Search Results (937)

Mycobacterium avium subsp. hominissuis (MAH) is a zoonotic pathogen with a broad host range and diverse clinical manifestations. We report here the first documented case of MAH-induced fatal vasculitis in zebra finch (Taeniopygia guttata). Histopathological examination revealed acid-fast bacilli within macrophages and endothelial cells, primarily affecting the heart and aorta. Mycobacterial DNA was detected in cloacal swabs from affected finches and environmental samples from their housing facility. PCR targeting the rpoB gene and insertion elements IS1245 and IS901, followed by sequencing, confirmed MAH infection. MAH DNA was identified in 4 of 13 finch cloacal swabs and 7 of 28 environmental samples. This study describes a novel, highly pathogenic manifestation of MAH in birds and underscores the potential for avian involvement in environmental and zoonotic transmission. Full article

Biosecurity measures applied on poultry farms, with a recent history of highly pathogenic avian influenza virus infection, were monitored using 24 h/7 days-per-week video monitoring. Definition of biosecurity breaches were based on internationally acknowledged norms. Farms of four different production types (two broiler, two layer, two breeder broiler, and one duck farm) were selected. Observations of entry to and exit from the anteroom revealed a high degree of biosecurity breaches in six poultry farms and good biosecurity practices in one farm in strictly maintaining the separation between clean and potentially contaminated areas in the anteroom. Hand washing with soap and water and/or using disinfectant lotion was rarely observed at entry to the anteroom and was almost absent at exit. Egg transporters did not disinfect fork-lift wheels when entering the egg-storage room nor change or properly disinfect footwear. The egg-storage room was not cleaned and disinfected after egg transport by the farmer. Similarly, footwear and trolley wheels were not disinfected when introducing young broilers or ducklings to the poultry unit. Biosecurity breaches were observed when introducing bedding material in the duck farm. This study shows a need for an engaging awareness and training campaign for poultry farmers and their co-workers as well as for transporters to promote good biosecurity practices. Full article

Sin Nombre virus (SNV) is the main causative agent of hantavirus cardiopulmonary syndrome (HCPS) in North America. SNV is transmitted via environmental biological aerosols (bioaerosols) produced by infected deer mice (Peromyscus maniculatus). It is similar to other viruses that have environmental transmission routes rather than a person-to-person transmission route, such as avian influenza (e.g., H5N1) and Lassa fever. Despite the lack of person-to-person transmission, these viruses cause a significant public health and economic burden. However, due to the lack of targeted pharmaceutical preventatives and therapeutics, the recommended approach to prevent SNV infections is to avoid locations that have a combination of low foot traffic, receive minimal natural sunlight, and where P. maniculatus may be found nesting. Consequently, gaining insight into the SNV bioaerosol decay profile is fundamental to the prevention of SNV infections. The Biological Aerosol Reaction Chamber (Bio-ARC) is a flow-through system designed to rapidly expose bioaerosols to environmental conditions (ozone, simulated solar radiation (SSR), humidity, and other gas phase species at stable temperatures) and determine the sensitivity of those particles to simulated ambient conditions. Using this system, we examined the bioaerosol stability of SNV. The virus was found to be susceptible to both simulated solar radiation and ozone under the tested conditions. Comparisons of decay between the virus aerosolized in residual media and in a mouse bedding matrix showed similar results. This study indicates that SNV aerosol particles are susceptible to inactivation by solar radiation and ozone, both of which could be implemented as effective control measures to prevent disease in locations where SNV is endemic. Full article

