Human herpesvirus 7 (HHV-7) is the least studied beta-herpesvirus in transplant settings. This prospective study examined the activity of HHV-7 during the first 12 weeks post-stem cell transplant in 59 paediatric patients. The presence of HHV-7, human cytomegalovirus (HCMV) and human herpesvirus 6 (HHV-6) in blood was monitored weekly by a multiplex nested polymerase chain reaction. Overall, 33 (55.9%) patients had one or more surveillance blood sample(s) positive for HHV-7. In contrast to HCMV and HHV-6, no obvious peak time of reactivation was observed for HHV-7. The occurrence of HHV-7 DNAaemia showed a significant negative association with HHV-6 (P = 0.022), but with no association with HCMV. A significant higher positive rate for HHV-7 was found in autologous versus allogeneic (P = 0.002), and in peripheral blood versus umbilical cord/marrow (P < 0.001) transplant. Acyclovir had no effect, whereas ganciclovir was associated with a lower rate of HHV-7 reactivation (P = 0.009). One patient died of HHV-7 associated brain stem encephalitis. The administration of colony stimulating factor, occurrence of acute graft versus host disease, time to neutrophil and platelet engraftment showed no significant association with the occurrence of HHV-7 DNAaemia. J. Med. Virol. 72:668-674, 2004.

Glycoprotein B (gB) and glycoprotein H (gH) of human herpesvirus 7 (HHV-7) are believed to play an important role in virus entry and as targets for host immune response. This study examined the genetic diversity of these glycoproteins among 90 HHV-7 isolates collected from different individuals in Hong Kong. Overall, both the gB and gH genes were found to be highly conserved. Nucleotide polymorphism was detected only at four positions of the gB-encoding region, and all of these were synonymous substitutions. Most (97.8%) Hong Kong isolates were of gB allele group C. Two isolates collected from a Pakistani family showed a novel sequence pattern that did not match known gB allele groups. This sequence pattern was detected consistently from serial samples collected from the same individual, indicating a stable genetic entity. The gH-encoding region exhibited nucleotide polymorphism at six positions. Three of these were nonsynonymous substitutions (codon 271 Lys --> Gln, codon 308 Gly --> Glu, codon 397 Asn --> Tyr). Most (84.4%) Hong Kong isolates were of the gH allele group B, and all others were of the gH allele group C. These data indicate the possibility of using gB or gH alleles as markers for studying world-wide population movements and genetics.

This cross-sectional survey assessed the determinants of human papillomavirus (HPV) infections among 2080 women who participated in cervical cancer screening. HPVs were typed by restriction and sequencing analyses. The prevalence of HPV was 7.3%(4.2% for high-risk, 1.9% for low-risk, and 2.1% for unknown-risk types). High-risk HPV prevalence decreased with age, whereas low- and unknown-risk HPVs had a second peak in older women. Young age was the only common variable associated with the 3 groups of HPV infections. Lifetime number of sex partners was associated with high- and low-risk types but not with unknown-risk HPVs. Previous Pap smear, treatment for cervical lesions, induced abortion, smoking and having smoker(s) in the family were risk factors for high-risk HPVs. Barrier contraception was protective for low-risk HPVs; current vaginal discharge had a negative association with unknown-risk HPVs. The results indicate that different risk profiles exist for infections with different HPV groups.

Human papillomavirus (HPV) type 58 has been found to be prevalent among Chinese patients with cervical cancer. This study examined the oncogenic risk of HPV58 variants in Hong Kong, a southern part of China. Altogether, 1924 women were studied: 42.8% with a normal cervix, 16.2% with cervical intraepithelial neoplasia (CIN) I, 12.7% with CIN II, 20.8% with CIN III, and 7.6% with invasive cervical cancer (ICC). The overall prevalence of HPV58 was 11.4%(220) and increased statistically significantly with the severity of neoplasia (P(trend)<.001, chi(2) test for trend). Among HPV58-positive women, the occurrence of E7 632C-->T (T20I) and E7 760G-->A (G63S) variants (T20I/G63S) showed a positive trend of association with the severity of neoplasia (P(trend)<.001, chi(2) test for trend). HPV58 variants carrying these two substitutions showed an odds ratio (OR) for ICC of 26.79 (95% confidence interval = 10.14 to 74.72), and this OR was 6.9-fold higher than the ORs of variants without these substitutions. Patients with CIN III or ICC who were also infected with T20I/G63S variants had a statistically significant younger age at diagnosis than those infected with other variants (median age = 37 years versus 48 years; P =.038, two-sided Mann-Whitney U test). Thus, HPV58 variants carrying E7 T20I/G63S substitutions may be associated with an increased risk for cervical cancer.

