Shigeru Ozawa

Contrasting Geographic Distribution Profiles of the Herpes Simplex Virus Type 1 BgOL and BgKL Variants in Japan Suggest Dispersion and Replacement

ABSTRACT Thelifelong latent infection-reactivation mode of infection of herpes simplex virus type 1 (HSV-1) transmitted by close contact has allowed a diversity of restriction fragment length polymorphism (RFLP) variations to accumulate in human populations. Whether and how the variants of the HSV-1 that is ubiquitous worldwide spread to different human populations is not clear. In our previous study the geographically gradient distribution of the HSV-1 BgKL variant, which is a good marker for the BgKL:SaCFJM:SaGHM:SaD/EL:KpMS variant, suggested that BgKL dispersed geographically. Southern hybridization analyses showed that in BgKL the BglII cleavage site between the BglII K and small “Q/#13” fragments is lost, the SalI cleavage sites between the SalI J and C and between SalI F and J fragments are lost, and the SalI E fragment is abnormally large (SaEL variation). The RFLP and geographic distribution of one more HSV-1 RFLP variant, BgOL, were comparatively analyzed. The BglII cleavage site between the BglII O and Q/#13 fragments is lost in BgOL. BgOL clinical isolates were not associated with any of the SaCFJM, SaEL, SaGHM, or KpMS variations, whereas one-fourth of the non-BgOL:non-BgKL isolates was associated with SaCFJM and SaGHM, indicating that BgKL and BgOL are distant in terms of diversification. BgOL is distributed highly in the northeastern region and the southwestern island of Kyushu but is rare between the two regions in Japan, in a remarkable contrast to BgKL. These are the first epidemiologic data to show contrasting geographic distribution profiles of two HSV-1 variants and suggest the gradual dispersion and replacement of HSV-1 variants.

Geographical Distribution of the Herpes Simplex Virus Type 1 BgKL Variant in Japan Suggests Gradual Dispersion of the Virus from Shikoku Island to the Other Islands

ABSTRACT Restriction endonuclease fragment length polymorphism (RFLP) is useful for the epidemiological study of herpes simplex virus type 1 (HSV-1). We report here the identification of a major BglII RFLP variant of HSV-1, designated BgKL, found in 27.0% of 636 HSV-1 clinical isolates. We have also established its geographic distribution in Japan. BgKL has an unusually large BglII K fragment. SalI cleavage analyses showed that 97% of BgKL variant isolates lack both the SalI C-J and the F-J cleavage sites and have an unusually large SalI D or E fragment, and 91% of the BgKL variants lack both SalI G and H fragments. Furthermore, 96% of BgKL isolates have an unusually small KpnI M fragment. Therefore, BgKL is a marker for these five mutations in most HSV-1 isolates and is a useful HSV-1 RFLP marker. The BgKL variant was found in 59% of HSV-1 isolates from Shikoku Island, 44% of HSV-1 isolates from the Chugoku region of Honshu Island, 31% of HSV-1 isolates from Kyushu Island, 0% of HSV-1 isolates from Okinawa Island, 49% of HSV-1 isolates from Osaka, 27% of HSV-1 isolates from Shiga, 13% of HSV-1 isolates from the Chubu Region, and 9% of HSV-1 isolates from the Tohoku Region of Honshu Island. Differences in the frequency of BgKL between the Shikoku-Chugoku-Osaka area (49%) and Kyushu, between Kyushu and Okinawa, between the Shikoku-Chugoku-Osaka area and Shiga, and between Shiga and Tohoku are all statistically significant. The BgKL frequency decreases in a geographical gradient suggest that this HSV-1 variant was dispersed from Shikoku to the surrounding regions and then to more distant regions. The BgKL frequency in Tokyo was similar to the nationwide average. These are the first data to suggest a geographic and demographic dispersion pattern of HSV-1. Implications for the epidemiology and diversification of HSV-1 are discussed.

Analysis of herpes simplex virus type 1 restriction fragment length polymorphism variants associated with herpes gladiatorum and Kaposi's varicelliform eruption in sumo wrestlers.

