In the present study, we evaluated the continuance and efficacy of inactivated vaccine against Salmonella Infantis (SI) in chickens raised on a commercial farm. Chickens (88-days-old) were inoculated with 1 or 0.5 doses of commercially available trivalent inactivated Salmonella vaccine; anti-SI antibody titer was examined continuously for 11 mo thereafter. Molting was induced 11 mo after vaccination, and SI was administered orally. SI colony-forming units (CFUs) were measured in cecal feces, cecal contents, liver, and spleen samples. Anti-SI antibodies in the 1 dose vaccination group could be detected in at least 90% of cases until the end of testing. SI discharge was significantly reduced in birds treated with either dose of vaccine. However, SI CFUs were elevated in the induced molting group, regardless of vaccination dose, particularly in the cecal feces, cecal contents, and spleen. Thus, the vaccine provided remarkable protection against SI infection under ordinary rearing methods but not during induced molting. To achieve sufficient SI protective efficacy, we recommend inoculation with 1 dose of vaccine. Moreover, the efficacy of inactivated Salmonella vaccine is recommended to be evaluated by challenging chickens with live Salmonella in addition to Salmonella antibody titration.

We characterized the histologic effects of two stressors (heat and coccidial infection) alone or in combination on bursa of Fabricius, thymus, and spleen in broiler chickens. Four hundred and eighty Cobb500 male chicks at 14 days of age were randomly assigned to two treatments in a 2×2 factorial design, with 15 replicates per treatment and eight birds per replicate. The treatment factors were temperature (25 and 35 C) and a mixed culture of 2.5 × 10⁵ sporulated Eimeria acervulina and Eimeria maxima oocysts (infection or no infection). Histologic lesion severity was scored in these tissues at different ages. At 21 and 28 days of age, bursal and thymic tissues from birds raised at 35 C exhibited significant increases in lymphoid depletion severity compared with those raised at 25 C. No significant differences were detected in the lymphoid depletion severity of birds infected with Eimeria when compared with uninfected birds. These results indicate that continuous exposure to heat stress–inducing temperatures results in lymphoid depletion of the bursa and thymus in broiler chickens, a potential histologic marker for the immunologic changes known to arise as a result of heat stress. Bursal and thymic atrophy are thought to contribute to immunologic changes that underlie the negative effects of heat stress on poultry production characteristics.

Domesticated Australian and Timor zebra finches (Taeniopygia guttata castanotis and Taeniopygia guttata guttata, respectively) were inoculated with canary (Serinus canaria) blood containing a Hawaiian isolate of Plasmodium relictum (lineage GRW04), a hemoparasite that causes avian malaria. In two experimental trials, TZFs but not AZFs developed parasitemia that was detected by microscopic examination of blood smears. In the second trial, in which molecular detection methods were used, a single AZF and five of six challenged TZFs were positive for the parasite. Additionally, P. relictum DNA was detected in multiple blood samples obtained from TZFs over the 28 days following challenge. TZFs may provide a useful, easily maintained, laboratory model for the study of Plasmodium interactions in passerines but are still inferior to canaries, the traditionally used model of avian malaria infection, in terms of supporting high-parasitemia infections.

The virucidal efficacies of a 0.2% food additive–grade calcium hydroxide [FdCa(OH)₂] solution, a quaternary ammonium compound (QAC) diluted at 1:500 (QACx500), and their mixture [Mix500; FdCa(OH)₂ powder added at a final concentration of 0.2% to QACx500] were investigated as fomites for avian influenza virus (AIV) and Newcastle disease virus (NDV) on abiotic carriers (steel, rubber, and plastic) at two different temperatures (room temperature [RT; 25 ± 2 C] and 2 C). These viruses were seeded on coupons (5 cm×5 cm) of rubber, steel, or plastic with 5% fetal bovine serum. After complete drying, the coupons were covered with the test solutions at RT or 2 C. After fixed incubation periods, viruses were recovered from the coupons and titrated. At RT, Mix500 required a short time (3 min) to inactivate AIV and NDV to effective levels (≥3 log virus reduction) on rubber, steel, and plastic carriers compared with QAC or FdCa(OH)_2. At low temperature, QACx500 inactivated AIV on steel and plastic carriers to effective levels within 60 min, whereas Mix500 did so within 10 min. QACx500 and FdCa(OH)₂ solutions could inactivate NDV on steel and plastic carriers within 20 and 10 min, respectively, and Mix500 could do so within 3 min. Viruses on the carriers required longer incubation periods for inactivation at 2 C than at 25 C. These results demonstrate desirable synergistic virucidal effects of Mix500 for important poultry viruses on abiotic carriers, while indicating high applicability within poultry farming.