Avian influenza viruses (AIVs) pose significant risks to occupational populations engaged in poultry farming, livestock handling, and live poultry market operations due to frequent exposure to infected animals and contaminated environments. This review synthesizes evidence on AIV exposure patterns and risk factors through a comprehensive analysis of viral characteristics, host dynamics, environmental influences, and human behaviors. The main routes of transmission include direct animal contact, respiratory contact during slaughter/milking, and environmental contamination (aerosols, raw milk, shared equipment). Risks increase as the virus adapts between species, survives longer in cold/wet conditions, and spreads through wild bird migration (long-distance transmission) and live bird trade (local transmission). Recommended control measures include integrated animal–human–environment surveillance, stringent biosecurity measures, vaccination, and education. These findings underscore the urgent need for global ‘One Health’ collaboration to assess risk and implement preventive measures against potentially pandemic strains of influenza A viruses, especially in light of undetected mild/asymptomatic cases and incomplete knowledge of viral evolution. Full article

Information on Culicoides transmitted parasites, especially trypanosomatids, infecting animals and insects, is scarce. Our goal was to clarify the seasonal patterns of both Culicoides and trypanosomatids detected in these insects and the relationships between Culicoides abundance and meteorological parameters. UV light traps were used to collect biting midges in four study sites in 2022–2023; collected Culicoides females were dissected and analyzed using microscopy and PCR-based methods. Out of 1631 parous Culicoides females belonging to 14 different species, 6.5% were found to be infected with trypanosomatids (5.0% with at least three Trypanosoma species and 1.5% with monoxenous parasites). The highest Culicoides abundance was detected in June. The prevalence of trypanosomatids in biting midges increased during the summer (5.3% in June, 8.8% in July, and 11.2% in August). Temperature was recorded to be a presiding environmental gradient structuring Culicoides species composition, while wind speed and precipitation explained little of the variation. Our results indicate that both avian and mammalian trypanosomes can be found in these insects, although further research is needed to better understand the development of these parasites in biting midges and Culicoides vectorial capacity. Full article

Background: Fowl typhoid (FT), a septicemic infection caused by Salmonella Gallinarum (SG), and H9N2 avian influenza are two economically important diseases that significantly affect the global poultry industry. Methods: We exploited the live attenuated Salmonella Gallinarum (SG) mutant JOL3062 (SG: ∆lon ∆pagL ∆asd) as a delivery system for H9N2 antigens to induce an immunoprotective response against both H9N2 and FT. To enhance immune protection against H9N2, a prokaryotic and eukaryotic dual expression plasmid, pJHL270, was employed. The hemagglutinin (HA) consensus sequence from South Korean avian influenza A virus (AIV) was cloned under the Ptrc promoter for prokaryotic expression, and the B cell epitope of neuraminidase (NA) linked with matrix protein 2 (M2e) was placed for eukaryotic expression. In vitro and in vivo expressions of the H9N2 antigens were validated by qRT-PCR and Western blot, respectively. Results: Oral immunization with JOL3121 induced a significant increase in SG and H9N2-specific serum IgY and cloacal swab IgA antibodies, confirming humoral and mucosal immune responses. Furthermore, FACS analysis showed increased CD4+ and CD8+ T cell populations. On day 28 post-immunization, there was a substantial rise in the hemagglutination inhibition titer in the immunized birds, demonstrating neutralization capabilities of immunization. Both IFN-γ and IL-4 demonstrated a significant increase, indicating a balance of Th1 and Th2 responses. Intranasal challenge with the H9N2 Y280 strain resulted in minimal to no clinical signs with significantly lower lung viral titer in the JOL3121 group. Upon SG wildtype challenge, the immunized birds in the JOL3121 group yielded 20% mortality, while 80% mortality was recorded in the PBS control group. Additionally, bacterial load in the spleen and liver was significantly lower in the immunized birds. Conclusions: The current vaccine model, designed with a host-specific pathogen, SG, delivers a robust immune boost that could enhance dual protection against FT and H9N2 infection, both being significant diseases in poultry, as well as ensure public health. Full article

