Biomedical subjects

S L Noll

Publications and source records attributed to S L Noll.

24 records · Page 2Linked to original sources

PubMedDate not supplied

Neonatal avian pneumovirus infection in commercial turkeys.

Eleven market turkey flocks developed a respiratory disease characterized by coughing, swollen sinuses and nasal discharge. These symptoms first appeared between 3 and 16 days of age. Avian pneumovirus (APV) RNA was detected by reverse transcriptase (RT)-polymerase chain reaction (PCR) in six of six flocks tested. APV was detected by immunohistochemistry in turbinates of three of three affected flocks tested. Virus isolation attempts were negative. Ten of 11 flocks became seropositive on the APV enzyme-linked immunosorbent assay. Five weeks prior to hatch of these affected market turkeys, several breeder flocks in one geographic area had developed clinical signs and experienced decline in egg production typical of APV infection. In two breeder flocks, acute and convalescent sera indicated APV infection during the period of declining egg production. Attempts to detect APV RNA by RT-PCR from choanal cleft swabs of newly hatched poults were successful. Attempts to isolate the virus from these PCR-positive samples were negative.

Age Factors↗

PubMedDate not supplied

Avian pneumovirus infection in Minnesota turkeys: experimental reproduction of the disease.

Avian pneumovirus (APV) is an emerging viral respiratory disease agent of turkeys in Minnesota. Clinical signs of APV infection include open mouth breathing, ocular and nasal discharge, and swelling of infraorbital sinuses. The virus spreads rapidly among flocks of susceptible turkeys and is associated with increased mortality rates. A flock of 11-wk-old turkeys experienced a respiratory problem characterized by coughing, sneezing, swollen sinuses, and nasal discharge. The reverse transcriptase-polymerase chain reaction (RT-PCR) performed on tissues from the nasal turbinates and tracheal tissues was positive for avian pneumovirus. Turbinate tissue was inoculated into chicken embryo fibroblasts, and cytopathic effect was observed after five blind passages. In an attempt to reproduce the disease, 50 microl of this cell culture-propagated virus was instilled into each conjunctival space and nostril of 23-day-old turkey poults. The poults were sacrificed at 2-day intervals for 12 days, and serum, tissues, and tracheal and cloacal swabs were collected. Between days 2 and 10 after exposure, the poults developed ocular and nasal discharge and swollen sinuses. The virus was detected by RT-PCR and virus isolation from the nasal turbinates of poults sacrificed on days 4 and 6 postinoculation. Antibodies to APV were detected by enzyme-linked immunosorbent assay.

Animals↗

PubMedDate not supplied

Vaccination of turkeys with an avian pneumovirus isolate from the United States.

Four-week-old poults obtained from avian pneumovirus (APV) antibody-free parents were vaccinated with different serial 10-fold dilutions of cell culture-propagated APV vaccine. The birds were vaccinated with 50 microl into each conjunctival space and nostril (total of 200 microl). Each poult of each group was vaccinated in groups that received doses of 4 x 10(4), 4 x 10(3), 4 x 10(2), 4 x 10(1), or 4 x 10(0) 50% tissue culture infective dose (TCID50) of APV vaccine, respectively. Respiratory signs were seen between 3 and 12 days postvaccination (PV) in the poults that were vaccinated with 4 x 10(4), 4 x 10(3), and 4 x 10(2) TCID50, respectively. In these groups, APV was detected from swabs collected at 5 days PV and seroconversion was detected at 2 wk PV. The groups that were originally vaccinated with 4 x 10(1) and 4 x 10(0) TCID50 developed mild clinical signs after vaccination, but neither virus nor antibody was detected PV. At 2 wk PV (6 wk of age), birds from each group, along with five unvaccinated controls, were challenged with APV. Upon challenge, the 4 x 10(4) and 4 x 10(3) TCID50 groups were protected against development of clinical signs and were resistant to reinfection. The group previously vaccinated with 4 x 10(2) TCID50 developed clinical signs after challenge that were considerably milder than those seen in the groups that had previously been vaccinated with lower doses or no virus. Even though 4 x 10(2) TCID50 vaccine dose administered by intranasal ocular route resulted in infection, incomplete protection resulted with this pivotal dose. Upon challenge, the 4 x 10(1) and 4 x 10(0) TCID50 groups exhibited milder disease signs than those seen in the challenged unvaccinated controls. In these groups, APV was detected in preparations of swabs collected at 5 days postchallenge (PC) and seroconversion was detected at 2 wk PC. These results indicate that the dose of APV vaccine that causes protection is higher than that required to produce infection.

Animals↗

PubMedDate not supplied

The incidence of perirenal hemorrhage syndrome in six flocks of market turkey toms.

Four flocks of the Nicholas strain and two of the British United turkey (BUT) strain of large white market turkey toms were monitored from 8 to 19 weeks of age to identify the presence, incidence, age distribution, and possible cause(s) of perirenal hemorrhage syndrome (PHS), or acute hypertensive angiopathy. Mortality rates varied among the flocks from 0.81% to 1.78% of total poults started. Nicholas flocks has a distinct peak in mortality between 9 and 14 weeks of age. PHS was the main cause of mortality from 8 to 14 weeks of age in all flocks except one, and the incidence diminished after 15 weeks of age. No significant bacterial pathogens were detected in any of the PHS cases. Distinct peaks in overall weekly mortality between 10 and 13 weeks of age similar to those in the four Nicholas flocks were also observed in six of 10 Minnesota flocks surveyed separately.

Age Factors↗

PubMedDate not supplied

Perirenal hemorrhage syndrome in market turkey toms: effect of management factors.

Differences in the overall mortality rates and mortality due to perirenal hemorrhage syndrome (PHS) were compared in large white Nicholas tom turkeys. The study evaluated the effects of 1) four different light and temperature treatments; 2) three feed additives proposed to have anti-stress effects (reserpine, acetylsalicylic acid, and increased calcium); 3) toe-clipping on mortality, various disease conditions, and production parameters. Mortality varied from 0.60% to 3.57% among groups. Increased room temperature (21 C), toe-clipping, step-up/step-down lighting, and dietary reserpine reduced the incidence of PHS as compared with lower room temperature (13 C), no toe-clipping, intermittent lighting (2 hours light, 4 hours dark), and no dietary reserpine. Dietary aspirin or elevated calcium levels had no effect on PHS incidence. Overall mortality was greatest in the warmer rooms.

Animal Husbandry↗

PubMedDate not supplied

The effects of stray voltage on turkey poults.

Three successive flocks of turkey poults experienced cumulative mortality of 10% to 26% through the fifth week of brooding. Stray electrical voltage was suspected after no definitive laboratory diagnosis could be made and no evidence of management deficiency was found. Alternating current voltages of 0.2 to 2.5 volts were detected between waterers and the floor and between the water line and gas line. When the water line was equipment-grounded to the electrical service entrance, the subsequent flock had no mortality problem. A series of experiments was conducted to determine the sensitivity of turkey poults to alternating current. Based on these experiments, the voltage levels measured at the farm probably did not cause the mortality experienced in the three flocks. The reason for the farm problem could have been 1) the poults experienced higher voltage than was present when measurements were taken, 2) the voltage may have been intermittent, or 3) there was a difference between the farm environment and the cage battery environment in the experiments.

Animals↗