Fowl cholera is caused by the bacterium Pasteurella multocida and is known to cause significant economic losses in the commercial turkey industry. Four hundred and thirty cases of P. multocida in commercial turkeys, submitted to the California Animal Health and Food Safety Laboratory System (CAHFS) from January 1, 1991, to December 31, 2017, were analyzed. Records examined included CAHFS branch location, date of submission, clinical signs, company and premise of origin, age and sex of submitted turkeys, macroscopic findings, organs in which P. multocida was isolated, and serotype and fingerprint information. Increased mortality as high as 1200 birds per day was the most common complaint at submission, with acute septicemic lesions observed in the majority of cases. The mean age of turkeys diagnosed with fowl cholera was 14 wk, with a median age of 17 wk. Cases most frequently occurred from September to November, with 36% of cases occurring during this time period. Serotyping was performed in 350 cases, while fingerprinting was performed in 171 cases. Serotypes 3 and 3,4 were frequently identified in the 26-yr time period, while the fingerprints identified varied over time. Despite the decreasing population of commercial turkeys in California since the 1990s, fowl cholera continues to be an economically significant disease in this sector.

Respiratory secretions, feces, feathers, and eggs of avian influenza–infected hens provide ample sources of virus which heavily contaminate barn and farm environments during a disease outbreak. Environmental sampling surveys were conducted in the Midwestern United States on affected farms during the 2015 H5N2 highly pathogenic avian influenza (HPAI) outbreak to assess the degree of viral contamination. A total of 930 samples were obtained from various sites inside and outside layer barns housing infected birds and tested with real-time reverse transcriptase PCR. The distribution and load of viral RNA in barns in which most birds were dead at the onset of depopulation efforts (high-mortality barns) were compared with those of barns in which birds were euthanatized before excess mortality occurred (normal-mortality barns). A statistically significant difference was seen between cycle threshold (Ct) values for samples taken of fans, feed troughs, barn floors, barn walls, cages, manure-associated locations, barn doors, egg belts, and the exterior of high-mortality vs. normal-mortality barns. In high-mortality barns, sample sites were found to be the most to least contaminated in the following order: cages, manure-associated locations, barn floors, egg belts, feed troughs, barn doors, barn walls, fans, exterior, and egg processing. Significant changes in Ct values over time following HPAI detection in a barn and depopulation of birds on an infected farm were observed for the manure-associated, barn floor, barn wall, and fan sampling sites. These results show that high mortality in a flock as a result of HPAI will increase contamination of the farm environment. The results also suggest optimal sampling locations for detection of virus; however, the persistence of RNA on highmortality farms may delay the determination that adequate sanitization has been performed for restocking to take place.

We identified low–molecular weight compounds derived from the antimicrobial peptide human neutrophil peptide-1 that bind to Lipid II, an essential precursor of bacterial cell wall biosynthesis. These compounds act as antibacterials on multiple biosynthesis pathways with specificity against gram-positive organisms. Here, we have tested a small subset of our most promising leads against the bacterium Clostridium perfringens and sporozoites of Eimeria tenella, an intracellular protozoan parasite that causes intestinal disease in poultry. We found one compound, 1611-0203 (2-{2,3,5,6-tetrafluoro-4-[2,3,5,6-tetrafluoro-4-(2-hydroxyphenoxy)phenyl]phenoxy}phenol), specifically to inhibit growth of both agents out of all compounds tested. Additionally, compound 1611-0203 inhibits Staphylococcus aureus and Enterococcus spp. Mechanism-of-action studies further reveal that 1611-0203 affects cell wall biosynthesis and inhibits additional biosynthetic pathways. Combined, our results indicate that compounds such as 1611-0203 have therapeutic potential to act as anti-infectives against various organisms simultaneously.

