CONG TRiNH NGHIEN CIJU - ORIGINAL PAPERS
OAC D\tM DjCH T 6 HUYtT THANH HOC CUA HOI CHU'NG NAO CAP DO VIRUS BANNA 6 VIET NAM, 2002 - 2012
Phan Thj Ng^, Biii Minh Trang, DSng Thu Thao, Nguyin Thdnh Luan Ho^ng Minh Dire*, Do Phirtfng Loan, Futoshi Hasebc**, Kouichi Morita**
Vi^'it Vg sinh Dich re Trung uang. Ha N^i, Vi^t Nam
* Cue Y te dtf phoiig, B0 Yie, Vift Nam
** Vien Yhpc Nhi^t d&i, Truirng dgi h{ic Nagasaki, Nhqt Ban
TOM TAT
Si> dgng ky thuat ELISA IgM gi^n tiep phat hi^n IgM kh^ng virus Banna tir 717 mlu djcti nio tuy cCia b^nh nhan Hgi chOng nao cap (HCNC) khong ro nguyen nhan dugc thu Ihap tLF9 linh/lhanh pho omJen Bac, Trung, Nam va Tay Nguyen, 2002 - 2012 Ket qua xac iJinh du-ang tinh trung binti VOT khang nguyfen virus Banna la 184/717 (25,66 %).Trenca so-nay, mat s6tJacdi6mdjch tStiuyetthanti hoc HCNC do virus Banna du'p'c xacdmh nhu'sau (1)Ty lexacdmh du'ong tinh la 13,63%-35,83 % trong so 9 tinh/thanh ptioco miu xet nghiem phat hien IgM khang virus Banna, (2) Cac tru'cmg hap xac dinh duang linh du'oc ghi nhan quanh nam, nhu'ng tap trung chCi yeu trong cac thang he 5, 6 va 7 vai fy le xac dinh du'ong tinh cao nhat la 34,78%
trong thang 6; (3) Sy phan bo cac truong hop duong tinh khac nhau theo nhom tuoi, thap nhat a nhom
< 1 tu6ila5,98%, cao nhat o nhom > 15tu6i la 28,26%; cac nhom tuoi khac dao dpng 19,02%-23,91 %.
Ti> khoa: Virus Banna, Reoviridae, hoi chung nao cap, IgM ELISA gian tiep I. DAT \ A N D E
Co rat nhieu tac nhan vims gay hgi chirng nao cap (HCNC) da dugc ghi nhan nhu virus viem nao Nhat Ban, virus dirdng rugt, virus Herpes simplex type 1,2... trong so nay virus viem nao Nhat Ban dugc ghi nhan la mot trong nhCrng nguyen nhan hang dau gay viem nao cho Ire em [1],[2]. Trong thap ky gan day, mot loai virus moi, virus Banna da dtrgc phat hien tir benh nhan HCNC va sot khong ro nguyen
nhan a Trung Quoc, nam 1987. Day la mot loai virus do muoi truyen thugc chi Coltivirus, ho Reoviridae [3],[4],[5].
O Viet Nam, virus Banna dugc phan lap va phat hien dau tien tu djch nao tiiy ciia benh nhan nu 3 tuoi a tinh Gia Lai nam 2005 [2], Tiep do, nghien ciru hoi cuu ciJng phat hien mot chijng virus Banna gay HCNC cho benh nhan nam 14 tuoi a Thanh Hoa, tu nam 2003 bang ket qua phan lap va dinh loai virus (so lieu chua cong bo). Nghien ciJru xac dinh sir luu
Tac gia' Phan Thi Nga
Dia chi: Vien Ve sinh Dich tl Trung ucmg Dienthoai: 0912816922
Email: [email protected]
Ngaynhanbai: 16/11/2012 Ngay dang bai: 28/02/2013
12 Tap chi Y hoc dir phong. Tap XXIII, so 1 (136)
hanh ciia virus Banna da xac dinh day la mot loai virus luu h^nh rat ph6 bi6n trong quin th8 mu6i a khu vuc chau A [3,4, 5, 6, 7].
Nghien cuu ve dich tl huy6t thanh hgc virus Banna 6 Trung Quoc dira tren ket qua xet nghiem 1141 mlu huyet thanh ciia b?nh nhan viem nao do virus 6 nhidu viing khac nhau, ty 16 xac dinh duong tinh voi khang nguyen virus Banna dao dgng trong khoang 0 - 27,3 % [7], Tuy nhien a Viet Nam, cho d6n nay chua c6 cong bo nao ve chan doan va giam sat huyet thanh hgc nguyen nhSn virus Banna gay HCNC.
