／Research Collaboration Center for Infectious Diseases Section of Viral Infections
A variety of arboviruses are prevalent in Thailand located in the tropics, of which we investigate chikungunya fever from an epidemiological, molecular biological, and immunological points of view. We focus on exploring the cellular factors necessary for viral replication with the experimental system of knock-out and -in cell libraries of susceptible cells, and chikungunya pseudovirus. In addition, we try to isolate virus from clinical samples and establish the reverse genetics system to clarify the characteristics of zika virus, another arbovirus which has been endemic long-termed in Thailand.
Another target is norovirus, a major cause of both sporadic cases and outbreaks of nonbacterial acute gastoroenteritis in all age groups worldwide every year. We investigate whether or not it is possible to predict the genotypes of norovirus which are involved in new epidemics by evolutionary phylogenic analysis with special reference to genotyping of epidemic strains. In addition, recent epidemiological analysis has revealed that "asymptomatic persons" who do not develop acute gastroenteritis even when infected with norovirus, might play a significant role as reservoirs in new outbreaks. Noroviruses highly evolve with diversification of their genome through mutation and recombination, which allows them to protect themselves from human host immunity and sustain their transmission in human communities. We try to clarify the retention and transmission of norovirus in asymptomatic persons, especially involvement in genome diversification to elucidate the actual condition of asymptomatic carriers. On the other hand, we try to explore cellular factors necessary for virus propagation in cells to establish a culture system of norovirus, which remains still difficult to grow in vitro yet.
- Prof.(concur.): Takeshi Kobayashi
- SA Assoc. Prof.: Hiroto Mizushima
- SA Assoc. Prof: Atsushi Yamanaka
- (1) Norovirus transmission mediated by asymptomatic family members in households. Phattanawiboon B., et al. PLoS One (2020) 23;15(7)
(2) The use of green fluorescent protein-tagged virus-like particles as a tracer in the early phase of chikungunya infection. Tumkosit U., et al. (2019) Virus Res. 272:197732
(3) Genome-Wide Screening Uncovers the Significance of N-sulfation of Heparan Sulfate as a Host Cell Factor for Chikungunya Virus Infection. Tanaka A. et al J.Virol. 2017, 91 e00432-17
(4) Distribution of norovirus genotypes and subtypes in river water by ultra-deep sequencing-based analysis. Boonchan M et al. Lett Appl Microbiol. 2017 65:98-104.
(5) Evolutionary constraints on the norovirus pandemic variant GII.4_2006b over the five-year persistence in Japan. Sato H et al Frontiers in Microbiology 2017 8:410