Calcium tetany is a poorly defined disease of broiler breeder hens that results from acute hypocalcemia. It is characterized by impaired mobility, increased mortality, and absence of gross lesions that would explain the impaired mobility. To evaluate if hens with impaired mobility had calcium tetany or other abnormalities, blood values from normal and affected hens were determined using the i-STAT® handheld clinical analyzer. Three flocks were evaluated weekly prior to peak production (range 25–30 wk of age) comparing normal hens to hens with clinically apparent calcium tetany. Calcium tetany suspect (CaTS) hens from four additional flocks were also evaluated. Significant hypocalcemia (P < 0.001) was observed in CaTS hens (average  =  1.14 mmol/L ionized calcium [iCa]) compared to normal hens (average  =  1.53 mmol/L iCa) in only one of three flocks sampled weekly. Clinically affected hens from one of the other four flocks also had hypocalcemia. Blood value abnormalities in mobility-impaired hens without hypocalcemia included hypernatremia. Findings in this study indicate calcium tetany is one cause of impaired mobility in breeder hens, but mobility impairment without hypocalcemia can also occur. Calcium tetany should be confirmed by finding significantly decreased levels of iCa in the blood, as diagnosis based on clinical presentation and necropsy results can be inaccurate. The i-STAT® handheld clinical analyzer is an efficient, relatively low-cost method to determine iCa and other blood chemistry values that may be associated with impaired mobility in broiler breeder hens.

Experiments were conducted to determine whether chukar partridge (Alectoris chukar) chicks would develop protective immunity after inoculation with coccidia. Young chukar chicks in battery cages inoculated with 100 or more oocysts of Eimeria kofoidi or Eimeria legionensis had significant protection at challenge 4 wk later, as measured by greatly reduced oocyst shedding and improved weight gain as compared with unvaccinated, challenged controls. However, when birds were housed in litter pens and vaccinated by various regimens (including two species of chukar coccidia at 100/dose), coccidiosis rapidly spread through all treatments and caused significant mortality. Vaccination with Coccivac-T or with 100 oocysts of Eimeria dispersa did not prevent mortality resulting from accidental contamination, and feed treatment with a Lactobacillus competitive-exclusion product had no benefit. Most if not all of the mortality was from E. kofoidi. This study illustrated the natural fecundity of chukar coccidia in a floor-pen environment where multiplication rate and reinfection combine to produce clinical disease from a small original exposure. Further, these results cast doubt on the potential use of low doses of live oocysts as a vaccine in the chukar partridge.

Understanding normal movement patterns and husbandry practices of poultry production systems is important for understanding the dynamics of disease spread, and for controlling outbreaks of highly infectious diseases, such as highly pathogenic avian influenza. To learn about these patterns in the noncommercial or “backyard” poultry-keeping sector, an open-ended questionnaire was administered to 18 backyard-flock owners in British Columbia, Canada, and responses were analyzed descriptively. Six participants reported that they visited premises that were part of the commercial poultry system in the last year; however, bird movements between commercial and noncommercial farms were always unidirectional, from commercial to backyard. Bird movements into and out of participants' flocks occurred multiple times per month (two flocks), three times per year (five flocks), once or twice a year (nine flocks) and every 3–5 yr (two flocks). Visitors had direct contact with three participants' flocks multiple times per week; for other flocks, visitors had direct contact three times or less per year. Fourteen participants rarely had direct contact with other backyard flocks, three had contact more than once per week, and one had contact every 3 mo. Participants stated that the health of their birds was excellent 7, very good 3, good 6, O.K. 1, and all right 1, and used a median of two biosecurity practices to maintain health in their flock. Our findings suggest that bird movements are not likely to transmit disease from backyard to commercial flocks; however, human movements between backyard and commercial premises could transmit diseases. Within the backyard-flock sector, the majority of small flocks appear to pose little risk of disease transmission because they are maintained in semi-isolation from other flocks; however, a minority of flocks has high contact levels with other flocks and could be important in disease spread.