Trong nghien cuu nay, khang nguyen vims Banna tinh che bSng phucmg phap sucrose gradient dugc sir dung lam khang nguyen gan ban de phat trien ky thuat ELISA gian tiep phat Men IgM tir djch nao tiiy ciia benh nhan HCNC nham muc dich xac dinh can nguyen virus Banna gay HCNC va 6^c diem dich te huyet thanh hgc HCNC do virus Banna a mot so tinh thanh cua Viet Nam, 2002 - 2012.
II. PHlTOfNG P H A P N G H I E N ClTU 2.1. Vat lieu
Mdu benh pham: Colli mlu dich nao tuy cua benh nhan HCNC nghi ngo do virus khong ro can nguyen de phat hien IgM khang virus Batma.
Dia diem, th&i gian thu thap mau: Cac mSu dich nao tiiy dugc thu thap tai benh vien cua mot so tinh a mien Bac, mien Trung, mien Nam va Tay Nguyen, 2002 - 2012.
Sinh ph&m: Cac sinh pham sir dung cho ky thuat ELISA IgM gian tiSp phat hien IgM khang virus Banna tu dich nao tuy ciia benh nhan bao gom khang nguyen virus Banna tinh ch6 CO ham lugng khang nguyen 0,5 mg/ml, cong hop la IgG khang IgM ngutri gan enzyme peroxidaze ciia hang SIGMA.
Cac sinh phSm, hoa chat va thi6t bi can thiet khac d6 thuc hien ky thuat ELISA va ky thuat
trung h6a tren te bao.
2.2. Phu'ong phap
Thiet ke nghien cuu: Nghien ciru thyc nghiem trong phong thi nghiem.
Boi tir0tg nghien ciru: Dich nao tiiy cua benh nhan c6 hgi chirng nSo c5p khong ro nguyen nhan nghi ngo do virus thu thap trong cac nam 2002-2012.
Dja diem thu thgp mau: Tai 9 tinh/thanh pho bao gom BSc Giang, Ha Ngi, Ha Tay (cii), Hai Phong, Thai Binh, Thanh Hoa, Hue, Gia Lai, Long An.
Ky thu^t ELISA gian tiep phat hi^n IgM:
Nguyen ly ky thuat: Ky thuat ELISA IgM gian tiep dira tren nguyen ly sir dung khang nguyen virus Banna tinh che dugc gan tren ban nhita vai ham lugtig khang nguyen gan ban la 50 ng/gieng. Cho tiep xuc vai dich nao tiiy ciia benh nhan (pha loang 1/10), neu trong mau dich nao tiiy c6 khang the khang virus Banna, no se ket hop vgi khang nguyen virus Banna. Tiep theo sir dung cong hop la IgG khang IgM nguai gan enzyme peroxydaze, no se ket hop dac hieu voi khang the IgM ngudi neu CO trong mau xet nghiem. Cho mot phuc hop CO chat khong mau Ortho-Phenylendiamin (OPD CO Hydrogen Peroxide, duoi su xuc tac cua Hydrogen Peroxide, ca chat khong mau phan img vai enzyme peroxydaze de tao thanh mau vang. Dimg phan ling bang axit sulfuric, mau vang chuyen thanh mau nau. Su c6 mat Ciia IgM dac hieu khang virus Banna dugc xac dinh bang su chuyen mau; mau chirng am va cac mau xet nghiem khong c6 IgM khang virus Banna se khong xuat hien mau. Ket qua xet nghiem se dugc ghi nhan bang mat do quang hgc (Optical density viet tat la OD).
Tieu chuan nhan dinh kit qua OD chimg am, chimg Blank < 0.200; OD chung duang >
0.400, cac mlu duong tinh khi OD ty s6 (P/N) cua mau xet nghiem/OD chiing am > 3 (Ky thuat dugc xay dung va thirc hien tai Vien Ve Tap chi Y hoc du phong, T§p XXIII, so 1 (136) 13
sinh Dich te Trung uong).
Ky thuat trung hoa: Chung virus su dyng de thuc hien ky thuat trung h6a c6 ky hi?u 05VN255 de phat hien khang the trung h6a khang virus Banna tir 5 mlu djch nSo tiiy cua benh nhan da dugc xac dinh duong tinh bang ky thuat ELISA phat hi?n IgM (Ky thuat dugc thuc hi?n tai Vi?n Y hgc Nhi?t ddi T r u ^ g Dai hgc Nagasaki, Nhat Ban). Tieu chuan nhan dinh ket qua: Gi^ tn nguSng giim 50% dim hoai tu.
