Emergence of swine influenza A virus, porcine respirovirus 1 and swine orthopneumovirus in porcine respiratory disease in Germany.

Respiratory disease is a significant economic issue in pig farming, with a complex aetiology that includes swine influenza A viruses (swIAV), which are common in European domestic pig populations. The most recent human influenza pandemic in 2009 showed swIAV's zoonotic potential. Monitoring pathogens and disease control are critical from a preventive standpoint, and are based on quick, sensitive, and specific diagnostic assays capable of detecting and distinguishing currently circulating swIAV in clinical samples. For passive surveillance, a set of multiplex quantitative reverse transcription real-time PCRs (mRT-qPCR) and MinION-directed sequencing was updated and deployed. Several lineages and genotypes of swIAV were shown to be dynamically developing, including novel reassortants between human pandemic H1N1 and the avian-derived H1 lineage of swIAV. Despite this, nearly 70% (842/1216) of individual samples from pigs with respiratory symptoms were swIAV-negative, hinting to different aetiologies. The complex and synergistic interactions of swIAV infections with other viral and bacterial infectious agents contribute to the aggravation of pig respiratory diseases. Using a newly developed mRT-qPCR for the combined detection of swIAV and the recently described porcine respirovirus 1 (PRV1) and swine orthopneumovirus (SOV) widespread co-circulation of PRV1 (19.6%, 238/1216 samples) and SOV (14.2%, 173/1216 samples) was evident. Because of the high incidence of PRV1 and SOV infections in pigs with respiratory disease, these viruses may emerge as new allies in the porcine respiratory disease syndrome.

Respiratory infections and coinfections: geographical and population patterns.

INTRODUCTION: Acute respiratory infections are the second cause of mortality in children younger than five years, with 150.7 million episodes per year. Human orthopneumovirus (hOPV) and metapneumovirus (hMPV) are the first and second causes of bronchiolitis; type 2 human orthorubulavirus (hORUV) has been associated with pneumonia in immunocompromised patients. OBJECTIVE: To define hOPV, hMPV and hORUV geographical distribution and circulation patterns. METHOD: An observational, prospective cross-sectional pilot study was carried out. Two-hundred viral strains obtained from pediatric patients were genotyped by endpoint reverse transcription polymerase chain reaction (RT-PCR). RESULTS: One-hundred and eighty-six positive samples were typed: 84 hOPV, 43 hMPV, two hORUV and 57 co-infection specimens. Geographical distribution was plotted. hMPV, hOPV, and hORUV cumulative incidences were 0.215, 0.42, and 0.01, respectively. Cumulative incidence of hMPV-hORUV and hMPV-hOPV coinfection was 0.015 and 0.23; for hOPV-hMPV-hORUV, 0.035; and for hORUV-hOPV, 0.005. The largest number of positive cases of circulating or co-circulating viruses occurred between January and March. CONCLUSIONS: This study successfully identified circulation and geographical distribution patterns of the different viruses, as well as of viral co-infections.

INTRODUCCIÓN: Las infecciones respiratorias agudas constituyen la segunda causa de mortalidad en los niños menores de cinco años, con 150.7 millones de episodios anuales. Entre los principales agentes etiológicos están Orthopneumovirus (hOPV) y metapneumovirus (hMPV) humanos como primera y segunda causa de bronquiolitis, respectivamente; Orthorubulavirus humano tipo 2 (hORUV) se ha asociado a neumonía en pacientes inmunocomprometidos. OBJETIVO: Definir patrones de distribución geográfica y de circulación de hOPV, hMPV y hORUV. MÉTODO: Se llevó a cabo un estudio piloto transversal prospectivo observacional. Se genotipificaron 200 aislamientos virales de pacientes pediátricos mediante transcripción inversa seguida de reacción en cadena de la polimerasa en punto final (RT-PCR). RESULTADOS: Se tipificaron 186 muestras positivas: 84 de hOPV, 43 de hMPV, dos de hORUV y 57 de coinfecciones. Se trazó la distribución geográfica. Las incidencias acumuladas de hMPV, hOPV y hORUV fueron de 0.215, 0.42 y 0.01, respectivamente. Las incidencias acumuladas de la coinfección de hMPV-hORUV y hMPV-hOPV fueron de 0.015 y 0.23; de hOPV-hMPV-hORUV, de 0.035; y de hORUV-hOPV, de 0.005. El mayor número de casos positivos de virus circulantes o cocirculantes se presentó entre enero y marzo. CONCLUSIONES: Fue posible identificar patrones de circulación y distribución geográfica de los diferentes virus, así como de las coinfecciones virales.

