The relation between electrophoretic mobility and serological subtype of HBSAg

The electrophoretic mobility of HBsAg in samples of serum has been correlated with subtype of the antigen. HBsAg samples have been placed in three major groups (ad, ay and 'intermediate') by both methods, and there has been 81.6% agreement between subtype and electrophoretic mobility.

The current pattern of hepatitis B virus infection in Australia

There is little recent data of the seroprevalence of hepatitis B in Australia. We have surveyed a large cohort of endoscopy patients attending a teaching hospital in central Sydney, and related the presence of hepatitis B virus (HBV) markers with putative risk factors for exposure using the SAS statistical package. Of the 2115 patients tested: 2.1% (45/2115) were HBV surface antigen positive, 0.75% (14/2115) viraemic, 9.5% (200/2115) anti-HBs and anti-HBc positive, 20.1% (430/2115) vaccinated (anti-HBs only) and the remaining 70% were susceptible. The adjusted OR of HBV infection was significantly increased in patients who had been diagnosed with human immunodeficiency virus (36.3-fold), born in Asia or Pacific islands (12.4-fold), born in North Africa, Middle East & Mediterranean countries (6-fold) or born abroad elsewhere in the world (2.7-fold), had household contact with someone diagnosed with hepatitis between 1980 and 1990 (3.9-fold), injected drugs between 1980 and 1990 (4.4-fold), resided in a military establishment for 3 months (2.3-fold) or in a hospital for 3 months (2.2-fold), never been vaccinated for hepatitis B (2.8-fold), received blood transfusion due to an accident and/or a haemorrhage (1.92-fold) and finally been a male gender (1.59-fold). The prevalence of HBV in this hospital population was higher than predicted on the basis of notifications to the passive surveillance scheme. Most HBV patients had multiple risk factors for infection, but the hierarchy of odds ratios provides a rational basis for targeted programmes to identify asymptomatic HBV carriers who might benefit from treatment.

Risk of hepatitis C virus infection in multiply transfused premature neonates

BACKGROUND

Reports from around the world indicate that multiply transfused patients are at increased risk of hepatitis C virus (HCV) infection, with reported rates of between 4% and 44%. Such reports are mostly of haematological and renal patients. As recipients of blood products in the newborn period, premature infants share this risk, but there is little information regarding their risk.

AIM

To assess the risk of HCV infection in children who, as premature neonates, received multiple blood products prior to the introduction of screening of donated blood for HCV.

METHODS

Premature infants born between January 1985 and January 1990 who had attended our high-risk follow-up clinic were selected on the basis of the number of transfusions of blood, platelets or fresh frozen plasma they received in the newborn period. Ethical approval to offer HCV testing to parents was obtained from the Central Sydney Area Health Service Ethics Review Committee. Parents of infants who received three or more transfusions were then contacted by mail with the approved letter explaining the study, and offered HCV testing. Detection of anti-HCV antibodies was undertaken using second, and later third generation enzyme immunoassay kits. Samples which were found to be 'indeterminate' were tested using a Wellcozyme HCV western blot assay (Murex Diagnostics Ltd, Datford, UK). Hepatitis C virus-ribonucleic acid (RNA) was detected using an 'in-house' polymerase chain reaction (PCR) assay. Alanine transaminase (ALT) was also measured, with values above 55 U/L considered abnormal.

RESULTS

Consent was obtained for 45 children (25 males, 20 females). The mean (+/- SEM) gestational age and weight of the children at birth was 26.7 +/- 0.2 weeks and 938 +/- 27 g, respectively. The children received 198 transfusions of blood products, an average of 4.4 U per child. All of the infants except for one were negative for anti-HCV antibodies. One infant was 'indeterminate' (low positive on third generation test but negative on second generation test), but proved negative subsequently on both western blot and PCR testing. HCV-RNA was not detected in any of the infants on PCR testing. All of the samples had normal ALT values, the mean being 16 U/L (range 8-52).

CONCLUSION

None of the children consenting to this study had evidence of current HCV infection. Because of the sample size, we were not able to estimate the true risk of infection from this study, except that the upper limit for the risk is about 1/200 per transfused blood sample.

Variable oncogene promoter activity of human papillomavirus type 16 cervical cancer isolates from Australia

The functional significance of sequence variation within the upstream regulatory region (URR) of six human papillomavirus type 16 (HPV16) cervical cancer isolates from Australia was investigated. Specific changes in transcription factor binding sites leading to increased promoter activity may explain the transforming ability of some episomal HPV16 isolates.

Squamous carcinoma of the head and neck: molecular mechanisms and potential biomarkers

Squamous cell carcinoma (SCC) of the head and neck remains a major health problem worldwide. Recent advances in cell biology suggest that cancer results from the accumulation of specific genetic mutations, many of which have now been identified. These mutations can cause the activation of genes that promote cellular proliferation or inhibit cell death (oncogenes), or they may inactivate genes that inhibit proliferation or promote cell death (tumour suppressor genes). Although there is no known set sequence of events leading to the formation of SCC of the head and neck, there is evidence that many of the genomic mutations implicated in other forms of cancer have an aetiological role in these tumours. Certain viruses, notably Epstein-Barr virus and some types of human papillomaviruses, are causally related to some head and neck cancers. There is now the prospect of using molecular markers to achieve earlier diagnosis and to aid in the prediction of both tumour behaviour and likely responses to particular treatment modalities.

Analysis of mutations in the URR and E6/E7 oncogenes of HPV 16 cervical cancer isolates from central China

High rates of cervical cancer have been reported from parts of China and this may reflect a predominance of cervical infection with particularly aggressive human papillomavirus (HPV) variants. This PCR-based investigation of cervical tumours from Sichuan province in central China demonstrated an HPV positivity rate of 88%. HPV 16 was most common (21/34, 61%), followed by HPV 18 (3/34, 9%), while types 33, 45, 58 and 59 were each identified in one specimen. Sequencing of up to 1349 bases of the 21 HPV 16-positive isolates, encompassing the enhancer/promoter of the upstream regulatory region (URR) and the E6 and E7 genes, revealed distinct patterns of genomic stability and variability. An overall mutation rate of 5% was seen in the URR. One isolate had a large deletion of 436 bases in the enhancer; while varying combinations of 21 point mutations were identified in the remainder, impacting several YY1, NF1, TEF-1 and Oct-1 sites. More sequence variations were found in E6 compared to E7 (81% vs. 52% of isolates showing at least one mutation), some of which resulted in changes to the translated amino acids. Since the E6/E7 genes encode the oncogenic proteins essential for malignant transformation, and as their expression is controlled by the URR, it is possible that some of the identified mutations altered the oncogenicity of the virus: either directly by changing amino acid sequences of the E6 or E7 oncoproteins, or indirectly through alterations to transcription factor binding sites in the URR.

Hepatitis C in injecting drug-using women during and after pregnancy

BACKGROUND

A high proportion of female injecting drug users (IDU) have evidence of hepatitis C virus (HCV) infection. We undertook a prospective study of patients attending a clinic for pregnant IDU to determine the impact of pregnancy on the course of HCV infection and whether pregnancy is affected by HCV infection.