Marek's disease (MD) is a lymphoproliferative disorder of domestic chickens caused by a highly contagious and oncogenic α-herpesvirus, Marek's disease virus (MDV). MD is characterized by bursal–thymic atrophy and rapid onset of T-cell lymphomas that infiltrate lymphoid tissues, visceral organs, and peripheral nerves with severe clinical signs that include transient paralysis, anemia, weight loss, and neurologic disorders. Using overlapping cosmids- and BAC-cloned MDV, it has been shown that MDV-encoded vIL-8, pp38, vTR, vLIP, RLORF4, and meq are among the many essential genes that play critical roles in viral pathogenesis. Of all the genes investigated so far, only meq has been shown to be consistently expressed in all MDV-derived tumors and lymphoblastoid cell lines. Meq is a basic leucine-zipper protein that shares homology with the jun/fos family of transcriptional factors. There are two copies of meq gene within the MDV genome that are only present in the serotype-1 strains. It has been shown conclusively that deletion of meq results in loss of transformation of T cells in chickens, with no effect on the early cytolytic phase of infection in lymphoid organs, which is essential for induction of innate and adaptive immunity. The goal of this study was to investigate 1) the effect of the meq oncogene on the expression pattern of select chicken immune and nonimmune-related genes, and 2) its potential role in MDV-induced apoptosis. We used real-time reverse transcriptase–polymerase chain reaction to evaluate the expression profiling of a panel of chicken genes in rMd5- and rMd5Δmeq-infected chickens at 5, 14, 21, and 35 days postinfection (dpi). Although the transcriptional activities of several immune-related genes, including IL-6, IL-10, cMGF, GM-CSF, iNOS, IFNβ, and INFγ, were higher in rMd5Δmeq-infected chickens at 5 dpi when compared to the rMd5-infected birds, the differences in expression levels of the tested genes between the two viral constructs were not significant. In addition, a reduction in the transcriptional activity of Bcl2 in recombinant fowlpox virus (rFPV) meq-infected chicken embryonic fibroblasts suggested that meq alone did not impede FPV-induced apoptosis. The likely suppressive nature and anti-inflammatory function of the meq oncogene and its possible role in virus-induced cell death is discussed.

Three types of infectious bursal disease virus (IBDV) strains are currently circulating worldwide: the low-pathogenic classic and variant strains and the high-pathogenic very virulent strains. There are also natural reassortant viruses that combine genomic segments A and B from different strains and exhibit particular pathogenic characteristics. Detection and characterization of the different IBDVs is extremely critical for improving disease control and performing epidemiologic studies. Here, we present a novel detection and genotyping method based on the simultaneous characterization of both IBDV genomic segments followed by a simple restriction fragment length polymorphism (RFLP) assay. This single restriction enzyme, multiplex reverse transcriptase-PCR/RFLP diagnostic test not only distinguished typical high-pathogenic from low-pathogenic strains but also detected natural reassortant IBDV. The test was based on the detection of single nucleotide polymorphisms (SNP), in both segments, which were strongly linked to the pathogenic phenotype. These SNPs are embedded in highly conserved genomic regions and can be identified with TfiI endonuclease. The application of this methodology in field samples confirmed that the assay is fast, specific, and may be easily adopted by any molecular diagnostic laboratory as an economical and routine method.

Campylobacter spp. are present in organs and tissues of broiler chickens but the dissemination route is unclear. The aim of the current study was to determine Campylobacter prevalence within circulating blood of commercial broilers. Broilers were acquired from 19 flocks originating from three commercial poultry processing companies. Using aseptic blood collection techniques, 5 ml of circulating blood was collected from each bird and the sample analyzed for Campylobacter. The Campylobacter colonization status of each bird was determined by aseptically sampling and analyzing the ceca. Campylobacter was recovered from 58% (11/19) of flocks sampled. From the 248 total birds sampled, 12% and 46% of the birds had Campylobacter in the blood and ceca, respectively. This study documents Campylobacter prevalence in the circulating blood of commercially raised broilers. Campylobacter presence in the circulatory system may indicate the path used by the organism for rapid dissemination to organs and tissues. From a processing viewpoint, Campylobacter presence in circulating blood of market-age broilers may increase the likelihood of cross-contamination between birds during slaughter.

Riemerella anatipestifer (RA) infections cause major economic losses in the duck industry. Detection of RA using conventional assays is time-consuming and laborious. In this study, a simple and rapid assay for the detection of RA was established based on the GroEL gene sequence of RA using loop-mediated isothermal amplification (LAMP) with a set of six primers (two outer primers, two inner primers, and two loop primers). This assay was able to detect all the tested RA strains with different serotypes. A minimum of 10 colony-forming units (CFU) of RA was detected, which represents 50-fold higher sensitivity than that of the standard polymerase chain reaction (PCR) method. This assay showed good specificity to RA strains and did not react with any other species of bacteria. The assay is rapidly completed and the amplification is achieved at a minimum of 20 min at 65 C. Furthermore, the assay successfully detected RA in the liver samples of ducklings infected with RA, suggesting that the assay could be used for the clinical diagnosis of RA infection.

Marek's disease (MD) is a lymphoproliferative disease of domestic chickens caused by a highly infectious, oncogenic α-herpesvirus known as Marek's disease virus (MDV). MD is presently controlled by vaccination. Current MD vaccines include attenuated serotype 1 strains (e.g., CVI988/Rispens), avirulent serotype 2 (SB-1), and serotype 3 (HVT) MDV strains. In addition, recombinant MDV strains have been developed as potential new and more efficient vaccines to sustain the success of MD control in poultry. One of the candidate recombinant MDV strains, named rMd5ΔMeq, was derived from Md5, a very virulent strain of MDV lacking the MDV oncogene Meq. Our earlier reports suggest that rMd5ΔMeq provided protection equally well or better than commonly used MD vaccines in experimental and commercial lines of chickens challenged with very virulent plus (vv ) strains of MDV. In this study, maternal antibody-positive (trial 1) and negative (trial 2) chickens from a series of relatively MD resistant lines were either vaccinated with the rMd5ΔMeq or CVI988/Rispens followed by infection of a vv strain of MDV, 648A, passage 10. This report presents experimental evidence that the rMd5ΔMeq protected significantly better than the CVI988/Rispens (P < 0.01) in the relatively resistant experimental lines of chickens challenged with the vv strain of MDV. Together with early reports, the rMd5ΔMeq appeared to provide better protection, comparing with the most efficacious commercially available vaccine, CVI988/Rispens, for control of MD in lines of chickens regardless of their genetic background.

