Heterakis gallinarum is a heavily prevalent poultry parasite that thrives in the ceca of various species of gallinaceous birds. It is a small roundworm, measuring between 4 and 15 mm long, in the family Heterakidae. Heterakis gallinarum has a direct life cycle not requiring an intermediate host to complete development, and it is generally believed that poultry raised at high density on litter are at greatest risk for accumulating large numbers of the nematode. This species typically only causes mild pathology that does not significantly affect bird performance. However, H. gallinarum is recognized as an economically important parasite by the poultry industry because its ovum serves as the vector for the protozoal parasite Histomonas meleagridis, the cause of histomonosis in poultry. Diagnosis of the nematode typically relies on fecal egg counts, which are prone to false negative diagnoses. Molecular tools are available for studying the nematode and diagnosing infected flocks. Treating and preventing H. gallinarum infection is made difficult due to the low efficacy of anthelmintics for eradicating H. gallinarum from infected birds and of disinfectants for destroying H. gallinarum ova on contaminated farms.

Our prior work has shown that live poultry vaccines have been intermittently isolated from wild birds sampled during field surveillance studies for Newcastle disease virus (NDV). Thus, we experimentally investigated the susceptibility of four native agriculturally associated wild bird species to the NDV LaSota vaccine and evaluated the shedding dynamics, potential transmission from chickens, and humoral antibody responses. To test susceptibility, we inoculated wild-caught, immunologically NDV-naïve house finches (Haemorhous mexicanus; n = 16), brown-headed cowbirds (Molothrus ater; n = 9), northern cardinals (Cardinalis cardinalis; n = 6), and American goldfinches (Spinus tristis; n = 12) with 0.1 ml (10^6.7 mean embryo infectious doses [EID_50/ml]) of NDV LaSota vaccine via the oculo-nasal route. To test transmission between chickens and wild birds, adult specific-pathogen-free white leghorn chickens were inoculated similarly and cohoused in separate isolators with two to five wild birds of the species listed above. This design resulted in three treatments: wild bird direct inoculation (five groups) and wild bird exposure to one (two groups) or two inoculated chickens (six groups), respectively. Blood and oropharyngeal and cloacal swabs were collected before and after infection with the live vaccine. All wild birds that were directly inoculated with the LaSota vaccine shed virus as demonstrated by virus isolation (VI). Cardinals were the most susceptible species based on shedding viruses from 1 to 11 days postinoculation (dpi) with titers up to 10^4.9 EID₅₀/ml. Although LaSota viruses were shed by all inoculated chickens and were present in the drinking water, most noninoculated wild birds cohoused with these chickens remained uninfected for 14 days as evidenced by VI. However, one American goldfinch tested positive for vaccine transmission by VI at 7 dpi and one house finch tested positive for vaccine transmission by real-time reverse-transcription PCR at 13 dpi. Only one directly inoculated cowbird (out of three) and two cardinals (out of two) developed NDV-specific hemagglutination inhibition antibody titers of 16, 16, and 128, respectively. No clinical signs were detected in the chickens or the wild birds postinoculation.

Broiler production is highly dependent on good health in the parent flocks. The so-called normal mortality in these flocks remains to be addressed to further reduce mortality of the breeders and to improve the quality of broilers. The aim of the present study, therefore, was to investigate the etiology of this breeder mortality to map out possible critical periods during production in relation to possible risks of importance to the offspring. Dead birds from four flocks were subjected to postmortem and bacteriologic examination from onset of lay until slaughter (20–60 weeks). Causes of mortality were divided into noninfectious and infectious etiology. The infectious group could be subdivided into suppurative salpingitis/peritonitis caused by Escherichia coli and other infections (e.g., sepsis, endocarditis, and arthritis) mainly caused by Gram-positive cocci. Data analysis showed that 41% of the birds died from noninfectious causes, while 55% died from infectious causes, and 4% had no known cause of death. The prevalence of noninfectious mortality was highest in the youngest birds and lowest in the oldest birds. In contrast, the infectious mortality was lowest in the young birds and highest at the end of production. Within each age group, the prevalence of salpingitis/ peritonitis was 26% in young birds (20–29 weeks) and progressed throughout production to 41% in the oldest birds (≥50 weeks of age). Mortality due to other infections was low at onset of production (12%), peaking at 40–49 weeks of age (25%). Consequently, 40–49 weeks of age is identified as a critical period with regard to causes of mortality, possible vertical transmission of E. coli to the offspring, and increased risk of Gram-positive coccal infections.