METHODS

One hundred and thirty-one IDU were recruited and followed up with liver function tests, HCV serology and HCV-RNA tests.

RESULTS

Of 131 patients, 125 had HCV antibodies (anti-HCV positive) at delivery, and of these 62% were HCV-RNA positive. The anti-HCV-negative women were younger and had a shorter duration of drug use than the anti-HCV-positive women. There were no differences between viraemic and non-viraemic women with respect to age, ethnicity, duration of injecting drug use, methadone maintenance dose, hepatitis B exposure or reported high-risk behaviour. Alanine aminotransferase (ALT) levels were higher and the proportion with ALT > 55 IU/L higher in viraemic women. Viraemia persisted in all 55 women who were viraemic at term. Eleven had an ALT flare post-partum that was unrelated to viral load and was clinically unsuspected. Four had concurrent elevated gamma-glutamyltranspeptidase and were considered to be drinking alcohol at hazardous levels. Four of 23 women who were HCV-RNA negative at term became positive during follow up.

CONCLUSIONS

Pregnancy does not adversely affect the course of hepatitis C. A modest rebound in ALT levels, but not HCV-RNA, occurs after delivery in some viraemic women. This supports the theory that immune mechanisms rather than direct viral cytopathology are involved in hepatocyte injury during HCV infection. Hepatitis C infection did not influence pregnancy complications and outcomes.

Evaluation of disinfection and sterilization of reusable angioscopes with the duck hepatitis B model

PURPOSE

Nosocomial transmission of viral hepatitis and retrovirus infection has been reported. The expected risk is greatest for the hepatitis B virus (HBV). The duck HBV (DHBV) has similar biologic and structural characteristics to HBV and has been adopted as a suitable model for disinfectant testing.

METHODS

Angioscopic examination of the external jugular vein was performed on DHBV-infected ducks. After use, the instrument was air dried for 3 minutes. Samples were obtained by flushing the channel with 5 mL of phosphate buffered saline solution. The samples were collected immediately after drying (control), after flushing with 5 mL of water, after glutaraldehyde disinfection for 5, 10, and 20 minutes, and after ethylene oxide gas sterilization. Angioscopes were either precleaned or uncleaned before disinfection/sterilization. Residual infectivity was assessed with inoculation of samples into the peritoneal cavity of day-old ducks (n = 231).

RESULTS

DNA analysis results of liver samples showed that all 38 control ducks became infected. The frequency of DHBV infection was reduced to 93% (14 of 15) by flushing the angioscope with 5 mL of sterile water. No transmission occurred after the use of any of the properly precleaned and disinfected/sterilized angioscopes. However, after the use of the uncleaned angioscopes, the transmission rate was 90% (9 of 10) and 70% (7 of 10) after 5 and 10 minutes of contact time, respectively, in 2% glutaraldehyde. Even after the recommended 20 minutes of contact time, there was still 6% (2 of 35) transmission. After ethylene oxide sterilization, two of the recipient ducklings (2 of 35) were infected with DHBV.

CONCLUSION

There was no disease transmission after reuse of disposable angioscopes adequately cleaned before disinfection or sterilization. However, if the angioscopes are inadequately cleaned, DHBV can survive despite glutaraldehyde disinfection or ethylene oxide sterilization. This contrasts with previous in vitro and in vivo data with solid surgical instruments. It is postulated that the presence of a narrow lumen or residual protein shielding within the lumen may compromise effective inactivation of hepadnaviruses on angioscopes, with the potential risk for patient-to-patient transmission.

Inactivation of duck hepatitis B virus by a hydrogen peroxide gas plasma sterilization system: laboratory and 'in use' testing

Human hepatitis B virus (HBV) is an important cause of nosocomial infections and can be transmitted by contaminated instruments. However, tests of the efficacy of sterilization of materials and equipment contaminated by HBV are difficult to perform because the virus cannot be cultured in the laboratory. In this study, we aimed to evaluate the capability of a low temperature, hydrogen peroxide gas plasma sterilizer (Sterrad, Advanced Sterilization Products, Irvine California,) to inactivate duck hepatitis B virus (DHBV). In laboratory efficacy studies using DHBV dried on to glass filter carriers and exposed to one-half of the hydrogen peroxide gas plasma sterilization process, there was a 10(7) or greater decrease in the viral titer, with no infectivity detected on the carriers after treatment. In-use studies were performed using a laparoscope that was experimentally contaminated with DHBV to mimic the possible transmission of infection between successive patients. Following exposure to the hydrogen peroxide gas plasma sterilization process no transmission of DHBV infection from the laparoscope occurred despite obvious visual soiling with blood (N = 8) while the transmission rate for the unprocessed laparoscope (positive control) was 100% (26/26), and that for instruments after a water wash was 63% (7/11). In conclusion the hydrogen gas plasma sterilization process completely inactivates DHBV a representative of the hepadna group of viruses.

Varicella vaccination of health-care workers

The objective of this open study was to evaluate the response of non-immune health-care workers to two doses of live attenuated varicella vaccine given two months apart. One hundred subjects (58 females; aged 17-49 yr, mean 22.8 yr) received two doses of varicella vaccine. Blood samples for antibody estimation were taken before vaccination, 2 months after the first dose and 6 weeks after the second dose. Reactions were recorded daily in diaries by the vaccinees and controlled by telephone contacts by the investigators. Ninety-four of 99 vaccinees (94.9%, 95% CL 88.6, 98.3) had detectable antibodies after the first dose [titers 4-1024, geometric mean titer (GMT): 53.2 (95% CL 42.4, 66.8)]. After the second dose, all vaccinees had antibodies (100%, 95% CL 96.6, 100.0) [titers 32-2048, GMT: 235.6 (95% CL 199.0, 278.8)]. Mild reactions limited to the injection site occurred in 1 in 4 subjects after each dose. Vesicular rashes occurred in one subject after the 1st dose and in 3 subjects after the 2nd dose, 1 subject was febrile (38.2 degrees C) after the 1st dose. Eighty-one subjects were retested 12 months after the second vaccination. Three had become seronegative (one developed mild varicella 2 months later). Two had boosted their titers (one after mild clinical varicella 1 month earlier, the other after close contact with clinical cases). The GMT of the group had fallen to 83.6 (95% CL 65.4, 106.8). The identification and vaccination of seronegative health-care workers is safe and efficient, and will benefit the workers themselves and the communities in which they work.

Molecular epidemiology and variation of hepatitis B in recent immigrant families to Australia

Natural variation in hepatitis B virus (HBV) was studied in asymptomatic carriers originating from countries of high endemicity. HBV DNA was detected by dot blot and/or polymerase chain reaction (PCR) in 34 of the 184 members of 22 new immigrant families who agreed to be tested after one of their children had been found to have current or past hepatitis B in a school survey. PCR products from both the S and distal-X pre-C regions were sequenced. One vaccinated child had the classical "escape" mutation at amino acid position 126 in the S-gene and two other children and two adults had other substitutions at amino acid positions 133, 120, 165, and 159. Mutations were more frequent in the distal-X pre-C region and included two pre-C mutants and 13 other amino acid substitutions. The strains originating in the various countries were placed in almost identical groups by phylogenetic analysis using each amplicon, and determination of subtype by antigenic analysis gave the same result as sequencing. The S-data allowed recognition of three dominant strains within genotype B, while the distal-X pre-C data provided better discrimination between family groups. No change was found when the sequence of samples obtained for the study was compared with those collected from 14 of the children two years earlier. There was some evidence of horizontal spread in addition to vertical transmission. Reports of mutations of HBV in patients with severe or unusual clinical features should be interpreted with caution until the prevalence of the mutant in asymptomatic carriers has been determined.