III. K E T QUA
Co 717 mau dich nao tiiy dugc thu thap tir benh nhan HCNC nghi nga do virus thugc 9 tinh/thanh pho trong khoang thai gian 2002 -
2012, cac mlu dich nSo hiy da dugc kiem tra am tinh v6i khang nguyen virus viem nao Nhat Ban bang ky thuat MAC-ELISA. Blng k? thuat ELISA gian tigp phat hien IgM khang virus Banna tir cdc mlu dich nao tiiy, kSt qua xac djnh ty 1? trung binh cdc mau dich nao tiiy phat hi?n CO IgM khang virus Banna la 25,66 %.
Trong s6 9 tinh/thanh ph6 c6 mlu benh phim x^t nghiem, ty le xac djnh ducmg tinh dao dgng trong khoSng 13,83% - 35,83%. Tinh/thanh ph6 CO mlu xet nghi?m duong tinh cao nhat a tinh Ha Tay cu la 35,83 %, tiep den la Ha Ngi c6 ty le xac dinh duong tinh v6i khang nguyen virus Banna la 34,00%; Ty 1? xac dinh duong tinh thap nhat voi khang nguyen virus Banna la 13,63 %.a tinh Bac Giang.
Bang 1. Ket qua xac djnh IgM khang virus Banna trong djch nSo tuy b^nh nhan HCNC, 2002 - 2012
K h u VLPC
Mi§n Bic
Mi^n Trung Tay nguyen Mien Nam long so
Tinh
B^c Giang Ha Tay (cu) HaNoi Hai Phong Thai Binh Thanh Hoa Hue Gia Lai Long An
So mau xet nghiem
216 120 50 48 108 65 18 20 72 717
So mlu du^ng tinh
30 43 17 11 36 21 4 5 17 184
Ty 1? % (•)
13,63 35,83 34,00 22,92 33,33 32,31 22,22 25,00 23.61 25,66
Tap chi Y hoc du phong, Tap XXIII, s6 1 (136)
' So mau xit nghif m n So mau dinmg tinh
Hinh 1. SIP phan bo theo thang cac truing ho-p HCNC xac djnh do virus Banna, 2002 - 2012 HCNC do virus dugc ghi nhan xay ra
quanh nam, nhung so mac dugc ghi nhan chii yeu trong cac thang 5,6 va 7, dinh cao ciia djch dugc ghi nhan trong thang 6 vai so mac dugc ghi tihan la 239/717 (chiem 33,33 % tong so mac). Bang ky thuat ELISA IgM gian tiep, cac
tntong hgp HCNC xac djnh dirong tinh voi khang nguyen virus Banna dugc ghi nhan quanh nam, nhung so cac mac dirge ghi nhan chii yeu trong cac thang 5,6 va 7, so mac cao nhat dugc ghi nhan trong thang 6 la 64/184 (chigm 34,78
% tong so cac tnrong hgp duong tinh).
Bang 2. SIP phan bo theo tuoi cac tru'O'ng ho-p HCNC xac djnh do virus Banna, 2002 - 2012
Nhom tuoi
So m l u xet nghiem
So m l u duong tinh
Ty ie % (+) di^ong tinh
<1
61
11
18,03
1 - 4
159
35
22,01
5 - 9
183
44
24,04
10-14
141
42
29,79
>15
173
52
30,06
Tap chi Y hoc dtr phong, Tap XXIII, s6 1 (136)
Ket qua xet nghiem cho thay, cac tnrong hgp xac dinh Banna duong tinh dirge ghi nhan 6 tat ca cac nhom tuoi, ty le xac dmh duong tinh dao dpng trong khoang 18,03 % - 30,06%, cy the ty
le xac dinh duong tinh voi khdng nguyen virus Banna 6 nhom tre < I tu6i la 18,03 %, 1- 4 tu6i la 22,01 %, 5- 9 tu6i la 24,04 %, 1 0 - 1 4 tu6i la 29,79 % va tren 15 tu6i la 30,06 %.
