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.     

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...     

Experimental avian paramyxovirus serotype-3 infection in chickens and turkeys

Avian paramyxoviruses (APMV) are divided into nine serotypes. Newcastle disease virus (APMV-1) is the most extensively characterized, while relatively little information is available for the other APMV serotypes. In the present study, we examined the pathogenicity of two divergent strains of APMV-3, Netherlands and Wisconsin, in (i) 9-day-old embryonated chicken eggs, (ii) 1-day-old specific pathogen free (SPF) chicks and turkeys, and (iii) 2-week-old SPF chickens and turkeys. The mean death time in 9-day-old embryonated chicken eggs was 112 h for APMV-3 strain Netherlands and > 168 h for strain Wisconsin. The intracerebral pathogenicity index in 1-day-old chicks for strain Netherlands was 0.39 and for strain Wisconsin was zero. Thus, both strains are lentogenic. Both the strains replicated well in brain tissue when inoculated intracerebrally in 1-day-old SPF chicks, but without causing death. Mild respiratory disease signs were observed in 1-day-old chickens and turkeys when inoculated through oculonasal route with either strain. There were no overt signs of illness in 2-weeks-old chickens and turkeys by either strain, although all the birds seroconverted after infection. The viruses were isolated predominantly from brain, lungs, spleens, trachea, pancreas and kidney. Immunohistochemistry studies also showed the presence of large amount of viral antigens in both epithelial and sub-epithelial lining of respiratory and alimentary tracts. Our result suggests systemic spread of APMV-3 even though the viral fusion glycoprotein does not contain the canonical furin proteases cleavage site. Furthermore, there was little or no disease despite systemic viral spread and abundant viral replication in all the tissues tested.     

Mixed paramyxovirus infection of wild and domestic birds in Israel

Five cases of dual isolations of different serotypes of avian paramyxoviruses (APMV) from domestic and wild birds are described: one case of mixed infection by APMV-1 and APMV-4 and four cases of infection by APMV-1 and APMV-2 serotypes. The double infection was proven by consecutive isolations of two viruses from allantoic fluid samples derived from single swabs after their respective treatment by antisera against each suspected virus. The finding of double APMV infection in poultry farms appears to be important for epizootiology and pathogenesis of APMV-caused diseases.     

Evaluation of pathogenicity of avian poxvirus isolates from endangered Hawaiian wild birds in chickens

Pathogenicity of two avian poxviruses isolated from endangered Hawaiian wild birds, the Hawaiian Goose and the Palila, was compared with fowl poxvirus in chickens. Immune responses were measured by ELISA pre- and postimmunization with Hawaiian poxviruses and after challenge with fowl poxvirus. Both isolates from Hawaiian birds developed only a localized lesion of short duration at the site of inoculation in specific-pathogen-free chickens and did not provide protection against subsequent challenge with virulent fowl poxvirus. On the other hand, birds inoculated with virulent fowl poxvirus developed severe lesions. In contrast to high antibody response in chickens immunized with fowl poxvirus, birds immunized with either of the two Hawaiian isolates developed low to moderate antibody responses against viral antigens. The level of immune responses, however, increased in birds of all groups following subsequent challenge.     

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.     

Serological survey on prevalence of antibodies to avian paramyxovirus serotype 2 in China

We report the prevalent status of avian paramyxovirus serotype 2 (APMV-2) in China. Between 2003 and 2005, 9156 sera in total were collected and screened for APMV-2 antibodies by using the hemagglutination inhibition assay. The averaged seropositivity ofAPMV-2 for chickens, ducks, peacocks, ostriches, and partridges was 42.9%, 25.1%, 45.8%, 47.6%, and 80.0%, respectively. The results of this survey indicate that the distribution of APMV-2 is very widespread in China and that more attention should be paid to the influence of APMV-2 on poultry production.     

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.     