Detection of persistent vegetative bacteria and amplified viral nucleic acid from in-use testing of gastrointestinal endoscopes

Hospital-acquired infection attributed to inadequate decontamination of gastrointestinal endoscopes prompted an in use evaluation of recommended procedures. Specimens were obtained from the internal channels of 123 endoscopes before, during and after decontamination by flushing with saline and brushing with a sterile brush, and examined for vegetative bacteria by broth and plate culture. Four endoscopy units were tested; the chemical disinfectants used were: 2% glutaraldehyde in Centres 1 and 2 (automated) and Centre 3 (manual); peracetic acid in Centre 4 (automated). Samples from patients in Centre 1 with known chronic hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV-1) infection were also examined for viral nucleic acid by ultracentrifugation, nucleic acid extraction, reverse transcription (for RNA) and polymerase chain reaction (PCR). No persistent vegetative bacteria were found following standard manual cleaning and disinfection for 20 min in 2% glutaraldehyde in Centres 2 and 3 (N = 37). At Centre 1, while plate culture yielded no growth, 34% of samples (10/29) grew vegetative bacteria in broth culture after cleaning and disinfection for 20 min in 2% glutaraldehyde. Investigation revealed an error in manual cleaning; no bacteria were detected in 37 samples taken after this was corrected. At Centre 4, despite the use of peracetic acid as a sterilant, three out of 20 (15%) of post decontamination samples grew bacteria; one contained persistent bacteria. HBV and HCV PCR analysis detected viral nucleic acid in three out of four and four out of six samples from viraemic patients undergoing endoscopy in Centre 1 during the period of improper manual washing. After proper cleaning was instituted, samples from nine out of nine HCV viraemic patients were negative. HIV RNA was detected in five of 14 samples taken from endoscopes after use on HIV positive patients but all post decontamination samples were negative. Detection of bacteria in washes from endoscope channels is a useful warning of a breakdown in decontamination practice. Inadequate brushing of internal channels may result in persistent HCV and HBV viral nucleic acid, the significance of which is not clear. These results reinforce the importance of adequate manual cleaning of endoscopes before chemical disinfection.

Transmission of hepatitis C virus to infants of human immunodeficiency virus-negative intravenous drug-using mothers: rate of infection and assessment of risk factors for transmission

The risk of perinatal transmission of hepatitis C virus (HCV) from a cohort of 95 human immunodeficiency virus (HIV)-negative intravenous drug users (IVDU) is described, 89 of whom were positive for antibodies to HCV (anti-HCV). Infection, defined as the presence of HCV RNA in a serum sample collected from an infant at any time during follow-up, was detected in six of 63 (9.5%) infants born to HCV antibody-positive viraemic mothers. No mother who was HCV RNA negative at delivery transmitted HCV to her infant. Hepatitis C virus antibodies became undetectable in uninfected infants by 15 months, but persisted in all HCV-infected infants throughout follow-up. An abnormal alanine aminotransferase (ALT) level was observed on at least one occasion in all HCV-infected infants and in six occasions in uninfected infants. Two of the six HCV-infected infants became HCV RNA negative during follow-up by 27 and 29 months. Both of these infants had a large ALT elevation (mean peak ALT 398U l-1) at around 12 months of age. Analysis of a range of potential risk factors revealed that maternal HCV RNA load was important in predicting transmission, but suggested that other factors play a role in perinatal transmission from mother to child. No difference was found between mothers who transmitted HCV to their infants and those who did not for HCV genotype, duration of drug use, duration of methadone use, methadone dose, history of alcohol abuse, past hepatitis B virus (HBV) infection, mode of delivery, maternal and gestational age, birth weight and incidence of breast-feeding. Mothers who transmitted HCV to their infants had a longer duration between membrane rupture and delivery than the mothers who did not transmit (P = 0.03). HCV RNA was not detected in breast milk and colostrum samples from 38 viraemic mothers, including two who transmitted HCV to their infant.

Cholestatic hepatitis after liver transplantation is associated with persistently high serum hepatitis C virus RNA levels

Viral recurrence is universal after transplantation for hepatitis C infection. This may lead to difficulties in differentiating allograft dysfunction caused by chronic rejection from hepatitis C virus (HCV) recurrence. Cases of severe cholestatic hepatitis have also been reported in conjunction with reinfection of the graft with HCV. Patients receiving transplants for HCV-related liver disease were studied before and after transplantation by HCV RNA quantitation of serial serum samples. Four major clinical patterns of HCV recurrence could be distinguished posttransplantation: group 1, asymptomatic hepatitis with no significant symptoms; group 2, cholestatic hepatitis with centrilobular ballooning; group 3, hepatitis leading to chronic allograft rejection; and group 4, persistently normal serum aminotransferase levels. Pretransplantation viral load was shown to be an important indicator of disease severity because the group 2 patients had significantly higher pretransplantation viral loads than patients in group 1 (P = 0.01) and group 4 (P = 0.005). The group 2 patients also had persistently significantly higher posttransplantation viral loads than the patients in group 1 (P = 0.01) and group 4 (P = 0.02), whereas patients who developed chronic allograft rejection showed marked decreases in serum HCV RNA before retransplantation. Patients from group 4 had the lowest viral loads after transplantation. These results show that persisting graft cholestasis due to HCV is associated with persistently high HCV RNA levels compared with other etiologies of graft dysfunction. Prospective studies are needed to determine whether such quantitation may be diagnostically helpful in distinguishing the different patterns of HCV-related graft dysfunction observed after liver transplantation.

Human papillomavirus and host variables as predictors of clinical course in patients with juvenile-onset recurrent respiratory papillomatosis

This study provides the first systematic evaluation of papillomavirus type and viral mutation occurring during the course of juvenile-onset recurrent respiratory papillomatosis. One hundred ninety-nine consecutive papillomas excised from 47 children between 1981 and 1996 at The New Children's Hospital in Sydney, Australia, were tested for human papillomavirus (HPV) DNA by PCR. PCR products from the viral upstream regulatory region (URR) enhancer were sequenced, and variation was related to clinical variables. Forty-four of the 47 children had HPV-induced papillomas, with type 11 accounting for 24 (55%) and type 6 accounting for 19 (43%); one (2%) was positive for either type 6 or 11. Overall, 183 (98%) of the 186 samples with amplifiable DNA were HPV positive. There was no change in HPV type over time and no statistically significant association between HPV type and disease aggressiveness. One novel, large-scale URR duplication was identified in an HPV type 11 isolate in the last of a series of six papillomas examined and the first from the bronchus. However, the duplication was not found in HPV type 11 isolates from the associated pulmonary carcinoma and its metastases in other organs. Three of 14 URR point mutations coincided with transcription factor binding sites, but there were no obvious associations with clinical course. Chi-square and multiple linear regression analyses of clinicopathological variables revealed early age at diagnosis (less than 4 years) as an independent predictor of aggressive disease (P < 0.001). A bimodal distribution of the age at diagnosis was noted, with peaks at 2 and 11 years of age.

