Dale Lauer

Molecular Epidemiology of Subgroup C Avian Pneumoviruses Isolated in the United States and Comparison with Subgroup A and B Viruses

ABSTRACT The avian pneumovirus (APV) outbreak in the United States is concentrated in the north-central region, particularly in Minnesota, where more outbreaks in commercial turkeys occur in the spring (April to May) and autumn (October to December). Comparison of the nucleotide and amino acid sequences of nucleoprotein (N), phosphoprotein (P), matrix (M), fusion (F), and second matrix (M2) genes of 15 U.S. APV strains isolated between 1996 and 1999 revealed between 89 and 94% nucleotide sequence identity and 81 to 95% amino acid sequence identity. In contrast, genes from U.S. viruses had 41 to 77% nucleotide sequence identity and 52 to 78% predicted amino acid sequence identity with European subgroup A or B viruses, confirming that U.S. viruses belonged to a separate subgroup. Of the five proteins analyzed in U.S. viruses, P was the most variable (81% amino acid sequence identity) and N was the most conserved (95% amino acid sequence identity). Phylogenetic comparison of subgroups A, B, and C viruses indicated that A and B viruses were more closely related to each other than either A or B viruses were to C viruses.

Evidence of Avian Pneumovirus Spread Beyond Minnesota Among Wild and Domestic Birds in Central North America

To detect avian pneumovirus (APV) in central North America, nasal turbinates or choanal deft tissues from domestic turkeys and wild birds were examined for the presence of APV RNA by reverse transcriptase-polymerase chain reaction (RT-PCR), whereas serum samples from domestic turkeys were analyzed for APV antibodies by enzyme-linked immunosorbent assay (ELISA). In 2002, the seroprevalence of disease in domestic turkeys in Minnesota remained high (42.3% of the flocks). In addition, there is evidence the disease has spread to turkey flocks in North Dakota (8.2%), South Dakota (7%), Iowa (10%), and Wisconsin (8.6%) as detected by RT-PCR and/or ELISA. House sparrows and ring-billed gulls sampled in Minnesota and snow geese from Saskatchewan, Canada, were found to harbor APV RNA. Sequence analysis of wild bird APV strains showed high amino acid sequence identity among wild bird isolates (<97%) and between wild bird and turkey viral isolates (93.2%-99.3%). This study demonstrated that APV infections were present in domestic turkey flocks and wild birds outside the state of Minnesota; however, the role of wild birds in spreading APV to domestic turkeys remains unclear.

Seroprevalence of Avian Pneumovirus in Minnesota Turkeys

Abstract Avian pneumovirus (APV) causes respiratory tract infection in turkeys and was first seen in the United States in Colorado in late 1996. In early 1997, the disease was recognized in Minnesota and caused estimated losses of up to

Serological evidence for the presence of influenza D virus in small ruminants

15 million per year. This virus has not been reported in the other turkey producing states. We here report the seroprevalence of APV in Minnesota from August 1998 to July 2002. The average rate of seroprevalence has been 36.3% (range = 14.2%–64.8%). A seasonal bias was observed, with peak incidences in the fall and spring. A higher rate of seropositivity was observed in counties with the highest concentration of turkeys.

Prevalence and Risk Factors for H1N1 and H3N2 Influenza A Virus Infections in Minnesota Turkey Premises

Influenza D virus (FLUDV) was isolated from diseased pigs with respiratory disease symptoms in 2011, and since then the new virus has also been spread to cattle. Little is known about the susceptibility of other agricultural animals and poultry to FLUDV. This study was designed to determine if other farm animals such as goats, sheep, chickens, and turkey are possible hosts to this newly emerging influenza virus. 648 goat and sheep serum samples and 250 chicken and turkey serum samples were collected from 141 small ruminant and 25 poultry farms from different geographical locations in the United States and Canada. Serum samples were examined using the hemagglutination inhibition (HI) assay and the sheep and goat samples were further analyzed using the serum neutralization assay. Results of this study showed FLUDV antibodies were detected in 13.5% (17/126) of the sampled sheep farms, and 5.2% (29/557) of tested sheep serum samples were positive for FLUDV antibodies. For the goat results, the FLUDV antibodies were detected in 13.3% (2/15) of the sampled farms, and 8.8% (8/91) of the tested goat serum samples were positive for FLUDV antibodies. Furthermore, all tested poultry serum samples were negative for FLUDV antibodies. Our data demonstrated that sheep and goat are susceptible to FLUDV virus and multiple states in U.S. have this virus infection already in these two species. This new finding highlights a need for future surveillance of FLUDV virus in small ruminants toward better understanding both the origin and natural reservoir of this new virus.

