Special Issue "Trends in Poultry Diseases"

A special issue of Veterinary Sciences (ISSN 2306-7381).

Deadline for manuscript submissions: closed (28 February 2022) | Viewed by 18854

Special Issue Editors

Dr. Giovanni Franzo
E-Mail Website
Guest Editor
Department Animal Medicine, Production and Health (MAPS), University of Padova, Padova, Italy
Interests: evolution; phylogenesis; bioinformatics; circoviruses; genetics
Special Issues, Collections and Topics in MDPI journals
Dr. Mattia Cecchinato
E-Mail Website
Guest Editor
Microbiology and Infectious Diseases, Department of Animal Medicine, Production and Health (MAPS), University of Padova, 35122 Padova, Italy
Interests: infectious bronchitis; avian metapneumovirus; avian influenza; infectious bursal disease; viral molecular diagnosis; control strategies; molecular epidemiology
Dr. Konstantinos Koutoulis
E-Mail Website
Guest Editor
Department of Poultry Diseases, Faculty of Veterinary Science, University of Thessaly, 43100 Karditsa, Greece
Interests: infectious bronchitis; infectious bursal disease; colibacillosis; salmonellosis; campylobacteriosis; probiotics
Special Issues, Collections and Topics in MDPI journals
Dr. Vasilios Tsiouris
E-Mail Website
Guest Editor
Unit of Avian Medicine, Clinic of Farm Animals, Faculty of Veterinary Medicine, School of Health Sciences, Aristotle University of Thessaloniki, 54627 Thessaloniki, Greece
Interests: gut health; necrotic enteritis; feed additives; plant extracts; Campylobacter spp; Eimeria spp
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

It is widely recognized that the demand for poultry meat and eggs has been increasing substantially in recent years due to the changes in food consumption patterns. The poultry industry has reacted to this increased demand by an expansion of broiler and layer production systems, which in turn has allowed ‘new’ and ‘old’ diseases to emerge and spread. Poultry infectious diseases, technopathy, and even those whose etiology is unknown have increased. Therefore, scientists continuously put in an effort to expand their research and hinder these diseases, limiting the associated vast financial losses to the poultry industry. Modern biotechnological tools are helping poultry production, allowing a faster and precise diagnosis, investigation of pathogenic mechanisms, reconstruction of disease spread and improvement of prevention, and control strategies such as the development of new vaccines, alternative to AGP feed additives, and techniques that are able to overcome the limits of the existing ones.

This Special Issue on “Trends in Poultry Diseases” intends to gather and disseminate the latest data and knowledge on different poultry diseases caused by various microorganisms, managerial practices, and technopathy, taking into account several aspects related to their epidemiology, diagnosis, and control.

Dr. Giovanni Franzo
Dr. Mattia Cecchinato
Dr. Konstantinos Koutoulis
Dr. Vasilios Tsiouris
Guest Editors

Manuscript Submission Information

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Keywords

  • poultry diseases
  • infectious diseases
  • vaccines
  • epidemiology
  • diagnosis
  • nutrition
  • technopathy

Published Papers (10 papers)