Horizontal transmission of hepatitis B in a children's day-care centre: a preventable event

Using molecular finger-printing, we provided evidence that, in a children's day-care centre, a known hepatitis B virus (HBV) hepatitis B e antigen (HBeAg) carrier transmitted HBV to another child (the index case). The chronic HBV carrier had an exudative skin lesion and a history of biting. We sought to identify other at-risk children and prevent further transmission. Blood samples were collected and tested serologically for HBV. Of the 90 other children, 78 (87 per cent) were tested and none had serological evidence of HBV infection; 73 (81 per cent) were of Caucasian background; 38 (49 per cent) had a history of HBV immunisation with serological confirmation. Therefore, 1 (2.4 per cent, 95 per cent confidence interval 1.0 to 12.8 per cent) of the 41 known susceptible contacts became infected. The risk of horizontal HBV transmission in a children's day-care centre is low but not negligible. Staff and children should be vaccinated when a child in a day-care centre is a known HBV carrier.

Sequence variation in the upstream regulatory region of HPV 18 isolates from cervical cancers

This study describes sequence variation in both the enhancer and promoter segments of the upstream regulatory region (URR) of 28 human papillomavirus (HPV) type 18 isolates from cervical cancers, 25 from women treated at an Australian center and three from overseas included for comparison. No large-scale changes were found in either region. Fourteen substitutions were identified in the enhancer region with the number in individual isolates ranging from one to eight. Four substitutions impacted cellular transcription factor binding sites but there were no obvious associations with clinicopathological variables. The promoter segment was found to be more highly conserved than the enhancer, but four of the five point mutations identified involved cellular transcription factor binding motifs including a substitution of C for T at nt 104 which affected 21 samples. This change was found to impact upon a previously unrecognized Yin Yang (YY1) binding site. Electrophoretic mobility shift assays (EMSA) showed that this substitution significantly reduced protein-DNA binding and evidence was sought for its possible clinical implications. Of the 24 women with less than Stage III disease and known clinical outcome, tumor recurrence was observed in all of the 6 women whose isolates had the "prototype" T at nt 104, whereas only 8 of the 18 cancers with the mutation at this YY1 site recurred. This is the first report on URR variation in HPV 18 isolates from the South Pacific region. The study also provides initial data on diversity in the promoter region and preliminary evidence suggesting that a specific point mutation in this region may be clinically significant.

Back to the future--the history and philosophy of medicine experiment at Sydney University

History and Philosophy of Medicine has been a compulsory unit in the first year of the medical curriculum at Sydney University for the past decade. Volunteer tutors are drawn from most clinical and basic science departments, and each year the programme is organized on a theme of current importance in medical practice. This course began as an experiment because no resources were available for specialist staff, but has proved outstandingly successful in generating both student and teaching staff interest and support for the programme. Students present short tutorial papers to their peer group followed by submission of an essay which takes into account the tutorial discussion. The open book examination includes analysis of an unseen piece of primary source material as well as questions derived from the classwork. The Faculties of Arts and Science encouraged this educational experiment and several medical students have now opted to undertake a year of historical research during the intercalated B Sci(Med) programme, and a number of the tutors have enrolled in postgraduate historial or ethical programmes. We suggest that this model may permit introduction of novel courses in times of financial cutback within the Universities, and even allow a foundation to be laid for future development.

Establishment of an in-use testing method for evaluating disinfection of surgical instruments using the duck hepatitis B model

Nosocomial transmission of hepatitis B virus (HBV), associated with interventional procedures, has been attributed to its survival on improperly decontaminated instruments. To date, guidelines for chemical disinfection of potentially contaminated heat-sensitive instruments have been based largely on extrapolation of data from in-vitro disinfectant testing. Direct infectivity testing has not been possible for HBV because of the lack of a practical culture assay or susceptible experimental animal model. In this study the related duck hepadnavirus was used to simulate in-vivo transmission of a HBV during surgery, and to evaluate the effectiveness of 2% glutaraldehyde disinfection of surgical laparoscopes. Multiple laparoscopic liver biopsies were performed on 'biohazardous' duck hepatitis B (DHBV) positive ducks. Laparoscopes were then subjected to different disinfection regimes using 2% glutaraldehyde, and residual infectivity tested by placing their tips into the peritoneal cavities of uninfected four-day-old ducklings. Direct transmission of DHBV occurred in all ducks when laparoscopes were not washed. Rinsing with water lowered the transmission rate to 64% and no infection transmission occurred after 5 min of contact time with the disinfectant. In contrast, previous in-vitro studies had shown complete viral inactivation after a shorter period of disinfection. It is postulated that the longer inactivation time observed in our study may be a result of surface interactions of virus and instrument, interfering with disinfectant access or activity. Tests of instrument surface samples for viral DNA by the polymerase chain reaction (PCR) did not correlate with transmission of virus infection in vivo. PCR is an inappropriate test for evaluating the efficacy of disinfectant action despite its sensitivity. This in use method will allow testing of other decontamination procedures and their effectiveness on more complex surgical instruments.

Human papillomavirus deoxyribonucleic acid as a prognostic indicator in early-stage cervical cancer: a possible role for type 18

OBJECTIVE

Our purpose was to determine the prognostic significance of human papillomavirus deoxyribonucleic acid in cervical cancers.

STUDY DESIGN

The polymerase chain reaction was used to detect human papillomavirus deoxyribonucleic acid types 6, 11, 16, 18, 31, 33, 52, or 58 in tumors from 148 patients (equal numbers of whom were disease free or had relapses) surgically treated for stage IB or IIA cancers in a major Australian hospital. Cox regression modeling was used to assess the effect of human papillomavirus status on tumor recurrence, taking into account patient age, clinical stage, histologic node status, and type of tumor.

RESULTS

Seventy of 74 (95%) of the recurring tumors and 62 of 74 (84%) of the nonrecurring tumors were human papillomavirus deoxyribonucleic acid positive. The rates of positivity of types 16 and 18 were 64% versus 31% in the recurrers and 65% versus 14% in the nonrecurrers. Human papillomavirus type 18 positivity was associated with a greater risk of recurrence than was type 16 positivity (hazard ratio 1.8; p = 0.03). Clinical stage, nodal metastasis, and young age (< or = 35 years) also had adverse effects on relapse (hazard ratio for each approximately 2).

CONCLUSION

Human papillomavirus type 18 positivity is a risk factor for tumor recurrence in surgically treated cervical cancer.

Post-transfusion hepatitis revisited

OBJECTIVE

To evaluate the risk of post-transfusion and postoperative non-A non-B hepatitis in Australia immediately before the introduction of screening for hepatitis C.

