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The Effect of Marek’s Disease Virus on the Erythrocyte Content of Chicken Blood
1518
RESEARCH NOTES
the egg as it ages may not be due directly to loss of acidity. Any relationship between the two seems likely to be secondary in nature.
REFERENCE Cunningham, F. E., 1959. The effect of season and age of bird on egg composition. M.S. Thesis, University of Missouri.
THE EFFECT OF MAREK'S DISEASE VIRUS ON THE ERYTHROCYTE CONTENT OF CHICKEN BLOOD
(Received for publication May 18, 1971)
Vickers et al. (1967) reported hematocrit readings significantly lower for chickens infected with Marek's disease virus (M.D.V.) than for non-infected chickens. The depression began at approximately two weeks post inoculation and persisted until the eighth week causing reductions in packed cell volumes from 16 to 36%. Jackowski et al. (1970) indicated hematopoietic destructive lesions to the bursa of Fabricius and thymus of chickens infected with M.D.V. They also reported a drastic reduction in packed cell volumes and a lack of hematopoiesis. In this experiment cell counts were made at weekly intervals on the blood from chickens experimentally infected with M.D.V. and on inoculated and uninoculated control chickens using a Coulter electronic particle counter*1 (Wisecup and Crouch, 1963). One hundred and fifty male Single Comb White Leghorn chicks at one day of age were inoculated intraperitoneally with 0.2 ml. of heparinized whole blood (i.e. 2.4 X 10s cells) drawn from 10 week old birds showing gross pathological lesions of Marek's disease upon post mortem. A second group of 150 chickens was inoculated intra** Coulter Electronic Particle, Counter, Coulter Electronics, Hialeah, Florida, U.S.A.
peritoneally at one day of age with 0.2 ml. (i.e. 2.4 X 108 cells) of whole heparinized blood from 10 week old birds showing no lesions of Marek's disease upon post mortem. A third group of 150 chicks remained uninoculated. The chickens were kept in environmental chambers, the infected group being kept in a separate unit. At weekly intervals over a 10 week test period, 10 chickens from each group were sacrificed and the blood collected in tubes containing 0.1 ml. of heparin per ml. of blood. This was diluted 1:50,000 in 0.85% millipore filtered saline and made up to a final volume of 100 ml. Ten such samples were run in triplicate on the Coulter counter and size ranges were established by automatically recording the number of particles as the lower threshold setting was increased by 4 unit increments. It was thus determined that chicken red blood cells fall within the size represented by threshold levels of 20 to 36 (upper and lower threshold levels respectively) at an aperture current setting of 0.25 amps and an amplification setting of 1.0. Having established these parameters, 10 blood samples from each group were counted in triplicate each week for 10 weeks under these conditions. The actual counts from the machine were averaged, corrected for co-incidence and multiplied by the dilution factor to give ac-
Downloaded from http://ps.oxfordjournals.org/ at University of British Columbia on June 21, 2015
K. H. NIELSEN AND G. W. ANDERSON Department of Microbiology, University of Guelph, Guelph, Ontario, Canada
1519
RESEARCH NOTES
/
FIG. 1. Erythrocyte population of MD infected and control chickens at different ages.
tual counts of erythrocytes per ml. The mean values of these counts for the three groups of chickens are shown in Fig. 1. A two-way factorial analysis of variance was carried out on these means as they changed with time post inoculation, and the M.D.V. infected group was found to have significantly reduced erythrocyte counts compared to those of the two control groups for the final 6 weeks of the 10 week test period. Thus M.D.V. appeared to cause an anaemic condition in chickens experimentally infected with M.D.V., whereas the inoculated control group, although also injected with mature red blood cells, did not show this marked anaemia.
ACKNOWLEDGEMENTS
This investigation was supported by a grant from the National Research Council of Canada. We are indebted to Dr. G. C. Ashton, Department of Mathematics and Statistics, University of Guelph, for his help with the statistical analyses. REFERENCES Jackowski, R. M., T. N. Fredrickson, T. W. Chomiak and R. E. Luginbuhl, 1970. Hematopoietic destruction in Marek's disease. Avian Dis. 14:374-385. Vickers, J. H., C. F. Helmboldt and R. E. Luginbuhl, 1967. Pathogenesis of Marek's disease (Conn.- A isolate). Avian Dis. 11: S31-545. Wisecup, W. G., and B. G. Crouch, 1963. Evaluation and calibration of an electronic particle counter for enumeration of multi species blood cells. Amer. J. Clin. Path. 39: 349-354.
NEWS AND NOTES (Continued from page 1500) food sources. Contributions may have been in research, education, administration, government or private enterprise. Society membership or organization affiliation is not required. Age is not a deciding
factor. Achievements must have been completed within the past 10 years. Although it is too late for 1971, nomination procedures and format are detailed below, so that mem-
(Continued on page 1541)
Downloaded from http://ps.oxfordjournals.org/ at University of British Columbia on June 21, 2015
\
The reason for this anaemic condition is not understood. One possible explanation is that M.D.V. stimulates pluripotent stem cells to produce lymphocytes rather than erythrocytes in a fashion similar to that of the leukemic diseases. Another and more plausible explanation is that M.D.V. affects the hematopoietic tissues, not only causing destruction of this tissue but also interfering with hematopoiesis ether by causing an inhibition and/or alteration in the metabolism resulting in a decreased synthesis of new erythrocytes, suggested by the appearance of anaemia before the appearance of lesions in the hematopoietic tissues. However, the present knowledge does not permit one to elucidate this anaemic condition with certainty.
