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Horizontal Transmission of Turkey Herpesvirus to Chickens
1830
J . W . KOUDELE AND A . M . FEYERHERM
fully its costs and benefits to producers, marketing agencies, and consumers, as well as to reveal problems and the feasibility of its use in egg marketing.
REFERENCE Koudele, J. W., and A. M. Feyerherm, 1976. Retail sales of eggs priced by the dozen and pound—a controlled experiment. Poultry Sci. 55: 1816-1823.
Horizontal Transmission of Turkey Herpesvirus to Chickens 5. AIRBORNE TRANSMISSION BETWEEN CHICKENS' CHO
(Received for-publication January 12, 1976)
ABSTRACT Airborne transmission of turkey herpesvirus (HVT) between chickens was studied in two trials using an experimental line of White Leghorns. HVT either did not spread or spread poorly to chickens that had been exposed for 8 weeks to the exhaust air from a cage containing donor chickens inoculated with HVT at 8 weeks of age. There was no airborne transmission of HVT to chickens that had been exposed for 4 weeks. This study indicated a possible but an infrequent spread of HVT between chickens via airborne route. POULTRY SCIENCE 55: 1830-1833, 1976
INTRODUCTION
A
IRBORNE transmission of turkey herpesvirus (HVT) from turkeys to turkeys, chickens to turkeys, and turkeys to chickens was reported by Witter et al. (1972). However, their one attempt to effect chicken-to-chicken transmission by airborne route was unsuccessful, although the results were considered inconclusive because of an accidental occurrence of Marek's disease in the recipient lot. This paper reports a possible but poor spread via airborne route of HVT between chickens.
which had been passaged 15 times in duck embryo fibroblast and 3 times in chick embryo fibroblast (CEF) cell cultures. The procedures of CEF culture and HVT preparation have been previously described (Cho et al., 1971). Cell-associated HVT was assayed in the secondary CEF monolayers by the method of Calnek et al. (1972). Experimental Chickens. An experimental line of White Leghorns (W.S.U.-V.S.) employed was the same as in the previous study (Cho and Kenzy, 1975). All chicks were hatched in an isolation unit and reared in isolators of Horsfall-Bauer type (HB).
MATERIALS AND METHODS EXPERIMENTAL DESIGN HVT. Used for inoculation of donor chickens was cell-associated HVT (FC 126 strain)
1. Supported by funds from Projects 0138 and 0303, College of Agriculture Research Center. Scientific Paper No. 4416.
Experiment 1. Two different age groups, 1 and 8 weeks old, of the W.S.U.-V.S. chickens from the same parent stock were treated as follows and housed in four identical HB cages in an isolation room. One group in Cage A consisted of 3 donor chickens
Downloaded from http://ps.oxfordjournals.org/ at Northern Arizona University on June 15, 2015