DESIGN

Retrospective testing of blood samples from a prospective study of cardiac surgery patients. Samples were taken from transfusion recipients and non-transfused controls at regular intervals for 12 months after surgery during 1987-1989. For all donor, recipient and control samples, alanine aminotransferase (ALT) levels were measured and tests for antibody to hepatitis B (anti-HBc, anti-HBs) and, when available, to hepatitis C (anti-HCV) were performed.

SETTING

Cardiac surgery units.

PARTICIPANTS

Participants were included if they lived in the metropolitan area, and had not had a transfusion in the past year.

MAIN OUTCOME MEASURES

Post-transfusion hepatitis (two consecutive samples showing raised ALT levels, > 90 IU/L with no other known cause); hepatitis C infection and carriage (antibody to hepatitis C).

RESULTS

Post-transfusion hepatitis occurred in 1.1% of 736 recipients of blood not screened for hepatitis C (i.e., two cases per 1000 unscreened units given). No hepatitis occurred in 514 controls. Seven of the eight patients with post-transfusion hepatitis seroconverted to hepatitis C virus infection. Seven of the 26 anti-HCV-positive donations transmitted hepatitis C, six of these were positive by recombinant immunoblot assay (RIBA) (one by second generation testing only) and one was RIBA indeterminate. Nineteen were RIBA non-reactive; one transmitted hepatitis but the recipient did not develop anti-HCV, although hepatitis C RNA was detected in the donation. Serum ALT was raised in four of the six infective donations.

CONCLUSIONS

Hepatitis C virus infection accounted for almost all cases of non-A non-B post-transfusion hepatitis. First generation anti-HCV tests detected about 85% of infective donations. Surrogate testing of donations by ALT or anti-HBc offers no additional advantage.

Associations between oncogenic human papillomaviruses and local invasive patterns in cervical cancer

The polymerase chain reaction (PCR) was used to detect human papillomavirus (HPV) DNA in Formalin-acetic acid alcohol (FAA)-fixed paraffin-embedded tissue from 40 patients whose primary cervical cancers showed a tentacular pattern of invasion at their advancing edges, and 40 patients (matched by age, International Federation of Obstetrics and Gynecology (FIGO) stage and histology type) whose tumors showed broad front invasion. The rate of HPV DNA positivity was the same in both the tentacular and the broad front tumors (83%), but the ratios of HPV 16 to HPV 18 in the two groups were markedly different (20:10 versus 27:4, respectively). HPV type 18 was detected more frequently in tentacular than broad front tumors (P = 0.03). The overall rates of recurrence and mortality were 15 and 9%, respectively (18 and 10% in the tentacular group compared with 13 and 8% in the broad front group). Univariate analysis showed statistically significant associations between HPV 18 and tumor recurrence (P = 0.04), but not between a tentacular pattern of invasion and tumor recurrence (P < 0.05). The findings to emerge from this survey indicate that the presence of particular HPV types may, in part, mediate the histological and clinical behavior of cervical cancers.

Identification of E6/E7 transcription patterns in HPV 16-positive cervical cancers using the reverse transcription/polymerase chain reaction

Studies indicate the presence of four different forms of human papillomavirus (HPV) E6/E7 mRNA resulting from differences in transcription patterns and post-transcriptional nuclear splicing. Through a retrospective analysis of 28 cervical cancer patients, correlations were sought between E6/E7 transcription patterns and histologic type, FIGO stage, and tumor aggression. A combined reverse transcription/polymerase chain reaction was used to study E6/E7 transcription patterns in fresh and/or fixed paraffin-embedded tissues of HPV 16-positive cervical cancers. Random cervical biopsies from nine women with no history of cervical disease were included as controls. Two sets of primers used in the investigations detected the full-length (FL) E6, E6*I, and E6*II mRNAs and the FL E6 and E6*I mRNAs, respectively; eight of the tumors were also analyzed using a third primer combination designed to identify the E6*III mRNA. At least two of the transcripts were detected in all of the tumors, whereas E6/E7 mRNAs were not identified in any of the control cervical biopsies. Overall, the transcription patterns were consistent, but the major E6*I mRNA was not detected in two of the tumors. No relationship was found between the E6/E7 transcription patterns and the histological type and differentiation of the tumors, nor with the FIGO stage and the clinical behavior of the disease. The study confirms that E6/E7 transcription is a constant feature of HPV 16-related carcinoma, but the findings indicate that there may be no clinical advantage in adding E6/E7 mRNA detection to the routine assessment of cervical tumors.

An autopsy survey of hepatitis B in Sydney

AIM

1) To determine the prevalence of hepatitis B in Sydney autopsies and 2) to determine the relationship between seroprevalence, hepatitis B risk factors and histological changes in the liver.

METHODS

One hundred autopsy subjects were studied for evidence of past or present hepatitis B infection, using RIA to detect the HBV antigens and antibodies in the serum and peroxidase-antiperoxidase technique to detect HBsAg and HBcAg in the liver. Both serum and liver were examined for the presence of HBV DNA.

RESULTS

Markers of hepatitis B virus infection were detected in either serum and/or liver of 29 subjects. Four subjects (4%) were seropositive for HBsAg. Eight subjects had been recently infected, 7 were chronically infected and 14 had recovered.

CONCLUSION

The 29% prevalence of HBV infection is higher than expected. In four cases the serum was either free of HBV markers or showed conventional evidence of recovery, yet the liver still contained HBsAg. There were few histopathological changes despite the presence of HBsAg in the liver. The only epidemiological factors possibly predisposing to HBV infection were tattooing and drug abuse.

Needlestick injury in medical students

OBJECTIVE

To determine the incidence of needlestick injuries and the prevalence of hepatitis B vaccination among medical students, dentistry students, and hospital staff.

DESIGN AND SUBJECTS

Anonymous survey of final year medical students and dentistry students enrolled at Sydney University in 1992, and nursing staff and doctors employed in the wards and emergency department of Royal Prince Alfred Hospital, Sydney.

RESULTS

During their clinical training, 22% of medical students and 72% of dentistry students had received one or more contaminated, penetrating "sharps" injuries. Of hospital staff, 50% of ward nurses, 71% of ward doctors, and 50% of emergency staff had received this type of injury during the previous two years. Students were significantly more likely to be vaccinated against hepatitis B than hospital staff (P < 0.001)--98% of medical students and 95% of dentistry students had received a full course of vaccination. The rate of vaccination among hospital staff ranged from 79% in emergency staff to 85% in ward nurses.

CONCLUSIONS

Clinical students sustain needlestick injuries at a rate comparable with hospital personnel and therefore face a significant risk of exposure to transmissible pathogens, including hepatitis B virus, HIV, and hepatitis C virus. The rate of hepatitis B vaccination is high among clinical hospital staff and almost universal among medical and dentistry students.

