Transmissible gastroenteritis
OIE Reference Laboratory Reports
Activities in 2010
Name of disease (or topic) for which you are a designated OIE Reference Laboratory: / Transmissible gastroenteritisAddress of laboratory: / Food Animal Health Research Program, Ohio Agricultural Research and Development Center
The Ohio State University, Wooster, OH 44691, USA
Tel.: / (+1-330) 263.37.44
Fax: / (+1-330) 263.36.77
e-mail address: /
website: / http://www.oardc.ohio-state.edu/lsaiflab/
Name of Head of Laboratory (Responsible Official): / Dr Linda J Saif
Name of OIE Reference Expert: / Dr Linda J Saif
Name of writer of this report
(if different from above): / Dr Linda J Saif
Part I: Summary of general activities related to the disease
1. Test(s) in use/or available for the specified disease/topic at your laboratory
Test / For / Specificity / TotalELISA / Antibody / TGEV & PRCV / 15
ELISA / Antibody / Differentiate TGEV/PRCV / 8
ELISA / Antigen / TGEV & PRCV / 15
CCIF* / Antigen / TGEV & PRCV / 15
SN (plaque reduction) / Antibody / TGEV & PRCV / 15
RT-PCR and nested PCR / Viral RNA / Differentiate TGEV/PRCV / 15
CCIF – cell culture immunofluorescent test using ST cells
2. Production and distribution of diagnostic reagents
The diagnostic reagents described in the above tests have been produced and standardized in our laboratory as indicated in our previous publications. They have been routinely provided in varying amounts depending on demand to diagnostic labs in the U.S., Canada, other OIE member countries and elsewhere as requested for reference reagents. In 2006/2007 they were provided to the American Type Culture Collection (ATCC) who will distribute them worldwide, including to be used as reference reagents for group I, II and III coronaviruses when testing for SARS or other coronaviruses in animals.
Part II: Activities specifically related to the mandate
of OIE Reference Laboratories
3. International harmonisation and standardisation of methods for diagnostic testing or the production and testing of vaccines
Besides within the U.S. and Canada, diagnostic tests, procedures or reagents have been provided to laboratories in Vietnam, China, Korea, South America and the Soviet Union to use for the detection and differentiation of TGEV and PRCV infections. These include highly specific monoclonal antibodies and reagents prepared in germfree animals and reference antibody positive and negative sera.
4. Preparation and supply of international reference standards for diagnostic tests or vaccines
Our lab was designated as a WHO reference lab for Animal Coronaviruses in 2004 and is part of the SARS WHO lab network. In this capacity we will supply TGEV/PRCV and bovine coronavirus strains and antisera to other WHO reference labs and to other international labs including those of OIE member countries through the ATCC.
Monoclonal antibodies (MAbs) specific for the N and S TGEV proteins have been produced and common or unique epitopes on the S protein of various strains of TGEV and PRCV defined. MAbs have been provided to various researchers and diagnostic labs noted in #3. TGEV strains (virulent and attenuated) and PRCV strains, ST cells and antisera have also been provided. We also have S or N gene clones as needed for research or diagnostic assays. A baculovirus expressed TGEV S protein worked well to replace TGEV for coating plates for ELISA antibody tests and could be tested commercially.
5. Research and development of new procedures for diagnosis and control
We developed a respiratory viral co-infection animal model for coronaviruses (CoVs) by infecting pigs with the immunosuppressive porcine reproductive and respiratory syndrome virus (PRRSV) followed by porcine respiratory coronavirus (PRCV). Our findings imply that the presence of existing or prior immunomodulating respiratory viral co-infections in individuals may be a contributing factor to more severe pneumonia and worse prognosis and alters innate immunity in co-infected hosts.
Detection of multiple respiratory pathogens was common in SARS patients during outbreaks and is common in animals. However, it is unclear how the respiratory viral co-infections influence disease outcome or accelerate CoV shedding in co-infected individuals. It is likely that co-infections by other respiratory viruses modulate innate immune responses and affect the severity of disease, but this has not been tested comprehensively in an animal respiratory CoV disease model.
