ABSTRACT
Since the emergence of highly pathogenic avian influenza (HPAI) H5N1 in Asia, the haemagglutinin (HA) gene of this virus lineage has continued to evolve in avian populations, and H5N1 lineage viruses now circulate concurrently worldwide. Dogs may act as an intermediate host, increasing the potential for zoonotic transmission of influenza viruses. Virus transmission and pathologic changes in HPAI clade 1.1.2 (H5N1)-, 2.3.2.1c (H5N1)- and 2.3.4.4 (H5N6)-infected dogs were investigated. Mild respiratory signs and antibody response were shown in dogs intranasally infected with the viruses. Lung histopathology showed lesions that were associated with moderate interstitial pneumonia in the infected dogs. In this study, HPAI H5N6 virus replication in dogs was demonstrated for the first time. Dogs have been suspected as a "mixing vessel" for reassortments between avian and human influenza viruses to occur. The replication of these three subtypes of the H5 lineage of HPAI viruses in dogs suggests that dogs could serve as intermediate hosts for avian-human influenza virus reassortment if they are also co-infected with human influenza viruses.
Subject(s)
Dog Diseases/virology , Influenza A virus/physiology , Orthomyxoviridae Infections/veterinary , Virus Replication , Animals , Dog Diseases/pathology , Dogs , Influenza A Virus, H5N1 Subtype/classification , Influenza A Virus, H5N1 Subtype/physiology , Influenza A virus/classification , Orthomyxoviridae Infections/pathology , Orthomyxoviridae Infections/virologyABSTRACT
A competitive enzyme-linked immunosorbent assay (C-ELISA) using a baculovirus-expressed recombinant nucleocapsid protein antigen (rNDV-N) and an rNDV-N-specific monoclonal antibody (5B3) was developed for the detection of Newcastle disease virus (NDV) antibodies, and its diagnostic performance was evaluated. The specificity and sensitivity of the C-ELISA was found to be 98.4 and 98.9%, respectively, for chickens, and 98.2 and 97.9% for ducks. However, the C-ELISA showed weak cross-reaction with hyperimmune antisera to some other avian paramyxovirus serotypes. In all experimentally vaccinated chickens, seroconversion rates at 7 d postinoculation were 100 and 40% when measured by C-ELISA and hemagglutination inhibition (HI), respectively. In field trials, the C-ELISA showed positive results in 98.9% of HI-positive sera and 40.8% of HI-negative sera from NDV-vaccinated chickens (n = 705). In domestic ducks (n = 158) from NDV-positive duck farms (n = 8), the positive rates according to C-ELISA were significantly higher than those according to the HI test. At the same time, 98.1% of ducks (n = 209) from NDV-negative duck farms (n = 11) were also negative by C-ELISA. Our results indicate that C-ELISA could be a useful alternative to HI testing for detecting NDV antibodies in different avian species such as chickens and ducks.
Subject(s)
Antibodies, Viral/blood , Enzyme-Linked Immunosorbent Assay/veterinary , Newcastle Disease/blood , Newcastle disease virus/immunology , Animals , Chickens , Ducks , Enzyme-Linked Immunosorbent Assay/methods , Gene Expression Regulation, Viral/physiology , Newcastle Disease/diagnosis , Nucleocapsid Proteins/genetics , Nucleocapsid Proteins/metabolism , Sensitivity and SpecificityABSTRACT
A serosurvey of feline herpesvirus type 1 (FHV-1), feline calicivirus (FCV), and feline parvovirus (FPV) in cats from Ho Chi Minh City area in southern Vietnam was conducted in December 1998, and we compared the results with our previous results in northern Vietnam (Hanoi area). The positive rate of FHV and FCV in domestic cats were 44% and 74%, respectively. They were rather higher than those in Hanoi area, while the seropositivity of FPV (44%) was similar to that in Hanoi area. In leopard cats, the positive rate of FPV was high (3/4) and it indicated that FPV was prevailing in leopard cats in Vietnam.
