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Shortly after the isolation of Marek's disease (MD) herpesvirus (MDV) in the late 1960s vaccines were developed in England, the United States, and The Netherlands. Biggs and associates at the Houghton Poultry Research Station (HPRS) in England attenuated HPRS-16, the first cell-culture–isolated MDV strain, by passaging HPRS-16 in chick kidney cells. Although HPRS-16/Att was the first commercially available vaccine, it never became widely used and was soon replaced by the FC126 strain of herpesvirus of turkeys (HVT) vaccine developed by Witter and associates at the Regional Poultry Research Laboratory (now Avian Disease and Oncology Laboratory [ADOL]) in East Lansing, MI. Ironically, Kawamura et al. isolated a herpesvirus from kidney cell cultures from turkeys in 1969 but never realized its potential as a vaccine against MD. Rispens of the Central Veterinary Institute (CVI) developed the third vaccine. His associate, Maas, had found commercial flocks of chickens with MDV antibodies but without MD. Subsequently, Rispens isolated a very low pathogenic strain from hen number 988 from his MD antibody-positive flock, which was free of avian leukosis virus and clinical MD. This isolate became the CVI-988 vaccine used mostly in The Netherlands. During the late 1970s, HVT was no longer fully protective against some new emerging field strains. The addition of SB-1, isolated by Schat and Calnek, to HVT improved protection against the emerging very virulent strains. In the 1990s CVI-988 became the worldwide vaccine gold standard. This review will present data from published papers and personal communications providing additional information about the exciting 15-yr period after the isolation of MDV to the development of the different vaccines.

Histomoniasis, commonly referred to as blackhead disease, is a serious threat to the turkey and game bird industries worldwide, and it is having an increasingly negative impact on the chicken industry as well. The Food and Drug Administration's (FDA) Center for Veterinary Medicine (CVM), charged with the approval and regulation of new animal drugs in the United States, understands the rising need for the availability of therapeutic options against histomoniasis. CVM has actively engaged in discussions with the poultry industry, academic institutions, and animal health companies regarding the current status of histomoniasis in the United States and varied success of past and current management, prophylactic, and therapeutic interventions that have been used against the disease. As effective options against the disease are severely limited, CVM encourages the poultry industry, academic institutions, and animal health companies to work together to research and develop viable management, prophylactic, and therapeutic strategies, such as litter management, deworming programs, vaccines or other biologics, novel technologies, and animal drugs. CVM also recognizes the potential challenges that the poultry industry, academic institutions, and animal health companies may encounter while working towards the approval of safe and effective drug products for the treatment and control of histomoniasis. With that recognition, CVM encourages interested parties to begin discussions with CVM early in order to align research of the drug product against histomoniasis with the drug approval requirements, such that it leads to the approval of a new animal drug in an efficient and expedient manner. This article provides information about the FDA's regulatory process for the approval of new animal drugs in the United States, with especial emphasis on drug products for the treatment and control of histomoniasis in turkeys, chickens, and game birds.

Fatigued walking condition (FWC) in ducks is an important welfare and processing issue during the loading/unloading to the processing plant that can be related to heart and bone development. An experiment was conducted to evaluate the effects of incubation conditions on duck embryo bone and heart development and their subsequent effects on ducks showing FWC at market age. Four groups of 2500 Pekin duck eggs were subjected to combinations of two incubation temperature profiles (elevated [E] and normal [N]) and two eggshell conductance profiles (G) (reduced [GR] and normal [GN]). At hatch 10 ducklings from each treatment combination were sampled for heart, liver, residual yolk, and total body weight as well as relative weights (organ percentage of whole body weight). Femur, tibia, and tarsus length and weight were also obtained, and relative asymmetry (RA) was calculated for each leg section. At 35 days of age during unloading of the truck at the slaughter plant, five hens and five drakes demonstrating normal walking and FWC were sampled. Body, heart, and ventricular weights were obtained along with femur, tibia and tarsus length, weight, and RA. Bone strength was evaluated using a three-point bending test, and tibia ash content was assessed. At hatch duckling bone characteristics and organ weights were found to be primarily affected by GR conditions, while heart development in older ducks was mainly impacted by E incubation temperatures. Tibia and relative weight at 35 days were also increased by GR and E. Fatigued ducks presented heavier tibias with more RA and cortical thickness but lower ash percentage. In conclusion, the changes in bone development during incubation and posthatch life were related to duck FWC presence during transportation to the processing plant.