A case-control study was conducted on 1986 Hong Kong women to assess the risk of human papillomavirus (HPV) type 16 variants for cervical neoplasia. In total, 255 women were HPV-16 positive and were analyzed for E6 and E7 sequence variation. Two novel substitutions at E6 (T86I and Q116E) and 1 at E7 (R66W) were found. Most HPV-16 variants were of Asian (50.6%) or European (44.3%) lineage, and both lineages showed similar risk associations for high-grade and invasive cervical neoplasia. No increased risk was observed for the subclasses European variant and European 350G, which carry a higher risk for invasive cancer in some Western populations. The E7 N29S substitution, reported to have a higher risk in Korean women, was found equally distributed among normal and various degrees of neoplasia. The epidemiology and risk implication of HPV-16 variant infection in Hong Kong differ markedly from other parts of the world.

Previous studies have suggested that a few uncommon human papillomavirus (HPV) genotypes are prevalent in Chinese cervical cancer patients. To elucidate the genotype spectrum of HPVs circulating among Hong Kong Chinese, a cross-sectional study was conducted on 553 women who attended a public sexually transmitted disease clinic. HPV DNA was detected from cervical samples using the polymerase chain reaction, followed by genotype identification based on restriction fragment length polymorphism and direct sequencing. The prevalence of HPV was 30.6% for all types combined, 14.8% for high-risk types, 10.8% for low-risk types, and 7.1% for unknown-risk types. Among the HPV-positive women, 89.9% had single type infections; whereas the other 10.1% harboured more than one HPV type. HPV11 was the most prevalent genotype, detected in 5.1% of subjects; followed by HPV16 (4.9%), HPV58 (4.3%), HPV6 (3.3%), and HPV53 and CP8304 (2.2% each). Other less common genotypes found were HPV18, 33, 39, 61, LVX160, MM4, MM7 (range: 0.7-1.6%); HPV26, 45, 54, 56, 59, and LVX100 (range: 0.4-0.5%); HPV35, 40, 52, 55, 68, MM8, and MM9 (0.2% each). This study shows that HPV58 is the second most common high-risk HPV genotype circulating among Chinese female sexually transmitted disease clinic patients in Hong Kong. This together with previous reports of the high prevalence of HPV58 among Chinese cervical cancer patients accentuate the importance of developing vaccines targeting at this otherwise uncommon genotype.

Controversies exist on the effect of pregnancy on human papillomavirus (HPV) infection. A cross-sectional section study was conducted to compare the prevalence and genotype distribution of cervical HPV infection between pregnant and non-pregnant women in Hong Kong. Cervical samples were collected from 308 pregnant women and from the same number of age-matched controls recruited from a cervical cancer screening center located at the same hospital. HPV was detected by the polymerase chain reaction, followed by genotype identification by restriction fragment length polymorphism and direct sequencing analyses. The prevalence of HPV for pregnant women was 10.1%, without significant variation with age, gestation, gravidity and parity. The prevalence of HPV for non-pregnant group was 11.4% and did not show significant difference when compared to the pregnant group either by overall or age-stratified subgroup analyses. When the analysis was stratified according to the risk-type of HPV infection, still no significant difference between pregnant and non-pregnant groups was observed (all types: 10.1 vs. 11.4%, P = 0.602; high-risk types: 5.8 vs. 7.8%, P = 0.338; low-risk types: 1.0 vs. 2.9%, P = 0.080; unknown-risk types: 3.2% vs. 1.3%, P = 0.105). The results of this study show no evidence for an influence of pregnancy on HPV prevalence, and a majority of HPV-infected pregnant women had normal cervical cytology. HPV positive results in pregnant women per se should be managed conservatively.