Bang 3. Ty I9 s6 mlc HCNC do virus Banna theo nh6m tu6i, 2002 - 2012
<1 n = 61
1 - 4 n = 159
3 - 9
n = 183 n = 141 n = 173 Tong 50
S6 m l u du'ong tinh
Ty le so mite theo nhom tu6i
Trong so 717 truong hgp HCNC khong ro nguyen nhan, xac dmh c6 184 truong hgp xac dinh duong tinh voi khang nguyen virus Banna, cac truong hgp xac djnh duong tinh dugc ghi nhan a tat ca cac nhom tuoi, Tuy nhien, ty le nhiem virus Banna a nh6m tre duoi 1 tuoi la thap nhat 5,98 %, ty le so mac HCNC do virus Banna a nh6m tuoi > 15 la cao nhat chiem
28,26 %; Cac nhom tuoi khac, ty le so mac dao dgng trgng khoang 19,02 - 23,91 %. Trong so 184 truong hgp xac dinh duong tinh voi khang nguyen virus Banna, c6 39,13 % truong hgp dugc xac djnh tir benh nhan nil: (72/184), c6 60,87 % truong hgp dugc xac dinh tir benh nhan nam (112/184), nhu vay ty le sg mac HCNC do virus Banna o nam cao hem nii.
Bang 4. Doi chieu ket qua giQ<a ky thuat trung hoa va ky thuat ELISA IgM gian tiep
Ky hieu mau
04CSF 42 04CSF 56 04CSF 78 04CSF 164 04CSF 333
Ky thuat ELISA
GiatrjP/N . (ELISA) > < " ' " ' "
19,03 Du-angtinh 20,01 Du'ong tinh 104,11 Di/ong linh 41,99 Duo'ng tinh 30,02 Ducng tinh
Ky thu|t trung hoa tren te bao
Hieu gia khang the trung hoa
<10 20 125 135
<10
Ket iuan
Am tinh Du'O'ng tinh Du'ong tinh Duong tinh Am tinh
Tap chi Y hoc du phong. Tap XXIII, s6 1 (136)
Co 5 mlu dich nao tiiy c6 ty s6 P/N duong tinh cao dugc xac dinh biing ky thuat ELISA IgM gian ti8p, ki^m tra lai bSng ky thuat trung hoa tren te bao theo nguyen ly Focus assay vai chung virus c6 ky hieu 05VN255, ket qua xac djnh CO 3 mlu dich nao tiiy xac dinh duong tinh bang ky thuat trung hoa tren te bao d6 la cac mlu dich nao tuy c6 ky hi?u 04CSF 56, 04CSF 78 va 04CSF 164 vai hieu gia khang the trung hoa tucmg ung doi voi mSu dich nao tuy o d d pha loang 1/20, 1/125 va 1/135. Day la bang chirng khang dmh virus Banna la tac nhan gay HCNC va xac dinh do tin cay ciia ky thuat ELISA gian tiep phat hien IgM trong chan doan giam sat c3n nguyen virus Banna gay HCNC.
IV. BAN LUAN
Trong chan doan ph6ng xet nghiem doi vai virus arbo c6 tinh huong than kinh, tieu chuan vang de xac dinh ca benh la phat hien dugc khang the khang virus trong dich nao tiiy, boi vi binh thuong, trong djch nao tiiy khong CO khang the dac hieu khang virus, khang the chi xual hien trong dich nao tuy de thirc hien chuc nang bao ve khi c6 tac nhan virus xuat hien gay benh cho to chuc nao bg [1]. Do vay, khi phat hien dugc khang the dac hieu khang mot loai virus nao do ciing dong nghTa voi viec khang dinh virus do la tac nhan gay benh. De phat hien IgM khang cac virus arbo noi chung, ky thuat MAC-ELISA dugc cgng nhan la ky thuat chuan thirc diing trong chan doan benh va dugc ap dung rgng rai trong chan doan viem nao Nhat Ban va sot xuat huyet dengue vi day la ky thuat c6 do nhay va dac hieu cao [1].
Nhirag de phat trien ky thuat MAC-ELISA d6i voi mot tac nhan virus moi nhu virus Banna la van de khong don gian, nhung phat tnen ky thuat ELISA gian dep phat hien IgM c6 the d6 dang thiet ke de thir nghiem, Trong nghien cuu
nay, ky thuat ELISA gian ti8p phat hien IgM da dugc su dung de phat hien IgM dac hieu khang virus Banna tir mlu dich nao tuy ciia benh nhan c6 tinh chat nhu la mot ky thuat sang Igc. Ket qua cho thay xet nghiem dich nao tiiy tir benh nhan HCNC a 9 tinh, ty le xac djnh duong linh trung binh la 25,80 % (bang 1).
