After the 1971–1973 outbreak of exotic Newcastle disease (END) in California, a free-of-charge diagnostic submission program was created for backyard poultry flocks. This program was implemented to improve disease surveillance in small poultry flocks. The aim of this study was to evaluate the spatial distribution of free-of-charge pathology submissions to the California Animal Health and Food Safety laboratories during the END outbreak in 2002–2003. Cases and controls were selected from within a 100-mile (161-km) radius of each of three laboratories, and their geographic distributions were evaluated. Global clustering of Cases was significant around all three laboratories, with mixed results at the local clustering level and the only significant clustering at the focal level around the Davis laboratory with an observed to expected ratio of approximately 5. The area of influence for all three laboratories was about 20 miles (32 km). The significant clustering of Cases around the laboratories indicates that more public information about the free-of-charge program could result in coverage of a larger portion of the population; however, the value of the information resulting from increased sampling should be considered relative to the additional cost of obtaining it.

Infections of avian influenza virus (AIV) in turkey breeder hens can cause a decrease in both egg production and quality, resulting in significant production losses. In North Carolina in 2003, a triple-reassortant H3N2 AIV containing human, swine, and avian gene segments was isolated from turkey breeder hens (A/turkey/NC/16108/03). This viral subtype was subsequently isolated from both turkeys and swine in Ohio in 2004, and in Minnesota in 2005, and was responsible for significant losses in turkey production. The objective of this study was to determine if currently available commercial, inactivated avian influenza H3 subtype oil-emulsion vaccines would protect laying turkey hens from egg production losses following challenge with the 2003 H3N2 field virus isolate from North Carolina. Laying turkey hens were vaccinated in the field with two injections of either a commercial monovalent (A/duck/Minnesota/79/79 [H3N4]) or autogenous bivalent (A/turkey/North Carolina/05 (H3N2)–A/turkey/North Carolina/88 [H1N1]) vaccine, at 26 and 30 wk of age, and subsequently challenged under BSL 3-Ag conditions at 32 wk of age. Vaccine-induced efficacy was determined as protection from a 50% decrease in egg production and from a decrease in egg quality within 21 days postchallenge. Results indicate that, following a natural route of challenge (eye drop and intranasal), birds vaccinated with the 2005 North Carolina H3N2 subtype were significantly protected from the drop in egg production observed in both the H3N4 vaccinated and sham-vaccinated hens. The results demonstrate that groups receiving vaccines containing either H3 subtype had a decreased number of unsettable eggs, increased hemagglutination inhibition titers following challenge, and decreased virus isolations from cloacal swabs as compared to the sham-vaccinated group. Phylogenetic analysis of the nucleotide sequence of the HA₁ gene segment from the three H3 viruses used in these studies indicated that the two North Carolina turkey isolates had 90.4 % similarity in HA₁ nucleotide sequence, but had only 77.4% and 76.1% sequence similarity to the HA₁ of the H3N4 duck isolate. This study provides the first detailed description of the clinical protection afforded to laying turkey hens by vaccination against challenge with a circulating field isolate of a H3N2 triple-reassortant AIV.

A rapid drop in egg production and a high culling rate in hens are associated with using four avian influenza (AI) inactivated vaccines. Average formalin levels in 22 batches of commercial AI vaccines are 0.34%, 0.59%, 0.79%, and 0.33%, respectively, in H5N1 Re-1, Re-4, Re-1 Re-4, and Re-1 H9N2 vaccines. Laying production rate dropped from the expected 96.1% to 68.3%, 62.6%, and 54.1%, respectively, in hens that received H5N1 Re-1 strain, Re-4 strain, or Re-1 Re-4 strain vaccines, and the culling rate was 8.8%, 15.0%, and 18.0%, respectively. AI vaccines containing 0.66%–0.81% formalin could significantly induce lower estradiol levels and decreased antibody titers of H5 subtype in a field study. In an experimental study, 200 16-wk-old laying hens were randomly divided into four groups and intramuscularly injected 0.5 ml per chicken formalin-oil preparation at the dose of 0.10%, 0.40%, and 0.81% formalin, respectively. The control hens were given 0.5 ml phosphate buffered saline. Egg performance and degenerative combs were examined daily. The results showed that 0.81% formalin preparation significantly induced an egg production drop and lower estradiol levels as compared to the lower formalin preparations. Significant degeneration of combs and ovarian follicles was also observed. These changes suggest that vaccines with more than the recommended formalin concentration lower hemaglutination inhibition antibody levels and induce an imbalance in estradiol secretion, resulting in degenerative change in ovarian follicles and uterus. Hence, new H5N1 vaccines with recommended formalin levels are urgently needed.