To generate a genotype VII Newcastle disease virus (NDV) vaccine with high yield in embryonated chicken eggs, we selected genotype VII NDV strain JS5/05, which possesses a high virus titer in embryos as the parental virus. Using reverse genetics, we generated a genetically tagged derivative (NDV/AI4) of JS5/05 by changing the amino acid sequence of the cleavage site of the F0 protein. Pathogenicity tests showed that NDV/AI4 was completely avirulent. NDV/AI4 was genetically stable and replicated efficiently during 10 consecutive passages in embryos. More importantly, serologic assays showed that oil-emulsion NDV/AI4 induced higher hemagglutination inhibition (HI) titers against the prevalent virus than oil-emulsion LaSota vaccine in chickens and geese. Moreover, NDV/AI4-induced HI titers rose faster than those elicited by LaSota in chickens. Both NDV/AI4 and LaSota provided protection against clinical disease and mortality after the challenge with the genotype VII NDV strain JS3/05. However, NDV/AI4 significantly reduced virus shedding from the vaccinated birds compared to LaSota. Taken together, these results suggest that NDV/AI4 can provide better protection than LaSota and is a promising vaccine candidate against genotype VII NDV.

The very virulent form of infectious bursal disease virus (vvIBDV) causes an immunosuppressive disease that is further characterized by the rapid onset of morbidity and high mortality in susceptible chickens. In 2009, vvIBDV was first reported in California, U. S. A., and since that time only a few cases of acute infectious bursal disease attributed to vvIBDV have been recognized in California. In other countries where vvIBDV has become established, it rapidly spreads to most poultry-producing regions. Two factors that may be involved in limiting the spread or reducing the severity of the clinical disease caused by vvIBDV in the U. S. A. are maternal immunity and competition with endemic variant strains of the virus. In this study, the ability of vvIBDV to infect and cause disease in maternally immune layer chickens was examined at weekly intervals over a 5-wk period during which their neutralizing maternal antibodies waned. Birds inoculated with vvIBDV at 2, 3, and 4 wk of age seemed healthy throughout the duration of the experiment, but macroscopic and microscopic lesions were observed in their bursa tissues. A real-time reverse transcriptase-polymerase chain reaction (RT-PCR) assay also confirmed the presence of vvIBDV RNA in their bursa tissues, indicating this virus was infecting the birds even at 2 wk of age when neutralizing maternal antibodies to infectious bursal disease virus were still relatively high (>2000 geometric mean antibody titer). No mortality was observed in any birds when inoculated at 2, 3, or 4 wk of age; however, inoculation at 5 and 6 wk of age resulted in 10% and 20% mortality, respectively. Three experiments on the competition between vvIBDV and the two variant viruses T1 and FF6 were conducted. In all three experiments, specific-pathogen-free (SPF) birds that were inoculated with only the vvIBDV became acutely moribund, and except for Experiment 1 (62% mortality) all succumbed to the infection within 4 days of being exposed. When the variant viruses were inoculated into SPF chickens at 4 wk of age and the vvIBDV was administered 10 days later, a real-time reverse transcriptase (RT)-PCR assay was positive for the variant T1 and FF6 viral RNA but negative for vvIBDV RNA, indicating the vvIBDV isolate could not establish an infection in the bursa tissues of these birds. No clinical disease or mortality was observed in the birds, but macroscopic and microscopic lesions typical of a variant virus infection were observed. When the interval was shortened to 2 days, both variant viruses and vvIBDV were detected by RT-PCR, but the vvIBDV viral load in the bursa tissue was significantly lower compared with that of birds inoculated with vvIBDV alone. No clinical disease or mortality was observed, and macroscopic and microscopic lesions in the bursa of these birds were not typical of a vvIBDV infection but instead resembled a pathogenic classic virus infection. When the variant viruses and vvIBDV were inoculated simultaneously into 4-wk-old SPF chickens only the vvIBDV RNA was detected in the bursa tissues of the birds, and no reduction in viral load as measured by real-time RT-PCR was detected. Mortality (30%–40%) was reduced in these duel-infected birds compared with the 100% mortality observed in birds that received vvIBDV alone. The data suggest that maternal immunity and competition with variant viruses are acting to reduce the clinical signs and anticipated mortality after an vvIBDV infection, which may increase the chances that vvIBDV is not being recognized in commercial poultry operations.