Studies have shown that infectious bursal disease virus (IBDV) infects lymphoid cells, mainly B cells and macrophages. This study was aimed to examine the involvement of chicken splenic-derived dendritic cells (ch-sDCs) in specific-pathogen-free chickens following inoculation with IBDV vaccine strain (D78) and a very virulent (vv) strain (UPM0081). Following IBDV infection, enriched activated ch-sDCs were collected by using the negative selection method and were examined based on morphology and immunophenotyping to confirm the isolation method for dendritic cells (DCs). The presence of IBDV on enriched activated ch-sDCs was analyzed based on the immunofluorescence antibody test (IFAT), flow cytometry, and quantitative real-time PCR (RT-qPCR) while the mRNAs of several cytokines were detected using RT-qPCR. The isolated ch-sDCs resembled typical DC morphologies found in mammals by having a veiled shape and they grew in clusters. Meanwhile, the expression of DC maturation markers, namely CD86 and MHCII, were increased at day 2 and day 3 following vvIBDV and vaccine strain inoculation, respectively, ranging from 10% to 40% compared to the control at 2.55% (P < 0.05). At day 3 postinfection, IBDV VP3 proteins colocalized with CD86 were readily detected via IFAT and flow cytometry in both vaccine and vvIBDV strains. In addition, enriched activated ch-sDCs were also detected as positive based on the VP4 gene by RT-qPCR; however, a higher viral load was detected on vvIBDV compared to the vaccine group. Infection with vaccine and vvIBDV strains induced the enriched activated ch-sDCs to produce proinflammatory cytokines and Th1-like cytokines from day 3 onward; however, the expressions were higher in the vvIBDV group (P < 0.05). These data collectively suggest that enriched activated ch-sDCs were permissive to IBDV infection and produced a strong inflammatory and Th1-like cytokine response following vvIBDV infection as compared to the vaccine strain.

Field isolates of coccidia from 20 natural outbreaks in the chukar partridge (Alectoris chukar) were received from gamebird farms in 10 U.S. states. These were propagated in the laboratory and identified by microscopy and PCR. Of 20 samples, 18 were Eimeria kofoidi, two were Eimeria legionensis only, and one was a mixture of the two species. One isolate of E. kofoidi also contained an unidentified species detected only by PCR, nucleotide sequencing, and phylogenetic analysis. The efficacy of anticoccidial drugs against chukar coccidia was tested with experimental infections in battery cages. Isolates of E. kofoidi were used to infect 2-wk-old chukars. Anticoccidial products were given in the feed at levels approved for other poultry or for chukars. Tests were terminated at 6 days postinoculation with measurement of weight gains, fecal diarrhea scores, and necropsy to observe for lesion severity. Lasalocid (120 ppm) was moderately effective in one test. When tested against four field isolates, other ionophores (monensin, salinomycin, semduramicin) showed moderate effectiveness in reducing lesions and improving weight gains. Rofenaid (a potentiated sulfa mixture), robenidine (30 ppm), diclazuril (2 ppm), and decoquinate (80 ppm) were highly effective. In a test of nine products against a highly virulent field isolate, only diclazuril (2 ppm) and clopidol (125 ppm) reduced the severity of lesions and improved weight gain relative to infected controls, suggesting the extent to which previous drug usage had selected for drug resistance.