Femoral head separation (FHS) and necrosis is a sporadic leg problem of unknown etiology in broiler breeders. To determine the underlying physiology of FHS, the blood chemistry and histopathology of the femoral growth plates of the affected chickens were compared with their age-matched controls and with birds having tibial dyschondroplasia. Femoral problems were categorized on the basis of 1) femoral head separating from articular cartilage without any visible damage to the growth plate (FHS) and 2) FHS with significant tearing and lesions in the growth plate (FHSL). Tibial dyschondroplasia was identified by a widening of the growth plate with an unresorbed plug of cartilage at the proximal end of the tibia. Control birds were without any femoral or tibial problems. The histopathology of FHSL growth plates revealed occasional chondrocyte death, hypocellularity, dysplasia in the prehypertrophic zones, and the absence of inflammatory infiltrates in the lesion areas. Hematoxylin and eosin staining showed brown chromogenic deposits in the metaphyseal bone marrow areas. Blood chemistry of chickens with FHSL showed a modest but significant elevation of cholesterol, triglycerides, and low-density lipoproteins. Only cholesterol and low-density lipoproteins were moderately elevated in FHS-affected chickens. Other blood parameters, such as protein, magnesium, and iron levels, showed differential changes in birds with leg problems, but there were no specific trends. Neither blood ovotransferrin, a marker of chronic inflammation, nor corticosterone, a marker of stress, showed any significant differences from the controls. These results indicate that FHS may be a metabolic problem in poultry, one that is related to fat metabolism disorders, possibly contributing to an unbalanced growth in the articular-epiphyseal complex that leads to its separation under sheer stress.

In four composting experiments, survival of avian influenza (AI) and Newcastle disease (ND) viruses was assessed by virus isolation in embryonated chicken eggs (ECEs) and by real-time reverse transcriptase–polymerase chain reaction. Specimens contained in nylon mesh bags consisted of 20-g samples of chicken manure, used litter, or feed that had been inoculated with allantoic fluid containing an AI virus (H6N2, Expt. 1) or an ND vaccine virus (Expt. 2). Other specimens consisted of 20-g samples of infected ECEs that had been homogenized and mixed with corn silage. As a control, allantoic fluid diluted in phosphate-buffered saline was contained in sealed vials. Except for the feed, in which the AI virus was inactivated soon after the specimen was inoculated, on day 0 the specimens buried in compost or placed outside at ambient temperatures contained at least 5.0 log₁₀ of virus and 7.7 log₁₀ of viral RNA. By day 7, temperatures in compost ranged from 50 C to 65 C, and viruses had been killed in all specimens in bags. In comparison, viruses in sealed vials remained viable to day 10. Viral RNA in mesh-bag specimens had been degraded to nondetectable levels by day 10, but it was still detected in sealed vials on day 21. In specimens that were held at ambient temperatures (13 C–28 C), the viruses in mesh-bag specimens were inactivated by day 21, but their RNA was still detected. In comparison, the viruses in sealed vials survived to day 21. In Expts. 3 and 4, viruses were inactivated in carcass specimens and in whole ECEs during composting. In an in vitro experiment, the time required for a 1-log₁₀ reduction of viruses was significantly shorter (P < 0.05) in water extracts from compost than in phosphate buffers at temperatures of 25 C to 45 C. This study provided evidence that microbial activity during composting contributed to the rapid killing of AI and ND viruses and to the degradation of their viral RNA.

