Strains of avian paramyxovirus type 1 of low pathogenicity for chickens isolated from poultry and wild birds in Denmark

Twenty-one strains of avian paramyxovirus type 1 of low virulence for chickens were isolated in Denmark between 1996 and the beginning of 2003. The low virulence of the strains was demonstrated by sequencing the fusion (F) gene at the cleavage site motif and in some cases by determining the intracerebral pathogenicity index in day-old chicks. By using a panel of monoclonal antibodies it was shown that the isolates belonged to four different antigenic groups (five C2 isolates, six E isolates, six H isolates and four G/Q isolates). They were placed in three distinguishable genetic groups by phylogenetic analysis of a partial sequence of the F gene. The origin of the six E isolates was probably contaminated vaccines; the other viruses were isolated from wild birds and from poultry which probably came into contact with wild birds.     

Antigenic and genetic characterization of an avian poxvirus isolated from an endangered Hawaiian goose (Branta sandvicensis)

An avian poxvirus from cutaneous lesions in a Hawaiian goose (Branta sandvicensis) was characterized in this study. The virus was isolated by inoculation onto the chorioallantoic membranes (CAMs) of developing chicken embryos. Cytoplasmic inclusion bodies were observed on histopathological examination of CAM lesions. Western blotting analysis using polyclonal antiserum against fowl poxvirus (FWPV) showed differences from FWPV, but a similar antigenic profile between Hawaiian goosepox (HGP) isolate and two previous Hawaiian poxvirus isolates were observed. Still three avian poxviruses from Hawaiian birds showed distinguishable reaction in approximately 27, 34, 35, and 81 kDa proteins when polyclonal antibodies against the Hawaiian poxvirus isolate (Alala/lanakila) were used. Restriction fragment length polymorphisms (RFLP) of DNA of this isolate also showed differences from those of FWPV and previous avianpox isolates from Hawaiian forest birds. While nucleotide sequences of a 5.3-kb PstI-HindIII fragment of the genome of HGP isolate revealed very high homology (99% identities) with Canary poxvirus (CNPV) ORF266-274, and like CNPV, homologs of three FWPV ORFs (199, 200, and 202) including any reticuloendotheliosis virus (REV) sequences are not present in the genome of HGP isolate.     

Surveillance for avian influenza virus in captive wild birds and indigenous chickens in Nigeria

Tropical Animal Health and Production - Several reports of avian influenza virus (AIV) have been made on commercial chickens and wild birds in sub-Saharan Africa, but there is paucity of...     

Pigeon paramyxovirus: association with common avian pathogens in chickens and serologic survey in wild birds

Pigeon paramyxovirus-1 (PPMV-1) was isolated from pigeons from east-central Alabama and used in association with chicken anemia virus (CAV), infectious bursal disease virus (IBDV), or finch Mycoplasma gallisepticum (MG) in specific-pathogen-free chickens to assess dinical disease and pathology. PPMV-1 infection in all groups was conducted at day 10 of age via the ocular route. The low passage PPMV-1 isolate was inoculated into chickens in different groups at 10 days post-CAV infection, 6 days post-IBDV infection, and 6 days post-finch MG infection, respectively. Additionally, to obtain information on the status of paramyxovirus infection in the wild bird population of the region, we used a multispecies competitive enzyme-linked immunosorbent assay kit to assess serum samples from 180 wild birds representing 24 species obtained throughout 2001. Mild respiratory signs characterized by sneezing were observed in PPMV-1-infected chicks. In the brain, PPMV-1 caused disseminated vasculitis in the neuropile and meninges, sometimes with small foci of gliosis. Most brains had only mild lesions. In the upper respiratory tract, lesions were confined to the larynx and proximal trachea as hyperplasia of laryngeal mucosa-associated lymphoid tissue. In the lung, PPMV-1 caused minimal to moderate multifocal interstitial pneumonia. Lymphocytic expansion occurred in the interstitium of the Harderian gland. PPMV-1 in the spleen caused expansion of the white pulp as a result of hypertrophy of the macrophages in the periarteriolar sheaths accompanied by lymphocytic hyperplasia at the periphery. No severe aggravation of either signs or lesions could be attributed to any of the avian pathogens used in association with PPMV-1. The serologic survey in wild birds showed antibody levels that were considered negative or doubtful. Interestingly, significantly (P < 0.05) higher mean titers were observed during the months of October and November 2001, following closely multiple PPMV-1 episodes of mortality in wild collard doves in northwestern Florida.     

