Biomedical subjects

M A Goodwin

Publications and source records attributed to M A Goodwin.

At least 91 records · Page 5Linked to original sources

PubMedDate not supplied

Active cross-protection induced by a recombinant baculovirus expressing chimeric infectious bursal disease virus structural proteins.

The VP2 structural gene encoded in the large genomic segment A of the variant GLS strain of infectious bursal disease virus (IBDV) was modified to encode a neutralization epitope (B69), found only on classic strains of IBDV. A chimeric cDNA clone of the large segment A, encoding VP3, VP4, and the modified variant IBDV VP2 structural proteins, was expressed in a recombinant baculovirus. The chimeric protein expressed was assessed with a panel of neutralizing monoclonal antibodies (MAbs), and it contained not only all previously MAb-defined GLS variant strain epitopes but also the B69 neutralization epitope found on classic IBDV strains. Complete active protection was afforded to specific-pathogen-free chickens by a subunit chimeric vaccine against virulent challenge with the classic IM and STC strains, as well as against the variant E/Del and GLS IBDV strains. Compared with a previously tested recombinant subunit vaccine, which incorporated unmodified baculovirus-expressed large-segment A GLS proteins, the recombinant chimeric subunit vaccine resulted in markedly improved active cross-protection against classic IBDV challenge.

Animals↗

PubMedDate not supplied

Blood glucose values and definitions for hypoglycemia and hyperglycemia in clinically normal broiler chicks.

Two analytical methods were used to establish expected blood glucose values for normal 2-week-old broiler chicks. The lower values (cut-offs) that define hypoglycemia are 137 mg/dl for the standard method and 60 mg/dl for the Chemstrip bG method. The upper cut-offs that define hyperglycemia were 363 mg/dl for the standard method and 280 mg/dl for the Chemstrip bG method. Results from these two tests are significantly (F = 110.9, df = 1/124, P < 0.00001) linear and highly correlated. Results from the present study will allow diagnosticians to make confident diagnoses of hypoglycemia and hyperglycemia in young broiler chicks.

Animals↗

PubMedDate not supplied

Immunosuppression and intracellular calcium signaling in splenocytes from chicks infected with chicken anemia virus, CL-1 isolate.

Hematocrits, histopathology, concanavalin A-induced lymphocyte proliferation, intracellular calcium signaling, and lymphocyte subpopulations were analyzed over a 6-week period in individual chicks inoculated with the CL-1 isolate of chicken anemia virus. Lymphoid depletion/atrophy was present in the thymus and bone marrow by 11 days post-infection (PI). Anemia was present at 14 days PI. The mean lymphocyte proliferation stimulation index (SI) of the inoculated group was significantly lower than that of the control group at 11 days PI. This response was reversed at 18 days PI, when the SI of the inoculated group was significantly higher than that of the controls; values subsequently returned to baseline. The increase in intracellular calcium levels in CAV-infected chicks and controls paralleled the proliferative response. Percentages of CD3-, CD4-, CD8-, and natural-killer-positive-staining cells decreased significantly at 18 and 25 days PI. The most dramatic decrease occurred in the CD8-positive-staining cell population at 18 and 25 days PI.

Animals↗

PubMedDate not supplied

Intralesional herpesvirus, reovirus-like particles, and bacteria in a flock of broiler chicks with spiking mortality, diarrhea, and enterotyphlitis.

The search for a solitary cause of spiking mortality (so-called spiking mortality syndrome) among broiler chicks has been thwarted by the fact that multiple agents cause similar mortality histograms. In the present case report, we describe intralesional herpesvirus, reovirus-like virus particles, and bacteria in small and large intestines from chicks with a spiking mortality histogram, diarrhea, and enterotyphlitis. We attributed the spiking mortality histogram to starvation coupled with diarrhea.

Animals↗

PubMedDate not supplied

Incidence of respiratory cryptosporidiosis in Georgia broilers: 1987-92.

