ABSTRACT
An avian influenza virus isolate, A/Mallard/Ohio/184/86 (H5N1), was evaluated for its effects on reproduction in isolation-reared adult mallard ducks (Anas platyrhynchos) and growth rate in juvenile mallards after intravenous inoculation. There was a significant decrease in egg production in the experimental group during the first week after inoculation, but it returned to the normal production level during the second week. No effect was seen on egg weight, shape, or fertility. Ducklings receiving this influenza virus isolate did not differ from controls in their rate of growth.
Subject(s)
Body Weight , Ducks/physiology , Influenza A virus/pathogenicity , Influenza in Birds/physiopathology , Reproduction , Animals , Antibodies, Viral/blood , Ducks/growth & development , Female , Fertility , Influenza A virus/immunology , Male , Oviposition , Random AllocationABSTRACT
Ten avian type A influenza viruses consisting of seven waterfowl-origin, one pheasant-origin, and two turkey-origin viruses were evaluated for their pathogenicity potential after intravenous inoculation into domestic turkeys and mallard ducks (Anas platyrhynchos). The replicative abilities and tissue trophism properties of each virus isolate were examined in both species. The overall virus-isolation rate and histopathological lesion score were greater in the turkeys than in the ducks. The waterfowl-origin viruses caused more tissue damage in turkeys than in ducks but had a narrower tissue distribution range. The pheasant isolate was extremely pathogenic in turkeys but had limited distribution and little effect in ducks. The turkey isolates were more pathogenic in turkeys than in ducks. The pancreas was the most severely affected organ in turkeys, followed by kidney and liver. The spleen and bursa were the most commonly affected organs in ducks.
Subject(s)
Ducks/microbiology , Influenza A virus/pathogenicity , Influenza in Birds/microbiology , Turkeys/microbiology , Animals , Influenza A virus/isolation & purification , Influenza A virus/physiology , Influenza in Birds/pathology , Injections, Intravenous , Kidney/microbiology , Kidney/pathology , Organ Specificity , Pancreas/microbiology , Pancreas/pathology , Species Specificity , Spleen/microbiology , Spleen/pathology , Virus ReplicationABSTRACT
The pathogenicity potential of two H13N2 influenza viruses, one isolated from turkeys and the other isolated from surface water, was evaluated in turkeys, chickens, and mallard ducks (Anas platyrhynchos) after intracranial and oculonasal inoculation. Both isolates replicated in turkey poults, causing depressed weight gain, morbidity and mortality; both also caused histopathological lesions, such as mild to severe pancreatitis, hepatitis, and nephritis in turkeys. These isolates replicated in mallard ducklings but not in chickens. There was depressed weight gain in ducklings given the H13N2 isolate from water. Neither isolate caused morbidity or mortality in ducklings or chicks after inoculation.
Subject(s)
Influenza A virus/isolation & purification , Turkeys/microbiology , Water Microbiology , Animals , Antibodies, Monoclonal , Chickens , Cross Reactions , Ducks , Influenza A virus/immunology , Influenza A virus/pathogenicity , Influenza in Birds/etiology , Influenza in Birds/pathology , Species Specificity , VirulenceABSTRACT
Avian influenza virus (AIV) of waterfowl origin, A/Mallard/Ohio/184/86 (H5N1), was used to evaluate the effect of AIV infection on the functional capabilities of the immune system in mallard ducks. The three main arms of the immune system--humoral, cell-mediated, and cellular--were evaluated. The integrity of the humoral immune system after AIV infection was evaluated by measuring total immunoglobulin and IgG antibody production to sheep erythrocytes and Brucella abortus antigen using hemagglutination and microagglutination assays, respectively. Cell-mediated immunity was evaluated using mitogen/antigen stimulation assays, and by measuring the cutaneous basophilic hypersensitivity response to intradermal phytohemagglutinin-P inoculation. The cellular component of the immune response was evaluated using whole-blood chemiluminescence and bacterial clearance assays. Results showed that infection with this AIV isolate suppressed T-cell function and enhanced macrophage phagocytic activity.
Subject(s)
Bird Diseases/immunology , Ducks , Influenza in Birds/immunology , Animals , Basophils/immunology , Escherichia coli Infections/complications , Escherichia coli Infections/immunology , Escherichia coli Infections/veterinary , Hypersensitivity, Delayed , Immunoglobulin G/metabolism , Immunoglobulins/metabolism , Influenza A Virus, H5N1 Subtype , Influenza A virus/immunology , Influenza A virus/isolation & purification , Influenza A virus/pathogenicity , Influenza in Birds/complications , Influenza in Birds/etiology , Lymphocyte Activation , Macrophages/immunology , Phagocytosis , T-Lymphocytes/immunologyABSTRACT
This is the first report of the isolation of H13N2 avian influenza virus (AIV) subtype from domestic turkeys. This subtype was also isolated from nearby surface water. The observation of large numbers of gulls in close association with turkeys on range before the virus isolations suggests that this virus subtype was transmitted from gulls to range turkeys. Turkey flocks infected by this virus subtype did not show any clinical signs of the disease, although seroconversion did occur. The H13N2 isolates were found to be non-pathogenic in chickens.