We evaluated a recently developed live vaccine candidate for fowl typhoid (FT)—JOL916, a lon/cpxR mutant of Salmonella Gallinarum (SG)—by comparing its safety and efficacy with that of the well-known rough mutant strain SG9R vaccine in 6-wk-old Hy-Line hens. Forty-five chickens were divided into three groups of 15 chickens each. The chickens were then intramuscularly inoculated with 2 × 10⁷ colony-forming units (CFUs) of JOL916 (JOL916 group), 2 × 10⁷ CFUs of SG9R (SG9R group), or phosphate-buffered saline (control group). After vaccination, no clinical symptoms were observed in any of the groups. No differences in body weight increase were detected among the three groups postvaccination. A cellular immune response was observed at 2 wk postvaccination (wpv) in the JOL916 group with the peripheral lymphocyte proliferation assay, whereas no response was detected in the SG9R group. Elevation of SG antigen-specific plasma immunoglobulin was observed 2 and 3 wpv in the JOL916 and SG9R vaccine groups, respectively. After virulent challenge on day 25 postvaccination, 0, 1, and 15 chickens in the JOL916 group, SG9R group, and control group, respectively, died by 12 days postchallenge; the death rate of the SG9R vaccine group was statistically similar to that of the JOL916 group. Postmortem examination revealed that the JOL916 vaccine offered more efficient protection than the SG9R vaccine, with significantly decreased hepatic necrotic foci scores, splenic enlargement scores, necrotic foci scores, and recovery of the challenge strain from the spleen. Vaccination with JOL916 appears to be safe and offers better protection than SG9R against FT in chickens.

To analyze the contribution of neuraminidase (NA) toward protection against avian influenza virus (AIV) infection, three different recombinant Newcastle disease viruses (NDVs) expressing hemagglutinin (HA) or NA, or both, of highly pathogenic avian influenza virus (HPAIV) were generated. The lentogenic NDV Clone 30 was used as backbone for the insertion of HA of HPAIV strain A/chicken/Vietnam/P41/05 (H5N1) and NA of HPAIV strain A/duck/Vietnam/TG24-01/05 (H5N1). The HA was inserted between the genes encoding NDV phosphoprotein (P) and matrixprotein (M), and the NA was inserted between the fusion (F) and hemagglutinin-neuraminidase protein (HN) genes, resulting in NDVH5VmPMN1FHN. Two additional recombinants were constructed carrying the HA gene between the NDV P and M genes (NDVH5VmPM) or the NA between F and HN (NDVN1FHN). All recombinants replicated well and stably expressed the HA gene, the NA gene, or both. Chickens immunized with NDVH5VmPMN1FHN or NDVH5VmPM were protected against two different HPAIV H5N1 and also against HPAIV H5N2. In contrast, immunization of chickens with NDVN1FHN induced NDV- and AIV N1–specific antibodies but did not protect the animals against a lethal dose of HPAIV H5N1. Furthermore, expression of AIV N1, in addition to AIV H5 by NDV, did not increase protection against HPAIV H5N1.

Infectious bronchitis virus (IBV) Cal99 variant was isolated from the kidneys of seven 2–5-mo-old game chickens with nephritis and respiratory disease. IBV Cal99 variant is usually associated with respiratory disease in broiler chickens in California. Macroscopically, the majority of the birds had moderately to severely enlarged and mottled pale kidneys, with increased urates in the ureters. Microscopically, most of the birds had acute nephrosis and interstitial nephritis. The birds also had sinusitis, tracheitis, bronchopneumonia, airsacculitis, salivary gland adenitis, and lymphoid depletion in the thymus and bursa of Fabricius. Immunohistochemistry was strongly positive for IBV antigen in the cytoplasm of tubular epithelial cells in the kidneys and also in the epithelium of the respiratory tract, salivary glands, proventriculus, intestine, and bursa of Fabricius. Infectious bronchitis virus was isolated from the trachea, lungs, kidneys, and cecal tonsils. Sequencing of the hypervariable region of the S1 gene of the kidney IBV isolate, designated IBV/CA99variant/07, revealed that the virus was 98% homologous to the Cal99 serotype of IBV.

Actions concerning animal health in turkey production are coming more and more to the fore. Litter quality has a great impact on the bird's health and welfare. This study aimed at evaluating the effects of using floor heating, different litter materials, and exposure to litter with a “critical moisture content” of 35% for 16 or 24 hr/day on the severity of foot pad dermatitis (FPD), a widespread disease in fattening turkeys. Four groups of 2-wk-old female turkeys, with 20 birds in each, were reared during 3 wk. All turkeys were fed a commercial pellet diet ad libitum. The first two groups were kept on wood shavings (35% moisture) without and with floor heating. The other two groups were housed on lignocellulose (Soft Cell®) of 35% moisture without and with floor heating. In each group, half of the birds were housed for 8 hr/day in adjacent separate boxes where the litter was kept clean and dry throughout the experimental period. Foot pads were assessed weekly for external and at day 35 for histopathologic scoring (scores: 0  =  healthy; 7  =  ulcer). At day 14 each bird had normal and healthy foot pads. The results indicate that using floor heating resulted in significantly lower FPD scores (0.8 ± 0.2) compared to groups without floor heating (2.0 ± 0.8). Using lignocellulose as a litter material resulted in significantly lower histopathologic FPD scores (1.4 ± 0.7) compared with wood shavings (1.7 ± 0.8). In all birds housed on dry litter for 8 hr/day, significantly lower FPD scores were found compared to birds housed on wet litter for 24 hr. In conclusion, using floor heating, even with wet litter (35% moisture), independent of the litter type, resulted in reduced severity of FPD compared to those birds housed in pens without using floor heating. Additionally, using lignocellulose as a litter material resulted in lower FPD compared with wood shavings. Keeping litter dry and “warm” could be achieved by using floor heating, which is considered a practical step to enhance animal health and welfare.