Infectious bursal disease virus (IBDV) causes important economic losses and negatively affects global trade in poultry and poultry products. This study determined the presence of IBDV in primary lymphoid tissues and muscle tissue of infected broilers and the role of vaccination as a mitigation strategy. In the first study, specific-pathogen-free (SPF) broiler chickens were challenged with STC (classical [cIBDV]), Indiana (variant [varIBDV]), rA (very virulent [vvIBDV]), or Ohio (serotype 2, avirulent) IBDV. Infection was confirmed in all groups, but only the cIBDV group experienced morbidity or mortality. Virus was only isolated in low titers from a few breast and/or thigh muscle tissue samples from cIBDV and vvIBDV-infected chickens. For the second study, SPF broilers from three different treatment groups were challenged with IBDV viruses that currently circulate in the United States, varIBDV or vvIBDV: 1) maternal antibody–positive (MAb ), vaccinated with recombinant HVT-IBDV vaccine (Vaxxitek^®, Merial; MAb /Vax); 2) MAb , not-vaccinated (MAb /Unvax); and 3) maternal antibody–negative, not-vaccinated chickens (MAb−/Unvax). MAb /Vax and MAb /Unvax chickens had significantly lower virus titers in primary lymphoid tissues compared to MAb−/Unvax chickens. No virus was detected in muscle tissues from any of the groups challenged with varIBDV, confirming the results of the first experiment. Only 1 of 36 (MAb /Vax) and 2 of 36 (MAb /Unvax) muscle samples were positive at minimal amounts (10^1.97 EID₅₀/ml) in vvIBDV challenge, compared to the 9 of 36 muscle samples that were positive in the MAb−/Unvax group. This study indicates that only cIBDV and vvIBDV strains can be found in muscle at low titers of SPF meat chickens and that the breeder vaccination with MAb transfer to progeny with or without accompanying progeny vaccination, as practiced in the United States, was an effective mitigation strategy for vvIBDV-challenged birds.

Infectious bursal disease virus (IBDV) contains two genome segments (segment A/segment B) that can reassort among the viruses. Reassortant IBDVs have been identified in several countries including the United States. These reassortant viruses usually include at least one genome segment from a very virulent (vv)IBDV strain. In vivo virulence of six reassortant IBDV from the United States was assessed relative to the virulence of three frequently described IBDV pathotypes: vvIBDV (rB strain), classic virulent (cv)IBDV (STC strain), and subclinical (sc)IBDV (Del-E strain). Morbidity and mortality in 4-wk-old specific-pathogen-free (SPF) leghorns indicated that reassortant IBDV with a vv genome segment A and non-vv segment B were less pathogenic than the vv/vv rB strain but more pathogenic than the cv/cv STC strain. The sc/vv IBDV strain D6337 (sc/vv) was comparable to the STC strain in pathogenicity. Viruses with a serotype 2 (ser2) genome segment A, regardless of the type of genome segment B, did not cause clinical disease in SPF chickens or turkeys. None of the reassorted viruses caused morbidity, mortality, or gross lesions in SPF turkeys. Histopathologic lesions in the bursa of turkeys were not observed in any group except those challenged with the serotype 2 OH strain, which had a mild lymphocytic depletion. No mortality was observed in maternally immune broilers inoculated with any of the IBDV pathotypes at 1, 2, 3, and 4 wk of age. No bursal lesions were observed in any of the broiler chicken groups at 1 wk of age except for the D2712 (ser2/cv)-inoculated birds that had mild lymphocyte depletion. Based on evaluation of bursal lesion scores and IBDV reverse transcriptase-PCR on broilers challenged at 2 wk of age, the K669 (vv/ser2) virus broke through the maternal immunity while the STC, Del-E, rB, D2712 (ser2/cv), and 7741 (vv/cv) viruses did not. All viruses broke through maternal immunity in the broilers at 3 wk of age except the Del-E scIBDV and D2712 (ser2/cv) reassortant IBDVs. At 4 wk of age, maternal antibodies were very low and bursal lesions were observed in all broilers challenged with the viruses. The data indicate that genome reassortant IBDVs are less pathogenic than is the rB (vv/vv) IBDV. However, the reassortant viruses with a vv genome segment A can still cause morbidity and mortality in SPF chickens, and they were able to break through maternal immunity produced via use of commercial classic and variant vaccines at an early age. This suggests that current breeder vaccination programs may not adequately protect against the reassortant vv/ser2 and vv/cv IBDV strains.

Tibial dyschondroplasia (TD) is an important tibiotarsal bone disorder characterized by an avascular and nonmineralized growth plate; it is attributed to abnormal differentiation of chondrocytes and causes lameness. Heat-shock protein 90 (Hsp90) is a proangiogenic factor in animal tissues; however, its gene expression increases in cases of chicken TD. The objective of this study was to evaluate the efficacy of epigallocatechin-3-gallate (EGCG) and apigenin in thiram-induced TD birds; these substances were used because of their Hsp90 inhibitory activities. The histologic study of growth plates was carried out with hematoxylin and eosin staining, and the Hsp90 gene expression was examined by reverse transcription quantitative real-time PCR. Results showed that as compared to a control group, TD-affected birds displayed changes in chondrocyte differentiation, with lack of blood vessels, and an increased expression of Hsp90 was observed significantly (P < 0.05). However, on administering the EGCG and apigenin to TD-affected birds, the normal chondrocyte columnar organization was restored with vascularization and decreased Hsp90 expression activity (P < 0.05), which ultimately abrogated the lameness. Our results suggested that Hsp90 is the key factor in the development of TD, and EGCG and apigenin have a novel effect on Hsp90 inhibition properties, thus reducing the lameness and leg deformity in chicken broilers.

