[Genotyping of Japanese encephalitis viruses isolated in Yunnan].
OBJECTIVE
Explore the genotype of the epidemic Japanese encephalitis virus (JEV) in Yunnan Province from molecular level and to understand the molecular differences of the virus isolated from Yunnan at different time, locality and host.


METHODS
Three-day suckling mice were inoculated with viruses continuously and when the disease developed and the mice were dying, the brain was taken and DNA was extracted from the supernatants of the brain after grinding; then the gene fragments of Prm-C region were amplified by RT-PCR. The viral gene sequences were compared with those of other 72 strains of JEV originated from both China and abroad at different times. Finally the genotypes were analyzed with the method which was established by Woan-Ru Chen.


RESULTS
All the 3-day suckling mice which were inoculated with the virus died within 78 h. The results of the nucleic acid-sequence analysis showed that 17 strains of the experimental virus belonged to genotype 1 and 2 strains belonged to genotype 3. The difference between genotype 1 and type 3 were more than 15%. While the difference between 17 strains of genotype 1 which were separated at different time, location and hosts were only 3.8%-5.2%.


CONCLUSIONS
The above results suggest that the genotype of the epidemic JEV in Yunnan Province are type 1 and 3 and the latter is the main type.
Yunnan Institute of Endemic Disease Control and Prevention, Dali, China.
Jing-lin
JL
Wang
Hai-lin
HL
Zhang
Ji-hua
JH
Zhou
Guo-dong
GD
Liang
D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000473:pathology / Q000821:virology*; D002681:China; D004664:Encephalitis Virus, Japanese / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D004672:Encephalitis, Japanese / Q000821:virology*; D005838:Genotype; D051379:Mice; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014759:Viral Envelope Proteins / Q000235:genetics
D012367:RNA, Viral; D014759:Viral Envelope Proteins; C074932:prM protein, Flavivirus