A long-term survey on the distribution of the human rotavirus G type in Thailand.

The distribution of the G type of human rotavirus was surveyed in Thailand between July 1993 and June 2007. A significant yearly change in the distribution of the G type distribution was found. From 1993-1994 to 1998-1999, the G1 type was the most dominant. In 1999-2000, G9 began to appear at a high frequency. In 2000-2001, 2001-2002, and 2002-2003, G9 was very common. In 2003-2004, G1 became the most prevalent type again, and since then it has been detected at the highest frequency. G12 strains, which were first detected in 1998-1999, were also found in 2004-2005 and 2006-2007. The G4 and G3 types were moderately prevalent in 2001-2002 and 2004-2005, respectively. Nucleotide sequence analysis of the VP7 genes of the G9 and G12 strains which reemerged in Thailand showed that they were each similar to the contemporary strains in other countries.