Microorganisms

Research

14 pages, 5482 KiB

Open AccessArticle

Effect of Egg Washing and Hen Age on Cuticle Quality and Bacterial Adherence in Table Eggs

by Garima Kulshreshtha, Cian Ward, Nicholas D. Calvert, Cristina Benavides-Reyes, Alejandro B. Rodriguez-Navarro, Ty Diep and Maxwell T. Hincke

Microorganisms 2024, 12(10), 2027; https://doi.org/10.3390/microorganisms12102027 - 8 Oct 2024

Viewed by 890

Abstract

The cuticle covering the outer surface of an eggshell functions as both a physical and chemical barrier against invading microorganisms. Contamination of eggs by microbial pathogens progresses in four stages: bacterial attachment to the egg surface, penetration through the cuticle and eggshell, multiplication [...] Read more.

The cuticle covering the outer surface of an eggshell functions as both a physical and chemical barrier against invading microorganisms. Contamination of eggs by microbial pathogens progresses in four stages: bacterial attachment to the egg surface, penetration through the cuticle and eggshell, multiplication within the underlying membranes, and the final stage of contaminating the egg contents. Therefore, it is important to study bacterial count at the first point of contact, i.e., on the surface of the eggs. In this study, we have evaluated the impact of differences in cuticle quality (due to egg washing and hen age) on bacterial load. We compared bacterial adherence on the eggshell surface of white eggs which were either washed (graded) or unwashed (ungraded), collected from Lohmann laying hens of different ages: early (24–28 weeks), mid-lay (44–48 weeks), and late (66–70 weeks). We aimed to determine the impact of hen age and egg washing on differences in cuticle quality and bacterial adherence. Our results indicate that hen age (up to 70 weeks) and commercial egg washing do not significantly impact bacterial adherence on eggshell surfaces. We have developed a novel method using green fluorescent protein (GFP)-expressing Salmonella typhimurium to estimate adherence of bacteria to the eggshell surface, with independent measurement of autofluorescence to quantitate cuticle deposition. S. typhimurium were localized, adhering to cracks visible on the outer cuticle in ungraded eggs, indicating that egg-associated pathogens usually enter the egg interior either through respiratory pores in eggshells or through shell micro-cracks. The results of this study can be utilized to optimize innovative methods for predictive microbiology in order to achieve egg safety. Full article

(This article belongs to the Special Issue Avian Pathogens 2.0)

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17 pages, 5570 KiB

Open AccessArticle

Stable Isotope Analysis Reveals Common Teal (Anas crecca) Molting Sites in Western Siberia: Implications for Avian Influenza Virus Spread

by Alexey V. Druzyaka, Olga R. Druzyaka, Kirill A. Sharshov, Nikita Kasianov, Nikita Dubovitskiy, Anastasiya A. Derko, Ivan G. Frolov, Jyrki Torniainen, Wen Wang, Mariya A. Minina and Alexander M. Shestopalov

Microorganisms 2024, 12(2), 357; https://doi.org/10.3390/microorganisms12020357 - 9 Feb 2024

Cited by 1 | Viewed by 1343

Abstract

The wetlands of southwestern Siberia (SWS) are a crossroads of bird migration routes, bringing avian influenza (AIV) strains that were previously isolated in different regions of the continent to Siberia. It is known that Anseriformes that breed in SWS migrate for the winter [...] Read more.

The wetlands of southwestern Siberia (SWS) are a crossroads of bird migration routes, bringing avian influenza (AIV) strains that were previously isolated in different regions of the continent to Siberia. It is known that Anseriformes that breed in SWS migrate for the winter to central Hindustan or further west, while their migration routes to southeast Asia (SEA) remain unconfirmed. Here, we mapped the molting sites of the migrating Common Teals (Anas crecca) via analyzing stable hydrogen isotope content in feathers of hunters’ prey and supplemented the analysis with the genetic structure of viruses isolated from teals in the same region. Post-breeding molt of autumn teals most likely occurred within the study region, whereas probable pre-breeding molting grounds of spring teals were in the south of Hindustan. This link was supported by viral phylogenetic analysis, which showed a close relationship between SWS isolates and viruses from south and southeast Asia. Most viral segments have the highest genetic similarity and the closest phylogenetic relationships with viruses from teal wintering areas in southeast Asian countries, including India and Korea. We assume that the winter molt of SWS breeding teals on the Hindustan coast suggests contacts with the local avifauna, including species migrating along the coast to SEA. Perhaps this is one of the vectors of AIV transmission within Eurasia. Full article