Virus Banna do muoi truyen dugc xac dinh luu hanh a Viet Nam, c6 nhieu loai muoi dugc xac djnh la vec-tg hoac c6 the la vec-to truyen virus, do vay neu lua chgn huyet thanh benh nhan de chung minh khang the ciia benh nhan trung hoa virus Banna c6 the se nham Ian voi khang the do nhiem tu nhien tnroc day hoac nhiem cheo voi khang nguyen cimg mot chi virus. Nen trong nghien ciiu nay mau dich nao tuy dugc lua chgn de phat hien khang the khang virus Banna bang ky thuat ELISA phat hien IgM gian tiep se la bang chiing khang djnh virus Banna la tac nhan gay HCNC [1].
De xac djnh ket qua duong tinh bang ky thuat ELISA phat hien IgM gian tiep, c6 5 mau dich nao tiiy duong tinh dugc lua chgn de kiem tra lai bang ky thuat trung hoa tren te bao, ket qua CO 3 mau duong tinh dugc khang dmh bang ky thuat trung hoa (bang 4). Tuy nhien, viec thuc hien ky thuat trung hoa rat phirc tap va can c6 nhieu thai gian de thirc hien, cho thay nghien cim phat trien ky thuat chan doan nhanh huyet thanh hgc c6 do nhay va dac hieu cao can dugc thirc hien trong nghien cmi tiep theo.
Cac truong hgp xac dinh duong tinh voi khang nguyen virus Banna dugc ghi nhan quanh nam, nhung tap trung chii yeu trong cac thang he 5,6 va 7 voi dinh cao ciia dich la thang 6 (hinh I). Trong so cac truong hgp xac djnh duong tinh, nhom tre < 1 tuoi c6 ty le so mac thap nhat chiem 5,98 % tong so mac; Cac nhom tuoi khac ty )e so mac dao dgng trong khoang 19,02 % - 28,26 %. Trong do ty le so mac cao nhat la nhom tuoi tren 15 la 28,25 % (bang 3).
Ket qua nay c6 diem phii hgp voi mot dac diem Tap chi Y hoc dir phong, Tap XXIII, so 1 (136) 17
do nhiem Arbo virus gay HCNC nhu virus viem nao Nhat Ban, d6 la ty le so mac 6 nhom duoi 1 tuoi rSt thap, nhung ty le so mac virus Banna 6 nhom tuoi > 15 cao hem cac nhom khac la 28,26
% (bang 3), thong thucmg ty le so mSc HCNC do virus viem nSo Nhat Ban o nhom tuoi > 15 khoang 10%[1].
Virus Banna la mot lo^i virus mdi dugc phat hien a Vict Nam trong thap ky vira qua, nhmig lieu chi khang dinh khang the tir benh nhan trung hoa dugc virus cho den nay van chua CO cong bo. Trong nghien ciru nay, mgt so mau djch nao tiiy xac dinh duong tinh biing ky thuat ELISA dugc kiem tra lai b3ng ky thuat trung hoa tren te bao (Focuss assay) d3 xac dinh khang the tir djch nao tuy ciia benh nhan HCNC trung hoa virus Banna phan lap tir benh nhan Viet Nam (chiing virus c6 ky hieu 05VN255). Day la tieu chi de khang dinh virus Banna la tac nhan gay benh theo gia dinh ciia Koch va dugc River cai bien [1]. Nghien ciru de xac dinh dac diem lam sang HCNC do virus Banna va dac diem phan tir ciia virus Banna phan lap tir benh nhan o Viet Nam can dugc thuc hien trong nhiing nghien ciru tiep theo.
V. KET LUAN
Xet nghiem 717 mau djch nao tuy ciia benh nhan HCNC khong ro can nguyen bang ky thuat ELISA gian tiep phat hien IgM khang virus Banna da xac djnh c6 184/717 mau duong tinh 25,8%. Tir ket qua cac truong hgp xac djnh duong tinh trong cac nam 2002 - 2012 da xac djnh; (I) Ty le xac dinh duong tinh vol khang nguyen virus Banna dao dong trong khoang 13,83% - 35,83 % tiiy theo cac dia phuong khac nhau; (2) Ty le xac djnh duong tinh vai khang nguyen virus Banna dugc ghi nhan quanh nam, nhung tap trung chii yeu trong cac thang 5, 6, 7 va 8 voi so xac djnh duong tinh cao nhat trong thang 6 la 34,78%; (3) Ty le xac
djnh duong tinh vcd khang nguyen virus Banna khac nhau theo cac nhom tuoi, cu the thap nhat 1^ nhom < 1 tu6i la 5,98 %, cao nhat la nhom
> 15 tu6i la 28,26%), cac nhom 1 - 4 tuoi, 5 - 9 tu6i v^ 10 - 14 tu6i dao dgng 19,02 % - 23,91
%; (4) Ty le xac djnh ducmg tinh voi khang nguyen virus Banna a nam cao hon 6 nil tuong irng la 60,87 %va 39,13%.