Respiratory infections and coinfections: geographical and population patterns / Infecciones y coinfecciones respiratorias: patrón geográfico y de circulación poblacional

Abstract Introduction: Acute respiratory infections are the second cause of mortality in children younger than five years, with 150.7 million episodes per year. Human orthopneumovirus (hOPV) and metapneumovirus (hMPV) are the first and second causes of bronchiolitis; type 2 human orthorubulavirus (hORUV) has been associated with pneumonia in immunocompromised patients. Objective: To define hOPV, hMPV and hORUV geographical distribution and circulation patterns. Method: An observational, prospective cross-sectional pilot study was carried out. Two-hundred viral strains obtained from pediatric patients were genotyped by endpoint reverse transcription polymerase chain reaction (RT-PCR). Results: One-hundred and eighty-six positive samples were typed: 84 hOPV, 43 hMPV, two hORUV and 57 co-infection specimens. Geographical distribution was plotted. hMPV, hOPV, and hORUV cumulative incidences were 0.215, 0.42, and 0.01, respectively. Cumulative incidence of hMPV-hORUV and hMPV-hOPV coinfection was 0.015 and 0.23; for hOPV-hMPV-hORUV, 0.035; and for hORUV-hOPV, 0.005. The largest number of positive cases of circulating or co-circulating viruses occurred between January and March. Conclusions: This study successfully identified circulation and geographical distribution patterns of the different viruses, as well as of viral co-infections.

Resumen Introducción: Las infecciones respiratorias agudas constituyen la segunda causa de mortalidad en los niños menores de cinco años, con 150.7 millones de episodios anuales. Entre los principales agentes etiológicos están Orthopneumovirus (hOPV) y metapneumovirus (hMPV) humanos como primera y segunda causa de bronquiolitis, respectivamente; Orthorubulavirus humano tipo 2 (hORUV) se ha asociado a neumonía en pacientes inmunocomprometidos. Objetivo: Definir patrones de distribución geográfica y de circulación de hOPV, hMPV y hORUV. Método: Se llevó a cabo un estudio piloto transversal prospectivo observacional. Se genotipificaron 200 aislamientos virales de pacientes pediátricos mediante transcripción inversa seguida de reacción en cadena de la polimerasa en punto final (RT-PCR). Resultados: Se tipificaron 186 muestras positivas: 84 de hOPV, 43 de hMPV, dos de hORUV y 57 de coinfecciones. Se trazó la distribución geográfica. Las incidencias acumuladas de hMPV, hOPV y hORUV fueron de 0.215, 0.42 y 0.01, respectivamente. Las incidencias acumuladas de la coinfección de hMPV-hORUV y hMPV-hOPV fueron de 0.015 y 0.23; de hOPV-hMPV-hORUV, de 0.035; y de hORUV-hOPV, de 0.005. El mayor número de casos positivos de virus circulantes o cocirculantes se presentó entre enero y marzo. Conclusiones: Fue posible identificar patrones de circulación y distribución geográfica de los diferentes virus, así como de las coinfecciones virales.

Antibody Epitopes of Pneumovirus Fusion Proteins.

The pneumoviruses respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) are two widespread human pathogens that can cause severe disease in the young, the elderly, and the immunocompromised. Despite the discovery of RSV over 60 years ago, and hMPV nearly 20 years ago, there are no approved vaccines for either virus. Antibody-mediated immunity is critical for protection from RSV and hMPV, and, until recently, knowledge of the antibody epitopes on the surface glycoproteins of RSV and hMPV was very limited. However, recent breakthroughs in the recombinant expression and stabilization of pneumovirus fusion proteins have facilitated in-depth characterization of antibody responses and structural epitopes, and have provided an enormous diversity of new monoclonal antibody candidates for therapeutic development. These new data have primarily focused on the RSV F protein, and have led to a wealth of new vaccine candidates in preclinical and clinical trials. In contrast, the major structural antibody epitopes remain unclear for the hMPV F protein. Overall, this review will cover recent advances in characterizing the antigenic sites on the RSV and hMPV F proteins.

