OBJECTIVETo investigate the abundance and seasonal dynamics of mosquitoes, and to detect Japanese encephalitis virus (JEV) in these mosquitoes at the nesting colony of ardeid birds.

METHODSMosquitoes were collected bimonthly from July 2009 to May 2010 by Centers for Disease Control. Light traps and dry ice, as a source of CO2, were employed to attract mosquitoes. Mosquitoes were first identified, pooled into groups of upto 50 mosquitoes by species, and tested for JEV infection by viral isolation and reverse transcriptase polymerase chain reaction.

RESULTSA total of 20 370 mosquitoes comprising 14 species in five genera were collected. The five most abundant mosquito species collected were Culex tritaeniorhynchus (95.46%), Culex vishnui (2.68%), Culex gelidus (0.72%), Anopheles peditaeniatus (0.58%) and Culex quinquefasciatus (0.22%). Mosquito peak densities were observed in July. All of 416 mosquito pools were negative for JEV.

CONCLUSIONSThis study provides new information about mosquito species and status of JEV infection in mosquitoes in Thailand. Further study should be done to continue a close survey for the presence of this virus in the ardeid birds.

Animals ; Bird Diseases ; epidemiology ; virology ; Birds ; Culicidae ; physiology ; virology ; Encephalitis Virus, Japanese ; isolation & purification ; Encephalitis, Japanese ; epidemiology ; veterinary ; virology ; Population Dynamics ; Reverse Transcriptase Polymerase Chain Reaction ; veterinary ; Seasons ; Thailand ; epidemiology ; Virus Cultivation ; veterinary

In order to determine the challenge dose of pigeon paramyxovirus type 1 (PPMV-1) inactivated vaccine (S-1 strain). The virus titer of PPMV-1 E5 allantoic fluid (Chuansha strain) was determined using SPF chicken embryos in this research. After inoculating 30-day-old and 120-day-old pigeons with low-HI antibody against PPMV-1 (HI antibody < or =2) with different doses of PPMV-1 (Chuansha strain), the clinical symptoms and histopathological lesions of the challenged pigeons were examined. The results showed that the minimal lethal dose (MLD) of PPMV-1 (Chuansha strain) was 102.5 ELD50, so we determined that 10(5.5) ELD50, which was 1000 times the MLD, could be taken as the challenge dose in the vaccine efficacy test for PPMV-1 inactivated vaccine (S-1 strain).
Animals ; Antibodies, Viral ; immunology ; Bird Diseases ; immunology ; mortality ; virology ; Chick Embryo ; Columbidae ; immunology ; virology ; Newcastle Disease ; immunology ; mortality ; virology ; Newcastle disease virus ; immunology ; pathogenicity ; Phylogeny ; Viral Vaccines ; immunology ; Virulence

The virus strains were isolated from the liver and spleen of the dead young ducks characterized with symptoms of hemorrhagic-necrotic hepatitis. These isolates could cause the death of muscovy duck-embryo and chick-embryo. 1-day-old birds infected with these isolates had the same character with clinically dead birds and the virus could be isolated from artificially infected birds. These isolates could proliferate in MDEF and result in CPE. The virus could proliferate in the cytoplasm in order of crystals and arranged in the latlic-like. The viron was shown spherical, icosahedron, cubic symmetry, no-envelope, with double-layered capsid, about 70 nm in diameter by electron microscopy. The genome segments of the virus were consisted of L1-3, M1-3 and S1-4, which were similar to that of avian reovirus (ARV). Compared to 68.2%, 69.3% - 70.1%, respectively. The system evolution analysis showed that S3 gene coding sigmaB protein was placed in different branch of MDRV and ARV, indicating that S3 gene of the virus was different from ARV and MDRV. The main clinical symptoms and lesions of ducklings caused by the virus were different from the diseases caused by MDRV and ARV. It was concluded that the virus was a Novel duck reovirus belonging to Orthoreovirus genus of the Reoviridae family.
Animals ; Animals, Wild ; virology ; Bird Diseases ; pathology ; virology ; Chick Embryo ; China ; Ducks ; Molecular Sequence Data ; Orthoreovirus, Avian ; classification ; genetics ; isolation & purification ; Phylogeny ; Reoviridae Infections ; pathology ; veterinary ; virology ; Viral Proteins ; genetics

