RESUMEN

Increased mortality associated with Streptococcus bovis infection occurred on three independent turkey facilities in California. The age of the flocks during these outbreaks ranged from 1 to 3 weeks of age. Gross lesions included extensive pale foci in the pectoral muscles, markedly enlarged, dark and friable or mottled spleens, and swollen livers. Histopathology revealed multifocal necrosis in the spleen and Kupffer cell hypertrophy with necrosis of macrophages. Electron microscopy of liver showed replicating coccoid bacteria within the phagosomes of macrophages. 5. bovis was consistently isolated from bone marrow, liver and spleen.

RESUMEN

Three California turkey premises that had repeated outbreaks of fowl cholera were studied for periods of 2 to 4 years. Using biochemical, serologic, plasmid DNA, and restriction endonuclease analyses of isolates of Pasteurella multocida from turkeys and wildlife on the premises, strains of the organism were found to be enzootic on two of the premises. On the third, a variety of strains of P. multocida were isolated from fowl cholera outbreak flocks.

Asunto(s)

RESUMEN

Strains of Pasteurella multocida, capsular serogroup A and somatic serotype 14, (A: 14) isolated from turkeys which had succumbed to fowl cholera were examined for virulence and infectivity. Groups of 2-week-old poults were injected intramuscularly with one of three strains. Slight to moderate virulence, based on mortality, was noted. Poults that survived exposure were frequently affected with exudative airsacculitis. Intramuscular, intra-air sac and intranasal exposure of 6-week-old poults with the most virulent strain, as determined in the first experiment, caused the death of one of five intramuscularly-exposed poults. No other clinical evidence was observed. At post mortem examination, marked exudative airsacculitis occurred in all intra-air sac exposed poults, both in inoculated and other air sacs. Pneumonia was also observed in these poults but only affected lungs adjacent to inoculated air sacs. Some poults became carriers of P. multocida.

RESUMEN

Three strains of Mycoplasma meleagridis of varying pathogenicity were characterized by conventional serologic methods and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The three strains (RY-39A, MC-25B, and RY-39C) did not differ by cross agglutination, immunofluorescence and immunodiffusion tests. However, the strains differed in their protein patterns as determined by SDS-PAGE.

Asunto(s)

RESUMEN

Newly hatched commercial turkey poults culled because of grossly visible cataracts were studied. A total of 43 affected and 23 unaffected control poults at various ages were necropsied, and the ocular changes in affected poults were compared with those of aged-matched controls. Affected poults had consistent cataracts coupled with a marked depletion in retinal inner plexiform, ganglion cell, and optic nerve fiber layers, with a resultant reduction in the size of the optic nerves. Lesions were seen in 1-day-old poults. Lens changes included microphakia and lens fiber degeneration throughout the lens, with nuclear liquefaction. The depletion in the numbers of retinal ganglion cells did not appear to progress over several weeks time. The ganglion cell depletion was not uniform within the retina. The cause for these ocular changes is unknown.

Asunto(s)

RESUMEN

A disease outbreak characterized by respiratory signs, occasional neurologic signs, and increased mortality in commercial meat turkeys from four separate companies in central California was investigated in the late summer and early fall of 1986. The disease syndrome affected turkeys from 6 to 15 weeks of age and caused a severe fibrinous pericarditis, perihepatitis, and airsacculitis. Bacteriologic and serologic examinations as well as virus- and chlamydia-isolation attempts initially failed to implicate an etiologic agent. Eventually culture attempts were made in a 5% CO2 incubator, resulting in isolation of Pasteurella anatipestifer. The disease syndrome was reproduced in young turkeys and broiler chicks inoculated with the organism.

Asunto(s)

RESUMEN

A virulent, encapsulated strain of Pasteurella multocida was compared with a spontaneously arising, avirulent acapsular variant following injection into the bloodstream of 14-week-old turkeys. Neither strain was detectable in the blood by 1 hour, but they reappeared 4 hours postinoculation in approximately equal numbers. The concentration of both strains increased with time, but the virulent strain reached concentrations 100,000-fold higher than the avirulent strain 15-24 hours after inoculation. In the liver and spleen the virulent strain reached higher concentrations than the avirulent strain, particularly 15 hours postinoculation. However, histopathological examination indicated that the difference between concentrations of the two strains was more likely due to an increased propensity for extracellular multiplication of the virulent strain rather than to greater efficiency in phagocytosis of the avirulent strain. In vitro, the two strains became associated minimally, though equally, with the mononuclear phagocytes and were destroyed. We conclude that humoral bactericidal defenses are primarily responsible for the differences in behavior between these two strains of P. multocida in vivo.

