Oscar J. Fletcher

Relationship of complement resistance and selected virulence factors in pathogenic avian Escherichia coli.

Complement resistance, antibiotic resistance profiles, and virulence profiles of 80 Escherichia coli isolates from the intestines of normal chickens (40 isolates) and chickens diagnosed as having colisepticemia (40 isolates) were compared. Differences were observed between the two groups for antibiotic resistance, siderophore production, presence of type 1 pili, complement resistance, motility, and size of plasmids. The systemic isolates were more likely to have siderophores and type 1 pili, and to be complement-resistant and motile than were the intestinal isolates. No differences between the two groups were observed for colicin production. Further comparison of the 10 most complement-resistant isolates from the systemic group and 10 most complement-sensitive isolates from the intestinal group revealed a correlation between an isolates resistance to complement and its ability to kill embryos, express type 1 pili, and be motile. Virulence of avian E. coli strains appears to be correlated with complement resistance and the interaction of this resistance with the ability to produce type 1 pili and be motile.

Effect of a direct-fed microbial (Primalac) on structure and ultrastructure of small intestine in turkey poults

The effects of dietary supplementation of the direct-fed microbial (DFM) Primalac in mash or crumbled feed on histological and ultrastructural changes of intestinal mucosa was determined in 2 populations of poults; 1 with and 1 without a Salmonella spp. challenge. Three hundred thirty-six 1-d-old female Large White turkey poults were randomly distributed into 8 treatment groups with 6 replicates of 7 poults in each pen. The poults were placed on 1 of 4 dietary treatments in a 2 x 2 x 2 factorial arrangement (mash or crumble feed, with or without DFM, not-challenged or challenged at 3 d of age). The DFM groups were fed a Primalac-supplemented diet from d 1 until the last day of the experiment (d 21). At 3 d of age, 50% of the poults were challenged with 1 mL of 10(10) cfu/ mL of Salmonella spp. (Salmonella enterica serovar Typhimurium, Salmonella Heidelberg, and Salmonella Kentucky) by oral gavage. The inoculated poults were housed in a separate room from nonchallenged controls. Feed and water were provided ad libitum for all birds. At d 21, 1 poult per pen (total of 6 poults per treatment) was randomly selected and killed humanely by cervical dislocation. After necropsy, the small intestine was removed, and tissue samples from duodenum, jejunum, and ileum were taken for light and electron microscopic evaluation. The DFM birds showed increased goblet cell (GC) numbers, total GC area, GC mean size, mucosal thickness, and a greater number of segmented filamentous bacteria compared with controls. Changes in intestinal morphology as observed in this study support the concept that poultry gut health and function, and ultimately bird performance, can be improved by dietary supplementation with DFM products such as Primalac as used in this study.

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.

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.

Parvovirus-Associated Cerebellar Hypoplasia and Hydrocephalus in Day Old Broiler Chickens

Abstract Cerebellar hypoplasia and hydrocephalus were identified in day old broiler chickens showing nervous signs, impaired mobility, and diarrhea. At postmortem examination, brains of chickens were misshapen and cerebellums were smaller than normal. Microscopically, cerebellar folia were reduced in size and irregularly shaped, and the ventricles were widely distended. Affected cerebellums had focal areas along the base of folia where the internal granular cell layer had been lost, and Purkinje cells were disorganized and located within the molecular layer. Parvovirus DNA was detected by polymerase chain reaction in three of nine brains with oligonucleotide primers designed for amplification of chicken and turkey parvoviruses. On the basis of phylogenetic analyses, the detected virus was most closely related to chicken parvoviruses. These findings suggest that a chicken parvovirus might cause a neurologic disease of young chickens characterized by cerebellar hypoplasia and hydrocephalus; however, its role as the cause of the disease remains to be confirmed.

Mycoplasma iowae associated with chondrodystrophy in commercial turkeys.

Opportunistic observations of and necropsies from selected commercial (meat) turkey flocks revealed skeletal lesions consistent with chondrodystrophy, characterized by leg and vertebral deformities, occurring at very low incidences in turkeys from two primary breeds and various multiplier breeder flocks. Mycoplasma organisms were cultured and identified as Mycoplasma iowae by immunofluorescence and polymerase chain reaction from some of the vertebral lesions but not from leg joints. This is the first detailed description of the gross and microscopic lesions of vertebral chondrodystrophy associated with M. iowae, which should now be considered in the differential diagnosis of turkeys with these lesions.