Newcastle disease (ND) is a big concern throughout the world because of the devastating losses that can occur with commercial and backyard poultry. The major problem in many countries is the loss of the vaccine's effectiveness due to inadequate use or storage conditions, particularly in hot climates. In the present study, stability of the five, most-used NDV vaccine strains (I-2, LaSota, B1, Clone 30 [C30], and VG-GA) was tested comparatively at different storage temperatures (4 and 37 C for the freeze-dried form and 4, 24, 37, and 45 C for the freeze-dried vaccine reconstituted in diluents). The vaccine stability was evaluated by the cumulative infectious titer drop and the theoretical shelf life at particular temperatures. Results showed that I-2 and LaSota are the most stable vaccine strains compared to B1, C30, and VG-GA; they registered the lowest titer drops and the longest shelf life whether at cool, high, or room temperatures and for both freeze-dried and reconstituted vaccines.

Globally, avian influenza (AI) is a serious problem in poultry farming. Despite vaccination, the prevalence of AI in México highlights the need for new approaches to control AI and to reduce the economic losses associated with its occurrence in susceptible birds. Recombinant proteins from avian influenza virus (AIV) have been expressed in different organisms, such as plants. The present study investigated the feasibility of designing and expressing the HA protein of AIV in the transplastomic microalga Chlamydomonas reinhardtii as a novel approach for AIV control and taking advantage of culture conditions, its reproductive range, and safe use in consideration of the generally regarded as safe food ingredient regulatory classification. The results showed that the HA protein of AIV in C. reinhardtii presents antigenic activity by western blot test and through its application in chickens, demonstrating its feasibility as a recombinant antigen against AIV.

In addition to being the causative agent of fowl cholera (FC), Pasteurella multocida is also one of the most prevalent opportunistic pathogens associated with respiratory diseases in various hosts. However, understanding of the traits that distinguish the virulent isolates that cause FC is still limited. The objective of this study was to characterize P. multocida isolates of Brazil by PCR–restriction fragment length polymorphism (PCR-RFLP) analysis in order to determine if strain-type correlates with virulence or with 22 previously studied virulence genes. The PCR-RFLP was used to classify the isolates into seven strain types, and the isolates in Profile II had a higher pathogenicity index (P < 0.05) than did those in Profiles I, V, and VI. The overall identity among the nucleotide sequences of the ompH was 89.8%. Furthermore, strains available in GenBank showed a high level of homology of the different bacterial serotypes with the groupings resulting from the PCR-RFLP. Strain Types I and II showed the highest identity with Serotypes 3 (100%) and 3-4 (99.1%), respectively. Detection of the pfhA gene indicated the presence of strains that are highly pathogenic. The screening detection of 22 virulence genes and inference through the decision tree models comparing the results of pathogenicity indices permitted the identification of the most highly pathogenic strains of P. multocida.

Mycoplasma gallisepticum (MG) is one of the major pathogens that cause respiratory signs in the poultry industry. To control MG infection, vaccination is the useful procedure. In this study, MG vaccine was developed by using the local Thai MG isolate (AHRL 20/52). Chitosan, a polysaccharide adjuvant derived from crustaceans, has been successfully used in various vaccines. The objectives of this study were to prepare MG bacterins by using chitosan, serving as an adjuvant, to determine protection against the field Thai MG isolate and to evaluate tissue reaction at the injection site. Six groups of 6-wk-old layers (20 birds/group) were intramuscularly vaccinated with bacterin containing various concentrations of chitosan (0.25, 0.5, and 1%), a commercially available MG bacterin, respectively. Sham-negative and sham-positive controls were included in the experiment. Six weeks postvaccination, all groups excluding the negative control were intratracheally challenged with 100 μl of 10⁸ colony-forming units of Thai MG isolate (AHRL 58/46). At 1, 2, 3, and 4 wk postchallenge, five birds from each group were euthanatized and necropsied to determine the gross and histopathologic lesions. For a tissue reaction study, three groups of 24 birds each including sham negative control, 0.5% chitosan bacterin and commercial vaccine were given as previously described. At 1, 2, and 3 wk postvaccination, 8 birds from each group were randomly selected to euthanatize, necropsy, and determine the gross lesions, and 3 out of 8 birds were randomly selected to determine the histopathologic lesions. The results demonstrated that prepared bacterins induced lower numbers of positive antibody birds compared to the commercial vaccine, but groups receiving bacterin containing 0.5 and 1% chitosan exhibited significantly lower tracheal lesions than the positive control and commercial vaccine groups (P < 0.05). Chitosan formulation caused less tissue reaction than the commercial vaccine. These results demonstrated that the prepared MG bacterins could effectively reduce MG-induced pathologic lesions and that chitosan could be used as adjuvant in MG bacterins.