The temporal incidence of respiratory cryptosporidiosis in Georgia broilers was established for 1987-92. Analyzed data showed that, for some years, the incidence of respiratory cryptosporidiosis was higher in southern Georgia than in northern Georgia. The incidence of respiratory cryptosporidiosis was never higher in northern Georgia than in southern Georgia. Because there was a significant (Z[rho] = 3.02, P = 0.003) relationship between the number of days < or = 0 C and the diagnostic frequency of respiratory cryptosporidiosis in the present study, we concluded that as the number of days below freezing increases, the diagnostic frequency of respiratory cryptosporidiosis in broilers decreases.

Animals↗

PubMedDate not supplied

Clinical and pathological findings in young Georgia broiler chickens with oculofacial respiratory disease ("so-called swollen heads").

Chickens with swollen heads generally are said to have swollen head syndrome. In this retrospective study, 16 accessions of young chickens during 1992 had "swollen heads." Clinical signs and lesions were accompanied by infection with multiple viruses, bacteria, and Cryptosporidium baileyi. The fact that almost half of the cases of chickens with swollen heads occurred in one broiler-producing company and predictably within 14 days post-vaccination suggests that management factors might be instrumental in inducing the incidence of swollen heads.

Animals↗

PubMedDate not supplied

Enteritis (so-called runting stunting syndrome) in Georgia broiler chicks.

So-called runting stunting syndrome (RSS) afflicts chicks worldwide. The present study in Georgia chicks is the first report of unique histologic features of RSS pathology in chicks in the United States. Various combinations of avian nephritis virus, enterovirus-612, and reovirus were always isolated from chick small intestines. Ultrastructurally, only small round viruses were seen in small intestinal lesions. Although finding intralesional virus in small intestinal segments from chicks with signs and gross lesions consistent with RSS constitutes a reasonable criterion for making a diagnosis of this disease, chicks without intralesional viruses and with bacterial or protozoal enteritis may also be small and abnormally feathered. Because just what constitutes RSS remains a diagnostic dilemma, we recommend that the use of the imprecise acronym "RSS" be discontinued.

Animals↗

PubMedDate not supplied

Effect of so-called chicken anemia agent maternal antibody on chick serologic conversion to viruses in the field.

Chicken anemia agent (CAA)-antibody-positive and -negative broiler chicks and specific-pathogen-free chicks were confined in six broiler houses. Data on seroconversion to common avian pathogens and production performance were collected. No significant differences were seen between CAA-antibody-positive and -negative chickens in geometric mean antibody titers against common avian pathogens or in production performance.

Anemia↗

PubMedDate not supplied

Reovirus-associated enteritis in Georgia broiler chicks.

The histopathology of reovirus-infected small intestines from clinically ill commercial broiler chicks afflicted with so-called runting stunting syndrome is described. We do not speculate that a cause-and-effect relationship necessarily exists between intralesional reovirus and illness in chicks in the present study. We propose that, in the future, similar cases be termed reovirus-associated enteritis (RAE). RAE must be differentiated from lesions attributed to infections by enterovirus-like particles.

Animals↗

PubMedDate not supplied

Adenovirus inclusion body ventriculitis in chickens and captive bobwhite quail (Colinus virginianus).

Gizzard erosions and ulcers are associated with dietary deficiencies and toxins. A retrospective study of histopathology reports over an 8-year period (1985-92) found six cases of adenovirus inclusion body ventriculitis in broiler and leghorn chickens and captive bobwhite quail (Colinus viriginianus) in south Georgia. The relationship between intralesional virus and the pathogenesis of ventricular lesions in chicks and quail in the present study is not known.

Adenoviridae Infections↗

PubMedDate not supplied

Multisystemic adenovirus infection in broiler chicks with hypoglycemia and spiking mortality.

The search for a solitary cause of spiking mortality (so-called spiking mortality syndrome [SMS]) among broiler chicks has been thwarted by the fact that many agents will cause similar mortality histograms. Recently, severe hypoglycemia has been said to be a characteristic finding in chicks that die with SMS. In the present case study, we report adenovirus inclusions in the pancreas, small intestines, and liver of chicks with hypoglycemia and spiking mortality. We attributed the hypoglycemia and mortality to hepatic insufficiency.