A Salmonella Gallinarum (SG)-specific bacteriophage isolated from sewage effluent was used to prevent horizontal transmission of SG in commercial layer chickens. Six-week-old chickens, each challenged with 5 × 10⁸ colony-forming units of SG, cohabited with contact chickens treated with 10⁶ plaque-forming units/kg of bacteriophage, prepared in feed additives, for 7 days before, and 21 days after challenge with SG. Mortality was observed for 3 wk after challenge and SG was periodically re-isolated from the liver, spleen, and cecum of chickens. SG re-isolation from organs was decreased and a significant (P < 0.05) reduction in mortality was observed in contact chickens treated with the bacteriophage, as compared to untreated contact chickens, indicating that bacteriophage administration in feed additives significantly prevented the horizontal transmission of SG. These results provide important insights into prevention and control strategies against SG infection and suggest that the use of bacteriophages may be a novel, safe, and effectively plausible alternative to antibiotics for the prevention of SG infection in poultry.

Waterfowl are the natural reservoirs of avian influenza viruses (AIVs), from which the virus can spread to other species including humans, poultry, and swine. For the surveillance of AIV in their natural reservoir, most laboratories initially screen the samples using real-time reverse-transcriptase–polymerase chain reaction because of its high speed and sensitivity. Thereafter, virus isolation is used to isolate viruses from positive samples. Although many studies point to the need of testing both cloacal and oropharyngeal (OP) samples in AIV surveillance programs, most laboratories focus only on cloacal samples. This study was undertaken to determine the utility of OP samples as target samples in AIV surveillance programs under a strict cold chain of samples from the field to the laboratory. A total of 16 AIV (15.1%) were isolated from the 106 OP samples examined. Upon subtyping, four hemagglutinin subtypes (H1, H3, H4, and H6) and three neuraminidase subtypes (N1, N2, and N8) were detected in nine different combinations. Mixed infection with two different subtypes was found in four samples. No AIVs were isolated from the corresponding cloacal samples. These results highlight the fact that testing of properly frozen OP samples could add value to the understanding of the epidemiology and ecology of AIV in waterfowl populations.

The nonpathogenic fowl adenoviruses (FAdVs) are suitable recombinant virus vectors. Two different replication-competent FAdV-9–based recombinant viruses carrying the enhanced green fluorescent protein (EGFP) gene within a nonessential DNA sequence at the left end genomic region were tested in chickens to study the antibody response by enzyme-linked immunosorbent assay to both the foreign proteins, EGFP and FAdV-9, and virus shedding through the feces. All inoculations were done intramuscularly: groups 1 and 2 with the recombinant viruses and group 3 with the wild-type FAdV-9 virus. Group 4 was mock inoculated. Sentinel birds also were included in groups 1–3 to study virus transmission. Boosting inoculations were done in all groups at 2, 3, and 4 wk after the first inoculation. Antibodies to EGFP were detected at 3–7 wk postinoculation in groups 1 and 2 only. Antibody response to FAdV-9 in groups 1–3 did not differ significantly (P > 0.06). Virus was not detected in the feces of chickens in groups 1 and 2, including the sentinel birds, but virus was present in the feces of chickens in group 3, including the sentinel birds. These results further supported our previous findings regarding the suitability of the nonessential region at the left end of the viral genome as an insertion site for foreign genes and its importance in in vivo replication. In this work, we demonstrated the potential of FAdV-9–based recombinant viruses as vaccines for poultry.

Tracheal and cloacal swabs as well as blood samples from 408 feral urban (Columba livia forma domestica) and 170 free-ranging wood pigeons (Columba palumbus) in Germany were tested for infection with avian influenza viruses (AIVs). Neither influenza A virus was isolated in the swab samples nor influenza A virus RNA detected using real-time reverse transcriptase–PCR (RT-qPCR). In three urban feral pigeons, avian paramyxovirus (APMV) serotype 1 was isolated. Two of 123 serum samples from hunted free-ranging wood pigeons contained specific antibodies against influenza A virus but not against the subtypes H5 and H7. In conclusion, our study indicates that even after the occurrence of zoonotic highly pathogenic avian influenza virus (HPAIV) subtype H5N1 in the area of investigation in Germany, pigeons do not play a major part in the transmission of influenza viruses. The risk of AIV infection for humans from urban and free-ranging wood pigeons is, if at all, of minimal importance.