Infectious laryngotracheitis virus (ILTV) is the causative agent of an acute respiratory avian disease known as infectious laryngotracheitis (ILT), which has been associated with economic losses in poultry. The presence of ILTV has been widely reported in South American countries; however, only one full genomic sequence (VFAR-043 strain) has been recently published, from an outbreak in Peru. The aim of this study was to determine the genetic relationship of the Peruvian strain with other ILTV strains from different geographic regions. The phylogenetic analyses revealed a close relationship between VFAR-043 and two U.S. origin strains (1874C5 and J2) using only the whole genome, Unique Long (UL), and Unique Short (US) genomic regions. Then these three genomic sequences were compared to evaluate their genetic variations using the USDAref as a reference strain. Genetic variations such as synonymous and nonsynonymous single-nucleotide polymorphisms, insertions, deletions, and nucleotide-codon variations were identified among these three strains. Moreover, the phylogenetic tree analysis using gene sequences of the US5 and ICP4 coding regions from South American isolates showed that VFAR-043 does not have a close relationship with either the Argentinian (US5) or Brazilian (ICP4) reported sequences. However, a close relationship was observed between VFAR-043 and another Peruvian isolate (USP-81) when the ICP4 gene sequence was analyzed. All these results suggest that VFAR-043 together with 1874C5 and J2 are closely related. These findings contribute to our understanding of the epidemiology of ILTV in South America.

Herpesvirus (HV) was detected using PCR in the organs of eight of 55 wild owls (14.5%) from seven species that were found dead in various locations in Slovenia between 1995 and 2015. HV was detected in three species: the Eurasian eagle owl (Bubo bubo), Ural owl (Strix uralensis), and long-eared owl (Asio otus). Phylogenetic analysis of partial DNA polymerase gene nucleotide sequences showed that the detected HVs are similar to the avian and mammal alphaherpesviruses. Two sequences were very similar to known bird HV sequences. One sequence was identical to the columbid herpesvirus 1 (CoHV1) sequence, and the other was very similar to the gallid herpesvirus 2 (GaHV2) sequence. The phylogenetic tree revealed a lower similarity of the other six analyzed Slovenian sequences with the sequences of alphaherpesviruses of birds and mammals. This is the first study to report the detection of different HVs in owls.

Given the importance of Avian avulaviruses (AAvVs) in commercial poultry, continuous monitoring and surveillance in natural reservoirs (waterfowls) is imperative. Here, we report full genomic and biologic characterization of two virulent AAvVs isolated from apparently asymptomatic green-winged teal (Anas carolinensis). Genetic characterization (genome length, coding potential, and presence of typical cleave motif [₁₁₂RRQKR| F₁₁₇]) and biologic assessment (HA, log 2⁹; mean death time, 49.2–50 hr; 10^–6.51 50% egg infective dose [EID₅₀]/0.1 mL; and 1.5 intracerebral pathogenicity index [ICPI] value) revealed virulence of both isolates. Phylogenetic analysis of the complete genome and hypervariable region of the fusion (F) gene revealed clustering of both isolates within class II strains in close association with domestic poultry–origin AAvVs representing genotype VII and subgenotype VIIi. The inferred residue analysis of F and hemagglutinin–neuraminidase genes showed a number of substitutions in critical domains compared with reference strains of each genotype (I–XVIII). The isolates showed a high nucleotide resemblance (99%) with strain isolated previously from backyard poultry; however, they also showed a variable similarity (16.1% to 19.3%) with the most commonly used vaccine strains, Mukteswar (EF201805) and LaSota (AF077761). In accordance with pathogenicity assessment and horizontal transmission, the clinical and histopathologic observations in experimental chickens indicated the velogenic viscerotropic nature of AAvV 1 isolates. Taken together, this study confirms the evolutionary nature of AAvVs and their potential role in disease occurrence, necessitating continuous surveillance of migratory/aquatic fowls to better elucidate infection epidemiology and potential impacts on commercial poultry.

