[Survey on host animal and molecular epidemiology of hantavirus in Chuxiong prefecture, Yunnan province].
OBJECTIVE
To determine the hosts of hantavirus (HV) and its molecular epidemiological characteristics, to provide evidence for prevention and control on hemorrhagic fever with renal syndrome (HFRS).


METHODS
Rodents were captured by a special trap within the residential area. The antigens of HV in lung tissues were detected by direct immuno-fluorescence assay (DFA). Nucleotide sequences of HV were amplified by RT-PCR with HV genotype-specific primer. The amplified genes were then sequenced. Phylogenetic tree were built on nucleotide sequence with ClustalX 1.83 software.


RESULTS
1421 rodents were captured and classified into 8 species of 4 Genera in the epidemic area within 10 counties of Chuxiong prefecture, Yunnan province, between 2005 and 2006. Out of the 1421 rodents, 1056 (74.31% ) of them were Rattus norvegicus and 280 (19.70%) belonged to Rattus flavipectus. The antigens of HV were detected by DFA in lung tissues and the total positive rate of HV was 5.15% (53/ 1029). After applying the sequencing nucleotide method to the 53 positive specimens, data showed that 21 specimens were positive and all of them belonged to Seoul type (15 samples were from Rattus norvegicus, 4 samples Rattus flavipectus, 2 samples Rattus nitidus). The partial S segments from 12 specimens were sequenced which appeared homologic with R22, L99 and HLD65 from GenBank in relatively high level (87.1% -99.7%). When compared to 76-118 strain of Hantaan type, their homologic degree was only 64.4%-69.1%. Results from Phylogenetic analysis showed that 12 specimens belonged to Seoul type. As for their homology, they were significantly similar to Seoul type and could be tentatively divided into two subtypes S1 and S3.


CONCLUSIONS
It was confirmed that the Seoul type virus, as HFRS's pathogenetic agent mainly carried by rats, prevailed widely in Chuxiong prefecture. Owing to the local ecological environment, we also noticed the characteristics of different HV subtypes among Seoul type.
Zhou
Ji-Hua
JH
Yunnan Institute of Endemic Disease Control and Prevention, Dali 671000, China.
Zhang
Hai-Lin
HL
Wang
Jing-Lin
JL
Yang
Wei-Hong
WH
Mi
Zhu-Qing
ZQ
Zhang
Yun-Zhi
YZ
Zhang
Yu-Zhen
YZ
Song
Xian-Yi
XY
Hu
Qiu-Ling
QL
Dong
Ying-Kuan
YK
Pu
Wen-Hua
WH
Hu
Hai-Mei
HM
Gao
Li-Fen
LF
Yuan
Qing-Hong
QH
Ya
Hong-Xiang
HX
Feng
Yun
Y
D000818:Animals; D000914:Antibodies, Viral; D002681:China / Q000453:epidemiology; D004199:Disease Vectors; D006476:Orthohantavirus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D006480:Hemorrhagic Fever with Renal Syndrome / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D012367:RNA, Viral / Q000235:genetics; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D029263:Seoul virus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D017423:Sequence Analysis, RNA
D000914:Antibodies, Viral; D012367:RNA, Viral