B. R.
Department of Veterinary Science, College of Agriculture Research Center, and Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington 99163
1831
TURKEY HERPESVIRUS TRANSMISSION
15 contact cagemates, and Cage D containing 16 air contacts. Five hatchmates of the contacts and 3 hatchmates of the donors were housed in Cage E as untreated controls. At 4 weeks post-exposure (PE), approximately one half of the contacts from each of Cages A through D were removed and examined for HVT viremia and antobodies. HVT viremia was detected by inoculating 0.1 ml. of heparinized blood onto each of two replica CEF monolayers and antibodies by micro agar gel precipitin (AGP) test as described previously (Cho et al., 1971). The remaining birds including inoculated donors and untreated controls were similarly examined at 8 weeks PE. Experiment 2. An isolation room containing 4 identical HB cages was employed. Five W.S.U.-V.S. chickens inoculated at 8 weeks of age with 7.5 x 104 PFU of HVT were housed in Cage A. In the adjacent Cages B and C, 20 untreated W.S.U.-V.S. chicks of 3 days old were respectively housed as air contacts. The exhaust air duct of Cage A was connected to the air intakes of both Cages B and C as described in Experiment 1. Hatchmates of the donors (2 birds) and
contacts (10 birds) were housed without any treatment in Cage D as untreated controls. At 4 weeks PE, 10 birds from each of Cages B and C were removed and examined for HVT viremia and antibodies. When Cages B and C were opened to remove sample birds, Cage D was also opened so that the birds were exposed to the room air similarly to those in Cages B and C. HVT viremia was examined by inoculating white blood cells (WBC) separated from heparinized blood samples from each bird. From each sample bird, 2 ml. of heparinized blood was collected, centrifuged at 1000 x gfor 20 minutes, and WBC layer (0.1 ml.) collected with as little red blood cells as possible was suspended in 1 ml. of tissue culture medium. The WBC suspension was then inoculated onto 2 replica CEF monolayers (0.3 ml. each) and the number of WBC per inoculum was counted. The WBC counts per inoculum ranged from 3.5 x 106 to 9.7 x 106 (median 7.8 x 106) for Cage B birds, and 2.3 x 106 to 6.0 x 106 cells (median 3.7 x 106) for Cage C birds. Plasma collected from each blood sample was tested for HVT antibodies by micro AGP test. The remaining birds including inoculated donors and untreated controls were similarly examined for HVT viremia and antibodies at 8 weeks PE. The WBC counts per inoculum to CEF cultures ranged from 6.5 x 106 to 1.1 x 107 (median 9.4 x 10 6 ) and from 5.3 x 10 6 to 1.3 x 107 cells (median 1.0 x 10 7 ) respectively for Cages B and C birds, from 3.6 x 106 to 8.6 x 106 cells (median 4.1 x 106) for donor chickens in Cage A, and 2.4 x 106 to 9.1 x 106 cells (median 5.8 x 10 6 ) for control chickens in Cage D.
RESULTS Experiment 1. The results of both Experiments 1 and 2 are summarized in Table 1. When approximately one half of the contacts from Cages A through D were examined at
Downloaded from http://ps.oxfordjournals.org/ at Northern Arizona University on June 15, 2015
inoculated at 8 weeks of age with HVT, and 15 uninoculated chicks of one week old as contact cagemates. Each donor chicken was inoculated subcutaneously in the dorsal cervical area with 5.5 x 104 plaque-forming units (PFU) of cell-associated HVT as determined by concurrent assay of the inoculum. The other group of 18 chicks of one week old without any treatment was housed in the adjacent Cage B and exposed to the exhaust air from Cage A by connecting the air exhaust duct of Cage A to the air intake of Cage B. A wire screen (No. 2 mesh) was installed at the air exhaust of Cage A to prevent big feathers from being blown into Cage B. Two other cages (Cages C and D) were set up the same as Cages A and B as a replica, Cage C containing 3 inoculated donors and
1832
B. R. CHO TABLE 1.—Airborne transmission of turkey herpesvirus (HVT) between chickens
4 weeks PE, 2 of the 7 contact cagemates of Cage C, but none of Cage A, were viremic with HVT. None of the 8 birds from each of Cages B and D, that had been exposed to the exhaust air respectively from Cages A and C containing inoculated donors, were viremic with HVT. HVT precipitins were not demonstrated in any of the birds examined at this time. At 8 weeks PE, 3 of the remaining 8 contact cagemates of Cage A were viremic with HVT and one of them also positive for HVT precipitins. The inoculated donors of Cage A were all viremic with HVT, one of them also being positive for HVT precipitins. Three of the 10 birds of Cage B, that had been exposed to the exhaust air from Cage A, were viremic with HVT and one of them with HVT precipitins as well. In Cage C, none of the 8 contact cagemates were viremic or positive
for antibodies, although all 3 donor chickens were viremic with HVT. The 8 birds of Cage D exposed to the exhaust air from Cage C were neither viremic with HVT nor positive for HVT precipitins.