Tuberculosis: medical students at risk

In 1979 an outbreak of tuberculosis occurred in medical students at the University of Sydney. Eight of 35 Mantoux-negative students who attended the autopsy of an immunosuppressed patient with unsuspected active tuberculosis became infected and one developed clinical disease. A report of the incident was prepared for publication because it supported the then controversial University policy of recommending BCG vaccination to medical and dental students in a country where the reported prevalence of tuberculosis is very low. The report was never published, mainly in order to protect the privacy of the individual students involved, but also because it was felt by the administration of the time that it might undermine confidence in infection control procedures in the autopsy room. The original report, updated and reproduced here, suggested that tuberculosis might be an emerging nosocomial problem. This has been all too clearly realised since its re-emergence as an opportunistic infection in AIDS patients. Worldwide, the problem of antibiotic resistance in Mycobacterium tuberculosis provides an added risk of a return to the situation which prevailed early this century when tuberculosis was a major occupational risk for young health care workers. Infection often restricted career choices, even in those whose disease was relatively benign. Our purpose in bringing this incident to light after so many years is to point out the relevance of the extensive studies of the problem which were conducted in the 1930s and 1940s to the current situation and to suggest that health care students are vulnerable to airborne infections as well as those spread by inoculation injuries. In retrospect, our 1979 conclusions about prospects for preventing nosocomial tuberculosis appear optimistic.

Detection of human papillomavirus type 16 E6/E7 transcripts in histologically cancer-free pelvic lymph nodes of patients with cervical carcinoma

Human papillomavirus (HPV) 16 E6/E7 mRNAs have been detected in paraffin-embedded sections of histologically cancer-free pelvic lymph nodes from four of six patients with HPV 16-associated cervical cancer. The cDNA obtained from the viral mRNA by reverse transcription was amplified by the polymerase chain reaction (PCR). Transcripts were present in a small but significant proportion (6/42, 14%) of the histologically negative/HPV 16 DNA-positive lymph node blocks; but neither HPV 16 DNA nor transcripts were found in 12 lymph node blocks from two patients whose cervical cancers were not HPV-related. Both of the HPV 16 mRNAs detectable by the PCR primers used in the assay (the E6*I and the full-length E6 transcript) were found in the primary tumors, but the transcription patterns in the lymph nodes were variable. The presence of HPV E6/E7 mRNAs in lymph nodes of patients with HPV-related cancer may be a more sensitive indicator of metastasis than conventional histology. In addition, their detections is likely to be more significant than that of HPV DNA sequences alone. The practical significance of the findings, however, awaits correlation with the ultimate clinical outcome.

Prevalence and distribution of human papillomavirus type-16 DNA in pelvic lymph nodes of patients with cervical cancer and in women with no history of cervical abnormality

The polymerase chain reaction (PCR) was used to investigate the prevalence and distribution of human papillomavirus (HPV)-16 DNA in paraffin sections of all pelvic lymph nodes removed from 14 patients with Stage Ib-cervical cancer at the time of resection of their primary tumours. The results were compared with those obtained from 8 women with no known history of cervical abnormality. In all, 22 cervical biopsies and 40 I lymph nodes (296 paraffin blocks) were examined. Nine of the 14 cervical cancer patients had primary tumours that were positive for HPV-16 DNA: only 3 of these had lymph nodes with histological evidence of metastasis, and HPV 16 DNA was detected in each of the corresponding paraffin blocks. HPV 16 DNA was also detected in varying proportions (8%-92%) of the histologically-negative lymph nodes from these women. There was no correlation between the HPV DNA-positive lymph nodes and their proximity to the primary tumour. HPV-16 DNA was not identified in any of the lymph nodes from the 5 women whose cancers were not HPV-16-related, or in those of women with no evidence of cervical abnormality. This preliminary survey suggests that HPV DNA is frequently transported from HPV-16-related cervical tumours to regional lymph nodes. However, its practical significance will not be clear until sufficient time has elapsed for correlation of the results with the clinical outcome.

Detection of HPV DNA in archival specimens of cervical cancer using in situ hybridisation and the polymerase chain reaction

An archival survey of 98 cervical cancer specimens dating from the 1920s to the 1980s was undertaken to determine whether changes had occurred in the prevalence of human papilloma-virus (HPV) DNA. HPV DNA was detected in paraffin sections of cancers fixed in 10% formalin by in situ hybridisation (ISH) using HPV 6, 11, 16, and 18 32P-labelled DNA probes under conditions of high stringency; and by the polymerase chain reaction (PCR) using 20-mer oligonucleotide primers to amplify 109 bases of the E6 region of HPV 16. In 30 instances results obtained from Southern blot hybridisations which had been carried out on specimens of fresh tissue from the same cancers collected during the 1980s were available for comparison. The rates of HPV DNA detection in cervical cancers ranged from 83% (by Southern or PCR) and 70% (by ISH) on specimens from the 1980s, to 50% and 63% (by ISH and PCR, respectively) on specimens from the 1920s. HPV 16 was by far the most common type, being identified by Southern or ISH in approximately 92% of HPV DNA-positive specimens. No significant change in the prevalence of HPV DNA, or of HPV types, in cervical cancers was found over the 65 year period examined.

Anal intercourse: a risk factor for anal papillomavirus infection in women?

OBJECTIVE

To determine whether anal intercourse is a risk factor for anal HPV infection in women.

DESIGN

Results derived from clinical examination, anal cytology and HPV DNA hybridisation were correlated with data obtained from a questionnaire administered to the patients at the time of their clinical examination.

SETTING

A sexually transmitted diseases (STD) clinic in Sydney, Australia.

SUBJECTS

31 women attending the clinic for HPV related problems.

METHODS AND RESULTS

A thorough history was elicited from each woman followed by physical examination of the anogenital region. Cervical and anal scrapes were collected for cytology and HPV DNA hybridisation. Of the 15 women who practised anal intercourse, a total of 12 (80%) had either clinical or subclinical HPV infection. Seven had overt anal warts, situated either internally or externally in the anal canal; and further 5 women had evidence of subclinical HPV infection as determined by positive cytological and/or HPV DNA hybridisation results on their anal scrapes. The women who did not have a history of anal intercourse had a lower (7/16, 43%), but not statistically significant, rate of anal HPV infection: five had anal warts and two had subclinical evidence of infection. No correlations were found between anal HPV infection and genital (cervical, vulval or vaginal) HPV infection; nor between the HPV typing patterns of women in either group.

CONCLUSION

The results obtained from these women do not indicate a close relationship between anal intercourse and the presence of detectable anal HPV infection.

Detection of human papillomavirus type 16 E6/E7 transcripts in fixed paraffin-embedded cervical cancers by the polymerase chain reaction

A simple, and sensitive method for the detection of human papillomavirus (HPV) 16 E6/E7 transcripts in RNA purified from formalin acetic alcohol (FAA)-fixed, paraffin embedded cervical cancer (CaCx) tissue is described. The entire procedure, including polymerase chain reaction (PCR) amplification of cDNA obtained from mRNA by reverse transcription, can be completed within a day. The results obtained compare favourably with those using total nucleic acids extracted from the same fixed material, and are consistent with results using RNA purified from corresponding fresh tumour tissue. Although developed for investigating the expression of HPV in tumours, this method should find general application in studies of gene expression and viral detection.

