Experimental transmission of Chlamydia psittaci to turkeys from wild birds

Wild birds were inoculated with Chlamydia psittaci to determine species that could be potential hosts and vectors in transmitting the agent to domestic turkeys. Infection occurred in turkeys exposed to starlings (Sturnus vulgaris), common grackles (Quiscalus quiscula), brown-headed cowbirds (Molothrus ater), and Inca doves (Cardafella inca). Mourning doves (Zenaidura macroura) shed the agent sparingly, but turkeys exposed to them did not become infected, These findings and knowledge of the habits of these various species are discussed. It was concluded that the Inca dove should be considered a potential source of turkey chlamydiosis in Texas. The species studied and other species not studied should be included in serologic surveys and surveillance studies attempting isolation of chlamydiae.     

Minimization of pathologic changes in Ornithobacterium rhinotracheale infection in turkeys by temperature-sensitive mutant strain

The protection elicited by a temperature-sensitive (Ts) mutant of Ornithobacterium rhinotracheale (ORT) vaccine against challenge with pathogenic strain was investigated. In Experiment 1, specific serologic response to ORT was detected in 12%-19% of Ts-vaccinated birds at 3 wk postvaccination by either drinking water or oculo-nasal instillation. At 7 days postchallenge, 100% of Ts-vaccinated turkeys of all groups were able to respond with an ORT-specific antibody response, but the control group was not, suggesting the potential of Ts strain to evoke immune protection. The study also revealed a statistically significant ability of the Ts strain to protect vaccinated turkeys against gross lesions caused by the pathogenic strain of ORT in treated groups vs. control. In Experiment 2, seroconversion was detected by enzyme-linked immunosorbent assay in birds after they were given the Ts strain in drinking water in field conditions. The results of the field study showed mean scores of gross lesions of nonvaccinated/challenged groups to be up to seven times higher than those of the vaccinated/challenged group. In addition, reisolation rates and quantification of ORT colonies per gram of lung tissue were significantly lower for vaccinated/challenged than for nonvaccinated/challenged turkeys. In conclusion, results from laboratory and field experiments suggest that use of the Ts mutant strain of ORT as a live vaccine would be a suitable method to evoke protection against ORT infection in turkeys.     

Experimental inoculation of wild turkeys (Meleagris gallopavo) with Mycobacterium bovis

Although avian species are known to be susceptible to infection with Mycobacterium spp. organisms, much remains unknown about the susceptibility of birds to infection with M. bovis. The objective of this current study was to determine if wild turkeys (Meleagris gallopavo) can be infected with M. bovis when inoculated by the oral or intratracheal route. Six turkeys were orally inoculated and another six were inoculated via the trachea with a high dose of M. bovis, 1 x 10(5) CFU/ml. Six turkeys were sham-inoculated controls. Two turkeys from each treatment group were sacrificed on days 30, 60, and 90 postinoculation. There were no gross or microscopic lesions consistent with mycobacteriosis in the 23 inoculated turkeys over the 90-day duration of this study. Fecal cultures were also consistently negative for M. bovis when sampled before inoculation and on days 1, 30, and 60 postinoculation. Two intratracheally inoculated turkeys were positive for M. bovis in visceral tissues at 30 days postinoculation. However, this finding was only indicative of passive persistence of mycobacteria in the tissues and not of infection, as there were no attendant lesions or clinical compromise to support infection. Thus, it can be concluded that young wild turkeys are resistant to infection with M. bovis and, therefore, pose minimal threat as reservoir or spillover hosts for this organism.     

A morphological study of skeletal development in turkeys during the pre-hatching stage

Skeletal chondrofication, ossification and growth of turkey embryos were investigated and analysed to enable assessment of the developmental status and evaluation of the experimental effects on skeletal development, skeletal mutations and development of cultured embryos. Ten embryos were prepared every 24 h from 8 to 28 days of incubation. The fixed embryos were cleared and stained in toto with Alcian blue & Alizarin red for cartilage and ossified components, respectively. Observation of the skeleton was performed under a stereoscopic microscopy, with special attention to the timing of chondrofication and ossification of the bones. The first occurrence of the primary ossification centres was observed in the femur, tibiotarsus, and the dentary and supra-angular of the mandible on the 12th day, followed immediately by the other long bones. Skeletal features of the skull were determined to show the latest appearance of cartilage and ossification. Hence, all elements of the hyolingual apparatus remained cartilaginous until hatching took place except for the ceratobranchial. Even though the vertebral column chondrified earlier as compared with the ribs and sternum, they ossified later. While chondrofication was present in all the regions of the vertebral column at the same time, ossification progressed from the cervical through caudal regions. The growth rate of the femur was eminently higher than that of the humerus with increase in time, particularly after the 20th day of incubation. This seems to be obviously natural because the eggs used in the study are from the broiler turkey, which gains giant muscle mass at a very short period; precocity is probably at the expense of the bones of the leg rather than those of the wing.     

A study of Marek's disease in Japanese quails vaccinated with herpesvirus of turkeys

In a study of outbreaks of Marek's disease in quails, 220 adult quails vaccinated with herpesvirus of turkeys (HVT) were examined pathologically and serologically for Marek's disease (MD). Forty-three of the 220 quails exhibited microscopic lesions similar to those of chickens with MD. MD-virus-specific antigen was found in feather tips of 44 of the 220 birds, and the HVT-specific antibody was found in sera of 56 of the 220 birds by agar gel precipitation. There was a positive correlation between the incidence of lymphomatous changes and the presence of MD-virus-specific antigen, and there was a negative correlation between the incidence of lymphomatous changes and the presence of antibody against HVT on a flock basis.     

