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United States Department of Agriculture

Agricultural Research Service

Research Project: Intervention Strategies to Control and Prevent Disease Outbreaks Caused by Avian Influenza and Other Emerging Poultry Pathogens

Location: Exotic and Emerging Avian Viral Diseases Research Unit

Title: Effect of coronavirus infection on reproductive performance of turkey hens

Authors
item Awe, Olusegun -
item Ali, Ahmed -
item Elaish, Mohamed -
item Ibrahim, Mahmoud -
item Murgia, Maria -
item Pantin-Jackwood, Mary
item Saif, Yehia -
item Lee, Chang-Won -

Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 15, 2013
Publication Date: September 30, 2013
Citation: Awe, O.O., Ali, A., Elaish, M., Ibrahim, M., Murgia, M., Pantin Jackwood, M.J., Saif, Y.M., Lee, C. 2013. Effect of coronavirus infection on reproductive performance of turkey hens. Avian Diseases. 57:650-656.

Interpretive Summary: Turkey coronavirus (TCoV) infection causes enteric diseases in turkeys and high mortality in young birds. TCoV has also been suspected in causing drops of egg production in turkey hens, but this has not been proven experimentally. In the present study, the possible effect of TCoV on the reproductive performance of experimentally infected turkey hens was examined. In two separate trials, turkey hens in peak egg production were inoculated orally with TCoV and cloacal swabs and intestinal and reproductive tissues were collected to detect TCoV nucleic acid. In the cloacal swabs, TCoV was detected consistently at 3, 5, 7 and 12 days post inoculation (DPI). All intestinal samples were also positive for TCoV at 7 DPI, and severe microscopic lesions were observed in the intestinal tissues. In one of the trials, TCoV was also detected from the oviduct of two birds at 7 DPI, however no or mild microscopic lesions were present. In both experimental trials, a 25 – 35% drop in egg production was observed in TCoV infected turkey hens between 4 and 7 DPI. In a separate trial, it was shown that TCoV can transmit from infected to contact control hens. These results show that TCoV infection can affect the reproductive performance in turkey hens causing transient drop in egg production. This drop in egg production most likely occurred consequence of the severe enteritis produced by the TCoV. However, the potential replication of TCoV in the oviduct and its effect on pathogenesis should be considered and further investigated.

Technical Abstract: Turkey coronavirus (TCoV) infection causes enteritis in turkeys of varying ages with high mortality in young birds. In older birds, field evidence indicates possible involvement of TCoV in egg production drops in turkey hens. However, no experimental studies have been conducted to demonstrate TCoV pathogenesis in turkey hens and its effect on reproductive performance. In the present study, we assessed the possible effect of TCoV on the reproductive performance of experimentally infected turkey hens. In two separate trials, 29-30 week-old turkey hens in peak egg production were either mock-infected or inoculated orally with TCoV (Indiana strain). Cloacal swabs and intestinal and reproductive tissues were collected and standard RT-PCR was conducted to detect TCoV RNA. In the cloacal swabs, TCoV was detected consistently at 3, 5, 7 and 12 days post inoculation (DPI) with higher rates of detection after 5 DPI (>90%). All intestinal samples were also positive for TCoV at 7 DPI, and microscopic lesions consisting of severe enteritis with villous atrophy was observed in the duodenum and jejunum of TCoV-infected hens. In one of the trials, TCoV was detected from the oviduct of two birds at 7 DPI, however no or mild microscopic lesions were present. In both experimental trials, a 25 – 35% drop in egg production was observed in TCoV infected turkey hens between 4 and 7 DPI. In a separate trial, we also confirmed that TCoV can efficiently transmit from infected to contact control hens. Our results show that TCoV infection can affect the reproductive performance in turkey hens causing transient drop in egg production. This drop in egg production most likely occurred consequence of the severe enteritis produced by the TCoV. However, the potential replication of TCoV in the oviduct and its effect on pathogenesis should be considered and further investigated.

Last Modified: 9/23/2014
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