Experiment 2 When 10 birds from each of Cages B and C, that had been exposed to the exhaust air from Cage A containing 5 inoculated donor chickens, were examined at 4 weeks PE, none of them were viremic with HVT or positive for HVT precipitins. At 8 weeks PE, only one of the 10 air contacts of Cage B was viremic with HVT and also positive for precipitins. None of the 10 air contacts of Cage C were viremic or positive for HVT precipitins. All 5 inoculated donors in Cage A were viremic with HVT and positive for HVT precipitins as well. The
Downloaded from http://ps.oxfordjournals.org/ at Northern Arizona University on June 15, 2015
HVT viremia and precipitins 4 weeks 8 weeks post-exposure post-exposure Experiment Cage Treatment of chickens (No. of birds) Viremia Precipitins Viremia Precipitins i A Inoculated donors Of" NT? NE V3 V/3 Contact cagemates (15)b 0/7 d 0/7 3/8 1/8 B Contacts to exhaust air from Cage A (18) 0/8 0/8 3/10 1/10 C e Inoculated donors (3) NE NE 3/3 1/3 Contact cagemates (15) 2/7 0/7 0/8 0/8 D e Contacts to exhaust air from Cage C (16) 0/8 0/8 0/8 0/8 E Controls (8)f NE NE 0/8 0/8 2 A Inoculated donors (5)* NE NE V5 T/5 B Contacts to exhaust air from Cage A (20)h 0/10 0/10 1/10 1/10 C Contacts to exhaust air from Cage A (20) 0/10 0/10 0/10 0/10 D Controls (12)' NE NE 0/12 0/12 a An experimental line of White Leghorns (W.S.U.-V.S.) inoculated with 5.5 x 104 PFU of HVT at 8 weeks of age. b All contacts (W.S.U.-V.S.) were exposed at 1 week of age. c Not examined. d Number of birds positive/no. of birds examined. e Replica of Cages A and B, respectively. f Three hatchmates of the donors and 5 hatchmates of the contacts. ^W.S.U.-V.S. chickens inoculated with 7.5 x 104 PFU of HVT at 8 weeks of age. h W.S.U.-V.S. chicks exposed at 3 days of age. 'Two hatchmates of the donors and 10 hatchmates of the contacts.
TURKEY HERPESVIRUS TRANSMISSION
12 untreated controls in Cage D were all free of HVT infection.
1833
ACKNOWLEDGEMENT The author thanks Mr. W. R. Bryson and Mrs. D. J. Edwards for technical assistance.
DISCUSSION
REFERENCES
In the present study, the donor chickens were inoculated with HVT always at 8 weeks of age. In the previous studies, HVT was found to spread to contact cagemates when donor chickens were inoculated with HVT at 8 weeks of age, whereas the virus either did not spread or spread poorly when donor birds were inoculated with HVT at younger ages (Cho et al., 1971; Cho and Kenzy, 1973, 1975).
Calnek, B. W., G. Garrido, W. Okazaki and I. V. Patrascu, 1972. In vitro methods for assay of turkey herpesvirus. Avian Dis. 16: 52-56. Cho, B. R., 1975. Horizontal transmission of turkey herpesvirus to chickens. IV. Viral maturation in the feather follicle epithelium. Avian Dis. 19: 136141. Cho, B. R., and S. G. Kenzy, 1973. Horizontal transmission of turkey herpesvirus to chickens. 2. Some factors affecting transmission. Poultry Sci. 52: 608-613. Cho, B. R., and S. G. Kenzy, 1975. Horizontal transmission of turkey herpesvirus to chickens. 3. Transmission in three different lines of chickens. Poultry Sci. 54: 109-115. Cho, B. R., S. G. Kenzy and S. A. Haider, 1971. Horizontal transmission of turkey herpesvirus to chickens. 1. Preliminary observation. Poultry Sci. 50: 881-887. Witter, R. L., and J. J. Solomon, 1972. Experimental infection of turkeys and chickens with a herpesvirus of turkeys (HVT). Avian Dis. 16: 34-44. Zygraich, N., and C. Huygelen, 1972. Inoculation of one-day-old chicks with different strains of turkey herpesvirus. II. Virus replication in tissues of inoculated animals. Avian Dis. 16: 793-798.