Many developing countries lack sufficient resources to conduct animal disease surveillance. In recent years, participatory epidemiology has been used to increase the cover and decrease the costs of surveillance. However, few diagnostic performance assessments have been carried out on participatory methods. The objective of the present study was to estimate the diagnostic performance of practitioners working for the Community-Based Animal Health and Outreach (CAHO) program, which is a participatory disease surveillance system for the detection of highly pathogenic avian influenza outbreaks in Egypt. CAHO practitioners' diagnostic assessment of inspected birds was compared with real-time reverse-transcriptase polymerase chain reaction (RRT-PCR) test results at the household level. Diagnostic performance was estimated directly from two-by-two tables using RRT-PCR as a reference test in two different scenarios. In the first scenario, only results from chickens were considered. In the second scenario, results for all poultry species were analyzed. Poultry flocks in 916 households located in 717 villages were inspected by CAHO practitioners, who collected 3458 bird samples. In the first scenario, CAHO practitioners presented sensitivity (Se) and specificity (Sp) estimates of 40% (95% confidence interval [CI]: 21%–59%) and 92% (95% CI: 91%–94%), respectively. In the second scenario, diagnostic performance estimates were Se = 47% (95% CI: 29%–65%) and Sp = 88% (95% CI: 86%–90%). A significant difference was observed only between Sp estimates (P < 0.01). Practitioners' diagnostics and RRT-PCR results were in very poor agreement with kappa values of 0.16 and 0.14 for scenarios 1 and 2, respectively. However, the use of a broad case definition, the possible presence of immunity against the virus in replacement birds, and the low prevalence observed during the survey would negatively affect the practitioners' performance.

Mycoplasma synoviae (MS), a remarkable pathogen in poultry, causes subclinical infection of the upper respiratory tract and an infectious synovitis, especially in the tendon sheaths and synovial membranes of joints. Because the specific detection of MS 16S rRNA gene–based PCR was unsuitable for strain differentiation, vlhA gene–based PCR was designed to differentiate the MS strains. The vlhA gene of MS encodes for hemagglutinin and other immunodominant membrane proteins involved in colonization, antigenic variations, and virulence. Sequence analysis of the vlhA gene based on the nucleotide insertion/deletion of the proline-rich repeat (PRR) region and the nucleotide polymorphisms of the RIII region in vlhA gene fragments was useful for typing and subtyping of MS strains. This study aimed to characterize the Thai MS field isolates and to differentiate the field and vaccine strains in Thailand by using sequence analysis of the partial vlhA gene. In total, 20 MS field isolates submitted from registered chicken farms in Thailand during 2015 were identified as Type C1 (n = 1), C2 (n = 4), E1 (n = 9), E2 (n = 1), and L (n = 5). The results revealed that six of the nine isolates resulting in respiratory signs were Type E1. In addition, four isolates from lame chickens showing joint swelling were identified as Type L, with a length of 105 nucleotides. This study provides the first molecular data of Thai MS isolates and the first evidence of Type L for being an arthropathic strain that differs from a previous study demonstrating that only MS Type B, with a longer PRR of 135 nucleotides, could be highly invasive strains and associated with infectious synovitis in chickens. Furthermore, one farm showed coinfection of MS Types E and L, but most of the farms were affected by only one type of MS. The results indicated that sequence analysis of the partial vlhA gene can be used as a tool for tracing MS characterization.