Enteric diseases represent one of the main causes of morbidity and mortality in poultry production, especially in turkeys (Meleagris gallopavo), significantly affecting the profitability of the sector. Turkey enteric complex (PEC) is a multifactorial syndrome characterized by diarrhea, stunting, poor feed conversion, and increased mortality in young turkeys. Its aetiologia includes multiple avian enteric viruses, including astrovirus, rotavirus, reovirus, parvovirus, adenovirus, and coronavirus, which can act singly or in co-infection, increasing clinical severity. This study performs a systematic review of the literature on these viruses and a meta-analysis of their prevalence in different regions of the world. Phylogenetic analyses were used to assess the genetic diversity of the main viruses and their geographical distribution. The results show a wide regional and genetic variability, which underlines the need for continuous epidemiological surveillance. Health and production implications are discussed, proposing control strategies based on biosecurity, targeted vaccination, and optimized nutrition. These findings highlight the importance of integrated management to mitigate the impact of CSF in poultry. Full article

Scavenging domestic ducks significantly contribute to the transmission and maintenance of highly pathogenic H5N1 clade 2.3.4.4b avian influenza viruses in Bangladesh, a strain of growing global concern due to its broad host range, high pathogenicity, and spillover potential. This study investigates the molecular epidemiology and pathology of HPAI H5N1 viruses in unvaccinated scavenging ducks in Bangladesh, with the goal of assessing viral evolution and associated disease outcomes. Between June 2022 and March 2024, 40 scavenging duck flocks were investigated for HPAI outbreaks. Active HPAIV H5N1 infection was detected in 35% (14/40) of the flocks using RT-qPCR. Affected ducks exhibited clinical signs of incoordination, torticollis, and paralysis. Pathological examination revealed prominent meningoencephalitis, encephalopathy and encephalomalacia, along with widespread lesions in the trachea, lungs, liver, and spleen, indicative of systemic HPAIV infection. A phylogenetic analysis of full-genome sequences confirmed the continued circulation of clade 2.3.2.1a genotype G2 in these ducks. Notably, two samples of 2022 and 2023 harbored HPAIV H5N1 of clade 2.3.4.4b, showing genetic similarity to H5N1 strains circulating in Korea and Vietnam. A mutation analysis of the HA protein in clade 2.3.4.4b viruses revealed key substitutions, including T156A (loss of an N-linked glycosylation site), S141P (antigenic site A), and E193R/K (receptor-binding pocket), indicating potential antigenic drift and receptor-binding adaptation compared to clade 2.3.2.1a. The emergence of clade 2.3.4.4b with the first report of neurological and systemic lesions suggests ongoing viral evolution with increased pathogenic potential for ducks. These findings highlight the urgent need for enhanced surveillance and biosecurity to control HPAI spread in Bangladesh. Full article

Pasteurella multocida (Pm) is a zoonotic pathogen that poses a significant threat to animal health and causes substantial economic losses, further aggravated by rising tetracycline resistance. To restore the efficacy of tetracyclines to Pm, we evaluated the synergistic antibacterial activity of doxycycline combined with metformin, an FDA-approved antidiabetic agent. Among several non-antibiotic adjuvant candidates, metformin exhibited the most potent in vitro synergy with doxycycline, especially against capsular serogroup A strain (PmA). The combination demonstrated minimal cytotoxicity and hemolysis in both mammalian and avian cells and effectively inhibited resistance development under doxycycline pressure. At 50 mg/kg each, the combination of metformin and doxycycline significantly reduced mortality in mice and ducks acutely infected with PmA (from 100% to 60%), decreased pulmonary bacterial burdens, and alleviated tissue inflammation and damage. Mechanistic validation confirmed that metformin enhances membrane permeability in Pm without compromising membrane integrity, dissipates membrane potential, increases intracellular doxycycline accumulation, and downregulates the transcription of the tetracycline efflux gene tet(B). Morphological analyses further revealed pronounced membrane deformation and possible leakage of intracellular contents. These findings highlight metformin as a potent, low-toxicity tetracycline adjuvant with cross-species efficacy, offering a promising therapeutic approach for managing tetracycline-resistant Pm infections. Full article