NEWS AND NOTES (Continued from page 1810) Ziraat Fakiiltesi, Zootekni Kursiisii, Ankara. United Kingdom: Dr. Colin Fisher, BOCM-Silcock Ltd. Development Farm, Risborough Road, Stoke Mandeville, Bucks. U.S.A.: W.R. Jenkins, Extension Service, U.S. Department of Agriculture, 5509 South Agriculture Building, Washington, D.C. 20250. U.S.S.R.: Mrs. Nina Selina, Room 536, U.S.S.R. National Branch of the W.P.S.A., Orlikov Pereulok 1/11, Moscow 1-139. W.P.S.A.-U.S.A. BRANCH The Board of Directors of the United States of America Branch of the World's Poultry Science Asso-
ciation met recently in the headquarters offices of the American Farm Bureau, Park Ridge, Illinois, to conduct its usual business and plan participation in the XVIth World's Poultry Congress to be held in Sao Paulo, Brazil, September 24-28, 1978. Dr. Wade Brant, President of the U.S.A. Branch, and the Board of Directors appointed Robert L. Hogue, Executive Secretary-Treasurer of the Indiana State Poultry Association as the Membership Chairman for the U.S.A. Branch; Dr. William E. Shaklee, recently retired from the U.S.D.A., as Historian and Archivist; Dr. Frank Rollins, Professor of Poultry Science and Extension Specialist, University of Arizona, as the Communication Officer.
(Continued on page 1840)
Downloaded from http://ps.oxfordjournals.org/ at Northern Arizona University on June 15, 2015
This study indicated a possible airborne transmission of HVT between chickens. However, this mode of transmission of HVT between chickens was infrequent and also inconsistent. This could be due to poor a n d / o r transient shedding of infectious HVT by the inoculated chickens. Infectious HVT has been demonstrated in the feather-tip preparation of inoculated chickens for only a relatively short period around 2 to 4 weeks post-inoculation (Zygraich and Huygelen, 1972; Cho, 1975).
J . W . KOUDELE AND A . M . FEYERHERM
fully its costs and benefits to producers, marketing agencies, and consumers, as well as to reveal problems and the feasibility of its use in egg marketing.
REFERENCE Koudele, J. W., and A. M. Feyerherm, 1976. Retail sales of eggs priced by the dozen and pound—a controlled experiment. Poultry Sci. 55: 1816-1823.
Horizontal Transmission of Turkey Herpesvirus to Chickens 5. AIRBORNE TRANSMISSION BETWEEN CHICKENS' CHO
(Received for-publication January 12, 1976)
ABSTRACT Airborne transmission of turkey herpesvirus (HVT) between chickens was studied in two trials using an experimental line of White Leghorns. HVT either did not spread or spread poorly to chickens that had been exposed for 8 weeks to the exhaust air from a cage containing donor chickens inoculated with HVT at 8 weeks of age. There was no airborne transmission of HVT to chickens that had been exposed for 4 weeks. This study indicated a possible but an infrequent spread of HVT between chickens via airborne route. POULTRY SCIENCE 55: 1830-1833, 1976
INTRODUCTION
A
IRBORNE transmission of turkey herpesvirus (HVT) from turkeys to turkeys, chickens to turkeys, and turkeys to chickens was reported by Witter et al. (1972). However, their one attempt to effect chicken-to-chicken transmission by airborne route was unsuccessful, although the results were considered inconclusive because of an accidental occurrence of Marek's disease in the recipient lot. This paper reports a possible but poor spread via airborne route of HVT between chickens.
which had been passaged 15 times in duck embryo fibroblast and 3 times in chick embryo fibroblast (CEF) cell cultures. The procedures of CEF culture and HVT preparation have been previously described (Cho et al., 1971). Cell-associated HVT was assayed in the secondary CEF monolayers by the method of Calnek et al. (1972). Experimental Chickens. An experimental line of White Leghorns (W.S.U.-V.S.) employed was the same as in the previous study (Cho and Kenzy, 1975). All chicks were hatched in an isolation unit and reared in isolators of Horsfall-Bauer type (HB).
