Spotty liver disease (SLD) is now a significant health concern for egg-laying poultry in nations like the United Kingdom and Australia, and it has also become prevalent in the United States. Among the organisms responsible for SLD are Campylobacter hepaticus, and, significantly, Campylobacter bilis. Focal lesions on the livers of infected birds have been observed as a result of these organisms. The Campylobacter hepaticus infection causes a reduction in egg production, along with decreased feed consumption that results in reduced egg size, ultimately leading to an increase in the death rate of prized hens. In the fall of 2021, the Poultry Diagnostic Research Center at the University of Georgia received two flocks (A and B) of organically raised pasture-laying hens, whose history suggested a possible SLD condition. A postmortem examination of Flock A hens revealed five of six had small, multifocal liver lesions, and confirmation of C. hepaticus infection was achieved through PCR analysis of pooled liver and gall bladder swab samples. A post-mortem examination of Flock B's submitted birds resulted in the observation of spotty liver lesions affecting six of seven birds. From the pooled bile samples of Flock B, a PCR test uncovered two hens that were positive for the presence of C. hepaticus. Five days after the initial visit to Flock A, a follow-up appointment was scheduled, as well as a visit to Flock C, which had not been affected by SLD, functioning as a control group for comparison. Six hens per house were sampled for liver, spleen, cecal tonsil, ceca, blood, and gall bladder tissue. Furthermore, feed, water nipples, and environmental water sources (still water located outside the property) were gathered from both the affected farm and the control farm. To ascertain the presence of the organism, all collected samples were processed by direct plating on blood agar and enrichment in Preston broth, subsequently incubated under microaerophilic conditions. After rigorous purification procedures on bacterial cultures from all specimens, isolated cultures demonstrating the attributes of C. hepaticus were analyzed using PCR to verify their identity. The PCR assay confirmed the presence of C. hepaticus in the liver, ceca, cecal tonsils, gall bladder, and environmental water within Flock A samples. Positive samples were absent from Flock C's collection. A further examination, ten weeks subsequent to the initial visit, confirmed the presence of C. hepaticus in the gall bladder bile and feces of Flock A. One environmental water sample also showed a weakly positive response to C. hepaticus. Flock C demonstrated no evidence of *C. hepaticus* as indicated by the PCR test. To evaluate the prevalence of C. hepaticus, 6 layer hens from 12 different flocks, aged 7 to 80 weeks, and kept in various housing systems, underwent testing for C. hepaticus infection. read more The 12-layer hen flocks were found to be both culture- and PCR-negative for C. hepaticus. Treatment for C. hepaticus remains unapproved, and vaccination against it is not yet possible. The conclusions of this study suggest the potential for *C. hepaticus* to be endemic in specific regions of the United States, where free-range laying hens may be exposed to the pathogen via environmental factors, including stagnant water in the areas they roam.

In Australia's New South Wales region in 2018, an outbreak of food poisoning, caused by Salmonella enterica serovar Enteritidis phage type 12 (PT12), was connected to eggs from a local layer flock. This report details the first Salmonella Enteritidis infection identified in NSW layer flocks, despite the persistent environmental monitoring program. Despite the low incidence of clinical signs and mortality in most flocks, seroconversion and infection were detected in some. Researchers investigated the oral dose-response of Salmonella Enteritidis PT12 in commercial laying hens. To isolate Salmonella, cloacal swabs were collected 3, 7, 10, and 14 days after inoculation. Additional samples of caecum, liver, spleen, ovary, magnum, and isthmus tissue were collected at necropsy at either day 7 or day 14 post-inoculation. These samples were processed using the standards of AS 501310-2009 and ISO65792002. A histopathological investigation encompassed the aforementioned tissues, in addition to lung, pancreas, kidney, heart, plus supplementary intestinal and reproductive tract samples. Salmonella Enteritidis was reliably detected in cloacal swab specimens collected between days 7 and 14 post-challenge. The gastrointestinal tract, liver, and spleen of every hen given an oral challenge with 107, 108, and 109 CFU of Salmonella Enteritidis PT12 became colonized, but colonization of their reproductive tracts was less predictable. Microscopic examination at 7 and 14 days following challenge displayed mild lymphoid hyperplasia in the liver and spleen. Further, the observed conditions included hepatitis, typhlitis, serositis, and salpingitis, with a heightened incidence in the birds receiving higher doses. The layers that were challenged did not display diarrhea, and their heart blood samples were negative for Salmonella Enteritidis. read more The PT12 Salmonella Enteritidis strain from NSW demonstrated the capacity to penetrate and establish itself within the reproductive tracts and various other tissues of the birds, suggesting a risk of egg contamination from these naive commercial hens.

