Seroprevalence of infectious bursal disease virus in free-living wild birds in Japan

Serum samples collected from 739 free-living wild birds of 44 species from Gifu, Mie and Hyogo Prefectures in Japan during the period 1989 to 1997 were tested for antibodies to infectious bursal disease virus (IBDV) serotypes 1 and 2 by a virus neutralization test. Serological evidence of infection with serotypes 1 and 2 was found in 15 (2%) of the sera of 6 species and 36 (4.9%) of the sera of 11 species, respectively. Antibodies to IBDV were detected from both sedentary and migratory species. These findings suggest that free-living wild birds have an important role in the natural history of IBDV. These findings raise the possibility that the IBDV prevalent in the breeding grounds of these birds in other countries could be imported by the migratory species. This is the first report of an extensive serological survey of IBDV in wild birds.     

Tuberculosis in captive exotic birds

Avian tuberculosis was studied clinically and pathologically in 137 affected birds from the National Zoological Park during a 7-year period (1969-1975). Twelve of 22 orders exhibited were affected by the disease, and the highest annual mortality was 4% (in 1975). Antemortem diagnosis of early cases of the disease, based on tuberculin testing, and serologic, hematologic, and radiographic studies, was inconsistent and often not conclusive. Pathologically, the diseases primarily involved digestive organs and spleen. There was a spectrum of lesions consisting of nodules of large foamy histiocytes packed with acid-fast bacilli to giant cell-containing granulomas that were often caseous but not cavitated or calcified. Amyloidosis was seen in approximately 20% of the cases. Mycobacterium avium serotype 1 was isolated from 30 tuberculous birds cultured. There was no sex predilection, and most of the affected birds were adults ranging from 1 to 10 years of age.     

Phylogenetic relationships among highly virulent Newcastle disease virus isolates obtained from exotic birds and poultry from 1989 to 1996

Newcastle disease virus [NDV (avian paramyxovirus type 1 [APMV1])] isolates were recovered from imported exotic birds confiscated following importation into the United States, from waterbirds in the United States, and from poultry. The exotic birds probably originated from Central and South America, Asia, and Africa. The NDV isolates were initially characterized as highly virulent because of a short mean death time in embryonated chicken eggs. The isolates were typed as neurotropic or viscerotropic velogenic by intracloacal inoculation of adult chickens. Intracerebral pathogenicity index values for the virulent NDV isolates ranged from 1.54 to 1.90, compared to a possible maximum value of 2.0. These isolates had a dibasic amino acid motif in the fusion protein cleavage site sequence required for host systemic replication. Sequence differences were detected surrounding the fusion protein cleavage site and the matrix protein nuclear localization signal, indicating evolution of highly virulent NDV. Phylogenetically, these isolates were categorized with other highly virulent NDV strains that caused outbreaks in southern California poultry during 1972 and in cormorants in the north central United States and southern Canada during 1990 and 1992. These isolates are related to NDV that may have the APMV1 strain chicken/Australia/AV/32 or a related virus as a possible progenitor. Recent virulent NDV isolates and those recovered during disease outbreaks since the 1970s are phylogenetically distinct from current vaccine viruses and standard challenge strains.     

Acute pancreatitis in chickens due to non-virulent Newcastle disease virus

A non-virulent Newcastle disease virus (strain APMV-1 96/89 VB) was isolated from a broiler chicken from a backyard flock. Using monoclonal antibodies, the virus was shown to be different from the vaccinal virus strains Hitchner, La Sota and Ulster. The virus was shown to replicate in the pancreas of one-day-old specific pathogen-free chickens infected orally, and the histological lesions observed in the pancreas of chickens inoculated with the fourth chicken passage of the virus five to nine days after infection were consistent with an acute pancreatitis.     

Hematologic and plasma chemistry values in captive psittacine birds

Organotin compounds including methyl- and butyltin species were determined in selected aquatic specimens (fish muscles, fish liver, mussels, algae) as well as in sediment and water from the mud flats of the German North Sea and the River Elbe. The concentration of tributyltin (TBT) ranged between 27-202 ng/g (fresh mass) in fish muscles, 54-223 ng/g (fresh mass) in fish liver, 10-25 ng/g (fresh mass) in common mussels and 42-97 ng/g (fresh mass) in bladderwrack. The concentration of total organotin compounds (mono-, di-, and trimethyltin + mono-, di-, and tributyltin) in water samples along the River Elbe up to the Elbe estuary ranged between 30-96 ng/l. Retrospective investigation of butylin compounds in mussel samples from the North Sea was performed by the analysis of cryogenically stored samples from 1985. A comparison of the results with that in muscles from 1993 shows that the total tin content and the TBT content decreased from 1985-1993 by a factor of 3.5 and 6.5, respectively. In addition estimated bioconcentration factors (BCF) for organotin compounds in samples from different trophic levels are presented.     

