An outbreak of duck virus enteritis (duck plague) in a captive flock of mixed waterfowl.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
R D Montgomery
Publications and source records attributed to R D Montgomery.
Renal coccidiosis caused by Eimeria gaviae n. sp. in a common loon (Gavia immer).
Renal coccidiosis was diagnosed in a common loon (Gavia immer). This is the first report of coccidium from the kidney of a member of the Order Gaviiformes. Morphologically, the coccidium was considered to be an Eimeria sp. distinct from Eimeria truncata, and was named Eimeria gaviae n. sp.
Animals↗
Effects of modified-live infectious bronchitis virus vaccines on the head-associated lymphoid tissue (HALT).
Specific-pathogen-free (SPF) leghorn chicks were inoculated with different modified-live infectious bronchitis virus (IBV) vaccines to determine if the vaccines interfered with immune competence of the head region. A total of 16 vaccines were evaluated comprising nine Massachusetts, three Arkansas, two Holland, one Florida, and one combination vaccine (containing both Connecticut and Massachusetts). Chicks were vaccinated when they were 4 weeks, 2 weeks, or 1 day of age. When all chickens were 4 weeks 3 days of age, their glands of Harder (GH) were assayed for the ability to respond to antigenic stimulation. Tissues from chicks given GH-depressing and non-GH-depressing vaccines were also collected and scored for histological changes in the head-associated lymphoid tissue (HALT) sites and the trachea. All 16 vaccines depressed the GH response to antigenic stimulation when given to 4-week-old chicks. Six of these vaccines (two Massachusetts, two Arkansas, and two Holland) also depressed the GH response when given to 2-week-old chicks, and one, an Arkansas vaccine, depressed the GH response when given to 1-day-old chicks. The main histological changes associated with the vaccines were increases in lymphocyte populations in the nasal mucosa, eyelid, and, for some, the lacrimal gland and the GH. In addition, lymphoid follicles were increased in the eyelid, to a lesser degree in the GH, and occasionally in the trachea. No relationship was found between histologic changes and vaccine-induced suppression of the GH response.
Animals↗
Reovirus associated with excessive mortality in young bobwhite quail.
Multiple submissions of bobwhite quail (Colinus virginianus) were received for diagnosis from a commercial-size quail operation. The history and clinical signs included respiratory distress, lethargy, and substantial mortality. Reovirus was recovered from quail in the first submission, and both reovirus and adenovirus were isolated from later submissions. To determine the pathogenicity of the isolated reovirus, the initial isolate was inoculated into young quail from a different source. Those inoculated by the subcutaneous route became lethargic, and more than half died during the 2 weeks of the trial. Reovirus was recovered from a high percentage of those inoculated by this route. To the authors' knowledge, the isolation of reovirus from quail has rarely been reported, and reovirus has never before been suggested as a pathogen in this species.
Animals↗
Attempts to reproduce a runting/stunting-type syndrome using infectious agents isolated from affected Mississippi broilers.
Various organisms, including 12 aerobic and 2 anaerobic bacteria, an infectious bronchitis virus (IBV), a reovirus, and 2 bacteriophages, were isolated from intestinal tracts of commercial broiler chicks undergoing a runting/stunting-type condition. In a series of trials, these agents were given alone and in combination to 1-day-old chicks in an attempt to reproduce the field condition. Because the agents were isolated and evaluated over time, an augmented designs variation of the analysis of variance proved particularly useful in analyzing the data collected and minimizing bird usage. Chicks inoculated with tryptose phosphate broth served as negative controls, and those inoculated with the original intestinal tract material were positive controls. Relative to the negative control chicks, body weights of the positive control chicks and of chicks inoculated with several of the agent combinations were depressed at 7, 14, and 21 days postinoculation. Common to combinations that most consistently caused weight depression were reovirus + IBV + others of the agents isolated. However, because none of the agent combinations reproduced the lethargy or dry feces seen in the positive controls, none was considered to be the ultimate cause of this particular runting/stunting-type condition. Further characterization of the disease syndrome was based on the positive control chicks. These chicks consistently had lowered body weights and transient lethargy and dry fecal pellets. Microscopic lesions consisted of lymphocytic renal and pancreatic interstitial infiltrates, dilated or cystic duodenal and jejunal crypts of Lieberkühn, increased crypt depth, and increased cellularity in the intestinal lamina propria. Electron microscopy revealed regular arrays of 26-nm viral particles, usually in association with membrane debris, in intestinal epithelial cells and crypt lumens and in intestinal and renal mesenchymal cells. These viral particles were theorized to be essential to reproduction of the complete malady seen.
Animals↗
Effects of Newcastle disease vaccines and Newcastle disease/infectious bronchitis combination vaccines on the head-associated lymphoid tissues of the chicken.
Ten Newcastle disease virus (NDV) and 10 NDV and infectious bronchitis virus (IBV) combination vaccines (NDV/IBV) were evaluated for their effect on the head-associated lymphoid tissue (HALT) of 2-wk-old chicks. After vaccination, the chicks were subjected to an in vivo assay that measures the ability of the gland of Harder (GH) to respond to killed Brucella abortus antigen given in the eye by titering B. abortus antibodies in the tears. Following this, several sites in the HALT and trachea were examined histologically and scored for microscopic changes. The results indicated that three of the NDV/IBV combination vaccines (one BI/Mass&Conn and two LaSota/Mass&Conn) interfered with the GH response to killed B. abortus, whereas none of the NDV vaccines did Histologically, several changes were noted in the vaccinated chicks; however, no changes in the GH were observed that could explain microscopically the GH depression. With the IBV-only vaccines reported earlier (16), and the NDV-only and NDV/IBV combination vaccines reported here, a total of 36 vaccines have been evaluated using the same testing protocol. The conclusions of these combined studies suggest that several of the modified live virus vaccines containing IBV, either alone or in combination with NDV, interfere with the ability of the GH/HALT to respond to antigenic stimulation.
Animals↗