Ceramic powder prepared by sintering of chicken feces, when mixed with avian influenza viruses or an avian adenovirus, inactivated these organisms to below detection levels. When the ceramic powder was mixed with double-distilled water, the pH of the water rose to 10 but the aqueous phase did not show any antivirus activity. After 10 washings with water or five washings with 1M Tris-HCl (pH 8.0), the ceramic powder still retained antivirus activity. Antivirus activity was not affected by the presence of organic material (33% fetal calf serum). When chicks were fed food containing 5% ceramic powder, there was no difference in body weight between normal feeding and the ceramic-mixture feeding. The mode of action of the ceramic powder remains unknown, but it possibly works by adsorbing the virus. These results show that the ceramic powder has antiviral activities and is a potentially useful tool against avian influenza on poultry farms.

Virulent Newcastle disease virus isolates from the 1971 and 2002 U.S. outbreaks are of the same serotype but a different genotype than current vaccine strains. Prior experiments with inactivated vaccines in chickens show significantly less virus shed in birds vaccinated with a homologous vaccine (same genotype as challenge) compared to chickens vaccinated with genotypically heterologous vaccines. Subsequent experiments have compared the protection induced in chickens by live vaccines of B1 and LaSota (genotype II), Ulster (genotype I), and recombinant viruses that express the hemagglutinin neuraminidase gene (HN) or the HN and fusion gene (F) of CA 2002 (genotype V). Vaccinates were challenged with virulent viruses CA 2002 (genotype V) or Texas GB (TXGB, genotype II). After challenge with CA 2002 the birds vaccinated with a live recombinant genotype V virus containing the HN of CA 2002 shed significantly less virus in oropharyngeal swabs compared to B1 and had fewer birds shedding virus compared to B1, LaSota, and Ulster vaccinates. After challenge with CA 2002 birds vaccinated with the recombinant containing both the HN and F of CA 2002 (rA-CAFHN) shed less virus, and fewer birds shed virus compared to LaSota-vaccinated birds. TXGB-challenged LaSota-vaccinated birds shed less virus, and fewer birds shed virus compared to TXGB-challenged rA-CAFHN–vaccinated birds. Genotypic differences between vaccine and challenge did not diminish ability of vaccines to protect against disease, but genotypic similarity did reduce virus shed and may reduce transmission. The development and use of vaccines of the same genotype as the expected field challenge may provide an additional tool for control of this important poultry pathogen.

Bordetella hinzii is commonly acquired from the respiratory tract of diseased poultry but is generally Regarded as nonpathogenic in avian hosts because attempts to demonstrate disease following experimental infection of chickens and turkeys have failed. Recently, with the availability of highly specific DNA-based methods for identification of this agent, it was recognized that some isolates used in previous studies were misidentified at the time of their acquisition as Bordetella avium, B. avium–like, or Alcaligenes faecalis type II, including a subset reported to cause disease in turkey poults. In this study six strains of B. hinzii, genetically distinct and representing all known host species, were evaluated for their ability to colonize and cause disease in turkeys following intranasal administration. Although five strains were able to colonize the tracheas of turkey poults, only a subset induced clinical signs of disease, B. hinzii–specific antibodies, or tracheal lesions. The sixth isolate was undetectable in tracheal swabs obtained 1 or 2 weeks postinfection. Birds of this group displayed no clinical signs and minimal tracheal lesions. All remained B. hinzii seronegative. Three of the six strains, differing in their capacity to colonize and/or cause disease in turkeys, were used to infect chicks intranasally. Only one was able to colonize the trachea but did not induce tracheal lesions. No clinical signs of disease were observed in any chick. These results demonstrate that some strains of B. hinzii are virulent in turkey poults and may asymptomatically colonize chicks, and suggest this agent may be of concern to poultry producers.