Goose parvovirus (GPV) is the etiologic pathogen of Derzsy's disease, causing great economic losses in the waterfowl industry. A novel GPV-related virus (NGPV), which caused short beak and dwarfism syndrome, has occurred in China since 2015. In this study, two GPV strains (RC45 and RC70) were isolated from diseased growing period geese (45 days old and 70 days old), and one NGPV strain GXN45 was isolated from a 45-day-old Cherry Valley duck in China. To better understand the genetic diversity between GPVs isolated from growing period waterfowls and other classical waterfowl parvoviruses, the complete genomes and main genes were sequenced and analyzed. Full-length genomic sequence alignments demonstrated that both RC45 and RC70 showed the highest identity with classical GPVs YZ99-6 and SHFX1201, whereas GXN45 shared the highest identity with NGPV SDLC01. Sequence alignment of the inverted terminal repeat region showed that GXN45, RC45, and RC70 had two 14-nucleotide (nt) deletions compared with the classical GPV virulent B strain and one 14-nt deletion compared with mule duck–origin NGPV M15 strain. Phylogenetic tree analysis of nonstructural and VP1 genes showed that GXN45 was clustered into a branch with NGPV QH15 strain except for the VP1 amino acid tree. Although both RC45 and RC70 formed one separate branch distinct from classic GPV isolates, they were in one large phylogenetic tree branch. This study will contribute to a better understanding of the genetic diversity and molecular characterization of three isolated parvoviruses and lay the foundation to further study the relationship between mutations of virus genome and viral pathogenicity.

To determine which type of egg-laying hen housing was best for the chickens, the workers in those housing systems, the environment, and society based on food safety and affordability, a combined research project involving egg suppliers, food manufacturers, food service representatives, and food retailers, as well as research institutions and nongovernmental organizations, was performed. This study reports the hen health and welfare portion based upon veterinary health inspections and compared mortality rates, skeletal abnormalities, causes of death determined by necropsy, and titers to infectious bronchitis and Newcastle disease viruses. Birds were housed on a preexisting Midwest layer complex, which consisted of conventional cages (CC). New houses were built adjacent to the CC house where enriched colony cages (EC) and an aviary system (AV) were installed. Two flock cycles from housing to 78 wk of age were followed. Total mortality was greatest for AV, while CC and EC birds were similar. Keel bone fractures were greatest for AV, next greatest for EC, and least for CC birds. Other skeletal abnormalities were greatest for AV birds. Birds dying from being caught in the structure, pick out, and persecution was most frequent for AV and next most frequent for EC, but nonexistent with CC birds. Infectious pododermatitis (bumblefoot) was most frequent for AV, next most frequent for EC, and essentially nonexistent for CC birds. There was little to no effect on antibody titers based upon housing type. Based upon these findings, it appears that EC housing is better for the health and welfare of egg-laying chickens than CC or AV housing.

Avian pox is commonly diagnosed in a variety of North American wild and domestic birds, yet little is known about the evolutionary relationships among the causative poxviruses. This study aimed to determine the phylogenetic relationships among isolates identified in different avian host species to better characterize the host range of specific viral strains and compare the genetic variability within and between viral clades. Skin lesions grossly and microscopically consistent with poxvirus infection from 82 birds collected in Canada, the United States, and the U.S. Virgin Islands were included in this study. A total of 12 avian species were represented; the most common species sampled were wild turkeys (Meleagris gallopavo), mourning doves (Zenaida macroura), and American crows (Corvus brachyrhynchos). Poxvirus samples from these birds were genotyped using PCR that targeted the 4b core protein gene followed by amplicon sequencing. Bayesian phylogenetic analyses of these viruses, in conjunction with publicly available sequences, representing avipoxvirus strains from six continents revealed statistically significant monophyletic clades based on genetic distances of sequences within and between observed clades. Genetic variation within the fowlpox clade was low compared to the canarypox clade. Host and geographic origins of viral isolates revealed overall clustering of viral strains within avian species, with a few exceptions. No genetic differences were observed between viruses from Canada and the United States within individual species. These results are novel in their characterization and comparison of the phylogenetic relationships of poxvirus isolates in wild bird species from North America. Further, we provide new data on the level of host specificity and specific strains circulating in North America.