MATERIALS AND METHODS EXPERIMENTAL DESIGN HVT. Used for inoculation of donor chickens was cell-associated HVT (FC 126 strain)
1. Supported by funds from Projects 0138 and 0303, College of Agriculture Research Center. Scientific Paper No. 4416.
Experiment 1. Two different age groups, 1 and 8 weeks old, of the W.S.U.-V.S. chickens from the same parent stock were treated as follows and housed in four identical HB cages in an isolation room. One group in Cage A consisted of 3 donor chickens
Downloaded from http://ps.oxfordjournals.org/ at Northern Arizona University on June 15, 2015
B. R.
Department of Veterinary Science, College of Agriculture Research Center, and Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington 99163
1831
TURKEY HERPESVIRUS TRANSMISSION
15 contact cagemates, and Cage D containing 16 air contacts. Five hatchmates of the contacts and 3 hatchmates of the donors were housed in Cage E as untreated controls. At 4 weeks post-exposure (PE), approximately one half of the contacts from each of Cages A through D were removed and examined for HVT viremia and antobodies. HVT viremia was detected by inoculating 0.1 ml. of heparinized blood onto each of two replica CEF monolayers and antibodies by micro agar gel precipitin (AGP) test as described previously (Cho et al., 1971). The remaining birds including inoculated donors and untreated controls were similarly examined at 8 weeks PE. Experiment 2. An isolation room containing 4 identical HB cages was employed. Five W.S.U.-V.S. chickens inoculated at 8 weeks of age with 7.5 x 104 PFU of HVT were housed in Cage A. In the adjacent Cages B and C, 20 untreated W.S.U.-V.S. chicks of 3 days old were respectively housed as air contacts. The exhaust air duct of Cage A was connected to the air intakes of both Cages B and C as described in Experiment 1. Hatchmates of the donors (2 birds) and
contacts (10 birds) were housed without any treatment in Cage D as untreated controls. At 4 weeks PE, 10 birds from each of Cages B and C were removed and examined for HVT viremia and antibodies. When Cages B and C were opened to remove sample birds, Cage D was also opened so that the birds were exposed to the room air similarly to those in Cages B and C. HVT viremia was examined by inoculating white blood cells (WBC) separated from heparinized blood samples from each bird. From each sample bird, 2 ml. of heparinized blood was collected, centrifuged at 1000 x gfor 20 minutes, and WBC layer (0.1 ml.) collected with as little red blood cells as possible was suspended in 1 ml. of tissue culture medium. The WBC suspension was then inoculated onto 2 replica CEF monolayers (0.3 ml. each) and the number of WBC per inoculum was counted. The WBC counts per inoculum ranged from 3.5 x 106 to 9.7 x 106 (median 7.8 x 106) for Cage B birds, and 2.3 x 106 to 6.0 x 106 cells (median 3.7 x 106) for Cage C birds. Plasma collected from each blood sample was tested for HVT antibodies by micro AGP test. The remaining birds including inoculated donors and untreated controls were similarly examined for HVT viremia and antibodies at 8 weeks PE. The WBC counts per inoculum to CEF cultures ranged from 6.5 x 106 to 1.1 x 107 (median 9.4 x 10 6 ) and from 5.3 x 10 6 to 1.3 x 107 cells (median 1.0 x 10 7 ) respectively for Cages B and C birds, from 3.6 x 106 to 8.6 x 106 cells (median 4.1 x 106) for donor chickens in Cage A, and 2.4 x 106 to 9.1 x 106 cells (median 5.8 x 10 6 ) for control chickens in Cage D.