As highly pathogenic avian influenza H5N1 virus continues to circulate in the world, poultry farm biosecurity and timely reporting of morbidity and mortality among commercial poultry farms in the United States are major concerns. To assess the vulnerability of poultry farms to the introduction and spread of a highly infectious pathogen, such as the currently circulating H5N1 influenza virus, a survey was administered to growers in two counties in Georgia representing areas of low and high poultry densities. Survey questions Regarding horizontal contacts and management were sent to commercial broiler and breeder-layer chicken producers. Responses were used to estimate and compare contact rates and patterns between the two Regions. The distribution of high-risk visitors (i.e., those going inside the poultry houses) to poultry farms did not vary significantly between growers in counties with high and low poultry densities or between breeder-layer and broiler growers. Compared with broiler producers in the county with high poultry density, broiler growers in the county with low poultry density were more likely to hire non-family employees to help with poultry management (62% vs. 17%; P  =  0.001) and assist other growers with their poultry (31% vs. 6%; P  =  0.025). Use of contracted litter services was significantly higher (P  =  0.019) among broiler growers in the poultry-dense county (40%) compared with the low-density county (6%). Compared with broiler growers, breeder-layer producers also were significantly more likely to hire non-family employees to help on the farm (53% vs. 17%; P  =  0.008). Poultry growers in the highly poultry-dense county were more likely to have a public road or field receiving poultry litter within a quarter mile of their poultry houses, compared with those in the lower density county. Data obtained in this study support the observations of published poultry disease outbreak investigations and highlight the differences in farm vulnerability to disease introduction within areas of different poultry densities and management practices.

This study was carried out to better understand factors that influenced the process of attenuation of Marek's disease (MD) virus by serial passage in cell cultures. Three virulent (v) pathotype and three very virulent plus (vv ) pathotype strains were passed by three techniques up to 131 times, and the passage level at attenuation was determined. The 18 attenuated or partially attenuated viruses were evaluated for protection against challenge with virulent MD virus, and the virus load (latent infection) in blood lymphocytes at 14–21 days postvaccination was determined. Viral pathotype strongly influenced the rate of attenuation. The mean passage level at attenuation for v and vv strains was 74 and >109, respectively. Full attenuation was achieved for nine of nine passage series with v pathotype strains but for only four of nine passage series with vv pathotype strains. Time to attenuation was not significantly influenced by multiplicity of infection at passage or by cell type, although a possible advantage of alternate high- and low-multiplicity passage was noted. Protection was not significantly influenced by pathotype or time to attenuation. Protection varied from 50% to 95% for the 18 passaged virus preparations; six attenuated viruses provided high protection that did not differ from that of the prototype Rispens strain. Virus load was not influenced by pathotype or by passage strategy and showed no positive correlation with protection. In several Cases the most protective vaccines had the least virus load. This finding differs from previous reports and warrants further study. Variation among different strains within the same pathotype was documented for attenuation rate, protection, and virus load. Also, variation was evident when the same strain was passaged by different strategies, probably reflecting random changes during serial passage. Strain 596A (v pathotype) was the first to become attenuated, provided the best protection, and had one of the lowest virus loads. In contrast, strain 617A (v pathotype) provided the least protection and had one of the highest virus loads. Such strains provide fertile opportunities for further study.

In this research we developed a real-time SYBR green assay to detect both Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) in a single reaction. A total of 30,000 samples from broiler breeder flocks were screened using traditional serology (plate agglutination, enzyme-linked immunosorbent assay, hemagglutination inhibition) and polymerase chain reaction (PCR; traditional and real-time). It was determined that the real-time SYBR green PCR assay developed in this research was more rapid than all three methods tested and more sensitive and specific than culturing or serology. The SYBR green assay was optimized and could detect as few as 30 template copies of DNA per sample. In addition, the SYBR green assay was less expensive than traditional culturing and serology. MG and MS are infectious bacteria that can rapidly spread and infect commercial chicken flocks. These diseases can cause a significant loss to the poultry industry and especially to broiler breeders because infected flocks are destroyed under the National Poultry Improvement Plan MG and MS clean programs. The real-time SYBR green assay developed in this research has the potential to reduce the time it takes to reach a correct diagnosis and to arrest outbreaks of MG and MS.