(This article belongs to the Special Issue Avian Pathogens 2.0)

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13 pages, 856 KiB

Open AccessArticle

Molecular Genomic Analyses of Enterococcus cecorum from Sepsis Outbreaks in Broilers

by Douglas D. Rhoads, Jeff Pummill and Adnan Ali Khalaf Alrubaye

Microorganisms 2024, 12(2), 250; https://doi.org/10.3390/microorganisms12020250 - 25 Jan 2024

Cited by 2 | Viewed by 1802

Abstract

Extensive genomic analyses of Enterococcus cecorum isolates from sepsis outbreaks in broilers suggest a polyphyletic origin, likely arising from core genome mutations rather than gene acquisition. This species is a normal intestinal flora of avian species with particular isolates associated with osteomyelitis. More [...] Read more.

Extensive genomic analyses of Enterococcus cecorum isolates from sepsis outbreaks in broilers suggest a polyphyletic origin, likely arising from core genome mutations rather than gene acquisition. This species is a normal intestinal flora of avian species with particular isolates associated with osteomyelitis. More recently, this species has been associated with sepsis outbreaks affecting broilers during the first 3 weeks post-hatch. Understanding the genetic and management basis of this new phenotype is critical for developing strategies to mitigate this emerging problem. Phylogenomic analyses of 227 genomes suggest that sepsis isolates are polyphyletic and closely related to both commensal and osteomyelitis isolate genomes. Pangenome analyses detect no gene acquisitions that distinguish all the sepsis isolates. Core genome single nucleotide polymorphism analyses have identified a number of mutations, affecting the protein-coding sequences, that are enriched in sepsis isolates. The analysis of the protein substitutions supports the mutational origins of sepsis isolates. Full article

(This article belongs to the Special Issue Avian Pathogens 2.0)

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13 pages, 284 KiB

Open AccessArticle

Belgian Cross-Sectional Epidemiological Study on Zoonotic Avian Chlamydia spp. in Chickens

by Anne De Meyst, Pieter De Clercq, Jelmer Porrez, Tom Geens, Lutgart Braeckman, Sander Ouburg, Servaas A. Morré and Daisy Vanrompay

Microorganisms 2024, 12(1), 193; https://doi.org/10.3390/microorganisms12010193 - 18 Jan 2024

Cited by 3 | Viewed by 1525

Abstract

Chlamydia psittaci, Chlamydia gallinacea, and Chlamydia abortus are the most common Chlamydia spp. in chickens and have a confirmed or suggested zoonotic potential. No recent data are available on their prevalence and impact in the Belgian chicken industry or in the recreational [...] Read more.

Chlamydia psittaci, Chlamydia gallinacea, and Chlamydia abortus are the most common Chlamydia spp. in chickens and have a confirmed or suggested zoonotic potential. No recent data are available on their prevalence and impact in the Belgian chicken industry or in the recreational chicken branch. Therefore, a cross-sectional epidemiological study was executed where samples were collected from both factory-farmed and backyard chickens. More specifically, pharyngeal chicken swabs were obtained from 20 chicken farms, 5 chicken abattoirs, and 38 different backyard locations and were analyzed using species-specific Polymerase Chain Reactions (PCRs) for the presence of the three avian Chlamydia spp. To investigate their zoonotic potential, samples were simultaneously collected from 54 backyard chicken caretakes and 37 professional chicken caretakers or abattoir employees and analyzed using species-specific PCRs as well. This study confirmed the presence of DNA of all three Chlamydia species in both the chicken industry and backyard settings. Chlamydia psittaci was the most prevalent in the industry chickens (11.0%), whereas Chlamydia gallinacea was the dominant species in the backyard chickens (14.5%). Chlamydia abortus infections were more common in the commercial chickens (9.0%) compared to the backyard chickens (2.6%). The DNA of all three species was also detected in humans (3.9% Chlamydia psittaci, 2.9% Chlamydia gallinacea, and 1.0% Chlamydia abortus). Full article