Duck hepatitis B virus: a model to assess efficacy of disinfectants against hepadnavirus infectivity

The efficacy of three proprietary glutaraldehyde disinfectants and their component bases was assessed using the duck hepatitis B virus (DHBV) model. Inactivation of infectivity of undiluted serum containing 10(6.8) ID50/ml DHBV was assessed after a mixture with an equal volume of disinfectant had stood at room temperature for 10 min. A dried spill of infectious serum was simulated using sterile filter paper disks, saturated with serum containing DHBV, dried and then exposed to test disinfectant for 10 min. Residual infectivity, and hence the reduction in virus titre, was determined by inoculation of dilutions of the treated samples into 1-day-old ducklings. A greater than 3 log10 reduction in virus titre could be demonstrated for the disinfectants as well as for some of their component bases. Disinfectant activity varied according to the method of viral presentation but a reduction of exposure time from 10 to 2.5 min did not diminish activity. The experimental protocol permits a comparative and quantitative assessment of the efficacy of both established and new disinfectants.

Factors associated with clinical and sub-clinical anal human papillomavirus infection in homosexual men

OBJECTIVES

(I) to determine the relative sensitivities of clinical examination, cytology and HPV DNA hybridisation for the detection of anal human papillomavirus infection; and (ii) to examine various factors which may influence presentation of anal human papillomavirus infection in homosexual men.

METHODS AND RESULTS

112 unselected homosexual men attending a Sydney STD clinic for routine screening underwent a complete anogenital and physical examination, during which blood samples (for haematological, serological and immunological investigations), rectal swabs (for culture of anal pathogens) and anal scrapes of the dentate line (for cytology and HPV DNA hybridisation) were collected. Papanicolaou-stained anal smears were examined for cytological abnormalities, including those indicative of HPV infection or anal intraepithelial neoplasia (AIN). HPV DNA was detected by high stringency dot hybridisations using radiolabelled HPV 6, 11, 16 and 18 DNA probes. Visible anal condylomata, situated either externally or in the anal canal, were present in 26% of these men; 46% had cytological evidence of HPV infection, and 19% of the smears showed evidence of mild to moderate dysplastic changes (AIN I-II). Detectable HPV DNA was present in 40% of the anal scrapes. By combining these results, a total of 73 men (65%) were found to have at least one of the indicators of HPV infection. These data, together with that relating to HIV antibody, immune status and past or present infection with other STDs, was correlated with information obtained from a questionnaire administered to the patients at the time of their clinical examination.

CONCLUSIONS

In this study cytology was found to be slightly more sensitive than HPV DNA dot hybridisation for the detection of HPV infection in the anal canal, providing the full range of HPV-associated cytological changes were accepted as a basis for diagnosis. Clinical anal lesions were more likely to be detected in young men, men who had symptomatic HIV infection and those with a history of past anal wart infection. The latter group also had a higher incidence of cytologically apparent HPV infection in their anal smears. There was a significant association between the detection of HPV 16/18 and the presence of anal dysplasia, but there were no significant correlations between HPV infection or anal dysplasia and HIV antibody, immune function status, sexual practices or history of other STDs.

Clinical and virological associations between external anogenital warts and cervical HPV infection in an STD clinic population

To determine the significance of overt anogenital warts as indicators of human papillomavirus (HPV) infection of the cervix, 177 women attending a Sydney STD clinic were screened for evidence of cervical HPV infection using clinical criteria together with cytology and HPV DNA dot hybridization. HPV DNA probing was also performed on biopsies of 50 exophytic warts. A very high prevalence of both anogenital warts (40%), and of cervical HPV infection (58%) was indicated in this group of women. In the exophytic warts, HPV types 6/11 were most commonly detected, whereas the rates of detection of types 6/11 and 16/18 in the cervix were similar. Of the 87 women with evidence of cervical HPV infection, 57 (66%) had a history of either past or current overt exophytic anogenital warts; while the corresponding figure for the 90 women with no evidence of cervical infection was 45 (50%). Cytological evidence of dysplasia (CIN I-III) was detected in 13 (7%) of the cervical smears: of these, 4 were positive for HPV 16/18 only, 2 for 6/11 only and 4 for both 6/11 and 16/18.

Postexposure treatment of experimental DHBV infection: a new therapeutic strategy

The therapeutic efficacy of antiviral agents for postexposure prophylaxis to hepadnavirus infection has been studied using acyclovir and foscarnet in the duck hepatitis B virus (DHBV) model. A total of 112 Pekin-Aylesbury ducks were inoculated with DHBV at 11 days post-hatch. Three days later, groups of these birds were injected intraperitoneally twice daily for 10 days with acyclovir (25 mg/kg) or foscarnet (250 mg/kg) or phosphate-buffered saline. Serum samples were taken before, during, and up to 4 weeks post-treatment and were analysed for DHBV DNA by dot hybridization. Liver tissue obtained at sacrifice was examined for viral DNA and for histological changes. At completion of treatment with acyclovir, 21 of 22 ducks were not viremic, compared with 6 of 26 control birds (P less than 0.001). Four weeks after withdrawal of acyclovir, 12 of 20 ducks remained nonviremic, compared with 2 of 23 controls (P less than 0.01). In liver tissue, viral DNA was detected in 10 of 19 treated ducks, compared with 21/24 controls (P less than 0.01). Histological changes of hepatitis were present in more of the control birds than in the treated group. The results with foscarnet treatment were similar, although a smaller inoculum of DHBV was used and fewer control birds became infected. The administration of antiviral agents soon after exposure prevented productive infection in approximately 50% of birds. Therefore, the use of a safe antiviral agent such as acyclovir, which can be given orally, should be considered in post-exposure prophylaxis against human hepatitis B virus (HBV) infection.

Low-dose intradermal vaccination of medical and dental students

In 454 medical and dental students who were vaccinated against hepatitis B by means of a low dose (0.1 mL) of serum-derived vaccine, seroconversion rates of 27%, 70% and 89% were obtained after the first, second and third doses, respectively. These figures are comparable with the results that have been reported for the conventional intramuscular schedule, as were the final antibody titres. A fourth intradermal dose boosted the percentage of students who were protected from 82% to 87%. There was a significant variation in the response to different batches of vaccine. This study shows that the low-dose intradermal method is practicable and effective and can be used to achieve great economy in hepatitis B vaccination programmes. The possibility of adding hepatitis B to the present formula of triple antigen should be investigated as a way of extending hepatitis B vaccination to all infants in our community.

Hepatitis delta virus in homosexual men in Sydney

In countries not generally endemic for hepatitis B, homosexual men who are carriers of hepatitis B surface antigen (HBsAg) have to date largely been spared additional delta virus infection. A focus of homosexually acquired delta has, however, recently been identified in California. To assess the prevalence and risk factors for delta virus infection in homosexual men in Sydney, we tested the sera of 204 homosexual men with acute or chronic hepatitis B infection for total antibody to delta and delta antigen. Total antibody to delta was detected in eight men and delta antigen in one other (4.4% of the total). All men with antibody or antigen had intravenous drug use as a risk factor. Overall nine of 22 (40.9%) male homosexual intravenous drug users had serological evidence of delta infection. Delta positive patients tended to be younger, to have engaged in prostitution, to have more severe chronic liver disease, to be more likely to have a symptomatic acute illness, and to be less likely to express hepatitis Be antigen (HBeAg) in their sera. Though the homosexual transmission of delta infection cannot be concluded from this study, the detection of delta markers in nine homosexual men (including four prostitutes) suggests considerable potential for dissemination of this virus homosexually.