Between 2006 and 2009, seven strains of infectious bronchitis (IB) virus (IBV) were isolated from vaccinated chicken flocks on different chicken farms in China. The pathogenic characters of seven IBV strains were assessed. Each of the seven strains was infective to the test chickens and could induce an immune response. The results from chicken embryo cross-neutralization assays showed that these strains were antigenically distinct from classic IBV strains of H120, M41, Conn, and Gray. Compared to H120 vaccine strain, point mutation, short insertion, and deletion occurred at many positions in the S1 protein of the seven strains. Five of the seven strains had the motif (HRRRR), which was identical to that of the epidemic IBV strains in China. Two new motifs (HRLRR and RRIRR) emerged in the isolated strains. The homology of the nucleotide and amino acid sequences of the S1 gene among the seven isolates was 81.7%–99.7% and 79.0%–99.4%, respectively. These seven strains were also genetically different from the vaccine strains and non-China IBV strains but closely related to large numbers of Chinese strains. The seven isolates and 36 reference IBV strains were clustered into six distinct groups (I–VI). The seven strains were categorized into groups I, II, and III, forming a big phylogenetic branch, which is closely related to Chinese IBVs, whereas the vaccine strains belonging to group VI are genetically distant from groups I, II, and III. The results from this study indicate that different IBV strains cocirculate in the chicken population in China.

Two different wild duck species common in Chile and neighboring countries, Chiloe wigeon (Anas sibilatrix) and cinnamon teal (Anas cyanoptera), were intranasally inoculated with 10⁶ mean embryo infective dose (EID₅₀) of the H7N3 low pathogenicity (LP) avian influenza virus (AIV) (A/chicken/Chile/176822/02) or high pathogenicity (HP) AIV (A/chicken/Chile/184240-1/02), in order to study the infectivity and pathobiology of these viruses. None of the virus-inoculated ducks had clinical signs or died, but most seroconverted by 14 days postinoculation (DPI), indicating a productive virus infection. Both LPAIV and HPAIV were isolated from oral swabs from two of six Chiloe wigeons and from oral and/or cloacal swabs from all five of the cinnamon teal at 2 DPI. Both LPAIV and HPAIV were efficiently transmitted to cinnamon teal contacts but not to Chiloe wigeon contacts. This study demonstrates that the cinnamon teal and Chiloe wigeons were susceptible to infection with both Chilean H7N3 LPAIV and HPAIV, but only the cinnamon teal showed contact transmission of the virus between birds, suggesting that the cinnamon teal has the potential to be a reservoir for these viruses, especially the LPAIV, as was demonstrated in 2001 with isolation of a genetically related H7N3 LPAIV strain in a cinnamon teal in Bolivia. However, the definitive source of the H7N3 Chilean LPAIV still remains unknown.

Marek's disease (MD) remains a serious problem in the production of poultry. The disease is caused by Marek's disease virus (MDV), and despite the ubiquitous use of vaccination to control losses, MD still affects poultry farming worldwide. The aim of this study was to develop a loop-mediated isothermal amplification (LAMP) method for the simple and inexpensive detection of MDV in feather tips of chickens. Two pairs of specific primers complementary to the meq oncogene of MDV were designed, targeting the sequence of the very virulent MDV strain, RB1B. Bst polymerase was used for the isothermal amplification of viral DNA at 65 C for 90 min in a water bath. The fluorescence signal was identified in MDV-positive samples after the addition of SYBR Green and ultraviolet (UV) illumination. The sensitivity of LAMP was 2 log ₁₀ plaque-forming units (PFU)/ml of HPRS₁₆ and 10³ copies/ìl of plasmid containing the target gene (meq) and was equal in sensitivity to PCR amplification. Due to the use of three sets of primers, LAMP was highly specific for MDV-1 DNA. The developed LAMP technique is a rapid and simple tool for the specific detection of MDV in samples of feathers taken from live chickens. Since the use of thermocyclers is not necessary for LAMP assay, it can be conducted by small laboratories and even field veterinarians.

Samples collected in 2008 and 2009, from 49 turkey flocks of 6 to 43 days in age and presenting clinical signs of enteric disease and high mortality, were tested by polymerase chain reaction and reverse transcription–polymerase chain reaction for the presence of viruses currently associated with enteric disease (ED) syndromes: astrovirus, reovirus, rotavirus, coronavirus, adenovirus, and parvovirus. Turkey astroviruses were found in 83.67% of the cases and turkey astrovirus 2 (TAst-2) in 26.53%. The investigations directly demonstrated the high prevalence of turkey parvovirus (TuPV) in 23 flocks (46.9%) experiencing signs of ED, making this pathogen the second most identified after astroviruses. Phylogenetic analysis on a 527 base pair-long region from the NS1 gene revealed two main clusters, a chicken parvovirus (ChPV) and a TuPV group, but also the presence of a divergent branch of tentatively named “TuPV-like ChPV” strains. The 23 Hungarian TuPV strains were separately positioned in two groups from the American origin sequences in the TuPV cluster. An AvaII-based restriction fragment length polymorphism assay has also been developed for the quick differentiation of TuPV, ChPV, and divergent TuPV-like ChPV strains. As most detected enteric viruses have been directly demonstrated in healthy turkey flocks as well, the epidemiology of this disease complex remains unclear, suggesting that a certain combination of pathogens, environmental factors, or both are necessary for the development of clinical signs.