Phylogenetic evidence of a novel lineage of canine pneumovirus and a naturally recombinant strain isolated from dogs with respiratory illness in Thailand.

BACKGROUND: Canine pneumovirus (CPV) is a pathogen that causes respiratory disease in dogs, and recent outbreaks in shelters in America and Europe have been reported. However, based on published data and documents, the identification of CPV and its variant in clinically symptomatic individual dogs in Thailand through Asia is limited. Therefore, the aims of this study were to determine the emergence of CPV and to consequently establish the genetic characterization and phylogenetic analysis of the CPV strains from 209 dogs showing respiratory distress in Thailand. RESULTS: This study identified and described the full-length CPV genome from three strains, designated herein as CPV_CP13 TH/2015, CPV_CP82 TH/2016 and CPV_SR1 TH/2016, that were isolated from six dogs out of 209 dogs (2.9%) with respiratory illness in Thailand. Phylogenetic analysis suggested that these three Thai CPV strains (CPV TH strains) belong to the CPV subgroup A and form a novel lineage; proposed as the Asian prototype. Specific mutations in the deduced amino acids of these CPV TH strains were found in the G/glycoprotein sequence, suggesting potential substitution sites for subtype classification. Results of intragenic recombination analysis revealed that CPV_CP82 TH/2016 is a recombinant strain, where the recombination event occurred in the L gene with the Italian prototype CPV Bari/100-12 as the putative major parent. Selective pressure analysis demonstrated that the majority of the nucleotides in the G/glycoprotein were under purifying selection with evidence of positive selection sites. CONCLUSIONS: This collective information on the CPV TH strains is the first evidence of CPV emergence with genetic characterization in Thailand and as first report in Asia, where homologous recombination acts as a potential force driving the genetic diversity and shaping the evolution of canine pneumovirus.

Epidemiology of RSV and hMPV in Belgium: a 10-year follow-up.

Objectives: Respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) are important respiratory pathogens. Both viral pathogens have similar clinical manifestations. The epidemiology of RSV is well known, that of hMPV is less clear. We reviewed the results of 10 consecutive years of molecular testing for RSV and hMPV in respiratory samples of Flemish patients. Methods: In the laboratory of the OLV hospital Aalst, Belgium, multiplex RT-PCR assays are used for the detection of RSV and hMPV. The lab receives invasive and noninvasive respiratory samples of patients from all over Flanders. Results: Between September 2006 and August 2016, 16,826 respiratory samples were analyzed for RSV and hMPV. Of these samples, 18% tested positive for RSV and 7.3% for hMPV. RSV consistently peaked in November/December each year within a very narrow time frame. The occurrence of hMPV was less predictable and spreaded more widely throughout the winter and spring. Both viruses were mainly found in samples from young children. RSV was most frequently detected in samples from infants <3 months, while hMPV peaked between 6 and 9 months. After the age of 1 year, RSV rapidly dropped. hMPV dropped a little later and slower. Both viruses slightly increased again at older age (>50 years). Conclusions: Despite their similarities, some of the epidemiologic characteristics of hMPV and RSV differ. The most striking difference is the annual distribution of RSV and hMPV infections.

European surveillance of emerging pathogens associated with canine infectious respiratory disease.