Surveillance for highly pathogenic avian influenza in wild birds in the USA

As part of the USA's National Strategy for Pandemic Influenza, an Interagency Strategic Plan for the Early Detection of Highly Pathogenic H5N1 Avian Influenza in Wild Migratory Birds was developed and implemented. From 1 April 2006 through 31 March 2009, 261 946 samples from wild birds and 101 457 wild bird fecal samples were collected in the USA; no highly pathogenic avian influenza was detected. The United States Department of Agriculture, and state and tribal cooperators accounted for 213 115 (81%) of the wild bird samples collected; 31, 27, 21 and 21% of the samples were collected from the Atlantic, Pacific, Central and Mississippi flyways, respectively. More than 250 species of wild birds in all 50 states were sampled. The majority of wild birds (86%) were dabbling ducks, geese, swans and shorebirds. The apparent prevalence of low pathogenic avian influenza viruses during biological years 2007 and 2008 was 9.7 and 11.0%, respectively. The apparent prevalence of H5 and H7 subtypes across all species sampled were 0.5 and 0.06%, respectively. The pooled fecal samples (n= 101 539) positive for low pathogenic avian influenza were 4.0, 6.7 and 4.7% for biological years 2006, 2007 and 2008, respectively. The highly pathogenic early detection system for wild birds developed and implemented in the USA represents the largest coordinated wildlife disease surveillance system ever conducted. This effort provided evidence that wild birds in the USA were free of highly pathogenic avian influenza virus (given the expected minimum prevalence of 0.001%) at the 99.9% confidence level during the surveillance period.     

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 survey for paramyxoviruses in caged birds, wild birds, and poultry in New Zealand

AIMS: To determine the presence of avian paramyxovirus (APMV) types 1, 2, and 3 in caged and wild birds, and APMV-2 and -3 in poultry in New Zealand. METHODS: Blood samples collected from caged (231) and wild birds (522) from various regions of New Zealand in 1997-99 were tested by haemagglutination inhibition (HI) test for antibodies to APMV types 1, 2, and 3. Blood samples collected from 1778 commercial poultry in 1996-99 were tested for APMV-2 and APMV-3 antibodies and the samples that reacted with APMV-3 antigen were tested for antibodies to APMV-1. Isolation of APMV was attempted from cloacal swabs collected from 116 of the caged birds and 175 of the wild birds sampled. RESULTS: Antibodies to APMV types 1, 2, and 3 were detected in 4.8, 1.7, and 2.6%, respectively, of caged bird samples. The majority of these caged birds were 'exotic' or 'fancy' poultry breeds. Amongst wild birds, 4.2% had titres to APMV-2 and over half of these were passerine birds; 1.7% of the samples had titres to APMV-1 and 0.8% to APMV-3 antigen. No virus was isolated from any of the cloacal swabs tested. Of the 1778 poultry serum samples tested, only 5 reacted with APMV-3 antigen and these were later found to be cross-reactions to APMV-1. No reactions were detected with APMV-2 antigen. CONCLUSIONS: APMV-1 is present in caged birds, wild birds, and poultry of New Zealand. There is no conclusive evidence of the presence of APMV-2 and APMV-3 in poultry or APMV-3 in wild birds. The results do not provide conclusive evidence for the presence of APMV-2 in wild birds in New Zealand.     

Pathogenesis of two strains of avian paramyxovirus serotype 2, Yucaipa and Bangor, in chickens and turkeys