Emergence of Multidrug-Resistant Salmonella enterica Serotype Newport in Minnesota

SUMMARY. Influenza virus infections can cause respiratory and systemic disease of variable severity and also result in economic losses for the turkey industry. Several subtypes of influenza can infect turkeys, causing diverse clinical signs. Influenza subtypes of swine origin have been diagnosed in turkey premises; however, it is not known how common these infections are nor the likely routes of transmission. We conducted a cross-sectional study to estimate the prevalence of influenza viruses and examine factors associated with infection on Minnesota turkey premises. Results from influenza diagnostic tests and turkey and pig premise location data were obtained from the Minnesota Poultry Testing Laboratory and the Minnesota Board of Animal Health, respectively, from January 2007 to September 2008. Diagnostic data from 356 premises were obtained, of which 17 premises tested positive for antibodies to influenza A virus by agar gel immunodiffusion assay and were confirmed as either H1N1 or H3N2 influenza viruses by hemagglutination and neuraminidase inhibition assays. Influenza infection status was associated with proximity to pig premises and flock size. The latter had a sparing effect on influenza status. This study suggests that H1N1 and H3N2 influenza virus infections of turkey premises in Minnesota are an uncommon event. The route of influenza virus transmission could not be determined; however, the findings suggest that airborne transmission should be considered in future studies.

Characterization of avian metapneumoviruses isolated in the USA

We report a concurrent increase in the number of isolates of Salmonella enterica serotype Newport and the rate of multidrug resistance in S. Newport isolates from animal and human populations in Minnesota. Antimicrobial susceptibility and pulsed-field gel electrophoresis analysis demonstrated heterogeneity of isolates and showed that 1 pulsed-field gel electrophoresis cluster contained most of the multidrug-resistant isolates with a resistance pattern and most class 1 integron isolates, implying the clonal origin of the isolates.

Development and Evaluation of a Blocking Enzyme-Linked Immunosorbent Assay for Detection of Avian Metapneumovirus Type C-Specific Antibodies in Multiple Domestic Avian Species

Abstract Avian pneumovirus (APV; officially known as turkey rhinotracheitis virus) is an emergent pathogen of birds in the USA that results in upper respiratory tract disease in turkeys. Six years after the first outbreak in the USA, the disease continues to ravage turkey flocks, primarily in the state of Minnesota. From 1997 to 2000, the industry recorded losses estimated at US

Historical and Recent Cases of H3 Influenza A Virus in Turkeys in Minnesota

15 million per annum. Researchers have developed sensitive diagnostic techniques, including the enzyme-linked immunosorbent assay and the reverse transcriptase–polymerase chain reaction, which, when used together, are highly sensitive in detecting APV outbreaks in commercial turkey flocks. Phylogenetic analysis of the nucleotide and predicted amino acid sequence of 15 US viruses isolated between 1996 and 2000 demonstrated that the US viruses are relatively homogenous but different from the European APV subgroups A and B, resulting in the classification of US isolates into subgroup C. Infectious APV was isolated from sentinel waterfowls placed close to an infected commercial turkey farm and from wild Canada geese captured in Minnesota, suggesting that free-ranging birds may be involved in the spread of APV. Current efforts to prevent and control the infection include improving management and biosecurity practices and developing attenuated live and deletion mutant vaccines capable of conferring protection.

Evaluation of five different antigens in enzyme-linked immunosorbent assay for the detection of avian pneumovirus antibodies.

ABSTRACT The first cases of infection caused by avian metapneumoviruses (aMPVs) were described in turkeys with respiratory disease in South Africa during 1978. The causative agent was isolated and identified as a pneumovirus in 1986. aMPVs have been detected in domestic nonpoultry species in Europe, but tests for the detection of these viruses are not available in the United States. To begin to understand the potential role of domestic ducks and geese and wild waterfowl in the epidemiology of aMPV, we have developed and evaluated a blocking enzyme-linked immunosorbent assay (bELISA) for the detection of aMPV type C (aMPV-C)-specific antibodies. This assay method overcomes the species-specific platform of indirect ELISAs to allow detection of aMPV-C-specific antibodies from potentially any avian species. The bELISA was initially tested with experimental turkey serum samples, and the results were found to correlate with those of virus neutralization assays and indirect enzyme-linked immunosorbent assay (iELISA). One thousand serum samples from turkey flocks in Minnesota were evaluated by our bELISA, and the level of agreement of the results of the bELISA and those of the iELISA was 94.9%. In addition, we were able to show that the bELISA could detect aMPV-C-specific antibodies from experimentally infected ducks, indicating its usefulness for the screening of serum samples from multiple avian species. This is the first diagnostic assay for the detection of aMPV-C-specific antibodies from multiple avian species in the United States.