Since 2013, the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) has collected antimicrobial use (AMU) and antimicrobial resistance data from sentinel broiler chicken flocks (Br, five provinces) and sentinel turkey flocks (Tk, one province 2013–2015, three provinces 2016–2017). The objectives of this paper were to describe various preventive strategies aimed at controlling necrotic enteritis (NE) and coccidiosis in the broiler chicken and turkey flocks participating in CIPARS and FoodNet Canada Farm Surveillance Program between 2013 and 2017, to quantify and identify trends in antimicrobials used in feed, and to describe temporal changes in the diagnoses of bacterial and protozoal diseases in relation to antimicrobial use in feed. Comprehensive data were collected (by questionnaire) enabling AMU assessment by various count-based metrics (i.e., frequency and number of medicated rations), weight-based metrics (i.e., inclusion rate in feed and kilograms consumed), and technical indicators (i.e., milligrams per population correction unit [mg/PCU]). Qualitative information such as reasons for use and frequency of diagnosed diseases provided context to the trends in AMU. Between 2013 and 2017, 646 broiler flocks (14.9 million kg biomass) and 234 turkey flocks (12.4 million kg biomass) were surveyed. Overall, antimicrobials used for the prevention of Clostridium perfringens infections (NE) contributed to 85% (109/128 mg/PCU_Br) and 95% (59/62 mg/PCU_Tk) of the quantity of antimicrobials administered via feed in broiler chickens and turkeys, respectively. Three NE programs were used: either 1, 2, or ≥3 antimicrobials administered throughout the production cycle. The treatment protocol in which a single antimicrobial was used throughout the cycle was the most frequent NE preventive program for broiler chickens (58%) and turkeys (76%). Bacitracin and virginiamycin were the top two most frequently used antimicrobials in both species for NE. For coccidiosis control, ionophores and chemical coccidiostats contributed to 66% (3091 kg) and 68% (1561 kg) of the total feed antimicrobial exposures in broiler chickens and turkeys, respectively. Documented coccidiosis programs included continuous or straight (1 drug/cycle), shuttle or dual control (≥2 drugs/cycle), and vaccination. Variations in coccidiosis programs between species were noted: broiler chickens frequently used a shuttle or dual-control program (68%), whereas turkey flocks used primarily a continuous or straight program (74%). Flocks raised without antibiotics and organic farms (10.3% of broiler chickens and 9.8% turkey flocks) used vaccines to prevent coccidiosis. A small number of broiler flocks (n = 6) used a combination of a vaccination and a coccidiostat during the cycle. During the surveillance timeframe used for this paper, the total feed AMU decreased over time in broiler chickens from 136 to 120 mg/PCU_Br and in turkeys from 85 to 62 mg/ PCU_Tk, with no remarkable changes in the frequency of flocks diagnosed with bacterial and protozoal diseases. Surveillance findings such as these will be used as valid reference points in light of the upcoming changes in Canadian federal AMU regulations and industry-led initiatives aimed at reducing AMU.

Twelve chukar partridges (Alectoris chukar) from a farm experiencing poor uniformity and increased mortality of up to 65% were submitted for diagnosis. Several birds had mild to moderate multifocal white foci or multifocal petechial hemorrhages throughout the liver. Livers and spleens of older birds were moderate to severely diffusely enlarged. In addition, some birds had caseous cores mixed with blood within the ceca as well as segmentally thickened cecal walls. Histopathology showed acute, multifocal, severe, often coalescing foci of necrosis with accumulation of fibrin and/or fibrinosuppurative inflammation in livers and spleens. Scattered within exudate were protozoa that were spherical or round and measured 12–20 µm in diameter. In the ceca, acute necrosis of the mucosa was observed, often with ulceration and fibrinosuppurative inflammation. Immunohistochemistry using an antiserum against Tritrichomonas foetus revealed round protozoa in ceca, small intestines, liver, spleen, and lung. Quantitative PCR to detect DNA of Histomonas meleagridis was negative. Non–species-specific PCRs amplifying the partial rDNA, the internal transcribed spacer (ITS) region, and the partial beta-tubulin gene yielded products of the expected size. Sequences of the PCR products had the highest homology to sequences of Tetratrichomonas gallinarum and less homology to sequences of H. meleagridis. In addition there was accumulation of amyloid in the space of Disse in the liver, splenic sinuses, and walls of the blood vessels. The typhlohepatitis and other inflammatory processes that were diagnosed might be the underlying cause of the amyloidosis. Other findings were clusters of Clostridium perfringens associated with the lesions in the ceca; multifocal granulomas in the lungs, occasionally associated with fungal hyphae; hyperkeratosis associated with bacteria and Candida sp. cells in the crop; mild infection of the bursal mucosa with Cryptosporidium.

