Biomedical subjects

M A Goodwin

Publications and source records attributed to M A Goodwin.

At least 73 records · Page 4Linked to original sources

PubMedDate not supplied

Studies of infectious laryngotracheitis vaccines: immunity in broilers.

Broiler chickens were vaccinated at 18 days of age against infectious laryngotracheitis (ILT) using chicken-embryo-origin (CEO) and tissue-culture-origin (TCO) vaccines, each vaccine given either by drinking water, spray, or eyedrop. Controls were not vaccinated. The broilers were challenged 3 weeks later with virulent ILT virus (USDA challenge strain). Serum samples taken before challenge were analyzed by a virus neutralization (VN) test to determine titers due to vaccination. Both vaccines, regardless of route of administration, produced low VN titers, geometric mean titer (GMT) being less than 4.0 in all vaccinated groups. When administered by the same route, the CEO vaccine produced higher titers than the TCO vaccine. Titers following drinking-water or eyedrop administration of vaccines were higher than titers following spray vaccination. There was an inverse relationship between pre-challenge VN titers of groups of birds and the percentage of birds in the groups dying from ILT virus challenge. The drinking-water route of vaccination provided the most protection, while the spray provided the least.

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PubMedDate not supplied

Studies of infectious laryngotracheitis vaccines: immunity in layers.

Ten-week-old layer chickens obtained from a commercial source were eye-drop vaccinated with chicken-embryo-origin (CEO) or tissue-culture-origin (TCO) vaccines for infectious laryngotracheitis (ILT). Controls were not vaccinated. Approximately one-third of the layers were challenged with virulent ILT virus at 21, 40, or 60 weeks of age. Serum samples taken from the layers before challenge were used in a virus neutralization (VN) test to determine vaccination titers at those three ages. Both vaccines induced low VN titers (geometric mean titer [GMT] less than 6). At 21 weeks of age, the titers produced by the two vaccines were not significantly different, but at 40 and 60 weeks of age the VN GMT of the CEO-vaccinated group was significantly greater than that of the TCO-vaccinated group. The VN GMTs did not drop over time in either group and actually rose between 21 and 60 weeks of age in the CEO group. Both vaccines protected layers against severe challenge with virulent ILT virus, neither being significantly better than the other under these experimental conditions. Unvaccinated sentinel chickens were maintained in contact with the vaccinated layers during three intervals between 1 day and 6 weeks post-vaccination. Diagnostic tests performed on the sentinels to detect lateral spread of vaccine virus from vaccinated to unvaccinated chickens showed scattered positive results.

Age Factors↗

PubMedDate not supplied

Intestinal cryptosporidiosis in chickens.

In a retrospective examination of histopathology reports from Aug. 1, 1985, through Sept. 31, 1987, 10 cases of small- or large-intestinal cryptosporidiosis (not epithelial cryptosporidiosis of the bursa of Fabricius) were found in chickens. Infection was evenly distributed among young chickens. Incidence of intestinal cryptosporidiosis increased during 1987. Although all infected birds were clinically ill, signs or gross lesions of intestinal disease were not always present. In all cases, mild to marked histologic lesions were associated with Cryptosporidium sp.; however, intestinal tracts were not cultured for other infectious agents. The numbers of Cryptosporidium sp. and character of inflammatory response were not significantly correlated. A difference (P = 0.01) among intestinal segment (small vs. large) infection with Cryptosporidium was seen. Light-microscopic appearance and organ distribution of Cryptosporidium sp. suggest that in addition to C. baileyi, other Cryptosporidium species infect chickens. Until the diagnostic procedure for outbreaks of gastrointestinal disease in poultry routinely includes histopathology, fecal flotation, and virus, bacteria, and chlamydia cultures, and until species of Cryptosporidium are isolated, identified, reported, and investigated experimentally, the importance of intestinal cryptosporidiosis in chickens will remain unknown.

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PubMedDate not supplied

Diarrhea associated with small-intestinal cryptosporidiosis in a budgerigar and in a cockatiel.

