy findings, isolation and identification of causative bacteria and other laboratory tests. The etiological investigations of 1751 dead chickens showed that about 39.81% bacterial, 22.73% viral, 13.65% mycoplasmal, 1.54% fungal, 10.11% parasitic, 31.64% systemic, 3.43% nutritional deficiency and 1.77% other diseases were associated with these mortality. Salmonellosis (21.99%), Colibacillosis (8.40%), Fowl cholera (6.52%), Avian mycoplasmosis (13.65%), Infectious bursal disease (11.20%), Newcastle disease (10.34%) and coccidiosis (6.23%) were recognized as major diseases associated with mortality in commercial chickens in Bangladesh. About 32 diseases were recorded, of which both single (76.30%) and mixed infections as two (21.53%), three (1.83%) and four (0.34%) types were associated with mortality of chickens. Significantly (p < 0.01) highest proportionate mortality rate was recorded in > 20 weeks old adult layer (45.52%) in comparison to > 2 to 8 weeks old grower (24.04%), > 8 to 20 weeks old pullet (18.16%) and up to 2 weeks old brooding (12.28%) chickens. Seasonal influence showed highest mortality rate during Summer (43.06%) in comparison to Rainy (27.81%) and Winter (29.13%) seasons. It may be concluded from this study that both the single and concurrent infections are associated with high mortality rate in commercial chickens in Bangladesh. Therefore, the interactions of different pathogens in naturally occurring diseases should be considered during diagnosis and evaluation of vaccination.  Key words: Occurrence; concurrent; mortality; diseases; chickens DOI = 10.3329/bjvm.v1i1.1911 Bangl. J. Vet. Med. (2003). 1 (1) :  15 - 20

PREVALENCE OF SUBCLINICAL GASTRO-INTESTINAL PARASITOSIS AND THEIR EFFECTS ON MILK PRODUCTION WITH THERAPEUTIC MANAGEMENT IN RED CHITTAGONG CATTLE

The prevalence of sub-clinical gastro-intestinal parasitosis and their effects on health and milk production with therapeutic management were studied in 87 Red Chittagong cattle (RCC) reared at the Bangladesh Agricultural University Dairy Farm (BAUDF), Mymensingh during the period from March to July 2008. Of the 87 RCC aged between 1 to 96 months which included 22 milch cows, 15 pregnant cows, 8 dry cows, 18 weaned calves and 24 unweaned calves. Parasitological examination of faecal samples of all the selected 87 RCC showed that 51.72% (n = 45) animals affected with different types of gastro-intestinal parasites, of which 37.93% had single, 12.64% had dual and only 1.15% animals had triple types of infection. An overall 34.48% paramphistomiasis, 25.29% balantidiasis, 2.30% toxocariasis, 2.30% strongyloidiasis, 1.15% trichuriasis and 1.15% fascioliasis was recorded in RCC. However, toxocariasis (18.75%), strongyloidiasis (18.75%) and trichuriasis (6.25%) were recorded in calves up to 6 months old, and paramphistomiasis (34.48%) and fascioliasis (1.15%) in cattle more than 6 months of age whereas balantidiasis (25.29%) was recorded in all age groups of cattle. The anthelmintic efficacy of the combined commercial preparations with Tetramisole hydrochloride 2.0g and Oxyclozanide 1.4g per bolus (Levanid®, Acme ; Tetranid®, Techno Drugs) @ 1 bolus / 100 kg body weight with a single oral dose caused 100% reduction of faecal egg count at day 7 post-treatment. A single oral dose of 1% copper sulfate solution @ 10 ml / kg and metranidazole (Flagyl®, Aventis) @ 4 mg /kg body weight resulted 100% and 42.85% reduction of Balantidium coli trophozoites, respectively. The average milk production records of RCC affected with gastro-intestinal parasitosis (1.41litre / day / animal) were compared with the mean milk production records at day 7 post-anthelmintic treatment (1.73 liter / day / animal) and results showed an average increased milk yield +0.32 litre / day / animal. This study indicates that RCC affected with sub-clinical gastro-intestinal parasitosis caused ill-health and decrease milk yield like zebu and cross-bred cattle. It may be concluded from this study that the RCC should be regularly monitored through faecal examination for the presence of gastro-intestinal parasites in order to provide rational treatment and control management to make the RCC farming profitable. DOI = 10.3329/bjvm.v8i1.7395 Bangl. J. Vet. Med. (2010). 8(1): 11-16

Prevalence of bovine tuberculosis and its effects on milk production in Red Chittagong cattle