Respiratory viral diseases infecting poultry lead to variable lesions in the respiratory organs, including nasal sinuses, trachea, lungs, and air sacs. Additional involvement of eyelids/conjunctiva was reported. The distribution and the intensity of lesions depend on multiple factors, including virulence, the host’s immunity, and secondary or concurrent infections. It may be challenging to detect remarkable lesions during experimental infections conducted in a controlled environment because some viruses fail to produce the intense lesions seen in field cases. This creates a challenge in developing a reliable model to study pathogenicity or vaccine efficacy experimentally. The development of the proposed histologic respiratory index (HRI) aims to help monitor the least microscopic changes that can be scored, thereby creating an objective and accurate grading of lesions in experimentally infected birds. HRI scores the changes in eyelids/conjunctiva and respiratory mucosa, including hyperplasia, metaplasia, inflammatory cellular infiltration in the submucosa, including lymphocytes and heterophils, and vascular changes (vasculitis) in nasal sinuses, trachea, and lungs. The score was validated in birds infected experimentally with avian metapneumovirus (aMPV) and low pathogenic avian influenza (LPAI-H4N6). The HRI reliably graded higher scores in the respiratory organs of experimentally infected birds compared with non-infected control ones. The HRI is the first of its type with poultry viral respiratory pathogens and it was initially proven to be a reliable in pathogenicity and vaccine trials of certain poultry respiratory viral diseases. Full article

The non-traditional companion animal (NTCA) sector, particularly involving avian species, has significantly expanded in Italy, raising concerns over the spread of infectious diseases. These animals can harbor various pathogens and act as reservoirs, posing risks to native wildlife through legal or illegal trade, escapes, or intentional releases. However, the epidemiology of avian pathogens in NTCAs remains poorly understood and is typically investigated only in symptomatic individuals. In the present study, cloacal and choanal cleft swabs were collected from 319 ornamental and raptor birds across 19 families, pooled and tested for beak and feather disease virus (BFDV), avian polyomavirus (APV-1), psittacid herpesvirus 1 (PsHV-1), and avian metapneumovirus (aMPV). BFDV and APV-1 were detected in 13.79% and 2.19% of birds, respectively, with five co-infections. No cases of PsHV-1 or aMPV were found. Both viruses showed a higher prevalence than in previous Italian and most of international studies, with several non-psittacine species, including birds of prey, testing positive—some for the first time. Mixed-species settings and participation in public exhibitions were proven as significant infection risk factors. The study highlights the growing relevance of BFDV and APV-1 in non-commercial birds and recommends improved biosecurity and preventive screening to reduce disease spread and safeguard animal health. Full article

Marek’s Disease Virus (MDV) is a highly contagious pathogen in chickens, resulting in immunosuppression and T-cell lymphomas. Understanding the role of host cytokines in MDV pathogenesis is crucial for developing effective interventions. This study investigated the in vivo effects of overexpressing avian interleukin-17 (IL-17) in Marek’s disease virus infection model and its impact on T-cell populations. We utilized a recombinant pCDNA3.1 plasmid that expresses IL-17 at days 4 and 10 post-MDV infection in chickens. Our findings demonstrate that IL-17 overexpression significantly enhanced MDV replication. However, treatment with the plasmid expressing IL-17 led to a reduction in MD disease severity. Additionally, IL-17 treatment markedly altered the frequency of CD4+ and CD8α+ αβ T-cells. Specifically, at 21-dpi, there was an increase in CD3+ CD8α+ αβ T cells and a decrease in CD3+ CD4+ αβ T-cells within the spleen of chickens treated with the plasmid expressing IL-17. These modulatory effects suggest a possible mechanism by which IL-17 facilitates immune system cell activation and enhances viral persistence. This study underscores the pivotal role of IL-17 in MDV infection dynamics and offers. Full article