A serologic and virologic survey was performed to determine the prevalence and distribution of Newcastle disease virus (NDV) infection in Chinese duck flocks. NDV infection was detected in nine of the 12 sampled farms throughout the two geographic regions covered by the survey. The percentage antibody positivity among the 406 serum samples was 35.7%. Three velogenic NDVs were obtained from different duck flocks identified by hemagglutination and hemagglutination-inhibition tests, a pathogenicity test, and reverse transcription–polymerase chain reaction on the fusion (F) genes. Phylogenetic analysis revealed that all three isolates clustered with the class II viruses; two were phylogenetically close to genotype VII NDVs, and the other was more closely related to genotype IX NDVs. These findings suggest that NDV infections were prevalent, and at least two distinct virulent genotypes may be responsible for recent epidemics in Chinese duck flocks.

Toll-like receptors (TLRs), a family of transmembrane and cytosolic proteins, detect microbial patterns, initiating innate immune responses in various organisms. Although they are abundant, genetic characterization and functional differences of TLRs in economically important avian species such as chickens and turkeys have not been investigated in detail. In this study, the putative TLR5 coding region from turkey genome was sequenced, and its homology to other vertebrate species was analyzed. Secondary structure analysis revealed protein motifs typical of the chicken TLR5 protein structure, with 97% amino acid identity between them. mRNA expression profiling in adult turkeys revealed abundant TLR5 expression in a broad range of tissues. Stimulation with the TLR5 ligand flagellin resulted in the production of the inflammatory mediators interleukin (IL)-1β, IL-6, and nitric oxide in peripheral blood mononuclear cells. To our knowledge, this is the first complete turkey TLR5 coding DNA sequence reported in sequence databases.

Antibiotic use and its implications have been discussed extensively in the past decades. This situation has global consequences when antibiotic resistance becomes widespread in the intestinal bacterial flora of stationary and migratory birds. This study investigated the incidence of fecal bacteria and general antibiotic resistance, with special focus on extended spectrum β-lactamase (ESBL) isolates, in two species of seabirds at remote Easter Island. We identified 11 species of bacteria from masked booby (Sula dactylatra) and Christmas shearwater (Puffinus nativitatis); five species of gram-negative bacilli, four species of Streptococcus (Enterococcus), and 2 species of Staphylococcus. In addition, 6 types of bacteria were determined barely to the genus level. General antibiotic susceptibility was measured in the 30 isolated Enterobacteriaceae to 11 antibiotics used in human and veterinary medicine. The 10 isolates that showed a phenotypic ESBL profile were verified by clavulanic acid inhibition in double mixture discs with cefpodoxime, and two ESBL strains were found, one strain in masked booby and one strain in Christmas shearwater. The two bacteria harboring the ESBL type were identified as Serratia odorifera biotype 1, which has zoonotic importance. Despite minimal human presence in the masked booby and Christmas shearwater habitats, and the extreme geographic isolation of Easter Island, we found several multiresistant bacteria and even two isolates with ESBL phenotypes. The finding of ESBLs has animal and public health significance and is of potential concern, especially because the investigation was limited in size and indicated that antibiotic-resistant bacteria now are distributed globally.

Spray application is a commonly used, time- and labor-efficient means to deliver live Mycoplasma gallisepticum (MG) vaccine to laying hens in commercial production facilities. The dosage of vaccine received by spray-vaccinated birds can vary due to variation in the spray plume and the vaccine suspension droplet trajectory. In this study, a total of 48 Hy-Line W-36 males were placed individually in isolation units following eye-drop application of gradient levels (1×, 10⁻¹×, 10⁻²×, 10⁻³×, 10⁻⁴×, 10⁻⁵×, 10⁻⁶×, and unvaccinated control) of the MG vaccine. The determined titer associated with a 1× dose was 2 × 10⁶ colony-forming units/dose. Serologic response was assessed weekly following vaccination via serum plate agglutination (SPA) for weeks one through seven postvaccination (p.v.). In addition, immunologic response was assessed at 5, 6, and 7 wk p.v. via MG enzyme-linked immunosorbent assay (ELISA). As indicated by SPA analyses, a 1× dose of vaccine resulted in 100% seroconversion, and dose levels of 10⁻¹× and 10⁻²× resulted in 75% and 37.5% seroconversion, respectively, at 6 wk p.v. The MG ELISA results at 6 wk p.v. demonstrated immunologic responses in 100%, 57.1%, and 28.6% of the 1×, 10⁻¹×, and 10⁻²× dosed birds, respectively. The lower dosage levels of 10⁻³×, 10⁻⁴×, 10⁻⁵×, and 10⁻⁶× did not elicit a response from any bird at 6 wk p.v. Utilizing the SPA data, a logistic regression model was used to determine the relationship between dosage level and seroconversion rate (R²  =  0.999 with a standard error of prediction of 1.6%). The model predicted a required effective dosage of 0.26× for 90% seroconversion at 6 wk p.v. under test conditions.