Canine infectious respiratory disease (CIRD) is a major cause of morbidity in dogs worldwide, and is associated with a number of new and emerging pathogens. In a large multi-centre European study the prevalences of four key emerging CIRD pathogens; canine respiratory coronavirus (CRCoV), canine pneumovirus (CnPnV), influenza A, and Mycoplasma cynos (M. cynos); were estimated, and risk factors for exposure, infection and clinical disease were investigated. CIRD affected 66% (381/572) of the dogs studied, including both pet and kennelled dogs. Disease occurrence and severity were significantly reduced in dogs vaccinated against classic CIRD agents, canine distemper virus (CDV), canine adenovirus 2 (CAV-2) and canine parainfluenza virus (CPIV), but substantial proportions (65.7%; 201/306) of vaccinated dogs remained affected. CRCoV and CnPnV were highly prevalent across the different dog populations, with overall seropositivity and detection rates of 47% and 7.7% for CRCoV, and 41.7% and 23.4% for CnPnV, respectively, and their presence was associated with increased occurrence and severity of clinical disease. Antibodies to CRCoV had a protective effect against CRCoV infection and more severe clinical signs of CIRD but antibodies to CnPnV did not. Involvement of M. cynos and influenza A in CIRD was less apparent. Despite 45% of dogs being seropositive for M. cynos, only 0.9% were PCR positive for M. cynos. Only 2.7% of dogs were seropositive for Influenza A, and none were positive by PCR.

Human metapneumovirus-associated severe acute respiratory illness hospitalisation in HIV-infected and HIV-uninfected South African children and adults.

BACKGROUND: Data on human metapneumovirus (HMPV)-associated severe acute respiratory illness (SARI) are limited in settings with high human immunodeficiency virus (HIV) infection prevalence. OBJECTIVES: To describe clinical characteristics and seasonality (all sites), and incidence (Soweto only) of HMPV-associated SARI among children and adults. STUDY DESIGN: Active, prospective, hospital-based, sentinel surveillance for patients hospitalised with SARI was conducted at four sites in South Africa from February 2009-December 2013. Upper respiratory tract samples were tested by multiplex real-time polymerase chain reaction assays for HMPV and other respiratory viruses. Incidence of hospitalisation, stratified by age and HIV-infection status, was calculated for one hospital with population denominators. RESULTS: HMPV was identified in 4.1% of patients enrolled, including 5.6% (593/10503) in children and 1.7% in adults (≥18 years; 119/6934). The majority of adults (84.0%) had an underlying medical condition, including HIV infection in 87/110 (79.1%). HMPV detection occurred perennially with periods of increased detection, which varied from year to year. The incidence of HMPV-associated hospitalisation in Soweto was highest in infants (653.3 per 100,000 person years; 95% confidence interval (CI) 602.2-707.6). The incidence was higher in HIV-infected persons compared to HIV-uninfected persons in age-groups 5-17 years (RR 6.0; 1.1-20.4), 18-44 years (RR 67.6; 38.0-132.6) and 45-64 years (RR 5.3; 3.4-8.3), while not differing in other age-groups. CONCLUSIONS: The burden of HMPV-associated SARI hospitalisation among adults occurred predominantly in HIV-infected persons. Among children, infants were at highest risk, with similar burden of hospitalisation in HIV-infected and HIV-uninfected children.

Detection of canine pneumovirus in dogs with canine infectious respiratory disease.

Canine pneumovirus (CnPnV) was recently identified during a retrospective survey of kenneled dogs in the United States. In this study, archived samples from pet and kenneled dogs in the United Kingdom were screened for CnPnV to explore the relationship between exposure to CnPnV and the development of canine infectious respiratory disease (CIRD). Within the pet dog population, CnPnV-seropositive dogs were detected throughout the United Kingdom and Republic of Ireland, with an overall estimated seroprevalence of 50% (n = 314/625 dogs). In the kennel population, there was a significant increase in seroprevalence, from 26% (n = 56/215 dogs) on the day of entry to 93.5% (n = 201/215 dogs) after 21 days (P <0001). Dogs that were seronegative on entry but seroconverted while in the kennel were 4 times more likely to develop severe respiratory disease than those that did not seroconvert (P < 0.001), and dogs with preexisting antibodies to CnPnV on the day of entry were significantly less likely to develop respiratory disease than immunologically naive dogs (P < 0.001). CnPnV was detected in the tracheal tissues of 29/205 kenneled dogs. Detection was most frequent in dogs with mild to moderate respiratory signs and histopathological changes and in dogs housed for 8 to 14 days, which coincided with a significant increase in the risk of developing respiratory disease compared to the risk of those housed 1 to 7 days (P < 0.001). These findings demonstrate that CnPnV is present in the United Kingdom dog population; there is a strong association between exposure to CnPnV and CIRD in the kennel studied and a potential benefit in vaccinating against CnPnV as part of a wider disease prevention strategy.

