Outbreak of H7N8 Low Pathogenic Avian Influenza in Commercial Turkeys with Spontaneous Mutation to Highly Pathogenic Avian Influenza.

Highly pathogenic avian influenza (HPAI) subtype H7N8 was detected in commercial turkeys in January 2016. Control zone surveillance discovered a progenitor low pathogenic avian influenza (LPAI) virus in surrounding turkey flocks. Data analysis supports a single LPAI virus introduction followed by spontaneous mutation to HPAI on a single premises.

Novel H5 Clade 2.3.4.4 Reassortant (H5N1) Virus from a Green-Winged Teal in Washington, USA.

Eurasian (EA)-origin H5N8 clade 2.3.4.4 avian influenza viruses were first detected in North America during December 2014. Subsequent reassortment with North American (AM) low-pathogenic wild-bird-origin avian influenza has generated at least two reassortants, including an EA/AM H5N1 from an apparently healthy wild green-winged teal, suggesting continued ongoing reassortment.

Novel Eurasian highly pathogenic avian influenza A H5 viruses in wild birds, Washington, USA, 2014.

Novel Eurasian lineage avian influenza A(H5N8) virus has spread rapidly and globally since January 2014. In December 2014, H5N8 and reassortant H5N2 viruses were detected in wild birds in Washington, USA, and subsequently in backyard birds. When they infect commercial poultry, these highly pathogenic viruses pose substantial trade issues.

Highly divergent virulent isolates of Newcastle disease virus from the Dominican Republic are members of a new genotype that may have evolved unnoticed for over 2 decades.

A Newcastle disease virus (NDV) outbreak in chickens was reported in the Dominican Republic in 2008. The complete genome of this isolate, chicken/DominicanRepublic(JuanLopez)/499-31/2008 (NDV-DR499-31/08), and the fusion proteins of three other related viruses from the Dominican Republic and Mexico were sequenced and phylogenetically analyzed. Genetically, these four isolates were highly distinct from all other currently known isolates of NDV, and together, they fulfill the newly established criteria for inclusion as a novel genotype of NDV (genotype XVI). The lack of any reported isolation of viruses related to this group since 1986 suggests that virulent viruses of this genotype may have evolved unnoticed for 22 years. The NDV-DR499-31/08 isolate had an intracerebral pathogenicity index (ICPI) score of 1.88, and sequencing of the fusion cleavage site identified multiple basic amino acids and a phenylalanine at position 117, indicating this isolate to be virulent. These results were further confirmed by a clinicopathological assessment in vivo. In 4-week-old chickens, NDV-DR499-31/08 behaved as a velogenic viscerotropic strain with systemic virus distribution and severe necrohemorrhagic lesions targeting mainly the intestine and the lymphoid organs. The clear phylogenetic relationship between the 2008, 1986, and 1947 ancestral viruses suggests that virulent NDV strains may have evolved in unknown reservoirs in the Caribbean and surrounding regions and underlines the importance of continued and improved epidemiological surveillance strategies to detect NDV in wild-bird species and commercial poultry.

Isolation of a virulent Newcastle disease virus from confiscated LaSota vaccine.

Vials of Newcastle disease vaccine labeled as LaSota were confiscated by the Arizona Division of Customs and Border Protection officials. Two different avian type 1 paramyxoviruses were isolated from all three vials of vaccine submitted to the National Veterinary Services Laboratories. The LaSota strain of avian paramyxovirus type 1 virus was isolated from all three vials and analyzed by nucleotide sequence analysis. A virulent Newcastle disease virus was also present in all three vials, but in low concentration. The virulence of the Newcastle disease virus was characterized by the intracerebral chicken pathogenicity index chicken inoculation assay but could not be determined by nucleotide sequence analysis from the virus isolated from embryonating chicken eggs. The intracerebral chicken pathogenicity index value for the isolated Newcastle disease virus was 1.55. Strains of Newcastle disease virus with intracerebral pathogenicity indexes significantly above 1.0 have been found to selectively kill many types of cancer cells while not affecting normal nonneoplastic cells and are considered to be a viable option for cancer treatment in humans by alternative medical researchers; however, the treatment is not approved for use in the United States by the Food and Drug Administration. Customs and Border Protection officials have been notified of an increased risk of Newcastle disease virus entering the United States for use as a nonapproved cancer treatment. Illegal importation of Newcastle disease vaccine for vaccination of backyard poultry is also a threat. This case report emphasizes the importance of conducting chicken inoculation for complete virus pathotyping and demonstrates the need for stringent security procedures at U.S. borders to detect known livestock pathogens that may be smuggled in for use in animal agriculture and reasons unrelated to animal agriculture.

Recovery of H14 influenza A virus isolates from sea ducks in the Western Hemisphere.

In 2010, H14 influenza A viruses were recovered from clinically normal sea ducks in the United States. These are the first H14 isolates recovered in the Western Hemisphere and represent the only documented H14 influenza A viruses isolated since the original isolates were recovered from near the Caspian Sea during 1982.

An rRT-PCR assay to detect the matrix gene of a broad range of avian paramyxovirus serotype-1 strains.