RESULTS Experiment 1. The results of both Experiments 1 and 2 are summarized in Table 1. When approximately one half of the contacts from Cages A through D were examined at
Downloaded from http://ps.oxfordjournals.org/ at Northern Arizona University on June 15, 2015
inoculated at 8 weeks of age with HVT, and 15 uninoculated chicks of one week old as contact cagemates. Each donor chicken was inoculated subcutaneously in the dorsal cervical area with 5.5 x 104 plaque-forming units (PFU) of cell-associated HVT as determined by concurrent assay of the inoculum. The other group of 18 chicks of one week old without any treatment was housed in the adjacent Cage B and exposed to the exhaust air from Cage A by connecting the air exhaust duct of Cage A to the air intake of Cage B. A wire screen (No. 2 mesh) was installed at the air exhaust of Cage A to prevent big feathers from being blown into Cage B. Two other cages (Cages C and D) were set up the same as Cages A and B as a replica, Cage C containing 3 inoculated donors and
1832
B. R. CHO TABLE 1.—Airborne transmission of turkey herpesvirus (HVT) between chickens
4 weeks PE, 2 of the 7 contact cagemates of Cage C, but none of Cage A, were viremic with HVT. None of the 8 birds from each of Cages B and D, that had been exposed to the exhaust air respectively from Cages A and C containing inoculated donors, were viremic with HVT. HVT precipitins were not demonstrated in any of the birds examined at this time. At 8 weeks PE, 3 of the remaining 8 contact cagemates of Cage A were viremic with HVT and one of them also positive for HVT precipitins. The inoculated donors of Cage A were all viremic with HVT, one of them also being positive for HVT precipitins. Three of the 10 birds of Cage B, that had been exposed to the exhaust air from Cage A, were viremic with HVT and one of them with HVT precipitins as well. In Cage C, none of the 8 contact cagemates were viremic or positive
for antibodies, although all 3 donor chickens were viremic with HVT. The 8 birds of Cage D exposed to the exhaust air from Cage C were neither viremic with HVT nor positive for HVT precipitins.
Experiment 2 When 10 birds from each of Cages B and C, that had been exposed to the exhaust air from Cage A containing 5 inoculated donor chickens, were examined at 4 weeks PE, none of them were viremic with HVT or positive for HVT precipitins. At 8 weeks PE, only one of the 10 air contacts of Cage B was viremic with HVT and also positive for precipitins. None of the 10 air contacts of Cage C were viremic or positive for HVT precipitins. All 5 inoculated donors in Cage A were viremic with HVT and positive for HVT precipitins as well. The
Downloaded from http://ps.oxfordjournals.org/ at Northern Arizona University on June 15, 2015
HVT viremia and precipitins 4 weeks 8 weeks post-exposure post-exposure Experiment Cage Treatment of chickens (No. of birds) Viremia Precipitins Viremia Precipitins i A Inoculated donors Of" NT? NE V3 V/3 Contact cagemates (15)b 0/7 d 0/7 3/8 1/8 B Contacts to exhaust air from Cage A (18) 0/8 0/8 3/10 1/10 C e Inoculated donors (3) NE NE 3/3 1/3 Contact cagemates (15) 2/7 0/7 0/8 0/8 D e Contacts to exhaust air from Cage C (16) 0/8 0/8 0/8 0/8 E Controls (8)f NE NE 0/8 0/8 2 A Inoculated donors (5)* NE NE V5 T/5 B Contacts to exhaust air from Cage A (20)h 0/10 0/10 1/10 1/10 C Contacts to exhaust air from Cage A (20) 0/10 0/10 0/10 0/10 D Controls (12)' NE NE 0/12 0/12 a An experimental line of White Leghorns (W.S.U.-V.S.) inoculated with 5.5 x 104 PFU of HVT at 8 weeks of age. b All contacts (W.S.U.-V.S.) were exposed at 1 week of age. c Not examined. d Number of birds positive/no. of birds examined. e Replica of Cages A and B, respectively. f Three hatchmates of the donors and 5 hatchmates of the contacts. ^W.S.U.-V.S. chickens inoculated with 7.5 x 104 PFU of HVT at 8 weeks of age. h W.S.U.-V.S. chicks exposed at 3 days of age. 'Two hatchmates of the donors and 10 hatchmates of the contacts.