Infectivity and transmissibility of H9N2 avian influenza virus in chickens and wild terrestrial birds

Genetic changes in avian influenza viruses influence their infectivity, virulence and transmission. Recently we identified a novel genotype of H9N2 viruses in widespread circulation in poultry in Pakistan that contained polymerases (PB2, PB1 and PA) and non-structural (NS) gene segments identical to highly pathogenic H7N3 viruses. Here, we investigated the potential of these viruses to cause disease and assessed the transmission capability of the virus within and between poultry and wild terrestrial avian species. Groups of broilers, layers, jungle fowl, quail, sparrows or crows were infected with a representative strain (A/chicken/UDL-01/08) of this H9N2 virus and then mixed with naïve birds of the same breed or species, or different species to examine transmission. With the exception of crows, all directly inoculated and contact birds showed clinical signs, varying in severity with quail showing the most pronounced clinical signs. Virus shedding was detected in all infected birds, with quail showing the greatest levels of virus secretion, but only very low levels of virus were found in directly infected crow samples. Efficient virus intra-species transmission was observed within each group with the exception of crows in which no evidence of transmission was seen. Interspecies transmission was examined between chickens and sparrows and vice versa and efficient transmission was seen in either direction. These results highlight the ease of spread of this group of H9N2 viruses between domesticated poultry and sparrows and show that sparrows need to be considered as a high risk species for transmitting H9N2 viruses between premises.     

Intracerebral pathogenicity for chickens of avian influenza viruses isolated from free-living waterfowl in Japan

The pathogenicity for chickens of 91 strains of avian influenza A virus isolated from such free-living waterfowl as whistling swan, pintail, tufted duck, mallard and black-tailed gull in Japan was tested. The majority of the virus strains infected and were pathogenic for the chickens. The virulence of these viruses seemed not to be as high as that of fowl plague virus. There were no significant differences in the intracerebral index score among the viruses belonging to the same subtype, irrespective of year of isolation or host.     

Potential of low pathogenicity avian influenza viruses of wild bird origin to establish experimental infections in turkeys and chickens

The potential of low pathogenicity (LP) avian influenza virus (AIV) isolates of wild bird origin to establish infection in commercial turkeys and broiler chickens was studied. Isolates, representing subtypes H5N1, H7N3, H6N2, and H3N6, were recovered in 2005 and 2006 from waterfowl and shorebirds in the Delmarva Peninsula region of the east coast of the United States. The LP AIV isolates were not pathogenic for 2-wk-old meat-type turkeys and broiler chickens. No mortality, clinical signs, or gross lesions were observed following intratracheal and conjunctival sac routes of exposures with 10(6.0) EID50 (embryo infectious dose) per bird. Isolates resulting in an established infection based on virus isolation were: A/mallard/Maryland/1159/ 2006 (H5N1) in the upper respiratory tract of turkeys; A/mallard/Delaware/418/2005 (H7N3) in the upper respiratory and intestinal tracts of turkeys and chickens; and A/shorebird-environment/Delaware/251/2005 (H3N6) in the upper respiratory and intestinal tracts of chickens. Infections were also confirmed by production of AIV-specific serum antibodies detected by hemagglutination inhibition.     

Isolation of avian paramyxovirus-2 from domestic and wild birds in Costa Rica

A survey for Newcastle disease virus (NDV) in wild birds of Costa Rica was conducted by swabbing wild-caught pet birds, backyard chickens, and wild birds captured in Japanese mist nets in tropical rain forests and agricultural areas. Cloacal swabs were collected from 876 birds of approximately 132 species representing 24 taxonomic families. Hemagglutinating agents were isolated from 18.7% of the birds. Paramyxovirus type 2(PMV-2) (Yucaipa-like), unreported in free-flying passerines in the Americas, was recovered from a finch, wren, and chicken, each from a different location. Pathogenicity trials with infected turkey poults and newly hatched chicks did not result in growth impairment or significant clinical signs of disease. Attempts to isolate NDV were negative.     

A comparison of the pathogenicity of four avian reoviruses in chickens

Four avian reoviruses were orally inoculated into 1-day-old chickens to determine pathogenicity, virus persistence in the intestinal tract, and effects on body weight gains. Avian reoviruses Reo-25 and W3-492 belonged to two separate serotypes, and viruses TC 897 and W3-410 were antigenically related to W3-492. Isolate W3-492, which was highly pathogenic, was very rarely recovered from cloacal swabs collected 2 weeks postinoculation, but inoculated chickens gained significantly less weight (P less than or equal to 0.001) than uninoculated controls during the 5-week test study. Isolate Reo-25 persisted the longest in the intestinal tract, and isolates TC 897 and W3-410, of intermediate persistence, had no significant effect on body weights. There was no apparent correlation between serotype and pathotype of avian reoviruses.     