Pneumovirus in dogs with acute respiratory disease.

To determine which respiratory viruses circulate among confined dogs, we analyzed nasal and pharyngeal swab specimens from shelter dogs with acute respiratory disease. An unknown virus was isolated. Monoclonal antibody testing indicated that it was probably a pneumovirus. PCR and sequence analysis indicated that it was closely related to murine pneumovirus.

Microbial contaminations of laboratory mice and rats in Taiwan from 2004 to 2007.

Limited data are available on the pathogen status of contemporary rodent colonies in Taiwan. Here we summarized the rodent pathogen diagnostic records of the Taiwan National Laboratory Animal Center during a 4-y period that representing approximately 10% of the rodent colonies in Taiwan. Demand for pathogen diagnostic service increased continuously from 2004 to 2007, with a 20% increase each year. In 2007, more than 20% of the mouse colonies were positive for mouse parvovirus, mouse hepatitis virus, Theiler murine encephalomyelitis virus, and Mycoplasma pulmonis, with fewer colonies diagnosed as having infections of pneumonia virus of mice, mouse adenovirus, lymphocytic choriomeningitis virus, and reovirus. Almost 40% of tested rat colonies were positive for Mycoplasma pulmonis and rat parvovirus, with fewer colonies containing Kilham rat virus, sialodacryoadenitis virus, pneumonia virus of mice, Sendai virus, and Syphacia spp. These data provide a sound overall picture of the health status of mouse and rat colonies in Taiwan.

Respiratory viruses in pediatric necropsies: an immunohistochemical study.

Infections of the respiratory system are responsible for the majority of hospitalizations and deaths in pediatric patients in developing countries. We selected 177 necropsies of pediatric patients who died as a result of serious respiratory infections. The histopathological findings and epidemiological data were reviewed, and lung tissue samples were separated for immunohistochemistry testing. Conventional immunohistochemistry techniques were used to detect viral antigens in formalin-fixed, paraffin-embedded (FF-PE) lung tissue samples using a pool of monoclonal antibodies against respiratory viruses (respiratory syncytial virus, influenza A and B, adenovirus, and parainfluenza 1, 2, and 3 viruses) as primary antibodies. The histopathological findings were classified into bronchopneumonia (BCP) and interstitial pneumonitis (IP) patterns. The immunohistochemistry results were compared with histopathological patterns and epidemiological data. Positive results for viruses were found in 34% and 62.5% of the BCP and IP cases, respectively. Males and infants below 1 year of age were more frequent in the group that had positive results for viruses. Acute enteritis was the main cause of hospitalization and sepsis the most frequent cause of death in this group. A clear seasonal distribution was observed, with the majority of cases occurring in the 2nd and 3rd trimesters (autumn and winter) of each year in the period studied. Immunohistochemistry is an affordable and easy-to-perform method for viral-antigen detection in FF-PE tissue samples. Although BCP is a classic histopathological pattern found in bacterial infections, it is possible that children with serious respiratory infections had concomitant viral and bacterial infections, regardless of their previous immunologic state.

Presence of avian pneumovirus subtypes A and B in Japan.

Four avian pneumovirus (APV) isolates from chickens clinically diagnosed with swollen head syndrome were genetically characterized as to the subtypes of the virus in Japan. The results of reverse transcriptase-polymerase chain reactions based on subtype-specific primers and direct sequence analysis of G genes indicated subtypes A and B but not C or D of APV were present in Japan. Several routes or sources are conceivable for APV to invade into Japan.

Experimental and field evaluation of a live vaccine against avian pneumovirus.

