Who We Are

Longhorn Vaccines and Diagnostics, LLC is a closely held, veteran-owned company. With an emphasis on innovation, the company has developed unique, groundbreaking products for the molecular testing market that meet critical unmet needs in both the Developed and Developing World.


Gerald W. Fischer, MD, is the Chairman and Chief Executive Officer of Longhorn and an internationally recognized leader in pediatric and infectious disease care and research. He received a B.A. from Lewis and Clark College in 1968 and an M.D. from the University of Oregon Medical School in 1971. In the mid-1980s, he was the lead investigator of the multi-site clinical trial of polyclonal antibodies to prevent bacterial infections in premature babies, which led to the discovery that anti-RSV antibodies could prevent RSV pneumonia. Dr. Fischer served as the Director of Pediatric Research for the Uniformed Services University of the Health Sciences and directed a large clinical Pediatric Infectious Disease program at the Walter Reed Army Medical Center. He was appointed Professor of Pediatrics in 1981 and was named a Fellow in the Infectious Disease Society of America. He has written 12 book chapters and over 100 peer-reviewed journal articles on preventing and treating infections in children.  Dr. Fischer has been the CEO of multiple biotechnology companies since he co-founded Virion Systems Inc. in 1988, supporting the development of multiple products to include MedImmune's Synagis.

Jeff Fischer, MBA, is the President of Longhorn and is responsible for oversight of all non-scientific aspects of the organization to include regulatory affairs. Mr. Fischer co-founded the company and has served as its Chief Financial Officer from 2007-2017. From 1998-2005, Mr. Fischer served as an executive vice president and CFO in the biotechnology industry. He is a former infantry officer in the United States Marine Corps and holds an MBA from the University of Texas at Austin.

Luke T. Daum, Ph.D. is Executive Vice President and Chief Scientific Officer for Longhorn Vaccines and Diagnostics. He received a B.S. from the University of Michigan, Ann Arbor (1996), an M.S. from Central Michigan University (1999) and a Ph.D. in Cell & Molecular Biology from the University of Texas at San Antonio (2006). Starting in 1999, he worked as a Civilian Scientist for the Air Force Institute for Operational Health (AFIOH). Dr. Daum possesses extensive experience with respiratory pathogens, molecular epidemiology and the development of pathogen diagnostics. He has trained several AF personnel, has published over 25 peer-reviewed scientific papers on molecular diagnostics, has presented over 50 scientific abstracts and lectures, and holds several patents.

Chris Helm, MBA, is the Executive Vice President of Global Business Development. Originally from South Africa, Chris has lived and worked in the UK, US, China, Japan and Hong Kong, and brings over 30 years of international business knowledge and experience to the organization.  Chris holds a BS in Agricultural Economics from the University of Reading, England and an MBA in International Business from the Shidler College of Business at the University of Hawai`i where he later taught in their Japan, China, and the Vietnamese EMBA programs in Honolulu and Hanoi.  After a marketing and business development career in animal genetics, health and nutrition, Chris founded the Asia Pacific Marketing Group in Hong Kong with offices in Hanoi and Ho Chi Minh City, and then held concurrent positions of Senior Advisor to the Vice President of Research and Interim Director, Office of Research Services, at the University of Hawaii, helping to run all of the university-wide research, before joining Cellular Bioengineering Inc in Honolulu as Director, Commercial Operations.

Dawn Litterio, CPA, MBA, is the Chief Financial Officer.  Dawn is responsible for all the accounting, financial reporting, and human resource aspects of the company. She has worked in a similar capacity in the biotech industry for the past 15 years, for a total of over 30 years’ experience in accounting and finance in other industries. Dawn holds a BBA in Accounting from Loyola University, New Orleans and an MBA from the University of Maryland.  She is also a licensed CPA in the state of Maryland.