Preferential cytotoxic effect of Newcastle disease virus on lymphoma cells

Susceptibility of lymphoma cells (Daudi, HD-Mar) to Newcastle disease virus toxicity was found to be higher than that of lymphoblastoid cells (Milstein) and of resting peripheral blood lymphocyte (PBL). Phytohemagglutinin- and/or pokeweed-mitogen-activated PBL however, exhibited, elevated sensitivity, similar to that of lymphoma cells. The level of cytotoxicity was monitored by cell viability, inhibition of DNA synthesis and release of 51Cr. When Daudi cells were mixed with PBL they were significantly more sensitive to the killing effect of the virus (70% mortality compared to 30% 30 h after infection, P < 0.05). The degree of sensitivity to viral cytotoxicity was unrelated to the efficacy of adsorption, which was similar for all cell lines as shown by immunofluorescent staining and flow cytometry. Also an influenza strain A/PR/8/34 (H1N1) adsorbed but did not affect the viability of any of the cells tested. Our results demonstrate that New-castle disease virus caused preferential damage to lymphoma cells as compared to non-cancerous normal cells.     

Evidence of genetic heterogeneity of some lentogenic Newcastle disease virus strains

Two distinguishable subpopulations were recovered from chickens infected with lentogenic strains of Newcastle disease virus originally ioslated from chickens in Australia and Ireland. In both instances, a subpopulation that rapidly eluted from chicken erythrocytes was recovered predominantly from tracheal swabs, and a slow-eluting subpopulation from cloacal swabs. The two subpopulations differed in thermostability of the hemagglutinatin and mean survival time of infected chicken embryos, as well as in elution pattern. The heterogeneity characteristic of the Aust-V4 strain and NI-Ulster strain could not be demonstrated in B1, NJ-LaSota, and ENG-F, lentogenic strains commonly used in vaccines. The question is discussed of whether standard vaccine strains are also hetrogeneous if a technique for separating stock populations is found, and the significance of possible heterogeneity to the effectivenss of the vaccines.     

Use of electromyography in seven injured wild birds

Seven wild birds with traumatic injuries affecting the peripheral nervous system were evaluated with the aid of electromyography. Initially, electromyography was performed on these birds because of loss of motor control and muscle atrophy that could not be explained by clinical signs alone. It can be difficult to assess postural reactions and reflexes in these birds. Use of electromyography to provide prognostic information for rehabilitation potential had not been reported. Reviews in the literature indicate that electromyography in human beings helps when assessing prognosis in sports-related injuries. Because wild birds require nearly total function for complete rehabilitation, electromyographic findings of functional motor units or evidence of axonal degeneration can assist in determining their potential for release.     

Comparative immune response from vaccinating chickens with lentogenic Newcastle disease virus strains

The immune response of chickens to 11 isolates of LaSota strain Newcastle disease virus (NDV) and to 7 isolates of B1 strain NDV was studied in specific-pathogen-free chickens. Most of the vaccine strains were from commercial vaccine producers. Comparison of immunogenicity were made of these vaccines; five other lentogenic NDV strains, not used commercially, were also evaluated. From the criteria of hemagglutination inhibition (HI) and virus serum (VN) neutralizing titers, differences were observed with certain isolates within the LaSota and B1 vaccine groups. Whereas the majority of vaccine strains fell within a predictable range, some proved considerably less in their ability to engender expected titers. Two-to threefold differences in titers were observed with some of the strains compared. Two cloned LaSota NDV strains did not compare favorably, or with expected higher titers, with uncloned or conventional LaSota strain virus isolates. Similarly, certain B1 and LaSota strains passaged in chickens did not demonstrate a greater immunogenic potential over conventional, commercial vaccines of similar strain designation but not passaged in chickens. Whereas none of the NDV strains demonstrated evidence of neurotropism or lethality, postvaccination respiratory reactions were difficult, if not impossible, to evaluate in laboratory isolation units. The complexity of selecting ND vaccines for field use is discussed briefly.     

Variability of antigenic epitopes of the fusion protein of Newcastle disease virus

Systems theory has been critiqued by a number of feminist writers who felt that it did not adequately address the issues of violence and male domination in families. This essay argues that systems theory describes the world from an "exogenic" perspective--the scientific world of nature, which is intrinsically amoral. In the exogenic world all causality is circular, as nature maintains a system that has survived for billions of years. Bateson found "mind" to be within the system of nature, implying that mind must also be amoral. However, most people view the world from an "endogenic" perspective, a personal construction of reality molded by the environment in which they live, and which inevitably incorporates morality. Humans believe that violence is wrong, not for intellectual reasons, but for moral reasons. Implications for therapy are presented. A postmodern or constructivist position is taken as a way to acknowledge the influence of relationships on problems and definitions of problems, while allowing for a moral or legal consensus to pervade the therapeutic enterprise.     

Antigenic characterization of Indian isolates and vaccine strains of Newcastle disease virus

Activation of cardiac muscle is mediated by the His-Purkinje system, a discrete pathway containing fast-conducting cells (Purkinje fibers) which coordinate the spread of excitation from the atrioventricular node (AV node) to ventricular myocardium [1]. Although pathologies of this specialized conduction system are common in humans, especially among the elderly [2], their molecular bases have not been defined. Gap junctions are present at appositions between Purkinje fibers and could provide a mechanism for propagating impulses between these cells [3]. Studies of the expression of connexins - the family of proteins from which gap junctions are formed - reveal that connexin40 (Cx40) is prominent in the conduction system [4]. In order to study the role of gap junction communication in cardiac conduction, we generated mice that lack Cx40. Using electrocardiographic analysis, we show that Cx40 null mice have cardiac conduction abnormalities characteristic of first-degree atrioventricular block with associated bundle branch block. Thus, gap junctions are essential for the rapid conduction of impulses in the His-Purkinje system.