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Research

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Article
Pathology and Molecular Epidemiology of Fowl Adenovirus Serotype 4 Outbreaks in Broiler Chicken in Abu Dhabi Emirate, UAE
Vet. Sci. 2022, 9(4), 154; https://doi.org/10.3390/vetsci9040154 - 23 Mar 2022
Viewed by 1391
Abstract
Background: Fowl adenovirus serotype 4 (FAdV-4), causing inclusion body hepatitis (IBH) and hydropericardium hepatitis syndrome (HPS), is responsible for the significant economic losses in poultry industry worldwide. This study describes FAdV disease and molecular characteristics of the virus as the first report in [...] Read more.
Background: Fowl adenovirus serotype 4 (FAdV-4), causing inclusion body hepatitis (IBH) and hydropericardium hepatitis syndrome (HPS), is responsible for the significant economic losses in poultry industry worldwide. This study describes FAdV disease and molecular characteristics of the virus as the first report in UAE. Methodology: Clinical, necropsy, histopathology, qPCR and phylogenetic analysis of hexon gene were used to diagnose and characterize the virus. Results: The age of the infected broiler chicken was 2–4 weeks. The morbidity and mortality rates ranged between 50 and 100% and 44 and 100%, respectively. Clinically, sudden onset, diarrhea, anemia and general weakness were recorded. At necropsy, acute necrotic hepatitis, with swollen, yellowish discoloration, enlarged and friable liver; hydropericarditis with hydropericardium effusions; and enlarged mottled spleen were observed. Histopathology examination revealed degeneration and necrosis, lymphocytic infiltration and inclusion bodies. The qPCR analysis detected the virus in all samples tested. Hexon gene sequence analysis identified FAdV serotype 4, species C as the major cause of FAdV infections in UAE in 2020, and this strain was closely related to FAdV-4 circulating in Saudi Arabia, Pakistan, Nepal and China. Conclusion: The serotype 4, species C, was the common FAdV strain causing IBH and HPS episodes in the region. This result may help design effective vaccination programs that rely on field serotypes. Full article
(This article belongs to the Special Issue Trends in Poultry Diseases)
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Article
Investigation of Serotype Prevalence of Escherichia coli Strains Isolated from Layer Poultry in Greece and Interactions with Other Infectious Agents
Vet. Sci. 2022, 9(4), 152; https://doi.org/10.3390/vetsci9040152 - 23 Mar 2022
Viewed by 1244
Abstract
Colibacillosis is the most common bacterial disease in poultry and it is caused by avian pathogenic Escherichia coli (APEC), which is assigned to various O-serogroups. Previous studies have shown that APEC strains are more often related to certain O-serogroups such asO78, O2 and [...] Read more.
Colibacillosis is the most common bacterial disease in poultry and it is caused by avian pathogenic Escherichia coli (APEC), which is assigned to various O-serogroups. Previous studies have shown that APEC strains are more often related to certain O-serogroups such asO78, O2 and O1. E. coli has been reported to act either as a primary or secondary agent in complicating other infections. The aim of this study was to investigate the occurrence of and characterize the O-serogroups of E. coli strains isolated from commercial layer and layer breeder flocks showing macroscopic lesions of colibacillosis and increased or normal mortality in Greece. Furthermore, we attempted to assess the interaction between infectious agents such as Mycoplasma gallisepticum (MG), Mycoplasma synoviae (MS), infectious bronchitis (IBV) and infectious laryngotracheitis (ILT) with E. coli infections in layer flocks with increased mortality. Our study revealed that in addition to the common serogroups (O78, O2), many other, and less common serogroups were identified, including O111. The O78, O111 and O2 serogroups were frequently detected in flocks with lesions of colibacillosis and increased mortality whereas O2, O88 and O8 were reported more commonly in birds with colibacillosis lesions but normal mortality rates. These data provide important information for colibacillosis monitoring and define preventative measures, especially by using effective vaccination programs because E. coli vaccines are reported to mainly offer homologous protection. Finally, concerning the association of the four tested infectious agents with E. coli mortality, our study did not reveal a statistically significant effect of the above infectious agents tested with E. coli infection mortality. Full article
(This article belongs to the Special Issue Trends in Poultry Diseases)
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Article
Absorption of N-acetylcysteine in Healthy and Mycoplasma gallisepticum-Infected Chickens
Vet. Sci. 2021, 8(11), 244; https://doi.org/10.3390/vetsci8110244 - 20 Oct 2021
Viewed by 1102
Abstract
N-acetylcysteine (NAC) is widely used as a mucolytic agent in cases with inflammation of the lungs. NAC is applied in poultry with aflatoxin B1 intoxication as an antioxidant, but its pharmacokinetics are not known. The present study was conducted to characterize the population [...] Read more.