Forty-two H9N2 subtype AIV strains were isolated from vaccinated commercial chickens in China from 2012 to 2015. Their HA genes had nucleotide sequence homology from 86.7% to 99.7%, and similarity to the classic vaccine strain was 88.6%–92.6%. A comparison was carried out with published HA genes (410 H9 strains) and whole genomes (306 strains) isolated in China during 2012–2015. Interestingly, 99.1% (448/452) of Chinese H9N2 AIV belonged to lineage h9.4.2, and 98.5% (445/452) of the viruses belonged to h9.4.2.5. Meanwhile, 99.6% (443/445) of lineage 9.4.2.5 viruses had PSRSSR↓GLF instead of PARSSR↓GLF motifs in the HA cleavage sites; 98.2% (444/452) of HA genes showed human receptor binding associated mutation Q226L. A total of 96.8% (337/348) of the viruses had three amino-acid deletions at 63–65 in the NA stalk, associated with enhanced virulence in chickens and mice; 97.1% (338/348) of M2 proteins had the S31N mutation associated with adamantane resistance in humans. Two H9 viruses isolated in this study were highly homologous to the human-origin H9N2 virus reported in 2013. The isolates were divided into four different genotypes (U, S, V, and W). Genotype S was the major one, accounting for 94.8% (330/348). Genotypes V and W were new reassortment genotypes, with genotype W recombined with the PB2 gene originating from the new wild waterfowl-like lineage. According to the cross-HI antibody titer data, HA gene evolution, and isolation history, the isolates were divided into A, B, and C antigenic groups successively. All the antigenic group viruses were found to circulate throughout China. This study emphasizes the importance of updated vaccine and strengthened veterinary biosecurity on poultry farms and trade markets.

Marek's disease (MD) is a major cause of mortality in backyard chickens. The diagnosis of MD is complex, however, and knowledge of Marek's disease virus (MDV) in spontaneous field cases such as in backyard chickens is largely unknown. In this study, 40 backyard chickens with a presumptive MD diagnosis based on histologic lymphoid infiltrations in peripheral nerves with and without lymphomas were investigated. Twenty-eight of the birds were submitted to the diagnostic laboratory for disease explorations, and 12 chickens were from a flock in which some members demonstrated anisocoria and pupil irregularities compatible with ocular MD. Histologic scores were established for brain, peripheral nerves, heart, lung, liver, kidney, and gonad sections, ranging from mild ( ) to severe ( ) lymphoid infiltrations. Twelve chickens had gross lymphomas, and all but two chickens had mild to severe peripheral nerve lymphoid infiltrates. There were no age or breed predispositions in the study group. Quantification of serotypes MDV-1, −2, and −3 performed with real-time PCR demonstrated high correlation (R² = 0.94) between fresh and fixed spleen specimens, as well as between histopathology scores and MDV-1 viral loads. MDV-2 DNA was detected in a portion of the chickens, likely consistent with naturally occurring virus, whereas the vaccine strain MDV-3 was rarely detected. Significant differences in MDV-1 viral loads between tumorous and nontumorous chickens were observed, in which a ratio of MDV-1 glycoprotein B/glyceraldehyde-3-phosphate dehydrogenase ≥ 0.5 was suggestive of gross tumors in this study. We propose that real-time PCR may be a good tool for MD diagnosis in backyard chickens.

The bacterium Avibacterium paragallinarum is the etiologic agent of infectious coryza of chickens. There are nine serovars of A. paragallinarum, and serovar C-1 has emerged in outbreaks of infectious coryza in layer hens in the Americas, with all isolates having been obtained from infectious coryza-vaccinated chickens. In the current study, the clinical and histopathologic outcomes of experimental infections in chickens with A. paragallinarum of serovar C-1 were investigated. The Japanese serovar reference strain, H-18, and a Mexican isolate, ESV-135, were included in the study. No differences in clinical sign scores or morbidity were observed between the two strains. The two bacterial strains caused microscopic lesions of lymphoplasmacytic inflammation in the mucosa of the nasal cavity, infraorbital sinus, and trachea. Similar severe lesions were observed in birds inoculated with both H-18 and ESV-135 strains. The lesions were present 48 hr after inoculation and persisted until day 10 after inoculation. Slight to severe, extensive hemorrhages were observed in the lumen, mucous membranes, and lamina propria of the nasal cavity and infraorbital sinus in most of the chickens inoculated with either the reference strain H-18 or the ESV-135 isolate. Hemorrhages in the upper respiratory tract of chickens experimentally infected with A. paragallinarum are reported here for the first time. The results have confirmed the high virulence of the reference strain H-18 as previously reported and have shown that the Mexican isolate was as virulent as the reference strain. The virulence of A. paragallinarum isolates may play a role in explaining why severe infectious coryza outbreaks are being seen in both vaccinated and nonvaccinated chicken flocks.