Avian influenza virus (AIV) remains a persistent threat to both the poultry industry and human health. Among the AIV subtypes posing public health threats, H7N9 AIV is responsible for five epidemic waves of human infection in China. Here, a detection system based on a mouse model was established, which can simultaneously and quantitatively analyze the dynamic changes in the viral genomic RNA (vRNA), complementary RNA (cRNA), and messenger RNA (mRNA) of H7N9 AIV by using reverse transcription primers with tag sequences to reverse transcribe the three species of RNAs into corresponding cDNA templates, which are then absolutely quantified using the TaqMan quantitative PCR method. This system specifically targets the PB2 and NA genes and, for the first time, enables a spatiotemporal analysis of all three viral RNA species within an animal model. Our results revealed that H7N9 AIV exhibits characteristic replication kinetics, with all three species of viral RNAs showing a rapid increase followed by a certain degree of decline. This system offers a powerful tool for us to further advance our understanding of the replication dynamics of AIV in mice. Full article

Avian pathogenic Escherichia coli (APEC) is highly infective in poultry, causing significant economic losses to the poultry industry. As an extraintestinal pathogenic strain, adherence is a critical step in the infection. The functions of several adhesins, including type I, P, and Curli fimbriae, have been extensively studied. However, the roles of other adhesins, like Sfm, remain largely unexplored. Sfm is widely present in E. coli. Although the Sfm cluster is an ortholog of the fim gene cluster of Salmonella type I fimbriae, the biological function of Sfm in APEC has not yet been elucidated. To investigate whether Sfm in APEC CE129 plays a role in virulence, in this study, we constructed recombinant strains by expressing Sfm in the fimbriae-deficient strain SE5000. Additionally, a CE129 sfmA mutant strain was constructed. The resulting changes in adherence, biofilm formation, resistance to macrophage phagocytosis, and resistance to serum bactericidal ability were observed. The adherence ability of CE129ΔsfmA was reduced by 41%. HD-11 cells demonstrated a 30% increase in the phagocytosis of CE129ΔsfmA, and a 50% reduction in SE5000 (pBR322-sfm). The sfm deletion mutant showed a 23.9% reduction in the resistance to serum bactericidal ability, while SE5000 (pBR322-sfm) displayed a 32% increase. SE5000 (pBR322-sfm) exhibited a 34% increase in biofilm formation, and CE129ΔsfmA demonstrated a 21% decrease. Real-time PCR was employed to examine the impact of Sfm deletion on the transcription level of key virulence factors (fimA, fliC, papC, tsh, ompA, and iss). The results indicated that Sfm in CE129 is closely associated with bacterial adherence and survivability, contributing to biofilm formation and influencing the expression of key virulence factors. This study yields initial insight into the functional roles of Sfm in APEC and provides a foundation for the effective control of E. coli in the poultry industry. Full article

Anseriformes (waterfowl) and Charadriiformes (shorebirds) are well-recognized natural reservoirs of low pathogenic (LP) influenza A viruses (IAVs). Historically, LP IAVs circulate among healthy individuals during seasonal, and often transcontinental, migrations. However, following the introduction of clade 2.3.4.4b highly pathogenic (HP) A/Goose/Guangdong/1/1996 lineage H5 IAV to North America in 2021, countless wild birds succumbed to fatal infections across the Western Hemisphere. Due to their small size and cryptic plumage patterns, opportunities for carcass recovery and postmortem evaluation in sanderlings (Calidris alba) and other shorebirds are rare. A multispecies mortality event in coastal Virginia, USA, in March–April 2024 included sanderlings among other wild bird species. Nine sanderlings underwent postmortem evaluation and clade 2.3.4.4b H5 IAV RNA was detected in pooled oropharyngeal-cloacal swabs from 11/11 individuals by real-time reverse transcription polymerase chain reaction. Histopathology was similar to that in waterfowl and included necrosis in the pancreas and brain and less commonly in the gonad, adrenal gland, spleen, liver, and intestine. Immunohistochemistry revealed IAV antigen labeling in necrotic neurons of the brain (neurotropism) and epithelial cells of the pancreas, gonad, and adrenal gland (epitheliotropism). Describing HP IAV-attributed pathology in shorebirds is key to understanding ecoepidemiology and population health threats in order to further document and compare pathogenesis among avian species. Full article