N-acetylcysteine (NAC) is widely used as a mucolytic agent in cases with inflammation of the lungs. NAC is applied in poultry with aflatoxin B1 intoxication as an antioxidant, but its pharmacokinetics are not known. The present study was conducted to characterize the population pharmacokinetics of orally administered NAC in broilers. It included 32 chickens, divided into four groups, treated with NAC at a dose rate of 100 mg/kg/day mixed with the feed: healthy broilers (n = 6); chickens infected with Mycoplasma gallisepticum (n = 10); healthy broilers (n = 6); and diseased chickens (n = 10) treated with NAC and doxycycline (via drinking water, 20 mg/kg body weight (b.w.)). Plasma concentrations were analyzed by Liquid Chromatography –Mass Spectrometry (MS)/MS. NAC was absorbed after oral administration in all four groups of chickens. In healthy chickens treated solely with NAC, maximum plasma concentrations of 2.26 ± 0.91 µg mL−1 were achieved at 2.47 ± 0.45 h after dosing. The value of absorption half-life was 1.04 ± 0.53 h. The population pharmacokinetic analysis showed that dose adjustment of NAC is not required in M. gallisepticum-infected broilers or when it is combined with doxycycline. Full article
(This article belongs to the Special Issue Trends in Poultry Diseases)
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Article
Infectious Bronchitis Hatchery Vaccination: Comparison between Traditional Spray Administration and a Newly Developed Gel Delivery System in Field Conditions
Vet. Sci. 2021, 8(8), 145; https://doi.org/10.3390/vetsci8080145 - 29 Jul 2021
Viewed by 1557
Abstract
The control of infectious bronchitis (IB) is essential in intensive broiler production and is pursued through strict biosecurity and mass vaccination. Despite effective and routinely adopted, hatchery spray vaccination has been hypothesized to affect chicks’ body temperature and wellbeing. Recently, gel administration has [...] Read more.
The control of infectious bronchitis (IB) is essential in intensive broiler production and is pursued through strict biosecurity and mass vaccination. Despite effective and routinely adopted, hatchery spray vaccination has been hypothesized to affect chicks’ body temperature and wellbeing. Recently, gel administration has been proposed as an alternative and proved feasible in experimental settings. In this study, IBV spray and gel vaccination methods were compared in field conditions. One hundred birds from the same hatch were enrolled in the study and vaccinated, half by spray and half by gel, with 793B and Mass vaccines. After vaccination, rectal temperature was measured and vaccine intake assessed. The two groups were housed for 35 days in separate pens and swabs and blood samples were collected at multiple time points for genotype-specific molecular analyses and serology, respectively. The temperature was significantly lower in spray-vaccinated chicks 10 min and an hour after administration. A similar trend in 793B titres was observed in both groups, while the Mass vaccine was detected later but persisted longer in gel-vaccinated chicks. No differences were observed in mean antibody titres. Compared to spray, gel administration appears equally effective and less impactful on body temperature, thus supporting its application for IBV vaccination. Full article
(This article belongs to the Special Issue Trends in Poultry Diseases)
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Article
Antimicrobial Resistance, FlaA Sequencing, and Phylogenetic Analysis of Campylobacter Isolates from Broiler Chicken Flocks in Greece
Vet. Sci. 2021, 8(5), 68; https://doi.org/10.3390/vetsci8050068 - 21 Apr 2021
Cited by 1 | Viewed by 2397
Abstract
Human campylobacteriosis caused by thermophilic Campylobacter species is the most commonly reported foodborne zoonosis. Consumption of contaminated poultry meat is regarded as the main source of human infection. This study was undertaken to determine the antimicrobial susceptibility and the molecular epidemiology of 205 [...] Read more.
Human campylobacteriosis caused by thermophilic Campylobacter species is the most commonly reported foodborne zoonosis. Consumption of contaminated poultry meat is regarded as the main source of human infection. This study was undertaken to determine the antimicrobial susceptibility and the molecular epidemiology of 205 Campylobacter isolates derived from Greek flocks slaughtered in three different slaughterhouses over a 14-month period. A total of 98.5% of the isolates were resistant to at least one antimicrobial agent. In terms of multidrug resistance, 11.7% of isolates were resistant to three or more groups of antimicrobials. Extremely high resistance to fluoroquinolones (89%), very high resistance to tetracycline (69%), and low resistance to macrolides (7%) were detected. FlaA sequencing was performed for the subtyping of 64 C. jejuni and 58 C. coli isolates. No prevalence of a specific flaA type was observed, indicating the genetic diversity of the isolates, while some flaA types were found to share similar antimicrobial resistance patterns. Phylogenetic trees were constructed using the neighbor-joining method. Seven clusters of the C. jejuni phylogenetic tree and three clusters of the C. coli tree were considered significant with bootstrap values >75%. Some isolates clustered together were originated from the same or adjacent farms, indicating transmission via personnel or shared equipment. These results are important and help further the understanding of the molecular epidemiology and antimicrobial resistance of Campylobacter spp. derived from poultry in Greece. Full article