野生鸟类禽流感病毒感染情况的调查

为了解野生鸟类禽流感病毒(AIV)的携带感染情况,2006年～2010年,本研究在湖南省主要候鸟迁徙地收集115只野鸟组织或拭子样品、75份野鸟的新鲜粪便样品和72份血清样品。组织或拭子样品采用RT-PCR方法检测和鸡胚接种病毒分离鉴定,血清样品分别进行H5(含Re-5和Re-4)、H6、H7、H9、H10和H11抗体检测。结果表明,从斑鸠和绿头鸭组织中分别分离到H5N1亚型和H3N2亚型AIV;72份血清中有17份抗体为阳性,其中H5(Re-5)亚型5份、H5(Re-4)亚型1份、H6亚型1份、H7亚型2份和H9亚型8份,阳性率分别为6.94%、1.39%、1.39%、2.78%和11.11%。H10和H11亚型未检测到抗体阳性。     

Serotyping of US isolates of Chlamydophila psittaci from domestic and wild birds.

The identities of chlamydial strains, which can infect a given host, are important to know for disease prognosis, disease control, and epidemiology. The microimmunofluorescence test (MIFT) was used with a panel of 14 serovar-specific monoclonal antibodies (MAbs) to serotype 150 chlamydial isolates from domestic and wild birds. The isolates were obtained from birds submitted to diagnostic laboratories or during investigation of outbreaks. The 150 US isolates included 96 from the order Psittaciformes, 14 isolates from the order Columbiformes, 2 from the order Passeriformes, 16 from the order Galliformes, 12 from the order Struthioniformes, and 3 from the order Falconiformes. A total of 93, or 97%, of the Psittaciformes isolates were of serovar A; 11, or 79%, of the Columbiformes isolates were of serovar B; 64% of the Galliformes isolates were of serovar D, and all the Struthioniformes isolates were of serovar E. The 3 Falconiformes isolates did not react with any of the MAbs to the avian and mammalian isolates and are presumed to represent a new strain. The results show that specific chlamydial strains are usually associated with certain types of birds and that some serovars may be unusually virulent for certain species of birds. The MIFT using serovar-specific MAbs provides a rapid method to serotype new isolates, making it a useful system for epidemiological studies.     

Pathogenesis of chicken-passaged Newcastle disease viruses isolated from chickens and wild and exotic birds

The pathogenesis of six Newcastle disease virus (NDV) isolates recovered from chickens (Ckn-LBM and Ckn-Australia) and wild (Anhinga) and exotic (YN parrot, pheasant, and dove) birds was examined after the isolates had been passaged four times in domestic chickens. Groups of 10 4-wk-old specific-pathogen-free white leghorn chickens were inoculated intraconjunctivally with each one of the isolates. The infected birds were observed for clinical disease and were euthanatized and sampled at selected times from 12 hr to 14 days postinoculation or at death. Tissues were examined by histopathology, by immunohistochemistry (IHC) to detect viral nucleoprotein (IHC/NP), and by in situ hybridization to detect viral mRNA and were double labeled for apoptosis (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling ([TUNEL] or IHC/caspase-3) and viral nucleoprorein (IHC/NP). Birds infected with the three low virulence viruses (Ckn-LBM, YN parrot, and Ckn-Australia) did not develop clinical disease. Microscopic lesions were observed only at the inoculation site and in organs of the respiratory system. The detection of viral nucleoprotein (N) was restricted to the inoculation site. The pheasant and dove isolates were highly virulent for chickens with marked tropism for lymphoid tissues, confirmed by the presence of large numbers of cells positive for viral N protein and viral mRNA. Viral N protein was detected early in the cytoplasm of cells in the center of the splenic ellipsoids. The apoptosis assays (TUNEL and IHC/caspase-3) showed increased apoptosis in the splenic ellipsoids as well. Apparently, apoptosis is an important mechanism in lymphoid depletion during NDV infection.     

Cross-immunity in chickens using seven isolates of avian infectious bronchitis virus

Groups of 75 chickens were each infected with one of 7 isolates of infectious bronchitis virus (Mass 41, Holland 52, SE 17, Ark 99, Clark 333, JMK, and Florida). Following recovery, they were challenged along with susceptible controls to the homologous and 6 heterologous isolates. Cross-immunity was determined by virus recovery 4 or 5 days post-challenge. Challenge with the homologous isolate resulted in 90-100% protection. Challenge with heterologous isolates gave variable results and an overall average resistance of 38%. The SE-17-recovered chickens had a 50% protection, whereas the Holland-52-recovered chickens ahd a 13.3% protection.     

