Seroepidemiology of Herpes Simplex Virus Type 1 in Yanji, Jilin, China

Transcription

1 Seroepidemiology of Herpes Simplex Virus Type 1 in Yanji, Jilin, China Microbiol. Immunol. Vol. 34 (6), , 1990 Yu-Yu LI,1 Yasufumi HIDAKA,*,1 Yoichiro KINO,2 and Ryoichi MORI1 1 Department of Virology, School of Medicine, Kyushu University, Fukuoka, Fukuoka 812, and 2The Chemo-Sero- Therapeutic Research Institute, Okubo Shimizu, Kumamoto, Kumamoto 860 (Accepted for publication, April 25, 1990) ôgh ô Abstract ôgs ô Sera from 158 individuals in Yanji, Jilin, China, were tested for antibodies to herpes simplex virus type 1 (HSV-1) by the passive hemagglutination method. Age-specific incidence rates for antibodies to HSV-1 were calculated. For sera from persons in the age group 10 years or less, the positive rate was 54% but in the age group higher than 10 years, it was more than 91% (P<0.01). In the part of China surveyed, primary HSV-1 infection occurred in early generation before about age 10. In children, the positive rate in the Han race was significantly higher than that in the Korean race (P<0.05). Seroepidemiological studies of herpes simplex virus (HSV) type 1 (HSV-1) have been performed in many countries (5, 7-10, 12). The incidence of antibodies to HSV-1 increases with age but varies considerably with socioeconomic conditions (3, 5, 7, 9, 10). Our group has reported a difference in age distribution of anti bodiesto HSV-1 among the sera from Fukuoka, Manila, Busan, and Indonesia (1, 4). Since no seroepidemiological studies on HSV-1 infection in China have been reported, sera from 158 individuals in Yanji, Jilin, an area in northeastern China, were tested for antibodies to HSV-1 by the passive hemagglutination (PHA) method. All the sera were collected from healthy individuals between November 1988 and March 1989; 94 sera were from males and 64 sera from females. In this area two races, the Hans and the Koreans, live together at about a 1:1 population ratio and their customs are different; for example, they have two languages-one race is educated in Chinese and the other in Korean. Therefore this area has been used for various epidemiological studies on the incidence of such diseases as gastric cancer in these races. In this study, 95 sera were collected from Hans and 63 from Koreans. The PHA cells (Phassay-HSV, The Chemo-Sero-Therapeutic Research In stitute)were prepared as follows: HSV-specific glycoproteins were purified from HEp-2 cells infected with HSV-1 KOS strain by lentil lectin affinity chromatography (Pharmacia). Sheep erythrocytes fixed with glutaraldehyde were sensitized with the glycoproteins by the tannic acid method. The PHA was performed as described 551

2 552 Y.-Y. LI ET AL Fig. 1. Relation between age and level of PHA antibody to HSV in sera from healthy individuals. ( œ), Han male; ( ), Han female; ( ), Korean male; ( ), Korean female. Fig. 2. Relation between age and HSV antibody-positive rate. by Hashido and Kawana (2) and Matsunaga et al (6). Briefly, fourfold dilutions of test serum (1:100 to a maximum 1:102,400) were prepared in a V - bottom 96-well microplate. After dilution, a suspension of the sensitized cells was

3 NOTES 553 Table 1. HSV antibody-positive rate according to race * Significantly different between races at P<0.05 (x2 test). ** Significantly different between races at P<0.01 (x2 test). added, the plate was agitated with a plate mixer, then allowed to stand for 3hr at room temperature. Individual titers of PHA antibody to HSV-1 in serum samples plotted against age are shown in Fig. 1. The positive rates versus age are shown in Fig. 2. The incidence of antibody to HSV-1 was dependent on age. The positive rate in the 1- to 10-year age group was 54%, which is significantly lower than in any other age group (P<0.01, x2 test). The positive rate in young adults in China was surprisingly high. In the area of our survey, almost all people suffered HSV-1 infection before age 10. The difference in positive rate between males and females was not significant (P>0.05). Their rates were almost the same in each age group. As for the difference between races, the incidence in the Han race was 98% and that in the Korean race was 79% (Table 1). This difference was significant (P<0.01) and it was mainly due to the difference in the 1- to 10-year group, which was significant (P<0.05). In the 1- to 3-year group the incidence in the Han race was 100% (1/1) and that in the Korean race was 25% (1/4) and in the 4- to 10-year group that in the Han race was 86% (6/7) and that in the Korean race was 42% (5/12). These numbers tested were too small and the differences were not significant (P>0.05) but the data was not opposite to the difference in the two races. In the young adult and adult age groups, the incidences in the two races were not significantly different (P>0.05). For the measurement of antibody to HSV-1, various methods, such as the neutralization test (NT), complement fixation test (CF), or enzyme-linked immuno sorbentassay, have been used (4, 5, 8, 10, 11). In this study, we measured antibody to HSV-1 by using the PHA test. In comparison of the antibody titer in the PHA and the NT test, the two titers correlated well with each other (the manufacturer's "Manual of Phassay"). Furthermore, this method can detect specific antibodies to HSV infection and is as sensitive as the NT test (2). In addition to these points, since this method is simple and faster than other methods, the PHA test is considered to be a useful method for measuring antibodies to HSV-1, though antibody to herpes simplex virus type 2 cannot be distinguished from that of HSV-1 by this PHA test.