Myocarditis in 9- and 11-Day-Old Broiler Breeder Chicks Associated with a Reovirus Infection

SUMMARY. Nine- and 11-day-old male broiler breeder chicks from a flock with excessively high mortality were found to have ascites, fibrotic and necrotic livers, and round, thin-walled hearts. Virus isolation on liver homogenates and sequencing of PCR products of the isolate identified a reovirus whose sequence varied from sequences of other published reoviruses. Histopathology supported a diagnosis of reovirus-associated myocarditis and myocardial necrosis. This virus was possibly transmitted vertically from the primary breeder flock. RESUMEN. Reporte de Caso—Miocarditis en pollitos reproductores pesados de 9 y 11 días de edad asociada con una infección por reovirus. Pollitos reproductores pesados de nueve y 11 días de edad, procedentes de una parvada con mortalidad excesivamente alta, mostraron ascitis, hígado fibrótico y necrótico, y corazones redondos, con paredes delgadas. Mediante el aislamiento viral de homogeneizados de hígado y la secuenciación de los productos PCR se identificó un reovirus cuya secuencia varía de las secuencias de otros reovirus publicados. La histopatología confirmó el diagnóstico de miocarditis y necrosis del miocardio asociada con reovirus. Este virus posiblemente se transmitió verticalmente, de la parvada de reproductores.

Disease prevalence in Georgia turkey flocks in 1986.

Disease prevalence in turkeys was estimated by totaling the flock size of necropsy cases submitted to the University of Georgia in 1986 for each disease reported and comparing it with the population at risk. Fowl cholera was the most prevalent disease in both commercial tom flocks (18.0%) and breeder hen flocks (14.7%). Prevalence of colibacillosis was 15.9% in commercial tom flocks, and prevalence of aspergillosis was 8.5% in commercial tom and 4.9% in breeder hen flocks.

Identification of Ascaridia numidae in Guinea Fowl (Numida meleagris) and Association with Elevated Mortality

SUMMARY. An outbreak of ascaridiasis occurred in 10-wk-old guinea fowl (Numida meleagris) on a commercial farm. Birds had exhibited elevated mortality (11.66%) in the previous week, as well as increased water consumption, weakness, anorexia, and stunted growth. Numerous nematodes, occasionally occluding the intestinal lumen, were present in the jejunum and ileum and were identified as Ascaridia numidae based on microscopic morphology. Ribosomal DNA 18S and 28S D3 sequences of the nematode were deposited into GenBank and found to be most similar to Ascaridia galli and Toxocara vitulorum, respectively; sequences for A. numidae had not been previously reported. Treatment with piperazine sulfate significantly reduced the number of adult worms in the intestines, greatly decreased eggs per gram of feces, relieved clinical signs in the flock, and returned the flock mortality back to expected levels. All findings implicate A. numidae as the cause of elevated mortality in this flock.

Comb Candidiasis Affecting Roosters in a Broiler Breeder Flock

Abstract A cutaneous mycosis caused by Candida albicans that involved the combs and less frequently the wattles, facial skin, ear lobes, and neck of male broiler breeders is described. Roosters were 35 wk old and housed with hens in two conventional broiler breeder houses on a farm in western North Carolina. Morbidity was approximately 10% in one house and less than 2% in the other house. Mortality and flock fertility were not affected. Three birds from the most affected house were examined. All birds had white adherent material on their combs that presented as crusty patches or lighter diffuse areas. Often, lesions were roughly circular or had a defined margin. Small black scabs were present in a few lesions. Similar but less extensive lesions were located on the wattles, facial skin, ear lobes, and rictus. In one bird, lesions extended down the neck, and they were accompanied by hyperemia and feather loss. Hyperkeratosis with little to no inflammation and intralesional fungi occurring as yeast and pseudohyphae were seen microscopically. High numbers of C. albicans were isolated and identified from the lesions.