A study on the susceptibility and disease development in wild-caught Eurasian tree sparrows (Passer montanus) involved experimental infection with genotype VII velogenic Newcastle disease virus (NDV) APMV1/chicken/Japan/Fukuoka-1/2004. Birds in two groups exposed to intranasal inoculation with high and low doses of the virus showed mortality in a subset of birds in each group, observed between days 7 and 15 after inoculation. A few birds displayed neurologic signs, ruffled feathers, labored breathing, marked emaciation, diarrhea, a depressed state, and ataxia, and ultimately died. Inoculation with a higher viral burden resulted in a greater frequency of mortality and a higher rate of detection for hemagglutination inhibition antibodies. Sparrows, having endured the 18-day observation period post-inoculation, displayed no observable clinical symptoms. Within the nasal mucosa, orbital ganglia, and central nervous system of deceased birds, histological lesions were identified, these abnormalities being consistent with the detection of NDV antigens by immunohistochemical analysis. While the oral swab and brain of the deceased birds contained NDV, the virus was not isolated from other organs, such as the lung, heart, muscle, colon, and liver. Tree sparrows, part of another experimental cohort, were intranasally inoculated with the virus, followed by a 1 to 3-day post-inoculation examination to scrutinize the initial course of the illness. In inoculated birds, inflammation of the nasal mucosa, showcasing viral antigens, occurred, and virus isolation from oral swab samples was achieved on the second and third days after inoculation. Our study's results highlight the susceptibility of tree sparrows to velogenic NDV, where the infection may be fatal, though some birds might experience only minor symptoms or remain entirely asymptomatic. Infected tree sparrows displayed a characteristic unique pathogenesis of velogenic NDV, specifically regarding neurologic signs and viral neurotropism.

The Duck Tembusu virus (DTMUV), a pathogenic flavivirus, significantly decreases egg production and induces severe neurological disorders in domestic waterfowl. read more Nanoparticles of ferritin, self-assembled with E protein domains I and II (EDI-II) from DTMUV (EDI-II-RFNp), were prepared, and their morphology was observed. Two experiments, each independent of the other, were performed. Cherry Valley ducks (14 days old) were inoculated with EDI-II-RFNp, EDI-II, and phosphate-buffered saline (PBS, pH 7.4), along with virus-neutralizing antibodies, interleukin-4 (IL-4), and interferon-gamma (IFN-γ). Subsequent analyses focused on serum antibody and lymphocyte proliferation measures. In a second experiment, ducks treated with EDI-II-RFNp, EDI-II, or PBS were exposed to virulent DTMUV, and clinical manifestations were assessed at seven days post-infection. At both seven and fourteen days post-infection, quantification of DTMUV mRNA in the lungs, liver, and brain was performed. Analysis of the results indicated near-spherical nanoparticles, designated EDI-II-RFNp, possessing diameters of 1646 ± 470 nanometers. The EDI-II-RFNp group demonstrated statistically higher levels of specific and VN antibodies, IL-4, IFN-, and lymphocyte proliferation relative to the EDI-II and PBS groups. In the DTMUV challenge test, mRNA levels in tissue and clinical observations were used to determine the degree of protection conferred by EDI-II-RFNp. Ducks vaccinated with EDI-II-RFNp exhibited less severe clinical symptoms and lower DTMUV RNA levels in their lungs, liver, and brains. EDI-II-RFNp's protective effect on ducks against the DTMUV challenge establishes its potential as a safe and effective vaccine candidate, offering a promising means of preventing and controlling DTMUV infections.

The presumed principal host species for the bacterial pathogen Mycoplasma gallisepticum in wild North American birds, since its jump from poultry to wild birds in 1994, has been the house finch (Haemorhous mexicanus), exhibiting higher disease prevalence than in any other bird species. In our investigation around Ithaca, New York, concerning purple finches (Haemorhous purpureus), we explored two hypotheses regarding the recent surge in disease prevalence. M. gallisepticum's escalating virulence, during its evolutionary trajectory, has coincided with its improved adaptation to various finch populations. Should this be accurate, initial strains of M. gallisepticum are anticipated to produce less severe eye damage in purple finches compared to house finches; conversely, more recent strains are expected to result in comparable degrees of ocular damage in both species. Following the M. gallisepticum epidemic's impact on house finch populations, Ithaca's purple finch abundance rose relative to house finches, potentially increasing their exposure to M. gallisepticum-infected house finches, as hypothesized.