Factors limiting the health of semi-scavenging ducks in Bangladesh

Snakebite Envenoming in Avian Species: A Systematic Scoping Review and Practitioner Experience Survey

Snakebite envenoming in avian species is infrequently reported in the veterinary literature, although perhaps not as rarely as recent publications suggest. A systematic scoping review was performed on the topic using PubMed and Google Scholar, 21 veterinary textbooks, and 139 conference proceedings. A practitioner experience survey was also performed, with recruitment from Facebook groups for exotic animal practitioners and professional organization email listservs. Only 31 texts met our inclusion/exclusion criteria, which meant they described clinicopathologic signs of snakebite envenomation in avian species, the treatment of snakebite envenomation in avian species, or expanded the geographic range or the number of captive avian and snake species involved. Reports included approximately 15-20 different species of both snakes and birds worldwide; however, no reports described clinicopathologic signs of naturally occurring snakebites from Asia, Australasia, or Europe. The few responses from our practitioner experience survey suggest that snakebite envenomation may be more common than previously reported. Clinical signs of snake envenomation in birds appear to depend on the snake species involved but often include local swelling and subcutaneous edema or hemorrhage with paired fang marks; weakness, bleeding, neurologic deficits, and death may follow. A wide variety of treatment protocols have been used to counter snakebite envenomation in birds, including the successful use of antivenom. Based on this body of evidence, much remains to be learned about snakebite envenomation of birds, particularly about the efficacy of different treatment protocols.

Prevalence and risk factors of Avian Influenza Viruses among household ducks in Chattogram, Bangladesh

Avian influenza viruses (AIV) increase commercial and backyard poultry mortality and morbidity, reduces egg production, and elevates public health risk. Household ducks propagate and transmit HPAI and LPAI viruses between domesticated and wild birds in Southeast Asian countries, including Bangladesh. This study was conducted to identify epidemiological factors associated with AIV infection among household ducks at Chattogram, Bangladesh. We randomly selected and collected blood and oropharyngeal swab samples from 281 households ducks. We evaluated the serum for AIV antibody using cELISA and tested for H5 and H9 subtypes using the HI test. We tested the swabs with real-time reverse transcriptase PCR (rRT-PCR) for M gene, and H5, H9 subtypes. In the duck populations, the household level AIV sero-prevalence was 57.7% (95% CI: 51.6-63.3) and RNA prevalence was 2.4% (95% CI: 1.0-5.0). H5 and H9 subtype sero-prevalence was 31.5% (95% CI: 22.2-42.0) and 23.9% (95% CI: 15.6-33.9). H5 and H9 subtype RNA prevalence were 0% (95% CI: 0.0-1.3) and 2.4% (95% CI: 1.0-5.0). We determined household-level OR (Odds Ratios) for the "combined (mixed materials-mud and concrete or metallic)" category was 2.2 (95% CI: 1.1-4.2) compared with "wooden/bamboo" category (p = 0.02); 2.8 (95% CI: 1.2-6.6) in households with duck plague vaccine coverage compared with no coverage (p = 0.01); and 2.4 (95% CI: 0.6-9.7) in households that threw dead birds in bushes and the roadside compared with households that buried or threw dead birds in garbage pits (p = 0.21). M gene phylogenetic analysis compared M gene sequences to previously reported Bangladeshi H9N2 isolates. The evidence presented here shows AIV circulation in the Chattogram, Bangladesh study areas. AIV reduction can be achieved through farmer education of proper farm management practices.

Occurrence and multidrug resistance of Campylobacter spp. at duck farms and associated environmental and anthropogenic risk factors in Bangladesh

Background

The alarming rise in multi-drug resistant (MDR) zoonotic pathogens, including Campylobacter spp., has been threatening the health sector globally. In Bangladesh, despite rapid growth in poultry sector little is known about the potential risks of zoonotic pathogens in homestead duck flocks. The aim of this study was to understand the occurrence, species diversity, and multi-drug resistance in Campylobacter spp., and identify the associated risk factors in duck farms in Bangladesh.

Methods

The study involved 20 duck farms at 6 sub-districts of Mymensingh, Bangladesh. Monthly occurrence of Campylobacter spp. in potential sources at the farms during February-September, 2018, was detected by culture and PCR-based methods. Campylobacter isolates were examined for resistance to different antimicrobials. Risk factors, concerning climatic and environmental disposition, farm management, and anthropogenic practices, of Campylobacter infection were estimated by participatory epidemiological tools.

