Karel A. Schat, DVM, PhD
Department of Microbiology and Immunology
Dr. Schat is a Professor in the Department of Microbiology and Immunology. He received the DVM degree from the State University, Utrecht, The Netherlands in 1970, and his PhD from Cornell University in 1978 studying virology. Since 1978, he has held successive positions at the College of Veterinary Medicine, Cornell University. He has obtained continuous funding (USDA, NIH, etc.). Throughout his career he has obtained continuous extramural funding to study avian virology and especially Marek's disease and recently chicken infectious anemia virus. He received the Pfizer Award for Excellence in Poultry Research at the 136th Annual Convention of the AVMA in New Orleans, July, 1999, and the Merck Award for Achievement in Poultry Science at the 98th Annual meeting of the Poultry Science Association in Auburn, August, 2005. In 2006, he will be working on the pathogenesis of infection with highly pathogenic avian influenza H5N1 strains in a joint project between the Australian Animal Health Laboratory (AAHL) of the CSIRO Livestock Industries, the CDC, and the College of Veterinary Medicine. This research will be conducted in the high containment facilities of AAHL during two 3-month periods. See for details: http://www.news.cornell.edu/stories/Nov05/Schat_avian_flu.kr.html.
Research
The following projects are currently in progress:
Marek’s disease (MD), a herpesvirus induced lymphoma in chickens. A major part of the research is focused on the interactions of cytokine responses and NO production in the pathogenesis of infection with very virulent strains of MD virus. Those strains have emerged over the last 5 to 10 years and are linked to new diseases syndromes. The role of pp38, an early antigen, in the pathogenesis is being examined using a tet-inducible cell line. Several new splice variants of the pp38 gene have also been identified and are being analyzed for their importance for viral replication and latency.
Chicken anemia virus (CAV), a circovirus causing immunosuppression. Recently it was determined that co-infection of CAV with MD virus or reticuloendotheliosis (RE) virus resulted in the absence of MD or RE virus-specific CTL 7 days post infection. In the future those studies would be continued to determine the impact of CAV infection on specific cell-mediated immune responses. 2.B. Transcriptional control of latent CAV: CAV can remain latent for long periods in gonadal tissues even in the presence of virus-neutralizing antibodies. Low levels of CAV DNA can be detected in embryonal tissues and gonads, while CAV RNA can be detected in embryos during specific embryonal development stages. Based on the presence of hormone receptor element (HRE) sequences in the promoter/enhancer region of CAV, it appears that CAV transcription is controlled by host reproductive hormones. This is being examined in embryos and in theca and granulosa cells from adult hens. 2.C. The possible use of antigen-antibody complexes as vaccines are being investigated.
Impact of West Nile virus (WNV) on American Crows. The introduction of WNV into the USA has caused major mortality in American Crows. However, some crows survive infection and develop virus-neutralizing antibodies, suggesting that differences in MHC class II genes may be important for survival. The Schat laboratory has begun to analyze variations in exon 2 of the beta chain of MHC class II in a large population of crows that were positive or negative for WNV. In addition, we are analyzing the same variations in house sparrows.
In collaboration with the CDC and the Australian Animal Health Laboratories (AAHL) (part of CSIRO Livestock Industries) Dr. Schat is examining the importance of specific mutations in H5N1 strains of Avian Influenza. These studies are conducted by Dr Schat in the high containmenat facilities of AAHL.