RESEARCH NOTES
the egg as it ages may not be due directly to loss of acidity. Any relationship between the two seems likely to be secondary in nature.
REFERENCE Cunningham, F. E., 1959. The effect of season and age of bird on egg composition. M.S. Thesis, University of Missouri.
THE EFFECT OF MAREK'S DISEASE VIRUS ON THE ERYTHROCYTE CONTENT OF CHICKEN BLOOD
(Received for publication May 18, 1971)
Vickers et al. (1967) reported hematocrit readings significantly lower for chickens infected with Marek's disease virus (M.D.V.) than for non-infected chickens. The depression began at approximately two weeks post inoculation and persisted until the eighth week causing reductions in packed cell volumes from 16 to 36%. Jackowski et al. (1970) indicated hematopoietic destructive lesions to the bursa of Fabricius and thymus of chickens infected with M.D.V. They also reported a drastic reduction in packed cell volumes and a lack of hematopoiesis. In this experiment cell counts were made at weekly intervals on the blood from chickens experimentally infected with M.D.V. and on inoculated and uninoculated control chickens using a Coulter electronic particle counter*1 (Wisecup and Crouch, 1963). One hundred and fifty male Single Comb White Leghorn chicks at one day of age were inoculated intraperitoneally with 0.2 ml. of heparinized whole blood (i.e. 2.4 X 10s cells) drawn from 10 week old birds showing gross pathological lesions of Marek's disease upon post mortem. A second group of 150 chickens was inoculated intra** Coulter Electronic Particle, Counter, Coulter Electronics, Hialeah, Florida, U.S.A.
peritoneally at one day of age with 0.2 ml. (i.e. 2.4 X 108 cells) of whole heparinized blood from 10 week old birds showing no lesions of Marek's disease upon post mortem. A third group of 150 chicks remained uninoculated. The chickens were kept in environmental chambers, the infected group being kept in a separate unit. At weekly intervals over a 10 week test period, 10 chickens from each group were sacrificed and the blood collected in tubes containing 0.1 ml. of heparin per ml. of blood. This was diluted 1:50,000 in 0.85% millipore filtered saline and made up to a final volume of 100 ml. Ten such samples were run in triplicate on the Coulter counter and size ranges were established by automatically recording the number of particles as the lower threshold setting was increased by 4 unit increments. It was thus determined that chicken red blood cells fall within the size represented by threshold levels of 20 to 36 (upper and lower threshold levels respectively) at an aperture current setting of 0.25 amps and an amplification setting of 1.0. Having established these parameters, 10 blood samples from each group were counted in triplicate each week for 10 weeks under these conditions. The actual counts from the machine were averaged, corrected for co-incidence and multiplied by the dilution factor to give ac-
Downloaded from http://ps.oxfordjournals.org/ at University of British Columbia on June 21, 2015
K. H. NIELSEN AND G. W. ANDERSON Department of Microbiology, University of Guelph, Guelph, Ontario, Canada
1519
RESEARCH NOTES
/
FIG. 1. Erythrocyte population of MD infected and control chickens at different ages.
tual counts of erythrocytes per ml. The mean values of these counts for the three groups of chickens are shown in Fig. 1. A two-way factorial analysis of variance was carried out on these means as they changed with time post inoculation, and the M.D.V. infected group was found to have significantly reduced erythrocyte counts compared to those of the two control groups for the final 6 weeks of the 10 week test period. Thus M.D.V. appeared to cause an anaemic condition in chickens experimentally infected with M.D.V., whereas the inoculated control group, although also injected with mature red blood cells, did not show this marked anaemia.
ACKNOWLEDGEMENTS
This investigation was supported by a grant from the National Research Council of Canada. We are indebted to Dr. G. C. Ashton, Department of Mathematics and Statistics, University of Guelph, for his help with the statistical analyses. REFERENCES Jackowski, R. M., T. N. Fredrickson, T. W. Chomiak and R. E. Luginbuhl, 1970. Hematopoietic destruction in Marek's disease. Avian Dis. 14:374-385. Vickers, J. H., C. F. Helmboldt and R. E. Luginbuhl, 1967. Pathogenesis of Marek's disease (Conn.- A isolate). Avian Dis. 11: S31-545. Wisecup, W. G., and B. G. Crouch, 1963. Evaluation and calibration of an electronic particle counter for enumeration of multi species blood cells. Amer. J. Clin. Path. 39: 349-354.
NEWS AND NOTES (Continued from page 1500) food sources. Contributions may have been in research, education, administration, government or private enterprise. Society membership or organization affiliation is not required. Age is not a deciding
factor. Achievements must have been completed within the past 10 years. Although it is too late for 1971, nomination procedures and format are detailed below, so that mem-
(Continued on page 1541)
Downloaded from http://ps.oxfordjournals.org/ at University of British Columbia on June 21, 2015
\
The reason for this anaemic condition is not understood. One possible explanation is that M.D.V. stimulates pluripotent stem cells to produce lymphocytes rather than erythrocytes in a fashion similar to that of the leukemic diseases. Another and more plausible explanation is that M.D.V. affects the hematopoietic tissues, not only causing destruction of this tissue but also interfering with hematopoiesis ether by causing an inhibition and/or alteration in the metabolism resulting in a decreased synthesis of new erythrocytes, suggested by the appearance of anaemia before the appearance of lesions in the hematopoietic tissues. However, the present knowledge does not permit one to elucidate this anaemic condition with certainty.