This study describes the molecular characterization of avian reoviruses (ARVs) isolated during an outbreak in commercial chickens between 2015 and 2016. In addition, a pathogenicity study of a selected ARV strain isolated from a field case of viral tenosynovitis in commercial broiler chickens was performed. On the basis of phylogenetic analysis of a 1088-bp fragment of the ARV S1 gene, the investigated sequences were differentiated into five distinct genotypic clusters (GCs), namely GC1, GC2, GC3, GC4, and GC6. Specific-pathogen-free (SPF) and commercial broiler chickens were challenged with the GC1 genetic type MK247011, at 14 days of age via the interdigital toe web. No significant effects in body weight gain and feed conversion were detected in both chicken types. The Δ interdigital web thickness was most severe at 4 days postchallenge (DPC) in both the SPF and broiler subgroups. The inflammation in SPF birds was slightly more severe compared with broilers. Neither mortality nor clinical signs occurred in the infected groups for the duration of the experiment, despite the presence of significant microscopic lesions in challenged birds. Microscopic changes of tenosynovitis became evident at 3 DPC, with the highest incidence and severity detected at 14 and 21 DPC, respectively. Seroconversion against ARV occurred 3 wk postchallenge, and the microscopic lesions detected in tendon and heart sections were highly compatible with those described in the field. Increased severity of tenosynovitis and epicarditis lesions were noted in the ARV-challenged groups compared with the control groups. Although SPF and broiler chickens showed comparable responses to the challenge with an ARV genetic variant, detected lesions were subclinical, denoting the limitations of our challenge approach. The age selected in this experiment possibly influenced the course of the infection. Data from this study highlight the genotypic diversity of isolates in California, and the outcome of the pathogenicity study can be used as a basis to improve protocols for pathogenicity studies to characterize ARV variants causing clinical disease in the field.

Clostridium perfringens (CP) type A and newly created type G strains are the key etiological factors in the induction of necrotic enteritis (NE), an important enteric disease that is responsible for the annual loss of $6 billion in the worldwide poultry industry. Several CP toxin genes were found to be critical in NE pathogenesis in chickens, but limited information is available on the CP lethal toxin tpeL gene. In this study, 19 CP strains isolated from NE-affected chicken farms were characterized microbiologically and molecularly and evaluated for their pathogenicity in commercial broiler chickens. Toxin typing by PCR revealed that all strains tested were positive for the netB toxin gene, but only five strains were positive for the tpeL toxin gene (LLY-TpeL 13, -TpeL 15, -TpeL 17, -TpeL 18, and -TpeL 19, simplified as TpeL 13, TpeL 15, TpeL 17, TpeL 18, and TpeL 19). High levels of TpeL proteins were detected in the concentrated culture supernatant from strains TpeL 13, 15, 17, and 19 by western blotting. Quantitative PCR showed that strains TpeL 13, 15, 17, 18, and 19 harbored a high number of copies of tpeL genes, while TpeL 18 had the highest number of copies of the tpeL gene among all CP strains tested when normalized with copy numbers of 16S rRNA gene as a housekeeping gene marker. The in vivo NE challenge test using multiple oral CP inoculations combined with a high-protein diet showed that TpeL 17 was the most virulent in inducing typical NE lesions, followed by TpeL 19 as the next most virulent, when tested in commercial broiler chickens. Infection with TpeL 17 reduced the growth rate significantly, as shown by reduced relative body weight gain percentage at day 5 postinfection. Availability of the virulent netB⁺tpeL⁺ CP strains is essential for the development of a CP-alone NE challenge model that could provide significant tools for understanding CP pathogenesis and for development of alternative to antibiotics.

