Characteristics of fowl cholera outbreaks in turkeys in Georgia in 1986

Information was gathered from 64 cases of fowl cholera (FC) in turkey flocks through diagnostic case records, flock records, and telephone and mail surveys. Forty-five cases came from flocks of commercial turkeys, of which 15 were presented twice, and four came from mature breeder flocks. The prevalence of FC was 18.0% of commercial flocks and 14.7% of breeder flocks at risk. The average age at first diagnosis of FC was 90 days in commercial turkey flocks and 32 weeks 5 days in breeder flocks. Acute mortality was the most common presenting complaint, with a 0.37% average mortality in commercial flocks on the day of first presentation, 0.80% in commercial flocks presented a second time, and 0.43% in breeder flocks. Pasteurella multocida was cultured from 69.8% of the 361 tissue samples submitted from these cases. Novobiocin, penicillin, and chlortetracycline (CTC) had the greatest in vitro activity against isolates. Serotype 3-cross-4 was found in all 18 commercial flocks from which isolates were typed. All breeder flocks and 88.6% of commercial flocks were vaccinated before disease onset. Flocks were treated for an average of 14.3 days, most commonly with high levels of sulfadimethoxine and/or CTC. Body weights of affected birds were comparable to those of birds in unaffected flocks, but mortality and feed efficiency were worse.     

Economic effects of clinical chicken anemia agent infection on profitable broiler production.

An outbreak of anemia dermatitis syndrome caused by chicken anemia agent (CAA) occurred in 15 broiler flocks. An average of 29% of chickens in these flocks were derived from a common breeder flock. The breeder flock had no antibody to CAA at 20 weeks of age but had seroconverted by 31 weeks. Diseased broiler flocks were derived from eggs laid by the breeder flock between 25 and 30 weeks of age. CAA infection in the breeder flock was subclinical, with no apparent effects on mortality or performance. A strategic program of therapeutic and/or prophylactic antibiotic therapy was begun in affected broiler flocks as soon as the disease was diagnosed. Nevertheless, when the cost of therapy was taken into account, affected broiler flocks had a net income 17.3% to 19.6% lower than normal flocks. Average bird weights were 3.3% to 3.5% lower in affected flocks than in unaffected flocks, and affected flocks had a significantly greater proportion of lighter birds. Average mortality in affected flocks was 2.0% to 2.3% higher than in normal flocks, with peak mortality occurring in the third week of life. There was no apparent effect on feed-conversion ratio.     

Probable infectious stunting syndrome in replacement pullets

Infectious stunting is recorded in detail in three egg-type pullet flocks and one egg-type breeder flock. Three different strains of brown egg birds were involved. The clinical effects were less severe than those usually seen in broilers. Excessive mortality during the first three weeks was a feature of all four flocks. Fibrous atrophy of the pancreas was seen in one flock and could still be found in individual birds at 18 weeks old. Bone disorders were seen in two flocks. Severe anaemia was seen in some birds in one flock. Severe emaciation of the pectoral muscles was an unexplained and prominent feature of all the flocks. As the birds grew the visible and clinical evidence of stunting was much reduced and it appeared that compensatory growth took place so that by 18 weeks old the flocks appeared normal and the culling rate at caging was negligible.     

Epidemiological and clinical investigations into big liver and spleen disease of broiler breeder hens

SUMMARY The epidemiological and clinical features of big liver and spleen disease (BLS) in flocks on two broiler breeder farms were investigated by serology and gross pathology. The most common necropsy findings on farm 1 were splenomegaly and hepatomegaly, with kidney enlargement in some birds. In one flock (farm 1), a decline in egg production began at 40 weeks of age and lasted for 9 weeks. Seroconversion to BLS antigen was first detected at 45 weeks (3.1% of birds) and increased to 72% at 50 weeks, which coincided with clinical recovery in the flock. Antigen was detected before antibody at 44 weeks and persisted at low incidence (<15%). Farm egg production statistics and serology indicated that the disease affected all flocks on the farm. In three of eight flocks, seroconversion was detected in birds before peak production. The birds in the remaining sheds did not seroconvert or become sick until after peak production. On the second farm, sampling began within a flock already experiencing BLS. Clinical signs and pathology were similar to those seen in flocks on farm 1. However, the lesions that were seen in the pancreas in 15% of birds have not been reported previously. BLS antibody was detected in 78%, and circulating antigen in 14%, of sick birds.     