Limited information is available on the effects of the recently emerged infectious bursal disease virus (IBDV) variant AL2. In this study, the effects of inoculation of 4-day-old chickens with increasing doses of IBDV AL2 were characterized. IBDV AL2 induced neither overt clinical signs nor mortality. Infected chickens showed reduced bursa indices (BI) and bursa lymphocytic depletion, as determined by histomorphometry. However, histomorphometry and BI values differed during the early stages of the infection. Because data from bursa histomorphometry were consistent with viral RNA detection, such values seem to be more appropriate for the assessment of AL2 viral infectivity in chickens. Both the histomorphometry and BI data indicated a dose–effect pattern. However, with time, even low doses of the virus ultimately resulted in significant damage to the bursa. Samples of spleen were used to assess B- (IgM ) and T- (CD4 and CD8 ) cell populations by flow cytometry. Infected chickens showed a significant increase of splenic IgM cells at 5 and 8 days postinoculation (PI). On day 8 PI, the number of total IgM cells in the spleen was inversely related to the virus concentration. Others have shown that cell-mediated immunity is essential for protection against IBDV. Our results indicate a significant increase (P < 0.05) of total spleen CD4 cell counts on day 8 PI in birds that received higher virus concentrations, indicating a role for these cells in protective immunity, while CD8 cell counts remained unchanged. We speculate that the changes in splenic CD4 and IgM cell populations are associated with protective immune responses against IBDV in the host.

Comparative sequence analysis of six independent chicken and turkey parvovirus nonstructural (NS) genes revealed specific genomic regions with 100% nucleotide sequence identity. A polymerase chain reaction (PCR) assay with primers targeting these conserved genome sequences proved to be highly specific and sensitive to detecting parvoviruses in experimentally infected chickens. In a nationwide survey, a total of 138 field enteric samples from poultry flocks were tested by PCR for parvovirus presence. Of the tested chicken samples that were collected in 54 farms, 77% showed the presence of parvovirus, while 78% of the turkey samples that were received from 29 farms were parvovirus positive. For the first time, our data clearly demonstrate that parvoviruses are widely distributed in commercial poultry flocks in the United States. The high prevalence of parvovirus infection in birds from enteric disease-affected flocks suggests a potential role of these viruses in the etiology of enteric disease of poultry. Phylogenetic analyses comparing NS gene segments showed that most of the chicken and turkey parvovirus isolates formed separate phylogenetic groups. These findings suggest that the chicken and turkey parvoviruses might have diverged from a common ancestor and have subsequently undergone host-specific adaptation.

Escherichia coli, Salmonella species, and Pasteurella multocida are the major bacterial pathogens isolated from poultry. Difference in susceptibility to antibiotics by microorganisms has become a major factor in drug choice and success of treatment. Great concerns have been raised Regarding emerging antimicrobial resistance among bacteria that may result in unpredictable antimicrobial susceptibility and failure of therapy. The primary objective of the present study was to determine the levels of antimicrobial susceptibility/resistance of E. coli, Salmonella species, and P. multocida isolated from diseased chickens. A total of 445 E. coli isolates, 387 Salmonella spp. isolates, and 80 P. multocida isolates from diseased chickens during the period ranging from 2001 to 2003 were obtained. Minimal inhibitory concentrations of 14 antimicrobial agents against each bacterial isolate were determined using a microbroth dilution assay described by the Clinical Laboratory Standards Institute. Resistance of E. coli isolates measured as follows: 98.20% were resistant to tilmicosin, 79.33% to tetracycline, 51.46% to spectinomycin, 44.04% to gentamicin, and 40% to ampicillin. Resistance to tetracycline was found in 72.61% of Salmonella spp. isolated, followed by resistance to spectinomycin (68.48%), ampicillin (63.57%), gentamicin (63.31%), and ticarcillin (61.76%). The resistance rate of P. multocida isolates to all antimicrobials tested was less than 5%, except for tetracycline (6.25%). In summary, E. coli and Salmonella isolates were sensitive to ceftiofur and fluoroquinolones but were resistant to other antimicrobials tested, while P. multocida isolates remained sensitive to all the antimicrobial agents tested in a 3-yr analysis.