Immunity in Pekin ducks experimentally and naturally infected with duck hepatitis B virus

The immune response to duck hepatitis B virus (DHBV) had not been elucidated. An assay was therefore established to detect the presence of antibody to DHB surface antigen (anti-DHBs) in serum of experimentally inoculated and naturally infected ducks. Anti-DHBs in serum was detected by indirect RIA from the percentage inhibition of binding of rabbit anti-DHBs to purified DHBsAg. Specificity was confirmed by positive and negative controls, infected and noninfected sera, and a mouse monoclonal antibody to DHB core antigen (anti-DHBc). Serum and liver samples were tested for DHBV DNA by dot-blot hybridization assay. Adult ducks repeatedly inoculated with DHBV remained non-viraemic but developed anti-DHBs. This antibody activity neutralized the infectivity of DHBV, which was experimentally inoculated into 1-day-old ducklings. In naturally infected flocks anti-DHBs was detected in a proportion of noninfected adult ducks as well as 1-day-old hatchlings. Anti-DHBs activity in hatchlings neutralized the infectivity of experimentally inoculated DHBV. Pekin ducks can therefore mount a neutralizing antibody response to DHBV, and immunity may be transferred in ovo from dam to off-spring.

Virus-liver cell interactions in duck hepatitis B virus infection. A study of virus dissemination within the liver

Thirty-five 1-day-old Pekin-Aylesbury ducks were inoculated intravenously or intraperitoneally with duck hepatitis B virus, and the time-course of infection was examined by Southern-blot, dot-blot, and in situ hybridization and by immunohistochemistry. Randomly scattered single infected hepatocytes were first seen on days 1 and 2 after inoculation and by day 3 occurred as single cells, pairs, and groups of 5-10 adjoining cells. From day 4 after inoculation all hepatocytes were positive for duck hepatitis B surface antigen and deoxyribonucleic acid. Duck hepatitis B virus deoxyribonucleic acid levels in liver extracts and serum increased logarithmically from days 2 to 3 to a plateau by days 4 to 5 after inoculation. Infected and control birds showed no significant differences during the first 7 days in terms of liver histology, hepatocyte morphology, or mitotic activity. It was concluded that (a) virus gains access to randomly distributed hepatocytes without first replicating in other cell types, and then begins disseminating to adjacent cells following anatomic boundaries; (b) markers of infection in liver and serum show reproducible kinetics, thus making this in vivo system amenable to further quantitative study; and (c) hepatocytes in this system are highly permissive to virus replication without the development of significant cytopathology.

Papillomavirus and cervical cancer: a clinical and laboratory study

It is now widely accepted that HPV types 16, 18, 31, and 33 are associated with the development of high grade intraepithelial neoplasia and malignant lesions in the cervix. On this basis, the identification of HPV types in cervical scrape samples has been advocated as a supplement to cytological screening tests. However, little is known of the distribution of the virus at different sites in the lower female genital tract or of how this distribution may change during the natural course of HPV infection. In this survey, HPV DNA dot hybridizations and, in some instances, Southern blot hybridizations with mixed HPV 6/11 and 16/18 probes were undertaken to detect HPV DNA in cervical scrapes and biopsies of the cervix, vagina, and vulva. A total of 92 women attending a Sydney hospital were screened: 59 of these patients had cervical disease, either invasive cervical carcinoma (CaCx) or cervical intraepithelial neoplasia (CIN), grades I-III. A group of 33 women who lacked evidence of cervical abnormalities served as controls. HPV DNA, predominantly type 16/18, was detected in the cervical biopsies of 96% of the CaCx patients, 80% of the CIN III patients, and 65% of the CIN I-II patients. In contrast only 9% of the cervical biopsies from the control group contained detectable HPV 6, 11, 16, or 18 DNA. A high proportion of the women with cervical abnormalities had evidence of concurrent vaginal and/or vulval papillomavirus involvement. The significance of these findings for routine screening and subsequent management of patients with HPV-associated cervical disease is discussed.

Human papillomavirus: the untreated male reservoir

Human papillomavirus infection currently is accepted as a major factor in the etiology of carcinoma of the cervix, vagina and vulva. While the nature of genital human papillomavirus infection in women is well documented, detailed knowledge of the disease in the male partners is lacking. Therefore, a prospective study was done to define the disease in the genitals of heterosexual men and to formulate an appropriate plan of management. We studied 52 men during an 8-month period for evidence of genital human papillomavirus infection. The majority of the lesions occurred on the shaft of the penis and on the foreskin of uncircumcised men. Deoxyribonucleic acid dot hybridization of biopsies of macroscopic warts and suspected warty lesions with mixed human papillomavirus types 6 and/or 11 and 16 and/or 18 probes revealed that 87 and 55 per cent, respectively, were positive for 1 or more of these human papillomavirus types. Of the macroscopic warts and subclinical lesions 52 and 29 per cent, respectively, contained the more potentially oncogenic types 16 and/or 18, either alone or in combination with types 6 and/or 11. There was no evidence of human papillomavirus in any semen or urine sample but human papillomavirus deoxyribonucleic acid sequences were detected in 31 per cent of the biopsies from apparently normal penile skin and in 18 per cent of the urethral mucosal biopsies. We suggest that management of human papillomavirus infection be directed toward prevention and contact screening, together with ablation of localized lesions.

Experimental duck hepatitis B virus infection: pathology and evolution of hepatic and extrahepatic infection

Seventy, 1-day-old ducklings inoculated intraperitoneally with duck hepatitis B virus and 30 controls have been studied over a 2-year period. Infection with duck hepatitis B virus occurred in all inoculated ducks, although this was not associated with clinical morbidity. Duck hepatitis B virus DNA was first detected in liver on Day 3, in pancreatic acinar cells on Day 4, serum on Day 6, splenic red and white pulp on Day 7 and in the renal glomurulus on Day 14, using a combination of dot, Southern blot and in situ hybridization techniques. Peak levels of circulating virus, as determined by DNA polymerase levels, occurred 1 to 4 weeks postinoculation. Mild degrees of portal inflammation were seen in sections of liver tissue in both infected and control ducks. However, moderately severe inflammatory changes were present in 8 of 22 infected birds compared with 0 of 18 controls (p less than 0.025). Appearance of this inflammatory infiltrate 6 weeks postinoculation coincided with a decrease in levels of duck hepatitis B virus DNA in hepatocytes and within the pancreatic acinar cells. At the same time, duck hepatitis B virus DNA became increasingly localized to the splenic germinal centers, and viral DNA was first detected in pancreatic islet cells. No histological changes accompanied the extra-hepatic tissue infection. The sequence and significance of duck hepatitis B virus infection in liver and extra-hepatic tissues is discussed in relation to the pathogenesis of hepatitis B virus infection in man.