Asunto(s)

RESUMEN

An acute upper respiratory disease was observed in two broad-breasted white (BBW) turkey primary breeder flocks. Associated clinical signs included sneezing, depression, and a deep dry cough originating from large conducting airways. Morbidity reached approximately 15-20% of the hens in an affected house. None of the turkeys died, and total feed consumption was not affected. A minimal effect upon egg production was noticed. Sera from an acutely affected flock exhibited a marked rise in titer to Bordetella avium compared with preinfection sera samples. In Case 1, B. avium was isolated in pure culture from affected birds. In Case 2, B. avium was diagnosed by serological results and clinical signs; bacteriological examination was not attempted. The findings presented here are consistent with an acute clinical outbreak of B. avium-induced turkey rhinotracheitis (turkey coryza) in BBW turkey breeder hens.

Asunto(s)

RESUMEN

An enzyme-linked immunosorbent assay (ELISA) was developed for detecting paramyxovirus type 3 (PMV-3) antibody. This test had a higher sensitivity than the hemagglutination-inhibition test, and no cross-reactivity with various paramyxoviruses or avian pathogens was detected when the sera were tested diluted 1:200. The incidence of PMV-3 infection in California was studied by testing 2037 turkey sera from 174 meat and breeder flocks for the presence of PMV-3 antibody using the ELISA. The age at which the infection occurs was around 5 to 8 weeks for meat flocks and 10 to 12 weeks for breeder flocks. Infection with the PMV-3, as determined serologically, was more frequent than manifested cases of disease, and 95.2% of the flocks aged over 11 weeks had PMV-3 antibody. No typical manifestations of PMV-3 disease (respiratory disease plus drop in egg production) were observed, probably because of the early infection which occurred before laying age.

Asunto(s)

RESUMEN

The incidence of hemorrhagic enteritis (HE) infection in California turkeys was studied by testing 2220 turkey blood samples from 173 flocks for HE virus (HEV) antibody by the enzyme-linked immunosorbent assay (ELISA). Maternal antibody was detected at 1 day of age in all flocks tested, and it vanished after 3 weeks. Acquired HEV antibody appeared at 8 to 10 weeks, and 100% of the meat and breeder turkey flocks were positive after 11 weeks of age. HEV infection occurred earlier in the meat flocks than in the breeder flocks, and it also occurred earlier during summer than during the fall and winter months.

Asunto(s)

RESUMEN

Three stable temperature-sensitive (ts) mutants were obtained by treating the S6 strain of Mycoplasma gallisepticum with 50 micrograms/ml of nitrosoguanidine. These mutants were morphologically and serologically indistinguishable from the parent S6 strain. Mutants ts 37 and ts 102 were apathogenic, and ts 100 was moderately pathogenic to chickens when inoculated directly into the air sac. To turkeys, ts 37 remained apathogenic, ts 102 was slightly pathogenic, and ts 100 was highly pathogenic, Intranasal immunization of newly hatched chickens with any of the mutants resulted in antibody production, but only ts 100 and ts 102 protected chickens against experimental M. gallisepticum infections 3 weeks later. Vaccination of 2-day-old turkeys with ts resulted in erratic antibody response; however, 5 weeks after immunization, turkeys were able to resist challenge with the virulent S6 strain at a highly significant level.

Asunto(s)

RESUMEN

Gentamicin-resistant salmonellae were isolated from turkey poults, hatching eggs, and litter on three unrelated farms and from a scrub jay (Aphelocoma coerulescens) on a fourth farm unrelated to the other three. The isolates were Salmonella arizonae from three of the farms (poults, eggs, scrub jay) and S. thompson (litter) from the fourth farm. The genes responsible for gentamicin resistance were located on the same conjugal plasmid. This plasmid also encoded resistance to kanamycin, streptomycin, ampicillin, and sulfadiazine.

Asunto(s)

RESUMEN

Turkey breeder candidates were exposed to attenuated Pasteurella multocida (Clemson University strain) via both mouth (one or three times) and wing-web stick (one or two times). Significant protection lasting to 25-30 weeks post-vaccination was conferred under such immunization programs. The best protection with the fewest adverse effects of vaccination was established when orally vaccinated turkeys were subsequently vaccinated via wing-web at 20 and 25 weeks of age. High doses of attenuated P. multocida via wing-web produced lameness (synovitis and osteomyelitis) and severe wing lesions in growing turkeys.

Asunto(s)