Small-intestinal cryptosporidiosis has not been described in budgerigars or cockatiels. Organisms of the genus Cryptosporidium were found during histologic examination of segments of small intestine from a budgerigar with chronic weight loss and from a cockatiel that died acutely. Parasitism was accompanied by non-purulent inflammation (lymphocytes and plasma cells predominated). Bacterial and viral pathogens were not isolated. The death of the budgerigar was attributed to malassimilation interpreted to have been caused by Cryptosporidium. The cause of death in the cockatiel was inhalation pneumonia. Because the index of suspicion for cryptosporidiosis was low, samples for isolation of Cryptosporidium were not collected. In the future, cryptosporidiosis should be included as a differential diagnosis for weight loss and death in pet birds, and isolation and speciation of Cryptosporidium sp. should be attempted and reported.

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PubMedDate not supplied

A geographic locus for respiratory cryptosporidiosis in Georgia broilers.

No geographic loci are known for cryptosporidiosis in birds. After initial examination of cases of respiratory cryptosporidiosis in Georgia chickens, analyzed data showed that the incidence of infection was lower above the fall line than below it. This difference may be due to geoclimatological factors.

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PubMedDate not supplied

Light-microscopic lesions associated with naturally occurring bursal cryptosporidiosis in chickens.

Information concerning histologic significance of naturally occurring bursal Cryptosporidium sp. infection in chickens was obtained by retrospective examination of histopathology reports and clinical data from histology accessions received during 1986. Cryptosporidiosis was diagnosed in 197 bursas. In two-thirds of the accessions, more than 50% of the examined bursas were infected with Cryptosporidium sp. The histologic morphologic lesion diagnosis for Cryptosporidium sp.-infected bursas most often was marked diffuse chronic-active superficial purulent protozoal bursitis with mucosal epithelial hyperplasia. Our study clearly indicates that Cryptosporidium sp. is associated with inflammation and disturbed growth in chicken bursas. Additionally, our data indicate that Cryptosporidium sp. infection is not dependent on bursal damage attributable to other agents, including infectious bursal disease virus.

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PubMedDate not supplied

Quantitation of intestinal D-xylose absorption in normal broilers and in broilers with pale-bird syndrome.

A micromethod was used in order to quantitate intestinal D-xylose absorption in young and extremely small birds. This test was performed in broilers collected from two farms from which birds were extremely uneven in body size and were passing poorly digested or undigested feed. A similar syndrome had been seen on all grow-outs during the 6 months before this investigation. Broilers were also collected and tested from three farms where no clinical signs of disease were seen. D-Xylose absorption peaks and curves for normal broilers closely resembled those observed in normal humans. Mean plasma D-xylose concentrations for virus-infected broilers and for broilers with pale-bird syndrome were consistently lower than concentrations for normal broilers (P = 0.009). Reoviruses, small coronavirus-like particles, small round virus particles, and abundant bacterial flagellar fragments were seen in fecal samples from broilers with pale-bird syndrome. Production performance was lowest on farms showing clinical signs of this syndrome.

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PubMedDate not supplied

Gastrointestinal transit times in normal and reovirus-inoculated turkeys.

Brilliant pigment powder was used to measure minimum gastrointestinal transit times (GTT) in control and cloned-reovirus-inoculated turkey poults. Compared with controls, inoculated poults had longer GTT at 120 hr (P less than 0.05) but not at 24 and 72 hr after receiving a single oral dose of cloned reovirus. Reovirus inoculation was associated with failure to eat following a fasting period. Feces passed by reovirus-inoculated turkeys were more fluid and less well formed than normal.

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PubMedDate not supplied

Studies on orthoreoviruses isolated from young turkeys. III. Pathogenic effects in chicken embryos, chicks, poults, and suckling mice.