(This article belongs to the Special Issue Avian Pathogens 2.0)

15 pages, 3443 KiB

Open AccessArticle

Hypothetical Proteins of Mycoplasma synoviae Reannotation and Expression Changes Identified via RNA-Sequencing

by Duoduo Si, Jialin Sun, Lei Guo, Fei Yang, Xingmiao Tian, Shenghu He and Jidong Li

Microorganisms 2023, 11(11), 2716; https://doi.org/10.3390/microorganisms11112716 - 6 Nov 2023

Viewed by 1603

Abstract

Mycoplasma synoviae infection rates in chickens are increasing worldwide. Genomic studies have considerably improved our understanding of M. synoviae biology and virulence. However, approximately 20% of the predicted proteins have unknown functions. In particular, the M. synoviae ATCC 25204 genome has 663 encoding [...] Read more.

Mycoplasma synoviae infection rates in chickens are increasing worldwide. Genomic studies have considerably improved our understanding of M. synoviae biology and virulence. However, approximately 20% of the predicted proteins have unknown functions. In particular, the M. synoviae ATCC 25204 genome has 663 encoding DNA sequences, among which 155 are considered encoding hypothetical proteins (HPs). Several of these genes may encode unknown virulence factors. This study aims to reannotate all 155 proteins in M. synoviae ATCC 25204 to predict new potential virulence factors using currently available databases and bioinformatics tools. Finally, 125 proteins were reannotated, including enzymes (39%), lipoproteins (10%), DNA-binding proteins (6%), phase-variable hemagglutinin (19%), and other protein types (26%). Among 155 proteins, 28 proteins associated with virulence were detected, five of which were reannotated. Furthermore, HP expression was compared before and after the M. synoviae infection of cells to identify potential virulence-related proteins. The expression of 14 HP genes was upregulated, including that of five virulence-related genes. Our study improved the functional annotation of M. synoviae ATCC 25204 from 76% to 95% and enabled the discovery of potential virulence factors in the genome. Moreover, 14 proteins that may be involved in M. synoviae infection were identified, providing candidate proteins and facilitating the exploration of the infection mechanism of M. synoviae. Full article

(This article belongs to the Special Issue Avian Pathogens 2.0)

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14 pages, 1414 KiB

Open AccessArticle

Morphometrical Identification and Phylogenetic Analysis of Rhinonyssidae (Acari: Mesostigmata) Parasitizing Avian Hosts: New Molecular Data

by Susana A. Sánchez-Carrión, Ivan Dimov, Francisco J. Márquez Jiménez and Manuel de Rojas Álvarez

Microorganisms 2023, 11(7), 1783; https://doi.org/10.3390/microorganisms11071783 - 10 Jul 2023

Cited by 1 | Viewed by 1323

Abstract

Members of the family Rhinonyssidae are tiny hematophagous endoparasitic mites that inhabit the nasal cavities of birds and can cause trauma to their hosts. Traditionally, identifying species in this group has relied on observing their morphometrical characteristics. Nevertheless, determining species within this particular [...] Read more.

Members of the family Rhinonyssidae are tiny hematophagous endoparasitic mites that inhabit the nasal cavities of birds and can cause trauma to their hosts. Traditionally, identifying species in this group has relied on observing their morphometrical characteristics. Nevertheless, determining species within this particular group has become more challenging due to the rising number of newly discovered species. Moreover, the morphometrical traits vary depending on the specific genus or group of species being studied. In this study, the complete internal transcribed spacer ITS1, 5.8S rDNA, and ITS2 regions of the ribosomal DNA from eighteen species of rhinonyssid mites belonging to four genera were sequenced to assess the utility of this genomic region in resolving taxonomic questions in this group and to estimate the phylogenetic relationships among the species. Mites were collected by dissecting the nasal cavities of birds under a stereomicroscope. Specimens used for morphometrical analyses were cleared in 85% lactic acid for 1–48 h and mounted in Hoyer’s medium. Other specimens were preserved at −20 °C for molecular studies. From the data obtained in this study, it can be concluded that a thorough review and an accurate morphometrical identification and determination of the discriminatory traits are needed in this group of mites. Moreover, although the ITS1–5.8S–ITS2 fragment solves different taxonomic and phylogenetic problems at the species level, it would be necessary to test new molecular markers, or even a combination of nuclear and mitochondrial markers or different domains of the nuclear 28S rDNA, to discover a reliable taxonomic situation for rhinonyssids. Full article