Co-infected animals had reduced weight gains, higher incidence of fever and more severe pulmonary lesions compared to infection by the individual viruses alone. Immunologic data revealed that suppression of innate immunity by the ongoing PRRSV infection enhanced early PRCV replication and exacerbated PRCV pneumonia. PRCV infection also led to enhanced PRRSV replication in lung, further exacerbating PRRSV pneumonia. Collectively, our observations suggest interactive effects between PRCV and PRRSV via early innate and later adaptive immune responses. Our findings have potential relevance to more severe pneumonia and a worse prognosis in individuals with existing or prior immunomodulating respiratory viral co-infections. They further provide valuable insights into host-pathogen interactions related to co-infections by CoVs, including SARS-CoV, and other respiratory viruses.
In addition PRCV, but not PRRSV induced increased levels of nitric oxide (NO) both in vivo (in bronchoalveolar lavage fluids) and in vitro (in infected alveolar macrophages). The NO induced inhibited PRCV, but not PRRSV replication in vitro. Thus NO may play a role in innate immunity by reducing PRCV replication in lung, and its absence in PRRSV infection may contribute to PRRSV persistence in alveolar macrophages.
6. Collection, analysis and dissemination of epizootiological data relevant to international disease control
See publications below.
7. Provision of consultant expertise to OIE or to OIE Members
We provided expertise to APHIS and NVSL, USDA, and FDA labs in the U.S. and to Canadian labs concerning issues, samples and PCR assays for testing of swine or food samples for TGEV and PRCV or antibodies for export.
We provided similar information on RT-PCR or antigen testing for TGEV/PRCV to the Veterinary Diagnostic Services in Canada and to the Veterinary Diagnostics Lab in Ho Chi Minh City, Vietnam. We provided PRCV strains to researchers.
We presented an invited talk and participated in discussions at the symposium, “Practical Alternatives to Reduce Animal Testing in Quality Control of Veterinary Biologicals in the Americas” in Buenos Aires, Argentina, February 18-19, 2010. The title of the talk was “Efficacy testing of vaccines for enteric infections: Correlates and concerns for mucosal vaccines”.
In capacity as Head of OIE reference lab, attended the Second Global Conference of OIE Reference Laboratories and Collaborating Centres OIE Headquarters, Paris, France, June 21-23, 2010.
8. Provision of scientific and technical training to personnel from other OIE Members
Dr Anastasia Vlasova, Post-doctoral Researcher, Soviet Union
Dr Kwonil Jung, Post-doctoral Researcher, Korea
Dr Feng Li, Visiting Scholar, China
Dr. Zongzhao Yang, Visiting Scholar, China
Dr. Ning Chen, Visiting Scholar, China
Dr. Quan Shen, Visiting Scholar, China
Mr. Zhenwen Zhang, Visiting Scholar, China
Ms. Celina Vega, Visiting Scholar, Argentina
Ms. Marina Bok, Visiting Scholar, Argentina
Mr. Enrique Uriate, Visiting Scholar, Argentina
Mr. Seraj Khan, Visiting Scholar, India
Dr. Vito Martell, Visiting Scholar, Italy
Dr. Pierfrancesco Pinto, Visiting Scholar, Italy.
9. Provision of diagnostic testing facilities to other OIE Members
We mainly provided diagnostic reagents (monoclonal antibodies, RT-PCR primers, hyperimmune antisera, cell lines, virus strains, reference positive and negative sera, etc.) and test protocols to colleagues in member countries. This is because it is difficult to import foreign animal specimens into the US for testing.
10. Organisation of international scientific meetings on behalf of OIE or other international bodies
Participated in the OIE/Fundacion PROSAIA sponsored symposium in Buenos Aires, Argentina, entitled “Practical Alternatives to Reduce Animal Testing in Quality Control of Veterinary Biologicals in the Americas”.