Adenoviridae Infections↗

PubMedDate not supplied

Esophageal and proventricular cryptosporidiosis in a chicken.

Examination of hematoxylin-and-eosin-stained sections of chicken esophagus and proventriculus revealed Cryptosporidium-colonized surface squamous and mucous gland columnar epithelial cells. This chicken also had malignant lymphoma (lymphosarcoma). The hypothesis that infection by Cryptosporidium sp. was either preceded by or followed by herpesvirus infection, immunosuppression, and neoplasia cannot be refuted. Clinicians and pathologists should be aware that esophageal and proventricular cryptosporidiosis can occur in chickens; they should also be aware that mild inflammation and necrosis can accompany parasitism.

Animals↗

PubMedDate not supplied

Multicentric histiocytosis in young chickens. Gross and light microscopic pathology.

During 1991-94, tissue specimens from 262 young chicken carcasses condemned at slaughter contained novel multicentric proliferations of histiocytelike cells. These tissues had been submitted to the USDA FSIS Eastern Laboratory because of grossly enlarged spleens, livers, or kidneys. The spleens were two to three times normal diameter and contained miliary white or yellow 1-3-mm foci. Similar miliary foci were present throughout the enlarged livers and kidneys. Microscopic examination of these tissues revealed discrete circular nodules expanding splenic periarteriolar lymphoid sheaths, hepatic periportal nodules, and discrete perivascular and more diffuse interstitial nodules replacing renal tubules. Nodules also were present in the pancreas, bone marrow, proventriculus, and lung, with more diffuse infiltrates in intestinal lamina propria. The cells composing these nodules contained irregularly oval, folded, or pleomorphic nuclei and relatively abundant eosinophilic cytoplasm. Mitotic figures and pyknotic nuclei were common. These cells were interpreted to be histiocytes (tissue macrophages or dendritic cells) and did not resemble lymphocytes. These proliferating cells also did not resemble the cell population of commonly diagnosed lymphoid neoplasms of young chickens. No intralesional organisms were detected and polymerase chain reaction analysis failed to detect Marek's herpesvirus DNA or leukosis/sarcoma and reticuloendotheliosis proviral DNA.

Animals↗

PubMedDate not supplied

Respiratory coccidiosis (Cryptosporidium baileyi) among northern Georgia broilers in one company.

Cryptosporidium baileyi causes respiratory disease in chickens. The purposes of this prospective study were to determine the incidence of C. baileyi tracheitis among broilers in a commercial setting, and the relationship between C. baileyi tracheitis and production performance parameters. All samples came from 56 farms that grow broilers for one company in northern Georgia. Tracheas were collected and examined with a light microscope and cultured for viruses and bacteria. Overall, 23 of 56 (41%) broiler flocks had C. baileyi tracheitis. Parasitism rates among C. baileyi-infected flocks ranged from a low of 10% to a high of 60%. Cryptosporidium baileyi tracheitis was very highly correlated (rho = 0.81, n = 56, P < 0.00001) to severity of tracheitis, negatively correlated (rho = -0.27, n = 56, P < 0.04) with average body weight, and correlated with airsacculitis (rho = 0.30, n = 56, P < 0.03) and condemnations (rho = 0.27, n = 56, P < 0.05). The present study indicates that C. baileyi infection rates are high, and the role that this parasite plays in the pathogenesis of respiratory disease and production losses could be unexpectedly large.

Animal Husbandry↗

PubMedDate not supplied

DNA in situ hybridization for the rapid diagnosis of massive necrotizing avian adenovirus hepatitis and pancreatitis in chicks.

The present study describes the use of DNA in situ hybridization for the rapid diagnosis of massive necrotizing adenovirus hepatitis and pancreatitis in broiler chicks. A light microscope and DNA probes were used to identify avian adenovirus in replicate sections of formalin-fixed paraffin-embedded liver and pancreas from field and experimental chicks. Avian adenovirus infection was confirmed by transmission electron microscopy and virus isolation.

Adenoviridae Infections↗

PubMedDate not supplied

Neonatal multifocal encephalomalacia and other lesions in the brains of Georgia chicks: 1991-95.