This report is one of the first studies describing the relationship between the occurrence of Mycoplasma spp. as regards the type of breed and health status of pigeons. The aim of the study was to evaluate the prevalence of Mycoplasma gallisepticum, Mycoplasma synoviae, Mycoplasma columbinum, Mycoplasma columborale, and Mycoplasma columbinasale in Polish populations of racing and ornamental pigeons in the context of their correlation with type of breed and health status. The study was conducted on 179 samples (100 racing and 79 ornamental pigeons) collected from pigeons in different regions of Poland. Tracheal swabs were examined for Mycoplasma spp. using genus-specific PCR. If Mycoplasma spp. were detected, the species were identified by species-specific PCR developed on the 16–23S rRNA intergenic spacer region. Ninety-two of 100 (92%) racing pigeons and 67 of 79 (85%) ornamental pigeons were Mycoplasma spp. positive. None of the tested pigeons were positive for M. gallisetpticum or M. synoviae. The average prevalence of M. columbinum was determined at 49%, M. columborale at 79%, and M. columbinasale at 23% in all birds tested. A single mycoplasma infection was found in 40% of pigeons whereas multiple infections were found in 49% of tested birds. Differences were found in the occurrence of mycoplasmas between racing and ornamental pigeons. Our results have shown a high prevalence of Mycoplasma species both as a single and as multiple infections.

The genetic evolution of highly pathogenic avian influenza (HPAI) in Egypt has developed a new clade H5N1 (2.2.1.2) since 2014. Meanwhile, the new avian influenza virus (AIV) clade mutually with the velogenic Newcastle disease virus (NDV) isolate of genotype VII in Egypt (genotype VII) has resulted in severe economic losses in the broiler industry. An inactivated bivalent vaccine containing H5 (belonging to H5N1 clade 2.3.2) recombinant baculovirus expressed by insect cell (recH5) and egg-based NDV LaSota strain (recH5/NDV vaccine) was evaluated for protection against the challenge of dual HPAIV H5N1 clade 2.2.1.2 and vNDV infection in commercial broiler chickens. Vaccination was performed when chickens were 10 days old, and then birds of the respective groups were challenged with 10⁶ 50% egg infective dose per chicken of each virus in 100 µl of allantoic fluid via the intranasal route at 21 days postvaccination in a single or sequential infection of both viruses. Results showed that the recH5/NDV vaccine was able to protect chickens against single or dual challenges of both viruses ranging up to 90%–100%. Unvaccinated chickens have demonstrated 100% mortalities to a single virus challenge. Vaccinated chickens showed significant decreases in both viruses, shedding titers up to <2 log ₁₀ after challenge in comparison with unvaccinated ones. Cessation of viral shedding was obtained at 7 to 10 days postchallenge. The vaccinated chickens showed high hemagglutination inhibition antibody titers >6 log ₂ against both H5N1 and NDV antigens at 2 wk postvaccination. The single vaccination of bivalent inactivated recH5-NDV vaccine at 10 days old in commercial chickens has provided significant clinical protective immunity against single or dual challenge with HPAI-H5N1clade 2.2.1.2 and vNDV-genotype VII.

Goose parvovirus (GPV) is a highly contagious disease caused by GPV in goslings and young Muscovy ducklings. In recent years, frequent GPV outbreaks have occurred in many regions of Jilin Province, China. In this study, to understand the immune-related characteristics of the currently prevailing GPV strains in some regions of Jilin Province, six GPV strains were isolated from six different regions of Jilin Province in 2016–2018. The results of phylogenetic analysis, clinical signs, and histopathologic analysis showed that four strains were virulent and two strains were attenuated. Specifically, we found that the two attenuated strains have the same amino acid mutation at the same position in the virus protein 3 (VP3) gene, and the virulent strains have more mutation sites than the attenuated strains. This finding suggests that changes in these sites may result in GPV replication or reduction in the immune response in goslings, thereby producing strong pathogenicity, and that attenuated strains are more conservative than virulent strains.

In 2017, the Turlock branch of the California Animal Health & Food Safety laboratory system received a significant increase in infectious coryza (IC) necropsy cases, with a total of 54 submissions originating from commercial broilers (n = 40), commercial layers (n = 11), and backyard chickens (n = 3). Layer flocks positive for IC were distributed within the adjacent counties of Merced and Stanislaus, while broiler flocks were concentrated within Merced County. The backyard flocks were located in Alameda and Sacramento counties. The clinical and pathologic presentation was consistent with IC, although septicemic lesions were also noticed. Avibacterium paragallinarum was isolated and identified by PCR from the respiratory tract as well as from extrarespiratory sites. Polymicrobial infections involving other viral (infectious bronchitis virus, infectious bursal disease virus) and bacterial (Mycoplasma spp., Escherichia coli, Ornithobacterium rhinotracheale, Gallibacterium anatis biovar haemolytica) agents were commonly reported. Thirteen selected Av. paragallinarum isolates were successfully characterized as serovar C (Page scheme) and serovar C2 (Kume scheme). They shared a unique enterobacterial repetitive intergenic consensus (ERIC) PCR, differing from the four reference strains, and showed consistent high minimum inhibitory concentration values for tetracycline, suggesting a common origin from a single clone. Based on these results, high biosecurity standards and proper immunization of susceptible, multi-age flocks should always be implemented and adjusted as needed. The importance of backyard flocks should not be underestimated due to their unique epidemiologic role.