TURKEY HERPESVIRUS TRANSMISSION
12 untreated controls in Cage D were all free of HVT infection.
1833
ACKNOWLEDGEMENT The author thanks Mr. W. R. Bryson and Mrs. D. J. Edwards for technical assistance.
DISCUSSION
REFERENCES
In the present study, the donor chickens were inoculated with HVT always at 8 weeks of age. In the previous studies, HVT was found to spread to contact cagemates when donor chickens were inoculated with HVT at 8 weeks of age, whereas the virus either did not spread or spread poorly when donor birds were inoculated with HVT at younger ages (Cho et al., 1971; Cho and Kenzy, 1973, 1975).
Calnek, B. W., G. Garrido, W. Okazaki and I. V. Patrascu, 1972. In vitro methods for assay of turkey herpesvirus. Avian Dis. 16: 52-56. Cho, B. R., 1975. Horizontal transmission of turkey herpesvirus to chickens. IV. Viral maturation in the feather follicle epithelium. Avian Dis. 19: 136141. Cho, B. R., and S. G. Kenzy, 1973. Horizontal transmission of turkey herpesvirus to chickens. 2. Some factors affecting transmission. Poultry Sci. 52: 608-613. Cho, B. R., and S. G. Kenzy, 1975. Horizontal transmission of turkey herpesvirus to chickens. 3. Transmission in three different lines of chickens. Poultry Sci. 54: 109-115. Cho, B. R., S. G. Kenzy and S. A. Haider, 1971. Horizontal transmission of turkey herpesvirus to chickens. 1. Preliminary observation. Poultry Sci. 50: 881-887. Witter, R. L., and J. J. Solomon, 1972. Experimental infection of turkeys and chickens with a herpesvirus of turkeys (HVT). Avian Dis. 16: 34-44. Zygraich, N., and C. Huygelen, 1972. Inoculation of one-day-old chicks with different strains of turkey herpesvirus. II. Virus replication in tissues of inoculated animals. Avian Dis. 16: 793-798.
NEWS AND NOTES (Continued from page 1810) Ziraat Fakiiltesi, Zootekni Kursiisii, Ankara. United Kingdom: Dr. Colin Fisher, BOCM-Silcock Ltd. Development Farm, Risborough Road, Stoke Mandeville, Bucks. U.S.A.: W.R. Jenkins, Extension Service, U.S. Department of Agriculture, 5509 South Agriculture Building, Washington, D.C. 20250. U.S.S.R.: Mrs. Nina Selina, Room 536, U.S.S.R. National Branch of the W.P.S.A., Orlikov Pereulok 1/11, Moscow 1-139. W.P.S.A.-U.S.A. BRANCH The Board of Directors of the United States of America Branch of the World's Poultry Science Asso-
ciation met recently in the headquarters offices of the American Farm Bureau, Park Ridge, Illinois, to conduct its usual business and plan participation in the XVIth World's Poultry Congress to be held in Sao Paulo, Brazil, September 24-28, 1978. Dr. Wade Brant, President of the U.S.A. Branch, and the Board of Directors appointed Robert L. Hogue, Executive Secretary-Treasurer of the Indiana State Poultry Association as the Membership Chairman for the U.S.A. Branch; Dr. William E. Shaklee, recently retired from the U.S.D.A., as Historian and Archivist; Dr. Frank Rollins, Professor of Poultry Science and Extension Specialist, University of Arizona, as the Communication Officer.
(Continued on page 1840)
Downloaded from http://ps.oxfordjournals.org/ at Northern Arizona University on June 15, 2015
This study indicated a possible airborne transmission of HVT between chickens. However, this mode of transmission of HVT between chickens was infrequent and also inconsistent. This could be due to poor a n d / o r transient shedding of infectious HVT by the inoculated chickens. Infectious HVT has been demonstrated in the feather-tip preparation of inoculated chickens for only a relatively short period around 2 to 4 weeks post-inoculation (Zygraich and Huygelen, 1972; Cho, 1975).