Previous studies have suggested a neuroinvasive and neuropersistent potential of human herpesvirus 7 (HHV-7). In this report, a case of fatal encephalitis is described and its association with HHV-7 infection is discussed. An 8-year-old girl received a peripheral blood stem cell transplant for relapsed acute lymphoblastic leukaemia. The post-transplant period was uneventful and a course of intrathecal chemotherapy was given on Day-30. On Day-41, she developed acute encephalopathy with diplopia and nystagmus. She ran a rapid downhill course and succumbed despite antiviral treatment. The only positive pathological finding was the multiple microscopic foci of haemorrhage associated with neuronal degeneration detected in the brain stem. All microbiological investigations were negative, except for the presence of HHV-7 DNA in cerebrospinal fluid and brain stem tissue samples.

Human herpesvirus 7 (HHV-7) is the least studied beta-herpesvirus in transplant settings. This prospective study examined the activity of HHV-7 during the first 12 weeks post-stem cell transplant in 59 paediatric patients. The presence of HHV-7, human cytomegalovirus (HCMV) and human herpesvirus 6 (HHV-6) in blood was monitored weekly by a multiplex nested polymerase chain reaction. Overall, 33 (55.9%) patients had one or more surveillance blood sample(s) positive for HHV-7. In contrast to HCMV and HHV-6, no obvious peak time of reactivation was observed for HHV-7. The occurrence of HHV-7 DNAaemia showed a significant negative association with HHV-6 (P = 0.022), but with no association with HCMV. A significant higher positive rate for HHV-7 was found in autologous versus allogeneic (P = 0.002), and in peripheral blood versus umbilical cord/marrow (P < 0.001) transplant. Acyclovir had no effect, whereas ganciclovir was associated with a lower rate of HHV-7 reactivation (P = 0.009). One patient died of HHV-7 associated brain stem encephalitis. The administration of colony stimulating factor, occurrence of acute graft versus host disease, time to neutrophil and platelet engraftment showed no significant association with the occurrence of HHV-7 DNAaemia. J. Med. Virol. 72:668-674, 2004.

BACKGROUND: Bacterial attachment plays an important role in the initiation of biliary sludge formation and stent blockage. In vitro studies were conducted to determine the effects of adherence factors, namely pili and glycocalyx production, and culture media, including brain heart infusion broth, modified Vogel and Bonner medium, and human bile, on the adherence of Escherichia coli to plastic stents. METHODS: Clinical isolates of E coli with different adherence mechanisms, that is, piliated (P+) or nonpiliated (P-), glycocalyx producing (G+) and nonglycocalyx producing (G-), were obtained from clogged stents. Adherence studies were conducted by using the modified Robbins device, and stents were removed at regular intervals to determine the number of attached bacteria/cm(2) with the viable plate count method. Polyethylene stents were used to compare the adherence curves of E coli with different adherence factors in brain heart infusion broth. The effects of different culture media on the adherence of P+G+ E coli to polyethylene stents were determined. In addition, the adherence of P+G+ E coli to different plastics in brain heart infusion broth and human bile was compared. RESULTS: P+G+ E coli adhered better than P-G+ and P-G- E coli to polyethylene stents. Modified Vogel and Bonner medium, which stimulates glycocalyx production, enhanced the attachment of P+G+ E coli, whereas human bile decreased E coli attachment to polyethylene stents, despite an increase in glycocalyx production. There was a difference in adherence of P+G+ E coli to polyethylene, polyurethane, and Teflon stents in brain heart infusion broth, but the differences were nullified in the presence of human bile. CONCLUSIONS: P+G+ E coli with both adherence factors adhere best to plastic stents. Media such as modified Vogel and Bonner medium that stimulate glycocalyx production also enhance bacterial attachment. The toxic effects of bile salts in human bile on the bacteria might alter the adherence mechanism and reduce E coli attachment.