(This article belongs to the Special Issue Trends in Poultry Diseases)
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Article
Molecular Epidemiology and Genotyping of Infectious Bronchitis Virus and Avian Metapneumovirus in Backyard and Commercial Chickens in Jimma Zone, Southwestern Ethiopia
Vet. Sci. 2020, 7(4), 187; https://doi.org/10.3390/vetsci7040187 - 25 Nov 2020
Cited by 3 | Viewed by 1575
Abstract
Poultry production plays a relevant role in the Ethiopian economy and represents a source of poverty alleviation for several social classes. Infectious diseases can therefore significantly impact the economy and welfare. Despite infectious bronchitis virus (IBV) and avian metapneumovirus (aMPV) being present, the [...] Read more.
Poultry production plays a relevant role in the Ethiopian economy and represents a source of poverty alleviation for several social classes. Infectious diseases can therefore significantly impact the economy and welfare. Despite infectious bronchitis virus (IBV) and avian metapneumovirus (aMPV) being present, the knowledge of their epidemiology and impact is extremely limited. In the present work, a cross-sectional study based on 500 tracheal swabs collected from 50 intensive and backyard unvaccinated flocks of the Jimma Zone was performed to investigate the circulation of these viruses and molecularly characterize them. IBV and aMPV presence was tested by molecular assays, and genotyping was carried out on positive samples. Accordingly, 6% (95% CI 2.06% to 16.22%) and 8% (95% CI 3.15% to 18.84%) of flocks tested IBV and aMPV positive, respectively. Particularly, IBV 793B (GI-13) strains were detected in backyard flocks only, and identical or closely related sequences (p-distance <2%) were detected in distantly spaced flocks, suggesting relevant viral circulation. On the contrary, both backyard and intensive flocks were affected by aMPV subtype B. Potential epidemiological links associated to the importation of parental birds from foreign countries could be established. These results highlight non-negligible circulation of these viruses, warranting further epidemiological studies and the evaluation of control measure implementation. Full article
(This article belongs to the Special Issue Trends in Poultry Diseases)
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Article
An Assessment of the Level of Protection Against Colibacillosis Conferred by Several Autogenous and/or Commercial Vaccination Programs in Conventional Pullets upon Experimental Challenge
Vet. Sci. 2020, 7(3), 80; https://doi.org/10.3390/vetsci7030080 - 30 Jun 2020
Cited by 11 | Viewed by 1493
Abstract
The prevention of avian colibacillosis has historically been investigated through vaccination, with variable outcomes. Commercial live (attenuated) and inactivated vaccines are reported to have limited efficacy in the context of heterologous challenge. Autogenous vaccination, using field isolates, is widely used, but scarcely documented. [...] Read more.
The prevention of avian colibacillosis has historically been investigated through vaccination, with variable outcomes. Commercial live (attenuated) and inactivated vaccines are reported to have limited efficacy in the context of heterologous challenge. Autogenous vaccination, using field isolates, is widely used, but scarcely documented. Different vaccination programs, including a live commercial vaccine and/or an inactivated autogenous vaccine, were compared for three different avian pathogenic Escherichia coli (APEC) strain (serotypes O78, O18 and O111) challenges. On the pullet farm, four groups of conventional pullets received different vaccination protocols. Group A was kept unvaccinated (control group). Group B was vaccinated three times with a live commercial O78 E. coli vaccine (at one day old, 59 and 110 days of age). Group C was immunized twice (at 79 and 110 days) with a three-valence autogenous vaccine (O78, O18 and O111). Group D was vaccinated first with the commercial vaccine (at one day old and 59 days), then with the autogenous vaccine (110 days). Birds were transferred to the experimental facility at 121 days of age and were challenged 10 days later. In each group, 20 birds were challenged with one of the three APEC strains (O78, O18, O111); in total, 80 birds were challenged by the same strains (20 per group). The recorded outcomes were: mortality rate, macroscopic lesion score in target organs and the bacterial recovery of the challenge strain from bone marrow and pooled organs. When challenged with O78 or O111 strains, birds from groups C and D proved to be significantly better protected, in terms of lesion scoring and bacteriological isolation, than those of groups A and B. With the O18 challenge, only birds of group D presented a statistically significant reduction of their lesion score. To the authors’ knowledge, this is the first report on the efficacy of an immunization program in poultry that combines commercial and autogenous vaccines. Full article
(This article belongs to the Special Issue Trends in Poultry Diseases)