(This article belongs to the Special Issue Avian Pathogens 2.0)

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15 pages, 722 KiB

Open AccessArticle

Detection of Pathogens and Ticks on Sedentary and Migratory Birds in Two Corsican Wetlands (France, Mediterranean Area)

by Baptiste Defaye, Sara Moutailler, Benjamin Vollot, Clémence Galon, Gaëlle Gonzalez, Rayane Amaral Moraes, Antoine-Simon Leoncini, Amalia Rataud, Gilles Le Guillou, Vanina Pasqualini and Yann Quilichini

Microorganisms 2023, 11(4), 869; https://doi.org/10.3390/microorganisms11040869 - 28 Mar 2023

Cited by 5 | Viewed by 2145

Abstract

Birds are one of the most species-diverse vertebrate groups and are susceptible to numerous hematophagous ectoparasites. Migratory birds likely contribute to the circulation of these ectoparasites and their associated pathogens. One of the many migration paths crosses the Mediterranean islands including Corsica and [...] Read more.

Birds are one of the most species-diverse vertebrate groups and are susceptible to numerous hematophagous ectoparasites. Migratory birds likely contribute to the circulation of these ectoparasites and their associated pathogens. One of the many migration paths crosses the Mediterranean islands including Corsica and its wetlands, which are migration stopovers. In our study, we collected blood samples and hematophagous ectoparasites in migratory and sedentary bird populations in two coastal lagoons: Biguglia and Gradugine. A total of 1377 birds were captured from which 762 blood samples, 37 louse flies, and 44 ticks were collected. All the louse flies were identified as Ornithomya biloba and all the ticks were from the Ixodes genus: Ixodes sp. (8.5%), I. accuminatus/ventalloi (2.9%), I. arboricola/lividus (14.3%), I. frontalis (5.7%) and I. ricinus (68.6%). Five pathogens were detected: Anaplasma phagocytophilum, Erhlichia chaffeensis, and Rickettsia helvetica in ticks, and Trypanosoma sp. in louse flies. Ehrlichia chaffeensis and the West Nile virus were both detected in bird blood samples in Corsica. This is the first report of these tick, louse fly and pathogen species isolated on the bird population in Corsica. Our finding highlights the importance of bird populations in the presence of arthropod-borne pathogens in Corsican wetlands. Full article

(This article belongs to the Special Issue Avian Pathogens 2.0)

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13 pages, 2353 KiB

Open AccessArticle

Genetic Analysis of Infectious Bronchitis Virus S1 Gene Reveals Novel Amino Acid Changes in the GI-16 Lineage in Peru

by Eliana Icochea, Rosa González, Gina Castro-Sanguinetti, Lenin Maturrano, Luis Alzamora, Luiz Sesti, Jorge Chacón and Juan More-Bayona

Microorganisms 2023, 11(3), 691; https://doi.org/10.3390/microorganisms11030691 - 8 Mar 2023

Cited by 9 | Viewed by 2298

Abstract

Infectious bronchitis is a highly contagious viral disease that represents an economic threat for poultry despite the wide use of vaccination. To characterize the virus circulating in Peru, we analyzed 200 samples, including nasopharyngeal swabs and multiple tissues collected from animals suspected of [...] Read more.

Infectious bronchitis is a highly contagious viral disease that represents an economic threat for poultry despite the wide use of vaccination. To characterize the virus circulating in Peru, we analyzed 200 samples, including nasopharyngeal swabs and multiple tissues collected from animals suspected of being infected with infectious bronchitis virus (IBV) between January and August in 2015. All animals had at least one positive sample for IBV by RT-PCR. Out of these positive samples, eighteen (18) were selected for viral isolation and a partial S1 sequencing. Phylogenetic analysis showed that sixteen isolates clustered with members of GI-16 lineage, also known as Q1, with nucleotide homology ranging from 93% to 98%. The two remaining isolates grouped with members of the GI-1 lineage. Our study reveals circulation of GI-16 lineage during this period in poultry systems in Peru, along with GI-1 lineage (vaccine-derived). Moreover, those IBV GI-16 isolates showed unique nucleotide and amino acid changes compared to their closest relatives. Altogether, these findings reveal the circulation of GI-16 lineage while describing changes at key regions of the S protein that might be of relevance for vaccine evasion. These results highlight the importance of genetic surveillance for improving vaccination strategies against infectious bronchitis. Full article