4 554 Y.-Y. LI ET AL In Japan and other industrial countries, an increase in the seronegative rate in young adults has been demonstrated (5, 7, 9, 10). We reported previously that the rate of seropositive young adults has decreased in Fukuoka, though the positive rate was 87% in the 11- to 20-year age group in Busan (4). In the present study the positive rate in 11- to 20-year-olds was 91%; therefore this area of China is now one of the most HSV-1 prevalent areas in the world. The newborn infants of young seronegative young women constitute one of the major problems of HSV infection because the babies cannot be protected from generalized HSV infection, which is fatal (11). Therefore, it is important to survey the rate of antibody to HSV-1 in adults. Fortunately, in the area surveyed in China, the HSV-1 anti bodypositive rate in adults including the age group of pregnant women is very high. However, we believe that the age distribution of HSV-1 antibody in China may shift to that in Japan in the future, because the style and environment in Chinese life are rapidly changing to those of other industrialized countries. Therefore it will be necessary to check the HSV-1 antibody positive rate in young adults in China again some years later. The difference in positive rate between the two races may be explained by differences in customs. The Hans feed their babies mouth-to-mouth more fre quentlythan the Koreans. The Korean fathers and mothers usually have jobs outside the home but the Han mothers usually stay home and take care of their children. The difference in HSV-1 infection in the young generation may be due to these differences in customs. We thank Dr. Mary L. Robbins for reviewing the manuscript. REFERENCES 1) Haksohusodo, S., Sakuma, S., Kino, Y., and Mori, R Seroepidemiology of herpes simplex virus in Yogyakarta, Indonesia. Microbiol. Immunol. 33: ) Hashido, M., and Kawana, T Measurement of herpes simplex virus antibodies using a passive hemagglutination assay and its application to the prediction of the time of infection. Clin. Virol. 16: (in Japanese). 3) Hashimoto, K Sero-epidemiology of herpes simplex virus infection-prevalence of neu tralizingantibodies of pregnant women in several regions. Clin. Viroḷ 10: (in Japanese). 4) Hayashi, Y., Nagata, M., Yoshizumi, H., Mori, R., Navarro, C.V., and Yang, H.D Difference in age distribution of antibody to herpes simplex virus in Fukuoka, Manila and Busan. Jpn. J. Med. Sci. Biol. 37: ) Hondo, R A seroepidemiological study of herpes simplex virus. Jpn. J. Med. Sci. Biol. 27: ) Matsunaga, S., Zaitsu, K., Kanaike, H., Kotani, T., and Otaki, Y Measurement of herpes simplex virus antibodies using Phassay-HSV. Rinsho-Kensa-Kiki Shiyaku 9: (in Japanese). 7) Smith, I.W., Peutherer, J.F., and MacCallum, F.O The incidence of herpes virus hominis antibody in the population. J. Hyg. 65: ) Tateno, I., Yokoyama, T., Suzuki, S., Sugiura, A., and Fukaya, I Age distribution of the neutralizing antibody to herpes simplex virus. Jpn. J. Exp. Med. 28: ) Terzin, A.L., and Masic, M.G Age-specific incidence of neutralization antibodies of herpe s simplex virus. J. Hyg. 77:

5 NOTES ) Ukkonen, P., Hovi, T., von Bonsdorff, C.-H., Saikku, P., and Pettinen, K Age-specific prevalence of complement-fixing antibodies to sixteen viral antigens: a computer analysis of 58,500 patients covering a period of eight years. J. Med. Virol. 13: ) Yeager, A.S., Arvin, A.M., Urbani, L.J., and Kemp, J.A. III Relationship of antibody to outcome in neonatal herpes simplex virus infections. Infect. Immun. 29: ) Yosbino, K., Taniguchi, S., Furuse, R., Nojima, T., Fujii, R., Minamitani, M., Tada, R., and Kubota, H A serological survey for antibodies against herpes simplex virus with special reference to comparatively heat-labile complement-fixing antibodies. Jpn. J. Med. Sci. Biol. 15: (Received for publication, February 14, 1990)