Bovine tuberculosis (bTB) is one of the most prevalent economically important zoonotic diseases and tuberculin test has been widely used to detect its prevalence worldwide. This study used a commercial immunochromatographic assay (ICGA) to detect the prevalence of bTB and to evaluate the differences in milk production between lactating cows with positive and negative results in Bangladesh. Thirty Red Chittagong (indigenous) cattle (RCC) were randomly selected from a herd of 87 RCC maintained at the Bangladesh Agricultural University Dairy Farm (BAUDF), Mymensingh during the period from March to July 2008, of which 30% cattle showed positive reaction to bTB. Of the 30 tested cattle, 35.29% (6/17) lactating cows, 20.0% (1/5) non-lactating pregnant cows, 33.33% (1/3) weaned calves and 20.0% (1/5) unweaned calves showed positive reaction to bTB. The detection of bTB in two calves and their respective mother cows indicates the possible transmission of TB organism through their colostrums / milk. Of the 17 lactating cows, 6 cows had positive and 11 had negative results to bTB. Cows with positive results produced less milk ( mean 1.29 litre / day / cow ) in comparison to cows with negative test ( mean 1.57 litre / day/ cow ) results which appeared as 17.83% reduction of milk production. Further study on the mastitis with or without bTB and its effect on milk production require data of more herds for conclusion of these results. Key words: Red Chittagong cattle, bovine tuberculosis, immunochromatographic assay, milk production doi: 10.3329/bjvm.v6i2.2332 Bangl. J. Vet. Med. (2008). 6 (2): 175-178

Clinico-pathological Studies on Natural and Experimental Infectious Bursal Disease in Broiler Chickens

The clinico-pathological studies on infectious bursal disease (IBD) were carried out in naturally occurred outbreaks of 19 to 22-day-old broilers (population 1000) and experimentally produced infection in 40-day-old 23 broiler chickens during the period from November 2002 to January 2003. Each of the experimental birds received 100 µl of 20% bursal homogenates intraocularly with a wild-type field strain (BD-3 Wt) of a Bangladeshi isolate of vvIBDV (BD-3/99). The natural infection caused 29.2% mortality and experimental infection resulted in 26.8% mortality after an incubation period of 48 to 72 hrs. Clinical investigation showed almost similar clinical signs in both the natural and experimental cases. Dullness, depression, anorexia, whitish loose diarrhoea, bloody diarrhoea in some chickens, ruffled feathers and severe dehydration were the recorded clinical manifestations. Necropsy examination revealed no significant pathological differences between chickens died of natural and experimental IBDV infection. Oedematous swelling of the bursa with petechial haemorrhages and slimy to gelatinous materials on the inner surface, and petechial haemorrhages on the thigh muscles were the main gross pathological lesions in both cases. Haemorrhages at the junction between proventriculus and gizzard found in chickens of natural infection but not in chickens of experimental infection. The experimentally infected chickens that survived up to the last day of 10 days observation revealed atrophied bursa with creamy or yellowish discolouration at necropsy. Key words: Infectious bursal disease; broiler chickens; clinical signs; pathology doi: 10.3329/bjvm.v2i1.1931 Bangl. J. Vet. Med. (2004). 2 (1) : 31-35

HOST DETERMINANTS BASED COMPARATIVE PREVALENCE OF SUBCLINICAL MASTITIS IN LACTATING HOLSTEIN-FRIESIAN CROSS COWS AND RED CHITTAGONG COWS IN BANGLADESH

A comparative prevalence of sub-clinical mastitis (SCM) based on host risk factors was studied by using California Mastitis Test (CMT) in 96 Holstein-Friesian cross cows (HFCC) of Abu Baker Dairy Farm at Pansha Upazilla in Rajbari district and 20 Red Chittagong cows (RCC) of Bangladesh Agricultural University Dairy Farm (BAUDF), Mymensingh during the period from January to June 2008. Out of the 116 lactating cows examined, 51 (43.97%) showed positive reactivity to CMT. Similar prevalence rate of SCM was recorded in both the HFCC (43.75%) and RCC (45.0%). The overall prevalence of SCM on the basis of lactation stages showed that all the three lactation stages had SCM but there was a tendency to increase its prevalence rates from early (30.43%), mid (32.26%) to late (69.23%) stages. The highest prevalence of SCM was recorded at late lactation stage in both the HFCC (68.75%) and RCC (71.43%) in comparison to their respective mid and early lactation stages. The parity-wise prevalence of SCM was recorded as 18.42%, 55.0%, 66.67%, 75.0% and 75.0% in HFCC whereas, it was 20.0%, 20.0%, 66.67%, 75.0% and 66.67% in RCC at their 1st, 2nd, 3rd, 4th and 5th parity, respectively. This study recorded a relationship between the increased prevalence of SCM with decreased of milk production in both the groups of lactating cows. The respective prevalence of SCM at high, medium and low level of milk production in HFC (14.29%, 33.33% and 70.59%) and RCC (14.29%, 50.00% and 71.42%) were found significantly (p < 0.01) correlated with milk production. An overall 19.18% quarters was affected with SCM, of which 4.31%, 7.33% and 7.38% showed mild, moderate and severe reaction to CMT. However, comparatively, higher percentage of quarter infection was recorded in HFCC (20.31%) than RCC (13.75%). It may be concluded from these observations that both the HFCC and RCC should be monitored by using CMT for the detection of SCM in order to provide rational treatment and control it to make the dairy farming profitable. DOI = 10.3329/bjvm.v8i1.7397 Bangl. J. Vet. Med. (2010). 8(1): 17-21