(This article belongs to the Special Issue Avian Pathogens 2.0)

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16 pages, 2983 KiB

Open AccessArticle

Genetic, Antigenic, and Pathobiological Characterization of H9 and H6 Low Pathogenicity Avian Influenza Viruses Isolated in Vietnam from 2014 to 2018

by Kien Trung Le, Lam Thanh Nguyen, Loc Tan Huynh, Duc-Huy Chu, Long Van Nguyen, Tien Ngoc Nguyen, Tien Ngoc Tien, Keita Matsuno, Masatoshi Okamatsu, Takahiro Hiono, Norikazu Isoda and Yoshihiro Sakoda

Microorganisms 2023, 11(2), 244; https://doi.org/10.3390/microorganisms11020244 - 18 Jan 2023

Cited by 3 | Viewed by 3209

Abstract

The H9 and H6 subtypes of low pathogenicity avian influenza viruses (LPAIVs) cause substantial economic losses in poultry worldwide, including Vietnam. Herein, we characterized Vietnamese H9 and H6 LPAIVs to facilitate the control of avian influenza. The space–time representative viruses of each subtype [...] Read more.

The H9 and H6 subtypes of low pathogenicity avian influenza viruses (LPAIVs) cause substantial economic losses in poultry worldwide, including Vietnam. Herein, we characterized Vietnamese H9 and H6 LPAIVs to facilitate the control of avian influenza. The space–time representative viruses of each subtype were selected based on active surveillance from 2014 to 2018 in Vietnam. Phylogenetic analysis using hemagglutinin genes revealed that 54 H9 and 48 H6 Vietnamese LPAIVs were classified into the sublineages Y280/BJ94 and Group II, respectively. Gene constellation analysis indicated that 6 and 19 genotypes of the H9 and H6 subtypes, respectively, belonged to the representative viruses. The Vietnamese viruses are genetically related to the previous isolates and those in neighboring countries, indicating their circulation in poultry after being introduced into Vietnam. The antigenicity of these subtypes was different from that of viruses isolated from wild birds. Antigenicity was more conserved in the H9 viruses than in the H6 viruses. Furthermore, a representative H9 LPAIV exhibited systemic replication in chickens, which was enhanced by coinfection with avian pathogenic Escherichia coli O2. Although H9 and H6 were classified as LPAIVs, their characterization indicated that their silent spread might significantly affect the poultry industry. Full article

(This article belongs to the Special Issue Avian Pathogens 2.0)

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9 pages, 239 KiB

Open AccessArticle

Prevalence of New and Established Avian Chlamydial Species in Humans and Their Psittacine Pet Birds in Belgium

by Anne De Meyst, Rachid Aaziz, Joachim Pex, Lutgart Braeckman, Morag Livingstone, David Longbottom, Karine Laroucau and Daisy Vanrompay

Microorganisms 2022, 10(9), 1758; https://doi.org/10.3390/microorganisms10091758 - 31 Aug 2022

Cited by 4 | Viewed by 2120

Abstract

The presence and zoonotic transfer of four different avian Chlamydia spp. was assessed in an epidemiological study in a psittacine bird population and its owners. Fecal swabs from 84 pet birds and pharyngeal swabs from 22 bird owners were collected from 21 locations [...] Read more.

The presence and zoonotic transfer of four different avian Chlamydia spp. was assessed in an epidemiological study in a psittacine bird population and its owners. Fecal swabs from 84 pet birds and pharyngeal swabs from 22 bird owners were collected from 21 locations in Flanders. Samples were examined using established and novel PCR platforms combined with culture on PCR-positive samples. Chlamydiaceae DNA was detected in 33 of 84 (39.3%) birds. The predominant part of the avian infections could be attributed to C. psittaci (22 of 84; 26.2%), followed by C. avium (11 of 84; 13.1%). C. gallinacea and C. abortus were not detected in birds or humans. C. psittaci was the only species detected in pet bird owners (4 of 22; 18.2%), stressing its zoonotic importance. This study showed that C. psittaci and the more recently discovered novel avian species C. avium are undoubtedly present in the Flemish psittacine bird population. Our results justify additional research in a larger psittacine bird population and its owners, focusing on C. psittaci and C. avium. In the meantime, increased awareness among pet bird owners and the implementation of preventive measures in the pet bird industry is advised to limit the circulation of established and novel emerging avian chlamydial species. Full article