Routine and quantitative histologic studies on femoral head separation (FHS) associated with coxofemoral joint disarticulation at necropsy were conducted on 125 femoral heads collected from 21- to 50-day-old clinically normal broilers. The study compared groups demonstrating grossly detached femoral heads (DFHs) with those having attached femoral heads (AFHs). Marked microscopic lesions compatible with osteochondrosis (OCD) consistently occurred along the separation surface in the DFH population. The histologic changes consisted of cartilage degeneration and necrosis sometimes forming small clefts or microfractures. Hemorrhage and less frequent inflammatory cells were often present along the separation surfaces. Small foci of OCD in the femur occurred in the AFH group with lesser frequency and severity. The histologic changes were mainly found within the proximal proliferative zone of the physis near the epiphyseal junction. Histomorphometry disclosed significant quantitative reductions in chondrocyte density with increased pyknosis occurring adjacent to the separation site and to a lesser extent in deeper regions of the growth plate for the DFH compared with AFH. Measurements made along the separation surface of the percentage length occupied by osteochondrotic defects and actual separated cartilage disclosed significant differences between evaluation groups. However, determinations of vascular canal areas present within two or more regions of the growth plate revealed a slight and significant increased area for DFH compared with AFH. Severity scores for the occurrence of microthrombi within the growth plate showed no difference between the groups. The pathogenesis of FHS in broilers is related to defective cartilage production or degeneration resulting in increased fragility. This contrasts with the proposed pathogenesis of OCD in mammals, which involves ischemic necrosis due to underlying vascular defects. The results for the FHS-disarticulation model also differ from those reported for glucorticoid-induced femoral head necrosis in broilers. The FHS-associated lesions occurred without histologic evidence of bacterial chondritis or osteomyelitis.

This study describes the first recognized clinical case of lymphoproliferative disease virus (LPDV) in Canada and extends the range of LPDV in Canada through its detection in Manitoba and Quebec. We assessed the prevalence of LPDV in eastern wild turkeys (Meleagris gallopavo silvestris) with the use of whole, clotted blood from live birds in Manitoba (n = 65) and tissue samples collected postmortem in Quebec (n = 4). We tested for LPDV proviral DNA through PCR amplification and sequencing of a portion of the gag (p31) gene. Samples were also tested for reticuloendotheliosis virus (REV) by PCR. Twenty-four birds (34.8%) were positive for LPDV, including all diagnostic cases. One bird (1.4%) from Quebec had gross and microscopic lesions consistent with LPDV. Two turkeys (2.9%) were REV positive, one (1.4%) of which was co-infected with LPDV. Phylogenetic analysis of LPDV strains from Quebec and Manitoba grouped with previously sequenced samples from Ontario and publicly available sequences from a North American lineage. This study contributes valuable information toward ongoing surveillance and monitoring of LPDV in North America.

Nematodes are widespread and common in poultry. Disinfectants are used to reduce infection rates in poultry houses, but there is little documentation of their effectiveness. An in vitro assay was developed to test the efficacy of products to damage Heterakis gallinarum eggs, and nine disinfectants and chemicals commonly used in the poultry industry were tested. Embryonated eggs of H. gallinarum were pipetted into wells of plastic cell culture plates (250–300 eggs/well in water). Measured amounts of test articles were added to the suspensions for 2, 4, 6, or 24 hr. After exposure, eggs were washed with water and treated with trypan blue (1 ml of 0.4% solution, added to each well) at room temperature for 2 min. Eggshell integrity was determined microscopically by counting the number of eggs that were clear (intact) or that contained blue dye (compromised). As a test of embryo viability, five eggs per well from treatments containing compromised eggs were transferred to a Petri dish and hatched manually, using forceps to open the eggshell. Released larvae were then observed for signs of controlled movement. In a test of Clorox bleach (NaOCl), Green Klean, Decon7, Kem San, PLT, Virkon S, NaCl, dry limestone (CaCO₃), and diesel fuel, only NaOCl (bleach) and Green Klean damaged the eggshell, and only 20,625 ppm of NaOCl rendered the larvae nonviable.