Results

Occurrence of Campylobacter spp. was detected in overall 36.90% (155/420) samples, more frequently in drinking water (60%, 30/50), followed by cloacal swab (37.50%, 75/200), egg surface swab (35%, 35/100) and soil of the duck resting places (30%, 15/50) but was not detected in feed samples (n = 20). PCR assays distinguished the majority (61.30%, 95/155) of the isolates as C. coli, while the rest (38.70%, 60/155) were C. jejuni. Notably, 41.7% (25/60) and 31.6% (30/95) strains of C. jejuni and C. coli, respectively, were observed to be MDR. The dynamics of Campylobacter spp., distinctly showing higher abundance during summer and late-monsoon, correlated significantly with temperature, humidity, and rainfall, while sunshine hours had a negative influence. Anthropogenic management-related factors, including, inadequate hygiene practices, use of untreated river water, wet duck shed, flock age (1–6 months), and unscrupulous use of antimicrobials were identified to enhance the risk of MDR Campylobacter infection.

Conclusion

The present study clearly demonstrates that duck farms contribute to the enhanced occurrence and spread of potentially pathogenic and MDR C. coli and C. jejuni strains and the bacterial dynamics are governed by a combined interaction of environmental and anthropogenic factors. A long-term holistic research at the environment-animal-human interface would be integral to divulge health risk reduction approaches tackling the spread of Campylobacter spp. from duck farms.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06834-w.

A systematic review and meta-analysis on the prevalence of infectious diseases of Duck: A world perspective

The Indian poultry industry is one of the fast-growing sectors of which duck farming plays an important role. Duck population in India is 33.51 million that is concentrated towards north-east and southern parts of the country who rears mainly for eggs and meat. Duck diseases are of great concern as they badly affect the financial status of the small, landless farmers. Databases such as Google Scholar, PubMed, J gate were used to search articles between 2000 and 2019 that showed the prevalence of viral, bacterial, and parasitic duck diseases. R open source software was used to derive forest plots by statistical analysis. Pooled prevalence estimates of duck diseases worldwide was found to be 20% (95%-CI:15–26). Also, continent-wise analysis of all duck diseases has revealed highest prevalence in North America, followed by Asia, Africa, Europe,Oceania and South America. This prevalence of data would be helpful to the policymakers to develop appropriate intervention strategies to prevent and control diseases in their respective locations.

Impact of improved small-scale livestock farming on human nutrition

Micronutrient deficiencies and stunting rates are high in many low-income countries. Increasing and diversifying food intake are often challenging for small-scale farmers in lowland areas as flooding often results in crop losses and drowning of livestock. A cluster-randomised controlled trial was conducted over 12-months in Bangladesh, involving 150 small-scale duck rearing households, including 50 control, and 50 households each in two intervention arms. Interventions focussing on improving duck health and duck nutrition were applied on a village level. Data analysis focussed on assessing the impact of interventions on duck mortality, sales and consumption, and on dietary diversity of household members. Improved duck rearing increased the consumption and the sales of ducks. Household selling more ducks were more likely to purchase and consume milk products, contributing to an improved households’ dietary diversity. Our results suggest that improving duck rearing can provide a suitable and sustainable alternative to maintain and improve dietary diversity of households in flood-prone areas.

Prevalence and Distribution of Avian Influenza Viruses in Domestic Ducks at the Waterfowl-Chicken Interface in Wetlands