The current U.S. Department of Agriculture (USDA)-validated real-time reverse transcription-polymerase chain reaction (rRT-PCR) assay designed to detect the matrix gene of avian paramyxovirus serotype-1 (APMV-1) is the primary screening assay used in the United States. It has previously been shown to be unable to consistently detect all members of class I APMV-1. Diagnostic testing relies on rRT-PCR to quickly detect APMV-1 in wild birds, backyard flocks, live bird markets, commercial poultry, and for export testing. Limitations of the current USDA assay have raised concerns about the potential for some strains of APMV-1 to remain undetected by the primary screening assay. Mismatches in the probe were shown to cause a loss in template binding efficiency, resulting in lack of detection by the assay. Here, we describe the development and analytical validation of a new rRT-PCR assay designed to target a highly conserved region of the matrix gene across a wide range of APMV-1 strains. Limit of detection testing revealed a 3 log10 decrease in sensitivity for one low-virulence strain when compared to the USDA validated assay. Conversely, the assay showed increased sensitivity for a class I isolate and two virulent strains of APMV-1 that were not detected by the USDA-validated assay. The new assay also demonstrated a high degree of specificity by the lack of detection of 43 non-APMV-1 viruses.

Complete genome sequencing of a novel newcastle disease virus isolate circulating in layer chickens in the Dominican Republic.

Newcastle disease virus (NDV) was isolated from an outbreak in layer chickens in the Dominican Republic in 2008. Infections with this isolate led to a 100% apparent case fatality rate in birds. Complete genome sequencing revealed that the isolate does not belong to any of the previously described NDV genotypes. Similarly, large differences were observed in the amino acid sequence of the fusion and hemagglutinin-neuraminidase proteins in comparison with all known NDV genotypes, suggesting the existence of an unknown reservoir for NDV. The work presented here represents the first complete genome sequence of NDV in the Dominican Republic.

Avian paramyxovirus serotype-1: a review of disease distribution, clinical symptoms, and laboratory diagnostics.

Avian paramyxovirus serotype-1 (APMV-1) is capable of infecting a wide range of avian species leading to a broad range of clinical symptoms. Ease of transmission has allowed the virus to spread worldwide with varying degrees of virulence depending on the virus strain and host species. Classification systems have been designed to group isolates based on their genetic composition. The genetic composition of the fusion gene cleavage site plays an important role in virulence. Presence of multiple basic amino acids at the cleavage site allows enzymatic cleavage of the fusion protein enabling virulent viruses to spread systemically. Diagnostic tests, including virus isolation, real-time reverse-transcription PCR, and sequencing, are used to characterize the virus and identify virulent strains. Genetic diversity within APMV-1 demonstrates the need for continual monitoring for changes that may arise requiring modifications to the molecular assays to maintain their usefulness for diagnostic testing.

Validation of a real-time reverse transcriptase-PCR assay for the detection of H7 avian influenza virus.

This report describes the validation of an avian influenza virus (AIV) H7 subtype-specific real-time reverse transcriptase-PCR (rRT-PCR) assay developed at the Southeast Poultry Research Laboratory (SEPRL) for the detection of H7 AI in North and South American wild aquatic birds and poultry. The validation was a collaborative effort by the SEPRL and the National Veterinary Services Laboratories. The 2008 H7 rRT-PCR assay detects 10(1) 50% embryo infectious doses per reaction, or 10(3)-10(4) copies of transcribed H7 RNA. Diagnostic sensitivity and specificity were estimated to be 97.5% and 82.4%, respectively; the assay was shown to be specific for H7 AI when tested with > 270 wild birds and poultry viruses. Following validation, the 2008 H7 rRT-PCR procedure was adopted as an official U.S. Department of Agriculture procedure for the detection of H7 AIV. The 2008 H7 assay replaced the previously used (2002) assay, which does not detect H7 viruses currently circulating in wild birds in North and South America.

Comparison of the recovery of Mycobacterium bovis isolates using the BACTEC MGIT 960 system, BACTEC 460 system, and Middlebrook 7H10 and 7H11 solid media.

The BACTEC Microbacteria Growth Indicator Tube (MGIT) 960 system was evaluated to determine how it compares with the BACTEC 460 radiometric system and solid media for recovery of Mycobacterium bovis from tissue samples. A total of 506 bovine lymph node samples were collected from abattoirs in the United States and Mexico between November 2003 and September 2004. Processed samples were inoculated into an MGIT 960 tube, BACTEC 460 vial, and Middlebrook 7H10 and Middlebrook 7H11 solid media. Ziehl-Neelsen slides were prepared to check for contaminants and confirm the presence of acid-fast positive bacilli. Samples containing acid-fast bacilli were confirmed as members of the Mycobacterium tuberculosis complex by a nucleic acid assay. Niacin and nitrate biochemical tests were used to distinguish M. bovis from M. tuberculosis isolates. Statistical analyses were performed to compare recovery rate, mean time to detection, contamination rates, as well as pair-wise comparisons in each category. The results showed that the MGIT 960 system had a higher recovery rate of M. bovis (122/129) than did the BACTEC 460 (102/129) and solid media system (96/129). The average time to detection was 15.8 days for the MGIT 960 system, 28.2 days for the BACTEC 460 system, and 43.4 days for solid media. Contamination rates were 6.9% for the MGIT 960 system, 3.4% for the BACTEC 460 system, and 21.7% for solid media. These results indicate the MGIT 960 system can be used as an alternative to the BACTEC 460 system for recovering M. bovis from tissue samples.