Climate change induced by recent global warming may have a significant impact on vector-borne and zoonotic diseases. For example, the distribution of Japanese encephalitis virus (JEV) has expanded into new regions. We surveyed the levels of hemagglutination-inhibition (HI) antibodies against JEV (Family Flaviviridae, genus Flavivirus) in wild birds captured in Korea. Blood samples were collected from 1,316 wild birds including the following migratory birds: Oceanodroma castro (n = 4), Anas formosa (n = 7), Anas penelope (n = 20), Fulica atra (n = 30), Anas acuta (n = 89), Anas crecca (n = 154), Anas platyrhynchos (n = 214), Aix galericulata (n = 310), and Anas poecilorhyncha (n = 488). All were captured in 16 locations in several Korea provinces between April 2007 and December 2009. Out of the 1,316 serum samples tested, 1,141 (86.7%) were positive for JEV. Wild birds captured in 2009 had a higher seroprevalence of ant-JEV antibodies than those captured in 2007. Wild birds with an HI antibody titer of 1 : 1,280 or higher accounted for 21.2% (280/1,316) of the animals tested. These findings indicated that wild birds from the region examined in our study have been exposed to JEV and may pose a high risk for introducing a new JEV genotype into Korea.
Animal Migration ; Animals ; Animals, Wild ; Bird Diseases/*epidemiology/virology ; Birds ; Encephalitis Virus, Japanese/genetics/*isolation & purification ; Encephalitis, Japanese/blood/epidemiology/*veterinary/virology ; Genotype ; Hemagglutination Inhibition Tests ; Population Surveillance ; Republic of Korea/epidemiology ; Seroepidemiologic Studies

Three Newcastle disease virus (NDV) strains recovered from ND outbreaks in chickens and duck flocks in north china during 2009 to 2011 were completely sequenced and biologically characterized. All the strains were velogenic and had the velogenic motif 112R-R-Q-K-R-F117 which was consistent with the results of biological tests. Analysis of the variable region (nucleotide 47 to 420) of the F gene indicated that the three isolates belonged to genotype VII d. Cross hemagglutination inhibition test indicated that the antigen homology between three isolates and LaSota were 82.5%-89.4%, the homology between the two isolates from chicken was 90%. A cross-protection experiment in which specific-pathogen-free chickens vaccinated with LaSota were challenged by SDLY01 isolate showed that LaSota vaccine could provide complete protection against SDLY01, however virus discharge could be detected on fifth day. Challenge experiment in which Cherry Valley duck of 30 day old challenged with SD03 strain indicated that cherry valley duck had no disease in experiment period, but virus discharge could be detected from Larynx and cloaca until fifth day. Genome length of three NDV isolates was 15192bp and belonged to genotype VII d. Sequence analysis clarified that the whole genomic sequence of these three isolates shared high homology with NDV virus strains isolated from goose and duck over the same period, which elucidated that NDV isolated from goose, duck or chicken had close genetics and epidemiological relationship.
Amino Acid Sequence ; Animals ; Bird Diseases ; virology ; Chickens ; Columbidae ; Ducks ; Geese ; Genome, Viral ; Molecular Sequence Data ; Newcastle Disease ; virology ; Newcastle disease virus ; chemistry ; classification ; genetics ; isolation & purification ; Phylogeny ; Sequence Alignment ; Viral Proteins ; chemistry ; genetics

In this study, apoptosis was induced by new type gosling viral enteritis virus (NGVEV) in experimentally infected goslings is reported in detail for the first time. After 3-day-old goslings were orally inoculated with a NGVEV-CN strain suspension, the time course of NGVEV effects on apoptotic morphological changes of the internal tissues was evaluated. These changes were observed by histological analysis with light microscopy and ultrastructural analysis with transmission electron microscopy. DNA fragmentation was assessed with a terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay and DNA ladder analysis. A series of characteristic apoptotic morphological changes including chromatin condensation and margination, cytoplasmic shrinkage, plasma membrane blebbing, and formation of apoptotic bodies were noted. Apoptosis was readily observed in the lymphoid and gastrointestinal organs, and sporadically occurred in other organs after 3 days post-infection (PI). The presence and quantity of TUNEL-positive cells increased with infection time until 9 days PI. DNA extracted from the NGVEV-infected gosling cells displayed characteristic 180~200 bp ladders. Apoptotic cells were ubiquitously distributed, especially among lymphocytes, macrophages, monocytes, and epithelial and intestinal cells. Necrosis was subsequently detected during the late NGVEV-infection phase, which was characterized by cell swelling, plasma membrane collapse, and rapidly lysis. Our results suggested that apoptosis may play an important role in the pathogenesis of NGVE disease.
*Adenoviridae/classification/pathogenicity ; Adenoviridae Infections/pathology/*veterinary/virology ; Animals ; *Anseriformes ; *Apoptosis ; Bird Diseases/*virology ; DNA Fragmentation ; Enteritis/*veterinary/virology ; Epithelial Cells/cytology/virology ; In Situ Nick-End Labeling ; Intestines/cytology/virology ; Leukocytes/cytology/virology ; Lymphoid Tissue/cytology/virology ; Macrophages ; Microscopy, Electron, Transmission