Avian leukosis subgroup J in broiler breeders in Switzerland

Since a new envelope subgroup (J) of the avian leukosis-sarcomatosis-complex was isolated for the first time from broiler breeders in the United Kingdom in 1989 and was characterized and associated with myeloid leukosis (syn. myelocytomatosis) the emergence of this subgroup was reported from all over the world. Thus the first known case of subgroup J avian leukosis in Switzerland in four imported broiler breeder flocks will be described. A total of 53 broiler breeder birds from four flocks showing reduced performance and increased mortality were submitted for postmortem examination. Approximately 20 blood samples from each flock were monitored serologically for antibodies against avian leukosis virus subgroup J (ALV-J). On necropsy myeloid leukosis (ML) was diagnosed in all four flocks. Furthermore the blood samples of three flocks showed significant ELISA-titres for ALV-J.     

The occurrence of a reovirus variant in a German broiler flock

Broilers deriving from a parent flock, which had been effected in the 6th. month of hatching egg production, show arthritis beginning with the 12th day of life. The tarso-metatarsal joint has been affected. Birds show stunting. Body weights at slaughter and feed conversion of the affected flocks were reduced. The percentage of condemned birds before slaughter was highly increase and came up to 3-5%. Chickens of other breeder flocks, which were reared with the diseased birds, showed viral arthritis at an age of 18-20th day of life. The boilers derived from parent flocks which had been vaccinated twice during the with a 1133 reo live vaccine and before laying with an oil based vaccine of the antigen type WVU. A reovirus has been isolated (isolate K 171/87), which caused viral arthritis in 1133-immune day old chicks after parenteral and oral application. Infection of these chickens with the pathogenic reovirus of the antigen type 1133 didn't cause a disease. Also by serological examinations it was shown, that the reo-isolate K 171/87 possesses a different antigenicity. The kind of occurrence indicates, that this reovirus infection has been transmitted vertically from one parent flock and it spread laterally to chickens of other parent flocks in broiler farms.     

Phenotypic and genotypic characterization of Salmonella arizonae from an integrated turkey operation

Fifty cases submitted between 2000 and 2002 were selected for retrospective analysis to evaluate possible relationships between Salmonella arizonae isolated from breeder flocks, hatching eggs, and meat bird flocks belonging to a single turkey integrator. In all the meat bird cases selected for this study, arizonosis was the primary diagnosis. In birds under 1 month of age, clinical signs and pathologic changes were observed in older birds. The Salmonella arizonae isolates were analyzed by antibiotic resistance pattern and serotype and genotyped by pulsed-field gel electrophoresis (PFGE). Serotyping and PFGE yielded similar results, but the antibiotic resistance patterns did not correspond to either serotyping or PFGE typing. The presence of common pulsed-field patterns in breeder flocks, eggs, and meat bird flocks suggested that S. arizonae was being transmitted vertically from the breeder flock.     

Neoplasms in the oviducts of turkeys

The reproductive tracts of turkey breeder hens from five flocks were examined grossly and histologically. Hens from one flock had a normal reproductive history, but hens from the four other flocks had poor records in both egg production and hatchability. Nodular growths occurred in the oviducts of birds in all five flocks. The incidence of lesions varied from flock to flock and from bird to bird. In four flocks, lesions were small and consisted of areas of dysplasia with adenomatous change. Histologically, the lesions in some birds in the fifth flock were adenocarcinomas. No metastases were observed.     

Detection of subgroup J avian leukosis virus infection in Australian meat-type chickens