TAI L I E U T H A M K H A O
1. DSng Dire Anh, Nguyen Thj Hong Hanh, Phan Thi Nga. Virus Y hgc. Nha xuat ban Y hgc 2010: 7 - 2 7 va 1 1 5 - 135.
2. Phan Thi Ngi, Nguyen Thanh Thiiy, Biii Minh Trang, Nguyen Thj Tuan, Dang Tuan Dat. Phat hien mot thanh vien virus thugc ho Reoviridae gay hgi chimg nao cap o Gia Lai, 2005. Tap chi Y hgc du phgng 2007, tap 17 so 2 (87): 5 - 9 .
3. Hoang Minh Dire, Biii Minh Trang, Tong Thi Ha, Vu Sinh Nam, Phan Thj Nga. Xac dinh cac loai muoi c6 kha nang la vec to ciia virus Baima o Viet Nam, 2001 - 2011. Tap chi Y hgc du phong, tap XXil, so 4 (131):
1 4 8 - 155.
4. Brown S E, B M Gorman, R B Tesh, and D L Knudson (1993), Coltiviruses isolated from Mosquitoes Collection in Indonesia.
Virology Journal 1993, 196(89): 363-367.
5. Lm H., Li M. H., Zhai Y. G., Meng W. S., Sun X. H., Cao Y X., Fu S. H., Wang H, Y, Xu L. H., Tang Q., Liang G. D. Banna vhus, China, 1987 - 2007. Emerging Infectious Disease 2010, Vol 16 No 3: 5 1 4 - 5 1 7 . 6. Nabeshima T, Nga P T, Guillermo P, Parquet
M, C Yu F, Thuy N T, Trang M B, Hien N T, Nam V S, Inoue S, Hasebe F and Morita K.
"Isolation and molecular characterization of Banna virus derived from mosquitoes in Northern and Central Vietnam", Imerginng Infecdous Disease 2008, 14 (8): 1276 - 18 Tap chi Y hoc dir phong, Tap XXIII, s6 1 (136)
1279. in China. Clinical Medical Journal 2005, 7. Tao S. J., Chen B. Q. Studies of Coltivirus 118 (7): 581 - 586.
SERO-EPIDEMIOLOGICALCHARACTERIZATION OF ACUTE ENCEPHALITIS DUE TO BANNA VIRUS IN VIETNAM, 2002 - 2012
Phan Thi Nga, Bui Minh Trang, Dang Thu Thao, Nguyen Thanh Luan Hoang Minh Due*, Do Phuong Loan, Futoshi Hasebe**, Kouichi Morita**
National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
* General Department of Preventive Medicine, Ministry of Health
** Institute of Tropical Medicine, Nagasaki University, Japan
Using indirect ELISA IgM technique detected IgM anti Banna virus from 717 cerebrospinal fluid samples of patients who has acute encephalitis syndrom unknown causes were collected from 9 provinces/cities in the North, Central, South and Highland Central from 2002 to 2012. Positive results identified the Banna virus antigen average is 184/717 (25.66%). On these results, sero-epidemiological characteristics of acute encephalitis syndrome virus Batma is determined as follows: (I) Propotion positive was ranged from 13.63 % - 35.83 % of the 9
provinces/cities, where samples were collected for the detection of IgM against Banna virus;
(2) The positive cases were recorded all year round, but mainly in summer months May, June and July with highest prositive cases in June to be 34.78 %; (3) The distribution positive cases by age groups were different age group, the lowest in age group < I year old was 5.98 %i, the highest in age group > 15 year olds was 28.26%), other age groups ranged 19.02 % - 23.91 %.
Keywords; Banna virus, Reoviridae, acute encephalitis sindrome, Indirect IgM ELISA
Tap chi Y hoc du phong, Tap XXIII, so 1 (136)