In vitro antibiotic sensitivity and therapeutic efficacy of experimental salmonellosis, colibacillosis and pasteurellosis in broiler chickens

Avian salmonellosis (AS), avian colibacillosis (AC) and avian pasteurellosis (AP) have been recognized as important bacterial diseases in poultry associated with morbidity and mortality in Bangladesh. The causative agents of these three diseases were isolated (5 isolates / disease) from dead chickens submitted for diagnosis at the BRAC Poultry Disease Diagnostic Centre, Gazipur during the period from January to December 2002. Five isolates of each of the Salmonella pullorum, Escherichia coli and Pasteurella multocida were evaluated against eight antibiotic containing disc which included ciprofloxacin, gentamicin, ampicillin, chloramphenicol, erythromycin, tetracycline, cephradine and penicillin G. Erythromycin in S. pullorum and Ciprofloxacin both in the E. coli and P. multocida were found highest sensitive, gentamicin, chloramphenicol, cephradine were found moderately sensitive to S. pullorum, gentamicin, tetracycline, erythromycin and ampicillin were found moderately sensitive to E. coli, and gentamicin ampicillin, cephradine and penicillin G were moderately sensitive to P. multocida. Therapeutic trials against experimentally produced S. pullorum, E. coli and P. multocida infection in three groups of broiler chickens showed that cephradine against S. pullorum and ciprofloxacin against both in E. coli and P. multocida were found highly effective both in vitro and in vivo studies, therefore, cephradine against salmonellosis and ciprofloxacin against colibacillosis and pasteurellosis are effective drugs of choice which could be used to control morbidity and mortality in poultry caused by these diseases.Key words: antibiotic sensitivity; salmonellosis; colibacillosis; pasteurellosis, broiler chickensdoi: 10.3329/bjvm.v2i2.2538Bangl. J. Vet. Med. (2004). 2 (2): 99-102

Outbreaks of Infectious Bursal Disease in Vaccinated and Unvaccinated Commercial Cockerel Farms in Bangladesh

Infectious bursal disease (IBD) is a contagious viral disease has been reported in young broiler and layer chickens from Bangladesh. This communication report the outbreaks of IBD on two vaccinated (Gumboro D78®, Intervet) and one unvaccinated commercial cockerel farms which were diagnosed on clinico-pathological findings and assessment of ELISA antibody titre. The outbreaks of IBD occurred on two vaccinated farms in cockerels of 29 to 31 days (Farm 1) and 30 to 33 days (Farm 2), whereas 19 to 22 days old in unvaccinated (Farm 3) birds. It caused 39.38% (Farm 1) and 75.0% (Farm 2) mortality in vaccinated and 29.20% (Farm 3) in unvaccinated cockerel farms. Clinical investigation showed rapid onset, dullness, depression, anorexia, whitish loose diarrhoea, soiling and pasting of the vent, ruffled feathers, trembling and finally prostration and death due to dehydration. Necropsy examination revealed dehydrated carcasses, enlargement and oedematous swelling of bursa Fabricius and some cases yellowish, haemorrhagic, yellowish and caseous exudate in the bursa. Skeletal muscles especially thigh muscles showed haemorrhages in some birds. The IBD ELISA antibody titre of both the vaccinated and the unvaccinated moribund cockerels showed at vulnerable state and the mean antibody titre of vaccinated farm 1 had 161 ± 59.22 and vaccinated farm 2 had 57.82 ± 14.85, whereas unvaccinated farms had 194 ± 90.35. The occurrence of IBD outbreaks in both the vaccinated and unvaccinated birds indicate not only vaccination failure but also defective control strategies, which resulted heavy economic loss (85.05%) in the three cockerel farms. Therefore, a sound control strategy requires monitoring of maternal derived antibody with correct vaccination policy as well as good biosecurity principles to control IBD in Bangladesh.Key words: Outbreaks, infectious bursal disease, cockerels, vaccination failure DOI = 10.3329/bjvm.v1i1.1912 Bangl. J. Vet. Med. (2003). 1 (1) : 21 - 24