The attenuation of an avian pneumovirus (APV) isolate (APV/MN/turkey/1-a/97) by 63 serial passages in cell culture (seven in chicken embryo fibroblasts and 56 in Vero cells) and its evaluation as a live attenuated vaccine in turkey poults is described. The birds were vaccinated with two different doses of attenuated virus (10(4.5) median tissue culture infectious dose (TCID(50))/ml and 10(2.5) TCID(50) /ml) at 2 weeks of age, and were challenged 2 weeks later with virulent APV. No clinical signs were seen in vaccinated, challenged birds, whereas severe clinical signs were observed in the mock-vaccinated, challenged group. Vaccinated birds developed anti-APV antibodies, which increased in titre following challenge with virulent virus. On challenge, none of the vaccinates was found to shed viral nucleic acid as detected by reverse transcriptase-polymerase chain reaction, but non-vaccinated, challenged birds did. The vaccine virus was also evaluated under field conditions in two farms. At one farm, the 'seeder bird approach' was used and two birds per 1,000 birds were vaccinated by the oculo-nasal route. In the second farm, the virus was given to all birds simultaneously in the drinking water. The birds vaccinated by the drinking water route seroconverted earlier and continued to shed virus for longer as compared with birds inoculated by the seeder bird approach. The overall results of this study indicate that the 63rd passage of APV was sufficiently attenuated and offered protection against challenge with virulent virus.

A single subtype of avian pneumovirus circulates among Minnesota turkey flocks.

The recent emergence of avian pneumovirus (APV) infection among US turkey flocks has resulted in a major economic threat to the turkey industry. In order to elucidate the molecular epidemiology of APV, comparative sequence analysis of the fusion (F) protein gene of APV was performed for 3 cell culture-adapted isolates and 10 APV positive clinical samples recovered from US turkey flocks. Relatively modest levels of nucleotide and amino acid sequence divergence were identified, suggesting the prevalence of a single lineage of APV among US turkey flocks. Additionally, numerous polymorphisms were identified that were only represented in the clinical samples but not in the in vitro propagated isolates of APV. Phylogenetic analyses confirm that the subtype of APV circulating in the upper Midwestern United States is evolutionarily related to, but distinct from, European APV subgroups A and B. Overall, the results of the present investigation suggest that there has been only a single recent introduction of APV into US turkey populations in the upper Midwestern United States.

Molecular epidemiology of subgroup C avian pneumoviruses isolated in the United States and comparison with subgroup a and B viruses.

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.

Neonatal avian pneumovirus infection in commercial turkeys.

Eleven market turkey flocks developed a respiratory disease characterized by coughing, swollen sinuses and nasal discharge. These symptoms first appeared between 3 and 16 days of age. Avian pneumovirus (APV) RNA was detected by reverse transcriptase (RT)-polymerase chain reaction (PCR) in six of six flocks tested. APV was detected by immunohistochemistry in turbinates of three of three affected flocks tested. Virus isolation attempts were negative. Ten of 11 flocks became seropositive on the APV enzyme-linked immunosorbent assay. Five weeks prior to hatch of these affected market turkeys, several breeder flocks in one geographic area had developed clinical signs and experienced decline in egg production typical of APV infection. In two breeder flocks, acute and convalescent sera indicated APV infection during the period of declining egg production. Attempts to detect APV RNA by RT-PCR from choanal cleft swabs of newly hatched poults were successful. Attempts to isolate the virus from these PCR-positive samples were negative.

Isolation of avian pneumovirus from mallard ducks that is genetically similar to viruses isolated from neighboring commercial turkeys.

Our earlier studies demonstrating avian pneumovirus (APV) RNA in wild geese, sparrows, swallows, starlings and mallard ducks suggested that wild birds might be involved in the circulation of APV in the United States. To determine whether turkey virus can be transmitted to the free flying birds, we placed APV-negative mallard ducks next to a turkey farm experiencing a severe APV outbreak and in an area with a large population of waterfowls. The sentinel ducks did not develop clinical APV disease but infectious APV (APV/MN-12) was recovered from choanal swabs after 2 weeks, and anti-APV antibodies detected after 4 weeks. Four APV isolates recovered from the neighboring turkeys that were experiencing an APV outbreak at the same time shared 95-99% nucleotide identity and 97-99% predicted amino acid identity with the duck isolate. In addition experimental infection of turkey poults with APV/MN-12 resulted in detection of viral RNA in nasal turbinates and APV-specific IgG in serum. These results indicate that the APV isolates from turkeys and ducks shared a common source, and the viruses from different avian species can cross-infect.