(This article belongs to the Special Issue Avian Pathogens 2.0)

14 pages, 1057 KiB

Open AccessArticle

Screening of Healthy Feral Pigeons (Columba livia domestica) in the City of Zurich Reveals Continuous Circulation of Pigeon Paramyxovirus-1 and a Serious Threat of Transmission to Domestic Poultry

by Désirée Annaheim, Barbara Renate Vogler, Brigitte Sigrist, Andrea Vögtlin, Daniela Hüssy, Christian Breitler, Sonja Hartnack, Christian Grund, Jacqueline King, Nina Wolfrum and Sarah Albini

Microorganisms 2022, 10(8), 1656; https://doi.org/10.3390/microorganisms10081656 - 17 Aug 2022

Cited by 5 | Viewed by 3049

Abstract

Pigeon paramyxovirus-1 (PPMV-1) is predominantly isolated from pigeons or doves and forms a separate group of viral strains within Avian Orthoavulavirus-1, the causative agent of Newcastle disease in poultry. Since the introduction of PPMV-1 into Europe in 1981, these strains have rapidly spread [...] Read more.

Pigeon paramyxovirus-1 (PPMV-1) is predominantly isolated from pigeons or doves and forms a separate group of viral strains within Avian Orthoavulavirus-1, the causative agent of Newcastle disease in poultry. Since the introduction of PPMV-1 into Europe in 1981, these strains have rapidly spread all over Europe, and are nowadays considered to be enzootic in feral and hobby pigeons (Columba livia domestica). Infections with PPMV-1 can range from asymptomatic to fatal. To assess whether PPMV-1 continuously circulates in healthy feral pigeons, 396 tissue samples of pigeons from the city of Zurich were tested by reverse transcriptase real-time PCR over the period of one year. PPMV-1-RNA was detected in 41 feral pigeons (10.35%), determined as the dominant European genotype VI.2.1.1.2.2. In 38 of the 41 pigeons where organ samples tested positive, PPMV-1-RNA was also detected in either choana or cloaca swabs. There were no significant differences in positivity rates between seasons, age, and sex. The current study shows that feral pigeons without clinical signs of disease can harbour and most likely excrete PPMV-1. Spill-over into free-range holdings of chickens are therefore possible, as observed in a recent outbreak of Newcastle disease in laying hens due to PPMV-1 genotype VI.2.1.1.2.2. in the canton of Zurich in January 2022. Full article

(This article belongs to the Special Issue Avian Pathogens 2.0)

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Review

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42 pages, 4876 KiB

Open AccessReview

Emerging and Novel Viruses in Passerine Birds

by Richard A. J. Williams, Christian J. Sánchez-Llatas, Ana Doménech, Ricardo Madrid, Sergio Fandiño, Pablo Cea-Callejo, Esperanza Gomez-Lucia and Laura Benítez

Microorganisms 2023, 11(9), 2355; https://doi.org/10.3390/microorganisms11092355 - 20 Sep 2023

Cited by 3 | Viewed by 4712

Abstract

There is growing interest in emerging viruses that can cause serious or lethal disease in humans and animals. The proliferation of cloacal virome studies, mainly focused on poultry and other domestic birds, reveals a wide variety of viruses, although their pathogenic significance is [...] Read more.