Surveillance of H9N2 is currently focused on areas central to the commercial poultry industry. This study determined the prevalence of H9N2 virus in commercial and backyard poultry flocks in Punjab Province, Pakistan. Oral and tracheal swabs were collected from commercial and backyard poultry from January 2015 through June 2016. Antisera against H5, H7, H9, and Newcastle disease viruses were used for virus identification. Molecular confirmation was made by reverse transcription PCR. Avian influenza virus subtypes H5 and H7 were not detected. The H9N2 virus was isolated in 5.7% of 905 tested flocks (5–10 birds/flock). Prevalence in commercial and backyard poultry was 6.7% of 687 flocks and 2.7% of 218 flocks, respectively. Hemagglutinin and neuraminidase-gene-based phylogenetic analysis of commercial and backyard poultry isolates showed 100% homology. Within sublineage B2 of Pakistan, identity among most recent isolates (2015) was 100%, compared to 75%–99% identity with previously isolated viruses (2010–12), indicating continued virus evolution. Most of the previously reported and currently studied viruses were isolated near the Pakistan-India border. Phylogenetic analysis showed that Pakistani and Indian isolates were closely related, indicating that avian influenza virus transmission may occur across this border.

Viral respiratory diseases, including avian metapneumovirus (aMPV), have a significant economic impact on poultry industries. The frequency and genotype diversity of aMPV in Turkish broiler flocks is not known at present. The aim of this study was to report the first molecular identification and phylogeny of aMPV, which is circulating in Turkish broiler flocks. Trachea tissue samples and tracheal swabs were collected from 110 broiler flocks distributed in different geographical regions in Turkey between March 2017 and March 2018. Detection of aMPV was confirmed with the use of universal reverse transcriptase (RT) PCR, and eight (7.2%) broiler farms were positive for aMPV. Sequence analysis of the G gene revealed the exclusive presence of subtype B viruses. Three field isolates clustered closely with a 2002 Israel isolate, indicating a potential transmission route between these two countries and through the Middle East. The remaining five field isolates were closely related to a vaccine strain, even though broiler flocks in Turkey are not routinely vaccinated against aMPV. Therefore, we speculate these five isolates could have originated from nearby vaccinated turkey farms. Additionally, the presence of some nucleotide substitutions compared to the reference vaccine sequence suggests prolonged circulation and evolution of the original vaccine virus or a vaccine subpopulation was selected under field conditions. This evidence emphasizes the need for further detailed and more systemic approaches to evaluate aMPV spread and evolution in order to design effective control strategies.

Salmonella enterica subspecies enterica serovar Gallinarum biovar Pullorum (Salmonella Pullorum) has strict host specificity for poultry, and pullorum disease seriously threatens the poultry industry. Virulence genes play a central role in Salmonella pathogenicity, but very few reports are available on the distribution of virulence genes in Salmonella Pullorum. In this study, we investigated 304 Salmonella Pullorum isolates recovered from chickens in China between 1953 and 2015 for the presence of 25 Salmonella virulence genes (invA, orgA, prgH, sitC, spaN, sifA, spiA, ttrC, mgtB, misL, siiE, spi4D, pipA, sipB, sopB, sefA, cdtB, pagC, shdA, msgA, lpfC, tolC, iroN, pefA, and spvB), including pathogenicity island genes, fimbriae genes, and virulence plasmid genes. PCR showed that 15 of the 25 virulence genes were present in all isolates tested, whereas cdtB was not present in any isolate. The presence rates of the remaining genes ranged from 97.7% to 99.7%. The variation rates of these virulence genes was low, and no significant differences were identified in the distribution of virulence genes over time. On the basis of the distribution of these virulence genes, the 304 Salmonella Pullorum isolates were divided into 10 virulence genotypes. The major genotype, which comprised 93.4% of all isolates, included isolates that carried 24 of the virulence genes assessed. The results of this study will help in the characterization of Salmonella Pullorum and in the study of the correlation between virulence genotypes and pathogenicity.