OBJECTIVE: To determine the extent of avian leukosis virus subgroup J (ALV-J) infection in Australian broiler breeder flocks, using virus isolation and molecular biological detection. Any resultant ALV-J viral isolates to be characterised by neutralisation cross testing in order to determine antigenic relationships to overseas isolates of ALV-J. STUDY DESIGN: Samples of blood, feather pulp, albumen and tumours were obtained from broiler breeder flocks which represented four genetic strains of meat chickens being grown in Victoria, South Australia, NSW and Queensland. Dead and ailing birds were necropsied on farm and samples were collected for microscopic and virological examinations. Virus isolation was carried out in C/O and DF-1 CEF cultures and ALV group specific antigen was detected in culture lysates using AC-ELISA. Micro-neutralisation assay was used for antigenic characterisation of selected isolates. Genomic DNA was isolated from cultured cells, tumours and feather pulp. ALV-J envelope sequences were amplified by PCR using specific ALV-J primers while antibodies against ALV-J were detected by ELISA. RESULTS: A total of 62 ALV-J isolates were recovered and confirmed by PCR from 15 (31.3%) of 48 breeder flocks tested. Antibody to ALV-J was detected in 20 (47.6%) of the 42 flocks tested. Characteristic lesions of myeloid leukosis caused by ALV-J were found in affected flocks. The gross pathological lesions were characterised by skeletal myelocytomas located on the inner sternum and ribs, neoplastic enlargement of the liver, and in some cases gross tumour involvement of the spleen, kidney, trachea, skeletal muscles, bone marrow, skin and gonads. Microscopically, the tumours consisted of immature granulated myelocytes, and were present as focal or diffuse infiltrations in the affected organs. Virus micro-neutralisation assays demonstrated antigenic variation among Australian isolates and to overseas strains of ALV-J. CONCLUSION: ALV-J infection was prevalent in Australian broiler breeder flocks during 2001 to 2003. Australian isolates of ALV-J show a degree of antigenic variation when compared to overseas isolates.     

Epizootiological investigation of an outbreak of pullorum disease in an integrated broiler operation.

An integrated broiler company experienced a major outbreak of pullorum disease during 1990. The outbreak resulted in the distribution of Salmonella pullorum-infected birds to more than 150 roaster flocks in five states. Twenty-two parent (multiplier) breeder flocks became infected. An epizootiological investigation uncovered a grandparent male line breeder flock as the index flock supplying males to the affected parent flocks. Transmission apparently occurred vertically through the egg and horizontally by contact in the hatcheries and by placement of chicks on contaminated litter.     

Subclinical infectious bursal disease in commercial broiler flocks in Saskatchewan.

Five commercial broiler flocks, not vaccinated for infectious bursal disease virus, derived from infectious bursal disease virus-vaccinated breeder flocks were surveyed for evidence of bursal damage and infectious bursal disease virus infection. They were compared with two groups of birds raised in isolation. Serum samples from one day old chicks contained maternal anti-infectious bursal disease virus antibodies which declined to undetectable levels by four weeks of age. Serum antibody levels remained undetectable in both control groups and one commercial flock, whereas four of the five commercial flocks had actively produced anti-infectious bursal disease virus antibodies by slaughter age. The weight of bursae from infectious bursal disease virus-positive flocks declined as compared to controls after four weeks of age. The decline in weight correlated with the appearance of histopathological lesions. Infectious bursal disease virus antigen was demonstrated in selected infected bursae and infectious bursal disease bursae and infectious bursal disease virus was isolated from some of these damaged bursae. Clinical infectious bursal disease was not observed in any of the commercial flocks. The importance of subclinical bursal damage and immunosuppression is discussed.     

Serological Incidence of Avian Reovirus Infection in Broiler-breeders and Progeny in Nova Scotia

The plaque neutralization test and the agar gel precipitation test were used to detect neutralizing and precipitating antibody to avian reovirus strain WVU2937 in sera from 14 commercial broiler breeder flocks and eight progeny flocks. Ten breeder flocks (71%) possessed positive agar gel precipitation reactors (598 sera tested) and 12 (86%) possessed plaque neutralization reactors (114 serum pools tested). All broiler flocks possessed agar gel precipitation reactors, but these were not examined for neutralizing antibody. As no avian reovirus vaccine had been used in Canada prior to this survey these reactions were presumably due to natural infection. Clinical evidence suggested that such infection was asymptomatic in most cases.The development and persistence of antibody to reovirus strain WVU2937 was followed in chicks exposed to the virus by oral inoculation or by contact. Neutralizing antibody was demonstrated in all birds by postinoculation day 17 and this persisted for at least six months. Precipitating antibody was also demonstrated in most chicks by postinoculation day 17, but by six months only 12% of the chicks were still agar gel precipitation positive.     