Review

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Review
Infectious Bronchitis Virus Evolution, Diagnosis and Control
Vet. Sci. 2020, 7(2), 79; https://doi.org/10.3390/vetsci7020079 - 22 Jun 2020
Cited by 17 | Viewed by 3152
Abstract
RNA viruses are characterized by high mutation and recombination rates, which allow a rapid adaptation to new environments. Most of the emerging diseases and host jumps are therefore sustained by these viruses. Rapid evolution may also hinder the understanding of molecular epidemiology, affect [...] Read more.
RNA viruses are characterized by high mutation and recombination rates, which allow a rapid adaptation to new environments. Most of the emerging diseases and host jumps are therefore sustained by these viruses. Rapid evolution may also hinder the understanding of molecular epidemiology, affect the sensitivity of diagnostic assays, limit the vaccine efficacy and favor episodes of immune escape, thus significantly complicating the control of even well-known pathogens. The history of infectious bronchitis virus (IBV) fits well with the above-mentioned scenario. Despite being known since the 1930s, it still represents one of the main causes of disease and economic losses for the poultry industry. A plethora of strategies have been developed and applied over time, with variable success, to limit its impact. However, they have rarely been evaluated objectively and on an adequate scale. Therefore, the actual advantages and disadvantages of IBV detection and control strategies, as well as their implementation, still largely depend on individual sensibility. The present manuscript aims to review the main features of IBV biology and evolution, focusing on their relevance and potential applications in terms of diagnosis and control. Full article
(This article belongs to the Special Issue Trends in Poultry Diseases)
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Other