Outbreaks of neonatal multifocal encephalomalacia with sepsis have been reported among flocks of very young chicks in Belgium, Scotland, and the United States. The purposes of the present study were to describe intralesional bacterial cocci in chicks with this type of encephalomalacia and to determine its incidence during 1991-95, and to determine the importance of this lesion with respect to the frequency of all other brain lesions/ diseases during the same time period. All laboratory records of broiler chickens examined at the Georgia Poultry Laboratory from Jan. 1, 1991, through Dec. 31, 1995, where the histopathologic diagnoses included the letter string *encephal* were retrieved for further study. The leading etiology for brain disease was nutritional encephalomalacia (57%), followed by neonatal encephalomalacia (22%), septic meningoencephalitis (16%), and Marek's disease (14%), in turn followed by nonpurulent encephalitis (7%), avian encephalomyelitis (3%), and mycotic meningoencephalitis (3%). Diagnosis of neonatal multifocal encephalomalacia with sepsis in the brains of Georgia chicks is a perennial one. Microscopically, the condition is characterized by mild to maximal multifocal locally extensive fibrin thrombosis of blood capillaries, and necrosis (encephalomalacia, malacia) of surrounding zones of brain stem and/or cerebral hemisphere neuropile. In 44% of cases of neonatal encephalomalacia fibrin thrombosis of blood capillaries was accompanied by intralesional gram-positive coccoid bacteria that were most abundant in medium- and small-sized arterioles or venules. Only gram-positive coccoid bacteria are found in cases of neonatal encephalomalacia (P < 0.05), and only gram-negative rod-shaped bacteria are found in cases of septic meningoencephalitis (P < 0.05). Therefore, bacterial culture and routine light microscopic histopathology are sufficient for diagnosing the condition when the differential diagnosis for neurologic disease in chicks includes neonatal encephalomalacia.

Animals↗

PubMedDate not supplied

Lack of correlation between microscopic lesion scores and gross lesion scores in commercially grown broilers examined for small intestinal Eimeria spp. coccidiosis.

Comparisons were made between microscopic lesion scores (MLSs) and gross lesion scores (GLSs) in sections from small intestine of broilers during three routine coccidiosis screenings. The duodenal and jejunal GLS were determined and recorded by different evaluators. During each screening, 2-cm sections of duodenum and jejunum were collected, and sections of intestine were then scored using a microscopic lesion scoring system. No correlation between MLS and GLS was observed in duodenum in two out of three coccidiosis screenings, and no correlation was observed between MLS and GLS in jejunum in three out of three screenings. Our findings demonstrate that, if used alone in coccidiosis screening, GLSs can underestimate infections and may not provide a true representation of the magnitude of Eimeria maxima infection within broiler flocks.

Animals↗

PubMedDate not supplied

Diagnosis of avian adenovirus infections using DNA in situ hybridization.

Three DNA oligonucleotide probes designated FN-23, FN-48, and FN-96 were evaluated for the diagnosis of aviadenovirus infections by DNA in situ hybridization. Paraffin-embedded tissues were obtained from birds with confirmed adenovirus infection, birds with putative adenovirus infections, and birds with intranuclear inclusions caused by herpesvirus and polyomavirus. In birds with confirmed adenovirus infection, probes FN-23 and FN-96 identified 78% and 72% of diseased individuals, respectively. Only probe FN-48 detected chickens with group II adenovirus infection. In birds with putative adenovirus infection, the DNA probes confirmed aviadenovirus infections in 76% of the population. Probes FN-23, FN-96, and FN-48 detected 85%, 74%, and 18% of adenovirus-infected birds, respectively. None of the DNA probes cross-hybridized with tissues from polyomavirus-infected psittaciform birds or with tissues from a chicken with infectious laryngotracheitis. In contrast, probe FN-23 did cross-hybridize to herpesvirus-infected tissues from two of eight psittaciform birds with Pacheco's parrot disease. Probes FN-48 and FN-96 did not react with these tissues.

Adenoviridae Infections↗