Infection of turkeys with Ornithobacterium rhinotracheale and Mycoplasma synoviae

Within 1 mo, two separate outbreaks of respiratory disease occurred in two flocks on the multiage market turkey farm in Slovenia. More severe dinical signs and higher mortality were observed in male birds. Ornithobacterium rhinotracheale (ORT) was isolated in pure culture from tracheas of the affected birds in both outbreaks. Commercial enzyme-linked immunosorbent assay test showed the presence of antibodies to ORT in sera of birds from both clinically affected flocks and also in two flocks of younger birds without clinical sings. Immunoblotting with ORT culture isolated during the outbreak as an antigen confirmed the presence of antibodies to ORT in sera of turkeys of all four flocks examined. In addition, three different serologic assays also detected antibodies to Mycoplasma synoviae (MS) in three out of four flocks. The concomitant infection with MS did not show an obvious effect on mortality rates nor on the antibody response against ORT. Younger birds appeared to be less susceptible to ORT pathogenicity because in those flocks the infection was subclinical.     

Selected blood chemistry values in mobility-impaired broiler breeder hens with suspected calcium tetany using the i-STAT handheld clinical analyzer

Calcium tetany is a poorly defined disease of broiler breeder hens that results from acute hypocalcemia. It is characterized by impaired mobility, increased mortality, and absence of gross lesions that would explain the impaired mobility. To evaluate if hens with impaired mobility had calcium tetany or other abnormalities, blood values from normal and affected hens were determined using the i-STAT handheld clinical analyzer. Three flocks were evaluated weekly prior to peak production (range 25-30 wk of age) comparing normal hens to hens with clinically apparent calcium tetany. Calcium tetany suspect (CaTS) hens from four additional flocks were also evaluated. Significant hypocalcemia (P < 0.001) was observed in CaTS hens (average = 1.14 mmol/L ionized calcium [iCa]) compared to normal hens (average = 1.53 mmol/L iCa) in only one of three flocks sampled weekly. Clinically affected hens from one of the other four flocks also had hypocalcemia. Blood value abnormalities in mobility-impaired hens without hypocalcemia included hypernatremia. Findings in this study indicate calcium tetany is one cause of impaired mobility in breeder hens, but mobility impairment without hypocalcemia can also occur. Calcium tetany should be confirmed by finding significantly decreased levels of iCa in the blood, as diagnosis based on clinical presentation and necropsy results can be inaccurate. The i-STAT handheld clinical analyzer is an efficient, relatively low-cost method to determine iCa and other blood chemistry values that may be associated with impaired mobility in broiler breeder hens.     

A highly fatal vascular disease of broiler breeder chickens

A broiler breeder operation experienced a sudden outbreak of high mortality in nine different houses of breeders at eight different locations. In the first house to be affected, the losses were mainly in the females, but later flocks had losses up to 6.4%, mainly in the males. Affected chickens ranged in age from 7 to 22.5 weeks. Multifocal areas of necrosis and vasculitis were found in skin, muscle, and internal organs. No involvement of the brain was identified, but many of the birds had uveitis. The outbreak lasted 3 weeks and ended without treatment. Neither infectious agents nor mycotoxins were identified.     

Herpes virus of turkey vaccine: viraemias in field flocks and in experimental chickens

In a field survey of viraemias due to vaccination of chickens with herpes virus of turkey, variation was encountered in titres and percentages of birds viraemic. The incidence of viraemias was much lower in sick than in healthy birds in flocks undergoing mortality from Marek's disease. In a concurrent experiment the same strain of chicken and the same commercial vaccine were used as in the field flocks affected with Marek's disease. A high incidence of viraemia and 84.6 per cent protection against Marek's disease were obtained with single vaccination at one day of age. Revaccination at 21 days of age produced no measurable benefits in the same experiment.     

Association of Enterococcus cecorum with vertebral osteomyelitis and spondylolisthesis in broiler parent chicks

Enterococcus cecorum is the most frequently occurring enterococcal species in the intestine of chickens of over 12 weeks of age, and there are few reports on its isolation from the skeleton of broiler parent chicks. In the present study, observations on vertebral osteomyelitis and spondylolisthesis ('kinky back syndrome') showing high incidence in 8 broiler parent flocks in different parts of Hungary are summarised. Clinical signs were seen only in roosters between 5 and 13 weeks of age. Diseased birds were alert and remained sitting on their hocks with their feet slightly raised off the ground. Incidence of the disease among male birds ranged from 8% to 30% depending on flocks. Enlargement and distortion of the body of the 6th vertebra were seen as the main pathological lesions. The cavity of the spinal canal was constricted by the distorted vertebral bodies. Resorption of bone tissue and sequestrum formation, signs of increased osteoclast activity, proliferation of fibrotic tissues, infiltration with heterophils and formation of sclerotic layers were detected in the vertebral bodies. From all 24 samples collected from the vertebral lesions, Enterococcus cecorum was isolated and identified using metabolic fingerprinting as well as 16S rRNA gene sequencing. Demonstration of E. cecorum from the vertebral lesions in all examined broiler breeder roosters showing the same clinical and pathological findings in different flocks suggested the pathogenic role of this microorganism for the first time in Hungary.     