The effects of chicken anemia virus (CAV) and infectious bursal disease virus (IBDV) coinfection in commercial layer-type and meat-type (broiler) chickens with specific maternal immunity were evaluated. In addition, the broiler progeny used had been vaccinated in ovo against IBDV. Layer chickens were inoculated intramuscularly on day 3 of age with CAV and orally on day 7 of age with an IBDV standard strain (APHIS). Broiler chickens were exposed to CAV and/or an IBDV variant strain (AL2) via the drinking water on days 3 and 14 of age. Following CAV and IBDV inoculation neither mortality nor overt clinical disease was observed in any layer or broiler group. In spite of maternal immunity against both IBDV and CAV, mean hematocrits of all layer groups inoculated with CAV (CAV, CAV APHIS) were lower than uninfected chickens. IBDV APHIS alone or in combination with CAV did not affect the layer weight gain. However, on day 30 of age and concomitantly with maternal antibody decay, bursa lymphocyte depletion became evident in CAV APHIS-infected layer chickens. These birds (CAV APHIS) also seroconverted to IBDV on day 35 of age. CAV persisted at low levels in the layer chickens throughout the experimental period in CAV- and CAV APHIS-infected chickens. Similarly, infected broiler chickens did not show changes in weight gain. Compared to CAV-infected or uninfected controls, CAV AL2- and AL2-infected broiler chickens showed significant lymphocyte depletion in the bursa as assessed both by bursal indices and histomorphometry. Broilers also seroconverted to IBDV after day 30 of age confirming that bursal lymphocyte depletion was due to IBDV resuming replication. Thymus histomorphometry revealed significant lymphocyte depletion in all infected broiler groups at 30 days of age, but only in CAV AL2-infected broiler chickens at 41 days of age, suggesting that IBDV infection delayed repopulation of the thymus.

Four avian mycoplasmas are commonly recognized as poultry pathogens: Mycoplasma gallisepticum (MG), Mycoplasma synoviae (MS), Mycoplasma meleagridis (MM), and Mycoplasma iowae (MI). The avian mycoplasmas are associated with respiratory disease, synovitis and arthritis, poor performance, skeletal deformities, and embryo mortality. Three main approaches are used for the diagnosis of avian mycoplasmosis: isolation and identification, detection of antibodies, and molecular detection of the organism's nucleic acid by PCR. In recent years real-time PCR technology has revolutionized the way clinical microbiology laboratories diagnose infectious diseases, but so far only a limited number of diagnostic real-time PCRs have been proposed for avian mycoplasma diagnostics. We developed a complete set of reliable diagnostic real-time TaqMan PCR assays for the four pathogenic avian mycoplasmas. The selected genomic targets of the developed assays were species specific and intraspecifically conserved and included the 16S–23S intergenic spacer Region of MS and MM, the upstream Region to the 16S ribosomal DNA of MI, and highly conserved foci of the mgc2 gene of MG. The four assays were demonstrated to be highly specific and sensitive to their target avian mycoplasma, with detection limits of one copy per reaction mix for the MG assay and 10 copies per reaction mix for the MS, MM, and MI assays. We believe that the incorporation of the developed assays in avian mycoplasma diagnostics will contribute to the accuracy, efficiency, and feasibility of diagnosis of these pathogens.