A vertically integrated monitoring program was set up for breeders hatched in 2013 and their offspring to detect differences in performance related to the reovirus vaccination schedule. Within the same organization in Belgium, 17 breeder flocks were vaccinated with one dose of live and one dose of inactivated reovirus vaccine, while 14 flocks received two doses of inactivated vaccine without live priming. The hatchability of the eggs produced by these birds was examined. Further, the daily growth, feed conversion, mortality, slaughterhouse condemnation, production index, and antibiotic use were monitored in 110 broiler flocks derived from the breeders. All gathered data were examined statistically. In eggs obtained from breeders vaccinated twice with inactivated reovirus vaccine, a significant 2.88% higher hatchability rate was observed. The progeny broiler flocks of these breeders showed a significant 18.2% lower mortality during the fattening period. Although not statistically significant, the slaughterhouse condemnation rate was 10.1% lower as well. The results may indicate that—under the epidemiologic conditions of this study—double administration of inactivated reovirus vaccine in broiler breeders can at least contribute to higher hatchability of breeder eggs and lower broiler mortality.

Corn stored outside could become contaminated with avian influenza virus (AIV) from wild bird droppings. AIV-contaminated ingredients could pass into the poultry flocks in nonpelleted chicken feed. The efficacy of two disinfectants at inactivating AIV in chicken feed was evaluated. Both Termin-8 (a blend of formaldehyde, propionic acid, terpenes, and surfactant) and Finio (a blend of approved phytochemicals and carboxylic acids) effectively inactivated AIV in chicken feed. Because stability of infectious AIV in chicken feed is limited, we evaluated addition of protein (skim milk powder) to the virus suspension. Protein prolonged the stability of AIV in untreated feed to 24 hr at 24 C. However, both feed disinfectants were able to inactivate the virus in feed even when protected by skim milk powder.

A 2-yr-old male gyrfalcon (Falco rusticolus) was presented for severe and generalized muscle spasticity and pododermatitis. The falcon had been treated for pododermatitis over the previous 4 mo. Muscle rigidity and spasms involved the entire bird but were more severe on the right leg. The bird was also tachypneic and hyperthermic at 45 C. While the plantar pododermatitis lesions had healed, there was still a small abscess on the lateral aspect of the right foot. Clinical signs were consistent with tetanus. Several bacteria were isolated from the abscess including Clostridium tetani. The isolate was confirmed to be toxigenic by PCR. Attempts to detect tetanus toxin in the bird's plasma were unsuccessful. The abscess was debrided. The gyrfalcon received equine tetanus antitoxin, intravenous metronidazole, methocarbamol, midazolam, a constant-rate infusion of Fentanyl, active cooling, and supportive care. Inhalant anesthesia with isoflurane was the only treatment that would lower the body temperature and reduce the clinical signs. The gyrfalcon died a few hours after admission. The characteristic clinical signs and isolation of toxigenic C. tetani from a wound were strong supportive evidence for a diagnosis of tetanus. This case constitutes the first reported natural occurrence of tetanus in an avian species. Further information is needed to determine whether gyrfalcons are more susceptible to tetanus than are other avian species and whether pododermatitis lesions may be risk factors.

Ornithobacterium rhinotracheale (ORT) has been considered exotic to New Zealand and thus, any samples from poultry suspected of ORT infection are submitted as part of an exotic disease investigation managed by Ministry for Primary Industries (MPI) and subjected to standardized test protocols carried out in the physical containment level 3 laboratory at MPI's Animal Health Laboratory (AHL). All previous exotic disease investigations concerning ORT produced negative results by bacterial culture and conventional PCR. Following the recent introduction of a real-time PCR for ORT at the AHL, several tracheal wash fluids from backyard chickens (Gallus gallus domesticus) were tested positive. This identification constituted the first detection of ORT in New Zealand poultry. As a result, a second premise was investigated with further samples testing positive for ORT by molecular assays. This paper describes the two exotic disease investigations associated with the first detection of ORT in New Zealand poultry and its implications.

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