There is growing interest in emerging viruses that can cause serious or lethal disease in humans and animals. The proliferation of cloacal virome studies, mainly focused on poultry and other domestic birds, reveals a wide variety of viruses, although their pathogenic significance is currently uncertain. Analysis of viruses detected in wild birds is complex and often biased towards waterfowl because of the obvious interest in avian influenza or other zoonotic viruses. Less is known about the viruses present in the order Passeriformes, which comprises approximately 60% of extant bird species. This review aims to compile the most significant contributions on the DNA/RNA viruses affecting passerines, from traditional and metagenomic studies. It highlights that most passerine species have never been sampled. Especially the RNA viruses from Flaviviridae, Orthomyxoviridae and Togaviridae are considered emerging because of increased incidence or avian mortality/morbidity, spread to new geographical areas or hosts and their zoonotic risk. Arguably poxvirus, and perhaps other virus groups, could also be considered “emerging viruses”. However, many of these viruses have only recently been described in passerines using metagenomics and their role in the ecosystem is unknown. Finally, it is noteworthy that only one third of the viruses affecting passerines have been officially recognized. Full article

(This article belongs to the Special Issue Avian Pathogens 2.0)

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29 pages, 2125 KiB

Open AccessReview

Necrotic Enteritis in Broiler Chickens: A Review on the Pathogen, Pathogenesis, and Prevention

by Shahna Fathima, Walid Ghazi Al Hakeem, Revathi Shanmugasundaram and Ramesh K. Selvaraj

Microorganisms 2022, 10(10), 1958; https://doi.org/10.3390/microorganisms10101958 - 30 Sep 2022

Cited by 38 | Viewed by 7345

Abstract

Clostridium perfringens type A and C are the primary etiological agents associated with necrotic enteritis (NE) in poultry. The predisposing factors implicated in the incidence of NE changes the physical properties of the gut, immunological status of birds, and disrupt the gut microbial [...] Read more.

Clostridium perfringens type A and C are the primary etiological agents associated with necrotic enteritis (NE) in poultry. The predisposing factors implicated in the incidence of NE changes the physical properties of the gut, immunological status of birds, and disrupt the gut microbial homeostasis, causing an over-proliferation of C. perfringens. The principal virulence factors contributing to the pathogenesis of NE are the α-toxin, β-toxin, and NetB toxin. The immune response to NE in poultry is mediated by the Th1 pathway or cytotoxic T-lymphocytes. C. perfringens type A and C are also pathogenic in humans, and hence are of public health significance. C. perfringens intoxications are the third most common bacterial foodborne disease after Salmonella and Campylobacter. The restrictions on the use of antibiotics led to an increased incidence of NE in poultry. Hence, it is essential to develop alternative strategies to keep the prevalence of NE under check. The control strategies rely principally on the positive modulation of host immune response, nutritional manipulation, and pathogen reduction. Current knowledge on the etiology, pathogenesis, predisposing factors, immune response, effect on the gut microbial homeostasis, and preventative strategies of NE in this post-antibiotic era is addressed in this review. Full article

(This article belongs to the Special Issue Avian Pathogens 2.0)

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Other

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9 pages, 2459 KiB

Open AccessCase Report

Fowl Typhoid Outbreak on a Commercial Turkey Farm in Croatia

by Liča Lozica, Siniša Faraguna, Branka Artuković and Željko Gottstein

Microorganisms 2024, 12(1), 165; https://doi.org/10.3390/microorganisms12010165 - 13 Jan 2024

Cited by 2 | Viewed by 1279

Abstract

Fowl typhoid is a septicemic disease caused by Salmonella enterica subsp. enterica serovar Gallinarum biovar Gallinarum. It is a host-specific disease primarily affecting chickens and turkeys, although it has been reported in various animal species and sporadically in humans. Here, we present a [...] Read more.

Fowl typhoid is a septicemic disease caused by Salmonella enterica subsp. enterica serovar Gallinarum biovar Gallinarum. It is a host-specific disease primarily affecting chickens and turkeys, although it has been reported in various animal species and sporadically in humans. Here, we present a case of a fowl typhoid outbreak on a turkey poult farm where the source of infection was the hatchery. The birds started showing symptoms of growth retardation at 21 days of age, after which the mortality rates gradually started to increase. Post mortem examination revealed that the main lesions were granulomatous proliferations in the small intestines. The results of the histopathological examination indicate that the severity of the infection was alleviated by the application of phytogenic mixtures and probiotics as a supportive treatment, even though the affected flock was eventually culled at 60 days of age. The farmer was advised to apply more strict biosecurity measures to prevent the spread of the disease on the farm and try to eradicate the pathogen from the barn. Since the outbreak, there have been no recurrent infections. Full article

(This article belongs to the Special Issue Avian Pathogens 2.0)

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