Ducks are a natural reservoir of influenza A viruses (IAVs) and can act as a reassortment vessel. Wetlands, such as Hakaluki and Tanguar haor in Bangladesh, have unique ecosystems including domestic duck (Anas platyrhynchos domesticus) rearing, especially household and free-range ducks. A cross-sectional study was, therefore, conducted to explore avian influenza status and its distribution and risk factors in the wetland areas. During the three consecutive winters of 2015-2017, specifically in December of these years, we collected a total of 947 samples including blood, oropharyngeal and cloacal swabs from domestic ducks (free-range duck (n = 312 samples) and household ducks (n = 635 samples) in wetlands. We screened serum samples using a nucleoprotein competitive enzyme-linked immunosorbent assay (c-ELISA) to estimate seroprevalence of IAV antibodies and swab samples by real-time reverse transcriptase polymerase chain reaction (rRT-PCR) to detect IA viral M gene. Eleven (11) M gene positive samples were subjected to sequencing and phylogenetic analysis. Serological and viral prevalence rates of IAVs were 63.8% (95% CI: 60.6-66.8) and 10.7% (8.8-12.8), respectively. Serological and viral RNA prevalence rates were 51.8% (95% CI: 47.2-56.4) and 10.2% (7.6-13.3) in Hakaluki haor, 75.6% (71.5-79.4) and 11.1% (8.5-14.3) in Tanguar haor, 66.3% (62.5-69.9) and 11.2% (8.8-13.9) in household ducks and 58.7% (52.9-64.2) and 9.6% (6.5-13.4) in free-range ducks, respectively. The risk factors identified for higher odds of AI seropositive ducks were location (OR = 2.9, 95% CI: 2.2-3.8, p < 0.001; Tanguar haor vs. Hakaluki haor), duck-rearing system (OR = 1.4, 1.1-1.8, household vs. free-range), farmer's education status (OR = 1.5, 1.2-2.0, p < 0.05 illiterate vs. literate) and contact type (OR = 3.0, 2.1-4.3, p < 0.001; contact with chicken vs. no contact with chicken). The risk factors identified for higher odds of AI RNA positive ducks were farmer's education status (OR = 1.5, 1.0-2.3, p < 0.05 for illiterate vs literate), contact type (OR = 2.7, 1.7-4.2, p < 0.001; ducks having contact with chicken vs. ducks having contact with waterfowl). The phylogenetic analysis of 11 partial M gene sequences suggested that the M gene sequences detected in free-range duck were very similar to each other and were closely related to the M gene sequences of previously reported highly pathogenic avian influenza (HPAI) and low pathogenic avian influenza (LPAI) subtypes in waterfowl in Bangladesh and Southeast Asian countries. Results of the current study will help provide significant information for future surveillance programs and model IAV infection to predict the spread of the viruses among migratory waterfowl, free-range ducks and domestic poultry in Bangladesh.

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

An epidemiological assessment of clinical poultry cases recorded through the existing passive surveillance at Kishoreganj District Veterinary Hospital during February-March 2016 was performed. A total of 200 cases (87 layers, 80 broilers, 21 ducks, and 12 pigeons) were included in this evaluation. The present study attempted to demonstrate the usefulness of passive surveillance data in quantifying the relative burden of poultry cases and their distribution along with drug prescription patterns. The cases were diagnosed based on clinical history, clinical signs, and observable post-mortem lesions by the registered veterinarian or intern veterinarian. The most prevalent diseases in chickens were infectious bursal disease (IBD) (31.7%; CI (confidence interval) 24.7-39.3%), coccidiosis (22.8%; CI 16.6-29.8%), Newcastle disease (ND) (21.6%; CI 15.5-28.5%), and coli-enteritis (8.4%; CI 4.6-13.6%). The most prevalent disease in ducks was duck plague (DP) (76.6%; CI 52.8-91.7%). Newcastle disease was most prevalent (66.7%; CI 34.8-90.0%) in pigeons. Infectious bursal disease, aspergillosis, and colibacillosis respectively were seen in a higher proportion of cases in broiler chickens than in layer chickens (58.7%, 12.5%, and 11.2% vs. 6.9%, 1.1%, and 3.4%; p ≤ 0.05). Contrarily, ND was seen in greater proportion of cases in layer chickens (32.1%) than in broiler chickens (10.0%) (p < 0.001). Infectious bursal disease, ND, coccidiosis, and aspergillosis were higher in older age broilers than in younger broilers (p ≤ 0.05). Antibiotics were often used to treat the poultry diseases such as trimethoprim with sulpha drugs (41%), ciprofloxacin (39%), sulphadiazine (27.5%), and erythromycin (26%). Through the present study, we can see how a passive surveillance system would be an effective tool for delineating disease distributions and common treatment regimens, thus helping to mitigate disease prevalence.

Duck virus enteritis (duck plague) - a comprehensive update

Duck virus enteritis (DVE), also called duck plague, is one of the major contagious and fatal diseases of ducks, geese and swan. It is caused by duck enteritis virus (DEV)/Anatid herpesvirus-1 of the genus Mardivirus, family Herpesviridae, and subfamily Alpha-herpesvirinae. Of note, DVE has worldwide distribution, wherein migratory waterfowl plays a crucial role in its transmission within and between continents. Furthermore, horizontal and/ or vertical transmission plays a significant role in disease spread through oral-fecal discharges. Either of sexes from varying age groups of ducks is vulnerable to DVE. The disease is characterized by sudden death, vascular damage and subsequent internal hemorrhage, lesions in lymphoid organs, digestive mucosal eruptions, severe diarrhea and degenerative lesions in parenchymatous organs. Huge economic losses are connected with acute nature of the disease, increased morbidity and mortality (5%-100%), condemnations of carcasses, decreased egg production and hatchability. Although clinical manifestations and histopathology can provide preliminary diagnosis, the confirmatory diagnosis involves virus isolation and detection using serological and molecular tests. For prophylaxis, both live-attenuated and killed vaccines are being used in broiler and breeder ducks above 2 weeks of age. Since DEV is capable of becoming latent as well as shed intermittently, recombinant subunit and DNA vaccines either alone or in combination (polyvalent) are being targeted for its benign prevention. This review describes DEV, epidemiology, transmission, the disease (DVE), pathogenesis, and advances in diagnosis, vaccination and antiviral agents/therapies along with appropriate prevention and control strategies.