The pathogenicity of four clone-purified reoviruses (81-51, 81-68, 81-311, and 82-88) was studied in experimentally infected specific-pathogen-free (SPF) chicken embryos and chicks. SPF and specific-antigen-and-antibody-negative (SAAN) turkey poults, and suckling mice. In SPF embryos, all four viruses caused death or lesions characteristic for avian reoviruses. SPF chicks inoculated orally with isolate 81-68 showed no signs of overt disease but did develop antibodies to reovirus. In some experiments, poults inoculated orally with isolate 81-68 exhibited increased mortality, abnormal feather development, lower body weight gain, and pasted vents. Body tremors, uncoordinated motor movement, and oily hair coats were seen in suckling mice inoculated intracerebrally with isolates 81-51, 81-68, and 82-88. Mice inoculated intracerebrally with isolates 81-68 and 82-88 exhibited retarded growth.

Age Factors↗

PubMedDate not supplied

Leukocyte changes associated with acute inflammation in chickens.

Leukocyte changes in chickens with turpentine-induced inflammation were investigated sequentially at 0, 6, 12, and 24 hours and at 2, 3, 4, 7, and 14 days. During acute inflammation, significant leukocytosis and heterophilia developed by 6 hours and persisted through 7 days. The peak mean heterophil and leukocyte counts occurred at 12 hours and 3 days, respectively. Left shifts were present at 12 and 24 hours as detected by 100-cell leukocyte differential counts. Heterophil mean nuclear scores documented nuclear hyposegmentation (left shift) during early inflammation and nuclear hypersegmentation (right shift) during convalescence. Mean monocyte and lymphocyte counts peaked at 2 and 3 days, respectively. Basophil and eosinophil counts were erratic. Toxic changes of heterophils were most apparent during intense left shifts and consisted of cell swelling, degranulation, cytoplasmic vacuolation, and cytoplasmic basophilia. Cytoplasmic basophilia was the last aspect of toxic change to resolve. Ultrastructurally, toxic heterophils had intracellular edema, dissolution of granules, retention of ribosomes, nuclear membrane blebs, and decreased heterochromatin density. All inflammation-associated alterations in cell counts and morphology returned to baseline values and appearance by 14 days after turpentine administration.

Acute Disease↗

PubMedDate not supplied

Small-intestinal cryptosporidiosis in a chicken.

Severe small-intestinal cryptosporidiosis was diagnosed in a chicken that had diarrhea, was weak, and had failed to thrive. Intestine segments also were parasitized by Eimeria sp. and bacteria. Disseminated foci of malignant lymphocytes were present in several organs. Spontaneously occurring intestinal cryptosporidiosis has not been reported in chickens.

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PubMedDate not supplied

Diarrhea associated with intestinal Cryptosporidiosis in turkeys.

Turkey poults were suffering from diarrhea on a farm in which several previous grow-outs of turkeys had experienced a clinically identical problem. Upon necropsy, significant gross lesions were restricted to the gastrointestinal tract. Segments of small intestine were pale and distended with cloudy mucoid material and a few gas bubbles. The ceca contained fluid and gas. Fresh organ portions were collected and fixed in 10% neutral buffered formalin and submitted for histological processing and examination (light microscopy and scanning and transmission electron microscopy). Small (2-4 micron) basophilic bodies identified as Cryptosporidium sp. were present in enterocytes of the middle and lower small intestine. The villi were moderately atrophic, the crypts were hypertrophic, and the lamina propria was infiltrated by large numbers of lymphocytes, heterophils, and fewer macrophages and plasma cells. Numerous intraepithelial leukocytes and exocytosing inflammatory cells also were present.

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PubMedDate not supplied

Histologic incidence and distribution of Cryptosporidium sp. infection in chickens: 68 cases in 1986.

