Areas of Expertise
- Virology
- Emerging and Re-emerging Infectious Diseases
- Molecular Mechanism of Attenuation and Vaccine Development
- Food Safety
- Cell Culture Adaptation of Enteric Viruses
- Interspecies Transmission
- Coronaviruses [porcine Epidemic Diarrhea Virus (PEDV), porcine deltacoronavirus, severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), etc.]
- Caliciviruses (norovirus, sapovirus, etc.)
Research Focus:
Diarrhea is the second leading cause of death among children under the age of 5 and is a common disease for young animals. My current research focus is on enteric caliciviruses and coronaviruses, including diagnosis of viral infections, molecular epidemiology, adaptation of enteric viruses in cell culture, mechanisms of virus attenuation, interspecies transmission of viruses, the mechanisms of enteric virus transmission through leafy greens, and the development of vaccines using conventional and reverse genetics technologies.
Porcine epidemic diarrhea virus (PEDV) causes a high mortality rate (up to 100 percent) in neonatal suckling pigs. To control the disease, an effective vaccine is urgently needed, but none is available in the US. From the studies of other swine enteric viruses (such as rotavirus and transmissible gastroenteritis virus) we know that oral immunization of sows with live attenuated vaccines is the most effective approach to protect newborn piglets against enteric viruses, including the highly virulent PEDV. However, knowledge of the molecular attenuation mechanisms of PEDV and other genetically related coronaviruses is limited. Our laboratory exploits conventional (e.g., cell culture adaptation) and state-of-the-art (e.g., reverse genetics) technologies to generate PEDV strains with reduced virulence, to identify genomic hot spots related to attenuation, and to generate PEDV vaccine candidates. The knowledge gained will advance the development of a safe attenuated PEDV and will aid in innovative vaccine design against other fatal animal and human coronavirus diseases, such as severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS).
Human noroviruses (HuNoVs) are the leading cause of foodborne illnesses in the US. Contaminated food is a major transmission vehicle for this virus. Among all kinds of foods, leafy greens are ranked number one in norovirus-outbreaks, followed by fresh fruits/nuts and shellfish. Our laboratory studies the mechanisms of HuNoV binding to leafy greens, how viral particles are transported from roots to leaves, and if they retain infectivity in plants. Such knowledge will lead to develop technologies to control HuNoV contamination of leafy greens.
Recently, we started to investigate the interspecies transmission mechanisms of porcine deltacoronavirus that infects birds and multiple mammalian species, including humans. We also study bovine coronavirus and try to understand in which situation it causes respiratory and/or enteric diseases in cattle.