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Case Report
First Detection and Identification of FAdV-8b as the Causative Agent of an Outbreak of Inclusion Body Hepatitis in a Commercial Broiler Farm in Greece
Vet. Sci. 2022, 9(4), 160; https://doi.org/10.3390/vetsci9040160 - 25 Mar 2022
Viewed by 1352
Abstract
Inclusion body hepatitis (IBH) is an economically important disease of chickens, with a worldwide distribution, caused by Fowl Aviadenoviruses (FAdVs). Currently, the increased number of cases, the virulence of the isolate strains, as well as the lack of cross-species protection highlight that detailed [...] Read more.
Inclusion body hepatitis (IBH) is an economically important disease of chickens, with a worldwide distribution, caused by Fowl Aviadenoviruses (FAdVs). Currently, the increased number of cases, the virulence of the isolate strains, as well as the lack of cross-species protection highlight that detailed in-field data are fundamental for the development of successful control strategies. This case report provides a detailed clinicopathological investigation of an unusual IBH outbreak in a commercial broiler farm in the region of Macedonia, Greece. The farm consisted of 64,000 birds, originated from the same breeder stock and placed in three different houses (Flock A–C). At 20 days of age, a sudden increase in daily mortality was recorded in Flock A. It is worth mentioning that, although all flocks were serologically (indirect ELISA) and molecularly (RT-PCR) positive for FAdV, the mortality rate, attributed to IBH, was much higher in Flock A compared to others. The clinical manifestation included non-specific symptoms such as depression, inappetence, yellowish mucoid diarrhea, and lack of uniformity. At necropsy, typically, enlarged, pale, and friable livers were dominant, while sporadically lesions were recorded in the pancreas, kidneys, skeletal muscles, and lymphoid organs. The histopathological examination of liver samples showed multifocal inflammation, necrosis, and the presence of basophilic/ eosinophilic inclusion bodies in hepatocytes. In addition, the loss of the architecture of pancreatic lobules and the presence of fibrosis and foci of mononuclear cell aggregates were suggestive of chronic pancreatic inflammation. PCR analysis confirmed the presence of FAdV, belonging to species E, serotype FAdV-8b. Performance and financial calculations revealed that IBH increased Feed Conversion Ratio (FCR), feed cost/chick as well as feed cost/kg live weight, whereas the Livability (%) and the European Production Efficiency Factor (EPEF) were decreased in the most severely affected flocks (Flock A). This study is the first report of the detection and identification of FAdV serotypes associated with IBH in commercial broiler flocks in Greece. However, there is still a lack of information about the circulating FAdV serotypes in the country, and therefore epidemiological studies are needed to establish control strategies for IBH. Full article
(This article belongs to the Special Issue Trends in Poultry Diseases)
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Case Report
A Case of Infectious Laryngotracheitis in an Organic Broiler Chicken Farm in Greece
Vet. Sci. 2021, 8(4), 64; https://doi.org/10.3390/vetsci8040064 - 16 Apr 2021
Cited by 1 | Viewed by 2137
Abstract
Infectious laryngotracheitis is an economically significant viral disease of chickens, that mainly affects the upper respiratory tract, and is present worldwide. This case reports the first outbreak of infectious laryngotracheitis in a four-week-old organic broiler farm and surrounding flocks in Greece, with typical [...] Read more.
Infectious laryngotracheitis is an economically significant viral disease of chickens, that mainly affects the upper respiratory tract, and is present worldwide. This case reports the first outbreak of infectious laryngotracheitis in a four-week-old organic broiler farm and surrounding flocks in Greece, with typical clinical symptoms and lesions, allegedly provoked by a wild strain of infectious laryngotracheitis virus. Our findings contradict the general perception indicating that the disease appears mainly in older birds and that vaccine strains are the primary cause of infectious laryngotracheitis outbreaks in most continents. A recombinant vectored vaccine was administered, supplementary to biosecurity measures, containing the viral spread. The responsible strain was potentially circulating in the area; therefore, an industry-wide holistic approach was applied, including the vaccination of neighboring broilers and breeders with the same vaccine, the rapid molecular diagnosis of the disease, and strict biosecurity protocols. The results of this holistic effort were effective because, following the application of vaccine and management protocols, manifestations of the disease in regional flocks dropped significantly, and there was no recurrence to date. These findings suggest that vaccination protocols should be modified, especially for organic broilers, to include vaccination against infectious laryngotracheitis. Full article
(This article belongs to the Special Issue Trends in Poultry Diseases)
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