In 1986, a retrospective examination of histologic data determined that 68 histology accessions at the Georgia Poultry Laboratories had a diagnosis of cryptosporidiosis. These cases represented 6.4% of the 1065 histologic examinations of chickens performed at the facility. Of the protozoan infections, only Eimeria sp. was diagnosed more frequently (105/1065 = 9.9%). Infected chickens came from 11 companies. Most of the cases were significantly (chi 2 = 103, df = 10, P less than 0.001) associated with two of these companies. These chickens ranged in age from 14 to 51 days. The number of cases per age group was significantly correlated (r = 0.85, t = 3.98, df = 6, P less than 0.01) with the number of cases per age group of the population of histology accessions. Additionally, cases of cryptosporidiosis had a significantly (P less than 0.05) uneven temporal distribution in that few cases were diagnosed during the winter.

Age Factors↗

PubMedDate not supplied

Studies on orthoreoviruses isolated from young turkeys. II. Virus distribution in organs and serological response of poults inoculated orally.

Day-old specific-antibody-negative turkey poults were inoculated orally with cloned turkey reovirus isolate 81-68. Virus reisolations from 11 different tissues revealed widespread distribution at 3, 5, and 7 days postinoculation (PI). Virus was isolated from the intestines until 21 days PI. Virus was isolated from tendons until day 7 PI and again at day 28 PI. Reovirus serum-neutralization antibodies appeared as early as 7 days PI. All inoculated birds showed positive VN serum titers (greater than or equal to 1:20) by day 21 PI. No reovirus was isolated from control poults, and they remained antibody-negative during the entire experiment.

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PubMedDate not supplied

Studies on orthoreoviruses isolated from young turkeys. I. Isolation and characterization.

Four virus isolates were recovered from the intestinal tracts of turkey poults with diarrhea, abnormal feathering, stunted growth, and increased mortality. The isolates were clone-purified and characterized according to cytopathic effect (CPE) in chicken embryo kidney cells, size, morphology, physicochemical properties, and replicative cycle. The isolates were identified as members of the family Reoviridae, genus Orthoreovirus.

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PubMedDate not supplied

Quantitation of intestinal D-xylose absorption in normal and reovirus-inoculated turkeys.

A micromethod was modified to quantitate intestinal D-xylose absorption in young and extremely small birds. This test was performed in control and cloned-reovirus-inoculated turkey poults to investigate intestinal absorptive function. Absorption peaks and curves for control poults closely resembled those observed in normal humans. Poult groups absorbed significantly less D-xylose at 24 and 72 hours (P less than 0.0001 and P less than 0.0008, respectively) but not at 120 hours (P = 0.3178) after receiving a single oral dose of cloned reovirus. The modified D-xylose absorption test is suitable for experimental and clinical determination of absorptive function of the small intestine in the fowl.

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PubMedDate not supplied

Comparison of Chemstrip bG visual blood glucose method with Accu-Chek III monitor method for measuring blood glucose in broiler chicks.

The purposes of this study were to 1) measure blood glucose values in a flock of broiler chicks tentatively diagnosed as having spiking mortality syndrome (SMS), and 2) compare the blood glucose values using two methods: the Chemstrip bG visual method and the Chemstrip bG Accu-Chek III monitor method. Results indicated that Chemstrip bG reagent test strips can be used successfully to assay blood glucose values in chicks with SMS and that these strips will detect hypoglycemia when hypoglycemia is present. Readings obtained by the visual method were as reliable as those obtained by the more expensive and time-consuming digital electronic monitor method. Blood glucose values were lowest in the chicks with the most severe clinical signs. Malassimilation is a differential diagnosis for hypoglycemia among neonatal mammals, and blood glucose values are lower in inappetent or starving chicks. Therefore, the hypothesis that gastrointestinal or endocrine disease could be major etiologies of hypoglycemia and spiking mortality should be investigated.

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PubMedDate not supplied

Necrotizing herpesvirus bursitis, thymusitis, and splenitis in chickens.

Spontaneous massive necrotizing herpesvirus bursitis, thymusitis, and splenitis in pale broiler chicks is described. Fibrinopurulent inflammation and necrosis was accompanied by intralesional solitary large dark blue intranuclear inclusion bodies in histiocytes and lymphocytes. Ultrastructurally, swollen nuclei with marginated chromatin contained herpesvirus.

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