Nine serologic types of avian paramyxovirus (APMV) have been recognized. Newcastle disease virus (APMV-1) is the most extensively characterized virus, while relatively little information is available for the other APMV serotypes. In the present study, we examined the pathogenicity of two strains of APMV-2, Yucaipa and Bangor, in 9-day-old embryonated chicken eggs, 1-day-old specific-pathogen-free (SPF) chicks, and 4-wk-old SPF chickens and turkeys. The mean death time in 9-day-old embryonated chicken eggs was more than 168 hr for both strains, and their intracerebral pathogenicity index (ICPI) was zero, indicating that these viruses are nonpathogenic in chickens. When inoculated intracerebrally in 1-day-old chicks, neither strain caused disease or replicated detectably in the brain. This suggests that the zero ICPI value of APMV-2 reflects the inability of the virus to grow in neural cells. Groups of twelve 4-wk-old SPF chickens and turkeys were inoculated oculonasally with either strain, and three birds per group were euthanatized on days 2, 4, 6, and 14 postinoculation for analysis. There were no overt clinical signs of illnesses, although all birds seroconverted by day 6. The viruses were isolated predominantly from the respiratory and alimentary tracts. Immunohistochemistry studies also showed the presence of a large amount of viral antigens in epithelial linings of respiratory and alimentary tracts. There also was evidence of systemic spread even though the cleavage site of the viral fusion glycoprotein does not contain the canonical furin protease cleavage site.     

Prevalence of avian haematozoa in wild birds in a high-altitude forest in Japan

The infection dynamics of avian haematozoa, which includes the genera Plasmodium, Haemoproteus, and Leucocytozoon, are complicated by a variety of environmental factors and host-parasite interactions. In Japan, the prevalence of haematozoa in wild birds has recently been determined in several local areas. However, no information on the annual prevalence of avian haematozoa in a single study site has been reported. Here, we investigated the long-term infection dynamics of haematozoa in wild birds inhabiting a mountain forest of Japan. Blood samples were collected from 415 wild birds captured in the Chichibu mountains in Saitama Prefecture at an altitude of 1650 m between 2007 and 2010. All obtained samples were examined for haematozoan infection using nested polymerase chain reaction (PCR) of the cytochrome b (cytb) genes of haematozoa. A total of 62 out of 415 (14.9%) forest birds were PCR positive for haematozoa. Relatively high infection rates of Leucocytozoon were found among several bird species (Parus ater, 64.3%; Parus montanus, 81.8%) and may be due to the host preference of vector black flies and host nestling pattern in this forest. Phylogenetic analysis of amplified cytb sequences revealed for the first time that a variety of lineages of avian haematozoa are distributed among wild bird hosts in a high-altitude forest stand in Japan. Notably, significant seasonal changes of the prevalence of avian haematozoa were not observed; however, continuous investigation will likely provide detailed information on host-parasite interactions, including local environmental factors, that influence the dynamics of avian haematozoan infections.     

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.     

A serological survey of selected pathogens in wild boar in Slovenia

Serum samples collected from 178 shot wild boars (Sus scrofa) were tested for the presence of antibodies against classical swine fever virus, Aujeszky's disease virus (ADV), porcine reproductive and respiratory syndrome virus, porcine respiratory coronavirus (PRCV), transmissible gastroenteritis virus, swine influenza virus, porcine parvovirus (PPV), swine vesicular disease virus, Actinobacillus pleuropneumoniae (APP), Mycoplasma hyopneumoniae, Salmonella spp., Brucella spp. and Haemophilus parasuis (HPS) throughout Slovenia during the hunting season 2003/2004. The number of samples corresponds to 3% of the total hunting bag. By enzyme-linked immunosorbent assay (ELISA) antibodies against ADV were detected in 55 sera (31%), against PRCV in five sera (3%), PPV in 87 sera (49%), APP in 93 sera (52%), M. hyopneumoniae in 38 sera (21%), Salmonella spp. in 85 sera (47%) and HPS in 33 sera (18%).     

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.     

The survey of wild birds for West Nile virus in Poland

Two thousand one hundred and forty birds belonging to 39 different species from different locations in Poland were examined. The study has taken place from the early spring till late autumn 2007-2010 when the activity of the mosquitoes was the highest. The brain samples were taken from the birds and whole cellular RNA was isolated, then the RT-PCR and NRT-PCR were performed to detect the presence of West Nile virus (WNV). The obtained results were confirmed by the commercial WNV Kit. No genetic material of WNV was found in the examined samples.