11. Participation in international scientific collaborative studies
In addition to the instances cited, we are pursuing collaborative studies on diagnosis and immunity to TGEV and PRCV and coronaviruses with Dr K.O. Cho, Dr S.Y. Kang, Korea; Dr Luis Enjuanes, Spain; Dr To-long Thanh, Vietnam; and DrAlexei Zaberazhny, Soviet Union; Drs Viviana Parreno and Fernandez Fernando, Argentina.
In January 2004, our lab was designated by WHO as an international reference lab for animal coronaviruses. In this capacity we will supply TGEV/PRCV strains and antisera to other WHO reference labs and to other international labs through the ATCC.
12. Publication and dissemination of information relevant to the work of OIE (including list of scientific publications, internet publishing activities, presentations at international conferences)
¡ Scientific publications in peer-reviewed journals
1. Jung, K., G.J. Renukaradhya, K.P. Alekseev, Y. Fang, Y. Tang and L.J. Saif. 2009. Porcine reproductive and respiratory syndrome virus modifies innate immunity and alters disease outcome in pigs subsequently infected with porcine respiratory coronavirus: implications for respiratory viral co-infections. J. Gen. Virol. 90:2713-23.
2. Jung, K., A. Gurnani, G.J. Renukaradhya and L.J. Saif. 2010. Nitric oxide is elicited and inhibits viral replication in pigs infected with porcine respiratory coronavirus but not porcine reproductive and respiratory syndrome virus. Veterinary Immunol. Immunopathol. 136:335-9.
3. Renukaradhya, G.J., Alekseev, K.P., Jung, K., Y. Fang and L.J. Saif. 2010. Porcine reproductive and respiratory syndrome virus-induced immunosuppression exacerbates the inflammatory response to porcine respiratory coronavirus in pigs. Viral Immunol. 23:457-66.
¡ Other communications
Book Chapters
1. Saif, L.J., M. Pensaert, K. Sestak, S.G. Yeo and K. Jung. 2011. Coronaviruses. In: Diseases of Swine. 10th Ed (J.J. Zimmerman, et al, Ed.), Ames, IA, Blackwell Publishing (in press).
2. Saif, L.J. 2010. Reoviridae, Coronaviridae. In: Fenner’s Veterinary Virology, 4th Ed (J. MacLachlan & E. Dubovi, Eds). Elsevier, The Netherlands.
Proceedings
1. Saif, L.J. 2010. Efficacy testing of vaccines for enteric infections: Correlates and concerns for mucosal vaccines. Proc. of Symposium, “Practical Alternatives to Reduce Animal Testing in Quality Control of Veterinary Biologicals in the Americas”, Buenos Aires, Argentina, ISBN: 978-987-25861-0-2, Ed. Fundacion PROSAIA, 2010, pages 52-61.
Abstracts and presentations
1. Saif, L.J., K. Jung, G.J. Renukaradhya, and X. Zhang. Respiratory viral co-infections and corticosteroid treatments influence disease. Proc. Conference of Research Workers in Animal Diseases, Chicago, IL, December 6-8, 2009, Abstract.
2. Renukaradhya, G.J., K. Alekseev, K. Jung and L.J. Saif. Altered immune responses to porcine respiratory coronavirus in pigs previously infected with porcine reproductive and respiratory syndrome virus: a respiratory viral co-infection model. Proc. Conference of Research Workers in Animal Diseases, Chicago, IL, December 6-8, 2009, Abstract
3. Saif, L.J. 2010. Efficacy and potency testing of vaccines for enteric pathogens: Correlates and concerns for mucosal vaccines. Symposium, “Practical Alternatives to Reduce Animal Testing in Quality Control of Veterinary Biologicals in the Americas” in Buenos Aires, Argentina, February 18-19, 2010, Abstract.
13. Inscription of diagnostic kits on the OIE Register
i) Did you participate in expert panels for the validation of candidate kits for inscription on the OIE Register? If yes, for which kits?
None
ii) Did you submit to the OIE candidate kits for inscription on the OIE Register? If yes, for which kits?
None
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Annual reports of OIE Reference Laboratories and Collaborating Centres, 2010 5