Causes of morbidity and mortality of wild aquatic birds at Billabong Sanctuary, Townsville, North Queensland, Australia

Infectious diseases are common causes of significant morbidity and mortality events of wild aquatic birds (WABs) worldwide. Reports of Australian events are infrequent. A 3-yr passive surveillance program investigating the common causes of morbidity and mortality of WABs was conducted at Billabong Sanctuary near Townsville, North Queensland, from April 2007 to March 2010. Forty-two carcasses were obtained and evaluated by clinico-pathologic, histologic, bacteriologic, and virologic (molecular) examinations. Morbidity and mortality were sporadic and more commonly observed in chicks and juvenile birds in April than other months of the year. Morbid birds were frequently unable to walk. Hemorrhagic lesions and infiltration of lymphocytes in various organs were the most common findings in dead birds. Identified bacterial diseases that could cause bird mortality were colibacillosis, pasteurellosis, and salmonellosis. Salmonella serotypes Virchow and Hvittingfoss were isolated from an Australian white ibis (Threskiornis molucca) chick and two juvenile plumed whistling ducks (Dendrocygna eytoni) in April 2007. These strains have been previously isolated from humans in North Queensland. A multiplex real time reverse transcriptase-PCR (rRT-PCR) detected Newcastle disease viral RNA (class 2 type) in one adult Australian pelican (Pelecanus conspicillatus) and a juvenile plumed whistling duck. No avian influenza viral RNA was detected from any sampled birds by the rRT-PCR for avian influenza. This study identified the public health importance of Salmonella in WABs but did not detect the introduction of the high pathogenicity avian influenza H5N1 virus in the population. A successful network was established between the property owner and the James Cook University research team through which dead birds, with accompanying information, were readily obtained for analysis. There is an opportunity for establishing a long-term passive disease surveillance program for WABs in North Queensland, an important region in Australian biosecurity, thus potentially significantly benefitting public health in the region and the country.

Monitoring of wild birds for Newcastle disease virus in north Queensland, Australia

Wild aquatic birds (WABs) are considered as reservoir hosts for Newcastle disease viruses (NDVs) and may act as vectors for transferring these viruses to poultry, causing outbreaks of disease. A 3-year epidemiological study was conducted on WABs of north Queensland from April 2007 to March 2010. Swab and fresh moist faecal samples of WABs were screened to detect Newcastle disease viral (NDV) RNA by one-step real time reverse transcriptase polymerase chain reaction (rRT-PCR) in multiplex primers, targeting the matrix gene. The potential reactor samples in rRT-PCR were processed for sequencing of the different NDV genes using conventional PCR. The overall NDV RNA prevalence was 3.5% for live bird samples (N=1461) and 0.4% for faecal samples (N=1157). Plumed whistling ducks (PWDs) had a higher prevalence (4.2%) than Pacific black ducks (PBDs) (0.9%) (χ(2) test, p=0.001). Univariate and multivariate logistic regression analyses were used to estimate the association between the proportion of reactor and non-reactor NDV RNA samples of PWDs and potential risk factors. The odds of reactor samples were 2.7 (95% Confidence Interval 1.5-4.9) times more likely in younger than older ducks (p=0.001) (data set B, multivariate analysis). Both NDV RNA class-one and class-two types were identified in samples of WABs (12 and 59, respectively) (Supplementary Table 1). Phylogenetic analysis of the matrix gene identified two reactor sequences of class-one type NDV RNA (PWD-48 and 55) which were closely related to the sequences of Australian Ibis and duck isolates (Fig. 2). Another reactor sample sequence was determined as class-two type NDV RNA (PWD-46, avirulent) based on analysis of the matrix and fusion genes which was more similar to the sequences of Australian I-2 progenitor virus and vaccine strain virus (Figs. 3 and 4). Our findings of higher prevalence in PWDs along with confirmation of class-one and class-two type NDV RNAs will significantly contribute to the design of surveillance programs for NDVs in northern Australia.