Ornithobacterium rhinotracheale (ORT) is a bacterium common to commercial poultry and wild birds throughout the world. It is also known as a causative agent of respiratory diseases. A total of 93 ORT isolates originating from chickens, pigeons, ostriches, quail, turkeys, and an Asian crested goshawk (Accipiter trivirgatus) in Taiwan, between 2004 and 2006, were used in this study. High genetic similarity (97%–100%) in 16S rRNA sequence was revealed among the 50 randomly selected isolates, in addition to a reference strain (ATCC-51464) and seven reference sequences from GenBank. In order to obtain a greater genetic discrimination among the ORT isolates, random amplified polymorphic DNA (RAPD) and single-enzyme amplified fragment length polymorphism (SE-AFLP) methods were further conducted. The results showed that both RAPD and SE-AFLP assays showed higher discriminatory abilities than the 16S rRNA sequence assay. Genetic clustering revealed that chicken- and quail-origin isolates were genetically distinct from those of the ostrich, pigeon, and Asian crested goshawk-origin isolates. However, among the two typing methods, the turkey-origin isolates showed diverse genetic characteristics to domestic avian species. With this information, ecologic and epidemiologic studies could be furthered for the reduction and control of ORT transmission in Taiwan.

In the present study, the hemagglutinating activity of seven reference strains, and nine Mexican and three Danish field isolates, of Gallibacterium was investigated by using fresh erythrocytes of 19 different types including chicken (broiler, rooster, layer hen), turkey, pigeon, quail, duck, Harris's hawk (Parabuteo unicinctus), house finch (Carpodacus mexicanus), cow, sheep, horse, dog, rabbit, pig, and human (groups A, B, AB, and O; Rh ). Agglutination was observed for broiler chicken, layer hen, quail, rabbit, and pig erythrocytes with a subset of Gallibacterium strains, whereas most tested strains agglutinated rabbit erythrocytes. Transmission electron microscopic examination of a hemagglutinating strain demonstrated a close interaction between the bacterial and erythrocyte surfaces. The results indicate that some Gallibacterium strains are able to agglutinate avian or mammalian erythrocytes, or both. However, the mechanisms enabling hemagglutination are not known and will be addressed in future studies.

Four infectious bronchitis virus (IBV) isolates were recovered from commercial broiler chicken flocks located on the Delmarva Peninsula (east coast of the United States) in the spring of 2006. Sequence analysis of the S1 subunit of the spike glycoprotein gene showed the four isolates were highly related to each other (≥99.6% nucleotide identity; ≥98.9% amino acid identity). Basic local alignment search tool analysis indicated the highest S1 amino acid identity of isolate DMV/5642/06, typical of the four Delmarva (DMV) isolates, was to CA/1737/04, an isolate obtained from broilers in California in 2004. A pathogenicity study conducted, using two-week-old commercial broilers, showed that DMV/5642/06 caused respiratory but not renal (kidney) disease. A vaccination–challenge study in three-week-old specific-pathogen-free leghorn chickens demonstrated that a commercial live attenuated IBV vaccine containing the Massachusetts strain conferred protection against challenge with DMV/5642/06 based on virus reisolation attempts and microscopic pathology.

A total of 15 Mycoplasma gallisepticum (MG) isolates from Chinese poultry farms and three reference strains (S6, BG44T, and F36) were characterized by nested polymerase chain reaction and sequence analysis for two identical and directly repeated sequences, DR-1 and DR-2, within the putative cytadhesin pvpA gene. The molecular variation patterns of the pvpA genes among the 15 MG isolates were identical to the reference strains S6 and BG44T, that is, a 60 bp deletion in DR-1 and DR-2 and repetition of 1) a proline residue 33 times and 2) a tetrapeptide motif 10 times (Pro-Arg-Pro-X, where X is Met, Gly, Asn, or Gln for 6, 1, 1, or 2 times, respectively). However, the variation pattern is quite different from that of the vaccine strain F36, in which only the DR-1 Region is retained, 24 of the 25 peptides comprising the linkage sequence between DR-1 and DR-2 are missing, and the entire DR-2 sequence is deleted. A comparison of the sequences within the DR-1 and DR-2 repeated Regions among clinical isolates from different geographic sites suggested that ≥30 proline residue repeats and 7–10 repeats of the tetrapeptide motif may exert an important role in the functionality of PvpA as an adhesin molecule. Size variation and differences in deletion patterns in the C-terminal coding Region of the pvpA gene were observed among the field isolates and vaccine strain F, providing the basis for strain differentiation.