Lameness and mortality of 0.55% to 1.00% per week occurred in 32-to-33-wk-old broiler breeder hens in a complex involving eight houses. Males were not affected. Laboratory evaluation of 19 birds, over 2 wk, revealed complete rupture or partial tear, primarily of the gastrocnemius tendon; the fibularis longus, fibularis brevis, and flexor muscles and their tendons were injured in a few birds. Rupture of the gastrocnemius tendon has been observed in broiler breeder chickens older than 12 wk of age and it is characterized by lameness secondary to unilateral or bilateral rupture of the tendon. The cause of this condition has been primarily attributed to reovirus infection but rupture by other causes can also occur. In this case, there was no evidence of synovitis or reovirus infection in the birds. The cause of the ruptures was attributed to aggressive males when the ratio of males to females was increased from seven or eight males per 100 females at 22–23 wk to nine or 10 per 100 at 31 wk of age.

An avian influenza virus (AIV), A/Emu/Israel/552/2010/ (H5N1), was isolated from a dead emu that was found in the Ein Gedi oasis near the Dead Sea. The virus molecular characterization was performed by reverse transcriptase–polymerase chain reaction (RT-PCR) and real-time RT-PCR using AIV subtype-specific primers. The virus was of high pathogenicity, according to its intravenous pathogenicity index of 2.85 and the nucleotide sequencing at the cleavage site of the hemagglutinin gene, GERRRKKR, which is typical for highly pathogenic chicken influenza A viruses.

An outbreak of Mycobacterium avium subsp. avium infection was diagnosed in one breed of domestic pigeons (Columba livia f. domestica) in the Czech Republic. Nodular granulomatous lesions were found in 42 (9.7%) pigeons of the 435 examined; histopathologic examination of livers with gross lesions of mycobacteriosis from 15 randomly selected pigeons revealed granulomatous inflammation typical for avian mycobacteriosis in all samples. Direct Ziehl-Neelsen (ZN) microscopy and conventional culture were performed for a total of 117 liver samples (42 pigeons with nodular lesions, 55 randomly selected pigeons without nodular lesions, and 20 randomly selected squabs). Acid-fast bacilli were observed in 19 (16.2%), and conventional culture yielded growth of M. a. avium in 40 (34.2%) liver samples. A triplex quantitative real-time PCR assay based on the IS901 detection system was performed successfully in 115 liver samples and revealed M. a. avium in 63 (54.8%) of them. Mycobacterium a. avium was also detected in two squabs. Eight domestic rabbits (Oryctolagus cuniculus f. domestica) living in the breeding facility were also examined. Pyogranulomatous lesions were only found in one adult male rabbit. At necropsy, both direct ZN microscopy and culture gave negative results for mycobacteria in all examined rabbit tissues. Mycobacterium a. avium was diagnosed in a liver sample of one juvenile rabbit using triplex qPCR, suggesting that M. a. avium infection can occur as early as juvenile animals.

Ventricular candidiasis is consistently one of the most prominent pathologic conditions diagnosed in stone curlews (Burhinus oedicnemus) in the United Arab Emirates, predominately affecting the captive population. Predisposing factors are a humid environment, stress, immunosuppression, inadequate nutrition, and an extended use of oral antibiotics. In this report, we describe the clinical signs, diagnosis, and pathologic result in stone curlews with ventricular candidiasis.

A young, captive-bred Harris's hawk, Parabuteo unicinctus, exhibited high fever and apparent paralysis of one leg shortly before death. Postmortem examination revealed milky white kidneys, white crystalline deposits in the pericardial sack, and white crystals in one intertarsal joint. Uric acid concentrations determined for the kidneys, heart muscle, skeletal muscle, and scrapings from the pericardial sack (20 mg) and intertarsal joint (2 mg) were, respectively, 12,200, 200, 110, 20,700, and 43,000 mg/100 g tissue. Compared with a healthy hawk, concentrations were elevated by a factor of 50 in the kidneys, 37 in skeletal muscle, and 18 in cardiac muscle.

Peracute onset of disease was reported in a 42-wk-old broiler breeder flock that was presented by error with feed containing monensin at approximately seven times the approved level for broiler chickens. Morbidity and mortality were extremely high, and the affected chickens displayed feed refusal, decreased water consumption, and severe paralysis that ranged from abnormal gait to a complete inability to move. During the first 10 days postingestion of the suspect feed, mortality in hens reached 13.7% and 70.9% in the roosters. Hen day production decreased from 67% to 3% in the same period of time. A total of 638 g/ton of monensin was detected in suspect feed samples by one laboratory and 740 g/ton in a second laboratory. Twenty-one days after removal of the suspect feed, the mortality rate returned to normal levels in both hens and roosters, albeit feed consumption and egg production remained extremely low, which prompted the company involved to eliminate the flock.