Molecular biological characterization of avian poxvirus strains isolated from different avian species

Fifteen strains of Avipoxvirus from different avian species were isolated and molecular biologically characterized. Most strains did not produce evident pocks on the chorioallantoic membranes of commercial and specific-pathogen free embryonated chicken eggs where, on the contrary, microscopic signs of viral growth were always detected. Polymerase chain reaction of highly conserved P4b gene was positive for all cases confirming to be a reliable diagnostic method for Avipoxvirus. Sequencing of these amplicons confirmed most strains clustered either with Fowlpox virus or with Canarypox virus whereas a possible new clade could be hypothesized for one strain from Japanese quail. Classification of Avipoxvirus strains by amplification of the newly identified locus fpv140 revealed major limitations as only five samples were positive. These results underline the importance to undertake similar studies on higher numbers of Avipoxvirus isolates and on wider genomic regions of this large viral group.     

Characterization of an avian cholera epizootic in wild birds in western Nebraska

Avian cholera killed an estimated 2500 birds in western Nebraska and eastern Wyoming from 28 November 1985 to late January 1986. Wild mallards (Anas platyrhynchos) suffered the most losses. Other wild waterfowl, wild turkeys (Meleagris gallopavo), a few domestic fowl, and a bald eagle (Haliaeetus leucocephalus) also died. Pasteurella multocida serotype 1 was the predominant isolate from these carcasses. Cold, wet weather persisted throughout the outbreak, but daily losses in the flock of 50,000 mallards using the area were low. Pasteurella multocida was isolated from nasal swabs of 35 of 37 cattle from a feedlot in which many of these mallards were feeding. Eighty percent of the cattle isolates had antigenic characteristics of serotype 3 or serotype 3 with cross-reactivity. Isolates from wild mallards, wild turkeys, and the bald eagle were virulent to game-farm mallards when inoculated subcutaneously, but P. multocida isolates from cattle were not.     

Genetic relationship of H3 subtype avian influenza viruses isolated from domestic ducks and wild birds in Korea and their pathogenic potential in chickens and ducks

The H3 subtype avian influenza virus (AIV) is one of the most frequently isolated subtypes in domestic ducks, live poultry markets, and wild birds in Korea. In 2002-2009, a total of 45 H3 subtype AIVs were isolated from the feces of clinically normal domestic ducks (n=28) and wild birds (n=17). The most prevalent subtypes in domestic ducks were H3N2 (35.7%), H3N6 (35.7%), H3N8 (25.0%), and H3N1 (3.6%, novel subtype in domestic duck in Korea). In contrast, H3N8 (70.6%) is the most prevalent subtype in wild birds in Korea. In the phylogenetic analysis, HA genes of the Korean H3 AIVs were divided into 3 groups (Korean duck, wild bird 1, and wild bird 2) and all viruses of duck origin except one were clustered in a single group. However, other genes showed extensive diversity and at least 17 genotypes were circulating in domestic ducks in Korea. When the analysis expanded to viruses of wild bird origin, the genetic diversity of Korean H3 AIVs became more complicated. Extensive reassortments may have occurred in H3 subtype influenza viruses in Korea. When we inoculated chickens and ducks with six selected viruses, some of the viruses replicated efficiently without pre-adaptation and shed a significant amount of viruses through oropharyngeal and cloacal routes. This raised concerns that H3 subtype AIV could be a new subtype in chickens in Korea. Continuous surveillance is needed to prepare the advent of a novel subtype AIV in Korea.     

Molecular characterization and phylogenetic analysis of Newcastle disease virus isolates from healthy wild birds

Wild waterfowl is considered a natural reservoir of potentially infectious agents and a source of pathogenic viruses like avian paramyxoviruses type 1 (APMV 1). In 1997, commercial poultry in Argentina had reached the status of being free from virulent Newcastle disease virus (NDV) infections. Vaccination and biosecurity measures are actively performed to maintain this preferential sanitary condition. However, the risk of reintroduction of pathogenic viruses is always present. In this context, we conducted a study to describe the status of wild healthy birds in a geographic region relevant for the poultry industry. The presence of anti-NDV antibodies was determined in different species in all areas sampled suggesting previous contact with NDV. Seven ND viruses were isolated and characterized as apathogenic strains by biological and molecular methods. The phylogenetic analysis revealed that the majority of the Argentinian isolates form a subgroup related to viruses of genotype II. The results presented here highlight the importance of maintaining strict biosecurity measures and vaccination programs in poultry industries in order to preserve the virulent NDV-free status for commercial flocks in the country.