Pasteurella multocida in wild mammals and birds in California: prevalence and virulence for turkeys

Samples collected from the oropharynx of wild mammals and birds trapped on 36 turkey farms in California were evaluated for the presence of Pasteurella multocida. A total of 966 animals were collected from 18 premises that had experienced an outbreak of fowl cholera within the past 2-8 months; samples were collected from 16 of these 18 premises within 2-8 weeks of outbreak notification and while the infected flock was still present. A total of 939 animals were trapped from an additional 18 premises that had not reported any outbreaks of fowl cholera within at least 4 months, if ever. Forty-eight isolates of P. multocida, of a variety of somatic serotypes, were recovered from 6 species of mammals and 3 species of birds. On only 2 of 7 premises was the somatic serotype of the isolates obtained from wildlife the same as the isolate obtained from tissues of turkeys that had died of fowl cholera on the same premises. Tests for virulence to turkeys were conducted with 31 of the isolates. Seventeen of these isolates caused mortality in turkeys. Wide ranges in mortality rates and median times to death were observed.     

Pathogenicity of avian influenza viruses isolated from wild mallard ducks and domestic turkeys

Groups of turkeys were exposed to different isolates of avian influenza virus from wild mallard ducks and domestic turkeys by the intracerebral, intravenous, intratracheal, and intra-airsac routes, and pathogenicity indices were calculated. For the intracerebral pathogenicity study, body weight was also measured. For intravenous, intratracheal, and intra-airsac pathogenicity studies, necropsy lesions were scored and serological responses were recorded. Only the intracerebral pathogenicity index and body weight gain post intracerebral infection demonstrated any differences between isolates. The other procedures failed to demonstrate any pathogenicity whatsoever. There was a correlation (R = 0.73) between intracerebral pathogenicity index and reduced weight gain postinfection. These studies suggest that growth suppression may be an objective measure of pathogenic potential of influenza viruses found to be nonpathogenic by other methods.     

Enteric helminths of juvenile and adult wild turkeys (Meleagris gallopavo) in eastern Kansas

Viscera of 49 wild turkeys (Meleagris gallopavo) collected in the spring of 2001 and 23 wild turkeys collected in the fall and winter of 2001-02 from 12 counties in eastern Kansas were examined for enteric helminths. Four cestode species, two trematode species, one nematode species, and one acanthocephalan species were identified. Two cestode and two trematode species present in the spring sample also were present in the fall and winter sample. Parasite prevalence was similar to previous studies of enteric helminths of wild turkeys except for the low numbers of nematode species and individuals recovered in the present study.     

A case of salinomycin intoxication in turkeys

A flock of 4287 heavy hybrid turkey hens were accidentally fed broiler premix containing salinomycin sodium and suffered a 34.5% death loss. Measures taken to ensure food safety for the remaining flock and consumer food safety included feed record studies, on-farm veterinary consultation, diagnostic laboratory studies, and CgFARAD and CFIA consultation. The remaining turkeys were processed 3 weeks after the initial toxicosis with no evidence of lesions that would render the product unfit for human consumption.     

Retrospective study of myocarditis associated with reovirus in turkeys

The myocarditis associated with reovirus in commercial turkeys was studied retrospectively. Fifty-two cases were identified between 1991 and 2009. The lesions occurred in four different poultry companies in California and affected male and female turkeys with an average age of 19 days. Increased mortality in the turkey flocks ranged from 0.35% to 3% per week in 47 cases. Reovirus was isolated from the heart in 14 out of 19 cases. Twenty-four out of 28 birds from nine cases had low vitamin E levels in the liver ranging from 0.29 to 2.5 ppm (normal 3.0 to > or = 15 ppm). Transmission electron microscopy of the heart revealed degenerative changes in the myocardial cells. Reovirus has been suggested as a probable etiology of this condition. Vitamin E deficiency might also contribute to the development of the lesions.     

Induction of vitamin A deficiency in turkeys

The objective of this study was to determine the relationship between the hepatic vitamin A (VitA) level and the pathologic changes in the oropharynx and esophagus of VitA-deficient turkeys. Study turkeys were provided with a diet sufficient (11,000 IU/kg) or deficient (2750 IU/kg) in VitA from 4 to 17 wk of age. Body weight, bacterial culture, and tissues from internal organs were collected at weekly intervals. VitA deficiency causes epithelial tissue damage in poultry. This epithelial damage was seen grossly as white plaques in the oropharynx and esophagus and histologically as squamous metaplasia of mucosal glands and keratinization of epithelium. No significant difference in body weights was seen among the groups. Moreover, no pathogenic bacteria was isolated during sampling periods. Liver VitA levels declined significantly after consumption of low VitA diet for 3 wk and were depleted after 5 wk. Squamous metaplasia due to VitA deficiency developed in the esophagus after 3 wk and in the oropharynx after 4 wk of consuming a VitA-deficient diet.     

A hitherto unreported paramyxovirus of turkeys

A newly isolated avian virus is described which was obtained from a flock of laying turkey hens with respiratory disease and accompanying egg production drop. Characterisation of the virus indicated it to be of the paramyxovirus group and to be related through antigenic crossing with Newcastle disease virus. Examination of turkey sera from five separate flocks indicated natural infection with the paramyxovirus to be relatively widespread. Experimental infection of turkeys produced only mild respiratory disease.