The geographical distribution of herpes simplex virus type 1 (HSV-1) restriction fragment length polymorphism (RFLP) variants BgK(L) and BgO(L) and the high relative frequency (RF) of BgK(L) in orolabial lesions has led to a dispersion-replacement hypothesis for these variants. The pathogenic properties of HSV-1 variants in mice and professional sumo wrestlers were examined here. The wrestlers herpes gladiatorum (HG) was caused by primary and non-primary HSV-1 infections and recurred in many wrestlers. HSV-1 neutralizing antibody titres in sera from wrestlers who did not develop HG were relatively high. HG was caused by distinct HSV-1 variants and strains from wrestlers living in the same sumo stable. The BgK(L) RF was significantly higher in HG cases, particularly in those with Kaposis varicelliform eruption. These data indicated that reactivation and transmission of latent HSV-1 infections, especially BgK(L), occurred frequently among wrestlers and was caused by severe skin damage. These results support the BgK(L) dispersion hypothesis.

The Herpes Simplex Virus Type 1 BgKL Variant, Unlike the BgOL Variant, Shows a Higher Association with Orolabial Infection than with Infections at Other Sites, Supporting the Variant-Dispersion-Replacement Hypothesis

ABSTRACT The identification and geographic distribution of the herpes simplex virus type 1 (HSV-1) BglII restriction fragment length polymorphism (RFLP) variants named BgKL and BgOL in clinical isolates from orolabial and cutaneous sites were described in our previous reports, in which the dispersion and replacement of HSV-1 variants were proposed. The base substitution sites deduced from the BgKL multiple RFLP variations were mapped to the UL12 (DNase), RL2 (α0 transactivator), and latency-associated transcript genes in the present study. The results show that the relative frequencies (RFs) of BgKL are significantly higher in orolabial and cutaneous HSV-1 infections than in ocular infections. For the BgOL variant, the opposite was found; i.e., the RF of BgOL was significantly lower in orolabial and cutaneous infections than in ocular infections. No significant differences in the RFs of non-BgKL:non-BgOL isolates were observed. The ratio of the BgKL RF to the BgOL RF was much higher for the orolabial and cutaneous infection groups than for the ocular infection group, whereas the BgKL RF-to-non-BgKL:non-BgOL RF ratios for the former groups were slightly higher than those for the latter group. The higher efficiency of orolabial and cutaneous infections caused by BgKL compared to the efficiency of infections caused by BgOL allows BgKL to spread more efficiently in human populations and to displace BgOL, because the mouth and lips are the most common HSV-1 infection sites in children. The present study supports our HSV-1 dispersion-and-replacement hypothesis and suggests that HSV-1, the latency-reactivation of which allows variants to accumulate in human populations, has evolved under competitive conditions, providing a new perspective on the polymorphism or variation of HSV-1.

[Probe types of Norwalk-like viruses genome detected by RT-PCR with seven primer pairs in Yamanashi Prefecture].

The reverse transcription-polymerase chain reaction (RT-PCR) gene assay, as well as electron microscopic examination, is commonly used to detect Norwalk-like viruses (NLVs). Types and number of primer pairs used are considered to be of critical importance for efficiency of the RT-PCR detection. This study was performed to determine primer pairs useful for the detection of NLVs. NLVs genes were detected by RT-PCR in 48 cases in Yamanashi Prefecture between December 1997 and March 2000. The probe type of the gene was G2P-C in 21, G2P-B in 10, G2P-A in 6, G1P-A in 3, G1P-B in 2, and a mixture of G2P-A and G2P-B in 6. The NLVs genes of G2P-C and G2P-B were estimated to have undergone mutation in the polymerase region and poorly specific to the primer pair 35/36, a combination that has been used most commonly for the RT-PCR assay in Japan. The primer pair G2R1/F1 that amplifies the capsid (CAP) region of NLVs genes can detect all NLVs genes of the Genogroup2. The combination of this primer pair with another primer pair G1R1/F1, which like G2R1/F1, amplifies the CAP region, makes discrimination between NLVs of different groups possible. Consequently, this combination, may be the most useful for the NLVs detection by RT-PCR.