Rapid serological profiling by enzyme-linked immunosorbent assay. IV. Association of infectious bursal disease serology with broiler flock performance

Breeder and broiler flocks were serologically evaluated using a multiple enzyme-linked immunosorbent assay (M-ELISA). The serologic status of two commercial broiler-breeder flocks and their progeny was monitored, and 840 sera were promptly assessed for antibodies against six infectious agents using the M-ELISA. Breeder flocks were sampled at lay, and broiler chicks were hatched from fertile eggs collected on the scheduled lay date of the breeders. The broiler chicks were placed for growout as eight separate flocks (four from each breeder), and the serologic survey of broilers included sequentially sampling each flock five times between 1 day of age and market. Association of broiler vaccination schedules, mortality, and condemnation data with the temporal serologic data obtained indicated that the earlier appearance of active antibody against infectious bursal disease (IBD) in some unvaccinated flocks was associated with subsequent higher growout mortality and with the poorer overall performance that these flocks experienced. The results of this serologic survey also demonstrated that if a constant, well-timed monitoring program had not been used, major serologic differences between flocks would not have been detected. Serologic profiles of selected broiler flocks by virus-neutralization (VN) tests for infectious bronchitis virus (IBV) and reovirus or by hemagglutination-inhibition (HI) tests for Newcastle disease virus (NDV) compared favorably with the serologic profiles obtained by M-ELISA. Comparison of vaccination histories with serologic results derived from M-ELISA, VN or HI tests indicated that response to vaccination for IBV and NDV at 1 day was either blocked or significantly delayed by moderate levels of maternal antibody and/or were suppressed by an apparent field outbreak of IBD that occurred in all eight broiler flocks.     

Outbreak of cutaneous form of poxvirus on a commercial turkey farm caused by the species fowlpox

The present report documents the occurrence of a poxvirus infection in commercial meat turkeys. The affected farm had six flocks, with a total of 11,680 birds at different ages; birds from two of these flocks were affected. The clinical picture was characterized by severe epithelial lesions and proliferations on the head and neck regions as reported for the cutaneous form of poxvirus infection. Except for these lesions, no adverse clinical signs or gross pathologic lesions were observed. Only a low number of birds was affected (n = 20) and no increase of mortality could be seen. Bacteriologic investigations from the lesions revealed multiresistant Staphylococcus aureus. Eosinophilic inclusions (Bollinger bodies) in histologic examinations in the cytoplasm of keratinocytes were noticeable. Typical pox virions were demonstrated by electron microscopy, and poxvirus was isolated on the chorioallantoic membrane of specific-pathogen-free chicken eggs. Further identification of the poxvirus species was carried out by PCR and sequencing, revealing an infection with the species fowlpox. Layers in vicinity of the turkey farm that also were affected by fowlpox were considered as potential source of infection. Although it is assumed that avian poxviruses are strongly species specific, the present case report reinforces the changing picture of poxvirus infections in turkeys. Furthermore, it supports the assumption of previous data that fowlpox virus has to be seen as recently emerging pathogen in turkeys.     

Fowl adenovirus serotype 4 associated with outbreaks of infectious hydropericardium in Haryana, India

During 1998, hydropericardium syndrome was observed among 3-to-6-wk-old broilers in 45 different flocks of Haryana, India, with mortality ranging between 10% and 30%. Fowl adenovirus (FAV) was isolated from one of the affected flocks by chicken embryo liver cell culture. Serum neutralization test and polymerase chain reaction assay coupled with restriction enzyme analysis confirmed that the isolated virus belonged to FAV serotype 4. The disease was reproduced in 28-day-old broilers by subcutaneous and oral inoculation of isolated FAV4 alone. Typical hydropericardium and basophilic intranuclear inclusions in hepatocytes were observed in experimental birds by day 4 postinoculation.