This report describes West Nile virus (WNV)–associated mortality in captive lesser scaup (Aythya affinis) ducklings that occurred in Saskatchewan, Canada, in July and August 2007. There were no clinical signs or gross necropsy findings suggestive of the cause of death; however, microscopic lesions were consistent with WNV infection, including nonsuppurative encephalitis and myocardial, pancreatic, and splenic necrosis. Necrosis of the thymus and thyroid was also observed in some birds, which has not previously been reported in association with WNV infection. Immunohistochemistry revealed WNV antigen in multiple tissues, including thymus and thyroid, and reverse transcription polymerase chain reaction resulted in the identification of WNV gene sequence in all of the ducklings that were tested. This outbreak is of interest because waterfowl (Anseriformes) are not thought to be particularly susceptible to WNV, and there is little information about WNV infection in prefledging birds. The apparent susceptibility of lesser scaup to WNV demonstrated in this study may have implications for declining lesser scaup populations in the wild.

Two blue and gold macaw (Ara ararauna) chicks died of fatal salmonellosis in Buenos Aires Province, Argentina. The birds were histopathologically and microbiologically examined. Salmonella enterica subspecies enterica serovar Typhimurium was isolated from the liver, spleen, heart, lung, kidney, and intestine of both birds. All strains were susceptible to ampicillin, cephalothin, cefotaxime, enrofloxacin, nalidixic acid, gentamicin, streptomycin, chloramphenicol, fosfomycin, tetracycline, nitrofurantoin, and trimethoprim-sulfamethoxazole. The XbaI-PFGE profile of the Salmonella Typhimurium isolated from the two animals, which shared the same cage, was identical and showed a unique pattern compared with 301 isolates included in the PulseNet national database of Salmonella pulsed-field gel electrophoresis patterns. This is the first report that describes fatal Cases of salmonellosis from blue and gold macaws.

Breeder squab candidates between the ages of 6 and 16 wk were submitted to the California Animal Health and Food Safety Laboratory, Turlock branch, as a result of respiratory distress and increased mortality. These Cases were submitted from one Northern California commercial squab operation on three separate occasions occurring between December 2007 and March 2008. Severe trichomoniasis was identified, primarily in the tracheal epithelium and lung of squabs, with few or no lesions in the oral cavity, crop, esophagus, and livers, where the organism commonly infiltrates. Infiltration of the trachea and lung sections with trichomonads was associated with a severe inflammatory response in the surrounding tissue. Diagnosis was confirmed with the use of histopathology and an immunoperoxidase special stain. Oxytetracycline supportive antibiotic therapy to prevent secondary bacterial infections was administered to remaining squabs on the farm, but no specific treatment Regimen was instituted. This novel respiratory presentation of trichomoniasis continued over a period of 3 mo, until mortality gradually returned to normal.

A Case of seminoma found in an adult guinea fowl (Numida meleagris) that has been exhibited in a zoo is reported. The right testis was extremely enlarged and replaced by round and polyhedral pleomorphic neoplastic cells showing nest, sheet, and diffuse growth patterns. The neoplastic cells had acidophilic cytoplasm and hyperchromatic and eccentrically placed nuclei. Metastatic lesions composed of diffuse growth of neoplastic cells similar to those of the primary tumor were seen in the liver, lungs, kidneys, and heart, and neoplastic emboli were often detected within blood vessels of these organs, indicating hematogenous metastasis. This is the first report of malignant seminoma with multiple metastases in the visceral organs in the guinea fowl.