Occurrence of mortality, wooden breast, and pulmonary disease in broiler chickens during the last 16 days of production in a teaching flock of 4000 commercial broilers was determined. A new syndrome was identified, in which broilers fell over for an unknown reason and were unable to right themselves (dorsal recumbency). Birds affected by dorsal recumbency were alert and responsive and showed no clinical signs except for occasional mild to moderate dyspnea. When turned over, they resumed normal behavior. Mortality (14 culls; 49 dead) during the last 16 days of production accounted for 1.6% of the flock and 36% of total mortality. Among these, 71% were heavy males, 70% had wooden breast, and 71% had pulmonary congestion and edema. Gross lesions of concurrent wooden breast and pulmonary disease occurred in 68% of the mortality, including 21 of 22 dead birds found on their backs. These findings indicate that wooden breast is associated with mortality prior to processing as a result of pulmonary disease in heavy male broilers. When birds with wooden breast fall onto their backs for unknown reason(s), they are unable to right themselves. If not found and turned over, they may not survive. Based on these findings, wooden breast is likely greater than just a problem with meat quality and should be considered an animal well-being issue.

Erysipelothrix rhusiopathiae septicemia was diagnosed in three cage-free commercial layer flocks from Washington State that experienced an increase in mortality and slight drop in egg production. Erysipelothrix rhusiopathiae was isolated from multiple organs and from environmental samples. An agar gel diffusion test of several E. rhusiopathiae isolates confirmed the presence of serotype 1b, and multiplex real-time PCR of the surface protective antigen (Spa) gene confirmed presence of SpaA. Bacitracin administered via the water reduced mortality minimally and only for a short period of time. Mortality was finally controlled by vaccination with a live attenuated swine E. rhusiopathiae vaccine delivered via the drinking water. This is the first report describing the use of an attenuated vaccine to control an E. rhusiopathiae outbreak in a chicken flock.

This study reports an outbreak of avian pox in a quarantine of canaries imported from Europe, with a mortality of 30% and clinical signs of dyspnea and blepharoconjunctivitis. During necropsy, beak cyanosis, serous blepharitis, caseous sinusitis, oropharyngitis, tracheitis, pulmonary edema, pneumonia, fibrinous airsacculitis, and splenomegaly were observed. Microscopically, edema, epithelial hyperplasia, hydropic degeneration, and vacuolated eosinophilic intracytoplasmic inclusion bodies were found; similar lesions were observed in the thymus, spleen, and other organs. The virus was isolated in chicken embryos, and it was identified and characterized using a sequence of 913 nucleotides of the DNA polymerase gene. Pathologic characteristics and molecular biology indicate the systemic presence of avian pox associated with an avipoxvirus of the B1 subgroup. Additionally, other lesions associated with Aspergillus sp., Macrorhabdus ornithogaster, and Isospora sp. were found, which could contribute to the high mortality. Canarypox virus should be considered a differential diagnosis in cases of dyspnea and high mortality in canary flocks.

In this case report, we describe the pathologic changes and the ultrastructural and molecular characteristics of an adenovirus in a sun conure (Aratinga solstitialis) that presented with a history of sudden death. On histologic examination, there was multifocal hepatic and splenic necrosis. Within some hepatocytes and unidentified cells in the spleen, renal interstitial fibroblasts, and ovarian stroma were intranuclear amphophilic inclusion bodies. Electron microscopy of affected tissue showed intranuclear icosahedral viral particles with an inner capsid (29.2–33.8 nm in diameter) and an outer capsid (70.2–71.7 nm in diameter). Next-generation sequencing and BLAST analysis of complementary DNA synthesized from RNA extracted from formalin-fixed tissues showed an adenovirus, designated sun conure adenovirus (SCAdv). A DNA in situ hybridization (ISH) probe, constructed from the SCAdv and similar sequences from GenBank, was also positive in the intranuclear inclusion bodies, whereas standard ISH for psittacine adenovirus 1 was negative. These results show that ancillary diagnostic testing, such as next-generation sequencing, even using formalin-fixed, paraffin-embedded tissues, along with ISH, can be useful in identifying additional, unknown viruses that show similar pathology to commonly known viruses but do not show up as positive on routine diagnostic tests.