Longitudinal analysis on the ecological dynamics of the cervicovaginal microbiome in hrHPV infection

The cervicovaginal microbiome (CVM) is a dynamic continuous microenvironment that can be clustered in microbial community state types (CSTs) and is associated with women's cervical health. Lactobacillus-depleted communities particularly associate with an increased susceptibility for persistence of high-risk human papillomavirus (hrHPV) infections and progression of disease, but the long-term ecological dynamics of CSTs after hrHPV infection diagnosis remain poorly understood. To determine such dynamics, we examined the CVM of our longitudinal cohort of 141 women diagnosed with hrHPV infection at baseline with collected cervical smears at two timepoints six-months apart. Here we describe that the long-term microbiome dissimilarity has a positive correlation with microbial diversity at both visits and that women with high abundance and dominance for Lactobacillus iners at baseline exhibit more similar microbiome composition at second visit than women with Lactobacillus-depleted communities at baseline. We further show that the species Lactobacillus acidophilus and Megasphaera genomosp type 1 associate with CST changes between both visits. Lastly, we also observe that Gardnerella vaginalis is associated with the stability of Lactobacillus-depleted communities while L. iners is associated with the instability of Megasphaera genomosp type 1-dominated communities. Our data suggest dynamic patterns of cervicovaginal CSTs during hrHPV infection, which could be potentially used to develop microbiome-based therapies against infection progression towards disease.

The C2H2 transcription factor SltA is required for germination and hyphal development in Aspergillus fumigatus

Germination of inhaled Aspergillus fumigatus conidia is a necessary sequitur for infection. Germination of conidia starts with the breaking of dormancy, which is initiated by an increase of the cellular perimeter in a process termed isotropic growth. This swelling phase is followed by polarized growth, resulting in the formation of a germ tube. The multinucleate tubular cells exhibit tip growth from the hyphae, after which lateral branches emerge to form the mycelial network. The regulatory mechanisms governing conidial germination are not well defined. In this study, we identified a novel role for the transcription factor SltA in the orchestration of germination and hyphal development. Conidia lacking sltA fail to appropriately regulate isotropic growth and begin to swell earlier and subsequently switch to polarized growth faster. Additionally, hyphal development is distorted in a ∆sltA isolate as hyphae are hyper-branching and wider, and show branching at the apical tip. ∆sltA conidia are more tolerant to cell wall stressors on minimal medium compared to the wild-type (WT) strain. A transcriptome analysis of different stages of early growth was carried out to assess the regulatory role of SltA. Null mutants generated for three of the most dysregulated genes showed rapid germ tube emergence. Distinct from the phenotype observed for ∆sltA, conidia from these strains lacked defects in isotropic growth, but switched to polarized growth faster. Here, we characterize and describe several genes in the regulon of SltA, highlighting the complex nature of germination.IMPORTANCEAspergillus fumigatus is the main human fungal pathogen causing aspergillosis. For this fungus, azoles are the most commonly used antifungal drugs for treatment of aspergillosis. However, the prevalence of azole resistance is alarmingly increasing and linked with elevated mortality. Germination of conidia is crucial within its asexual life cycle and plays a critical role during the infection in the human host. Precluding germination could be a promising strategy considering the role of germination in Aspergillus spp. pathogenicity. Here, we identify a novel role for SltA in appropriate maintenance of dormancy, germination, and hyphal development. Three genes in the regulon of SltA were also essential for appropriate germination of conidia. With an expanding knowledge of germination and its different morphotypes, more advances can be made toward potential anti-germination targets for therapy.

Clinical performance of high-risk HPV testing on self-samples versus clinician samples in routine primary HPV screening in the Netherlands: An observational study

Background

High-risk human papillomavirus (hrHPV) testing on self-collected samples has potential as a primary screening tool in cervical screening, but real-world evidence on its accuracy in hrHPV-based screening programmes is lacking.

Methods

In the Netherlands, women aged 30–60 years invited for cervical screening can choose between sampling at the clinician's office (Cervex Brush) or self-sampling at home (Evalyn Brush). HrHPV testing is performed using Roche Cobas 4800. We collected screening test results between January 2017 and March 2018 and histological follow-up until August 2019. The main outcome measures were mean cycle threshold (Ct) value, cervical intraepithelial neoplasia (CIN) grade 3 or cancer (CIN3+) and CIN grade 2 or worse (CIN2+).

Findings

30,808 women had a self-collected and 456,207 had a clinician-collected sample. In hrHPV-positive women with adequate cytology, Ct values were higher for self-collection than clinician-collection with a mean Ct difference of 1·25 (95% CI 0·98–1·52) in women without CIN2+, 2·73 (1·75–3·72) in CIN2 and 3·59 (3·03–4·15) in CIN3+. The relative sensitivity for detecting CIN3+ was 0·94 (0·90–0·97) for self-collection versus clinician-collection and the relative specificity was 1·02 (1·02–1·02).

Interpretation

The clinical accuracy of hrHPV testing on a self-collected sample for detection of CIN3+ is high and supports its use as a primary screening test for all invited women. Because of the slightly lower sensitivity of hrHPV testing on a self-collected compared to a clinician-collected sample, an evaluation of the workflow procedure to optimise clinical performance seems warranted.

Funding

National Institute for Public Health and the Environment (the Netherlands) and the European Commission.

Rapid, random-access, and quantification of hepatitis B virus using the Cepheid Xpert HBV viral load assay

BACKGROUND

Monitoring viral load (VL) is an essential part of the management of patients chronically infected with hepatitis B virus (HBV). The commercial HBV VL assays currently available are generally performed on high-throughput platforms for batch wise testing of plasma samples, with relatively long turn-around-times. Rapid VL testing could provide immediate input to clinical decision making.

METHODS

One hundred two stored plasma samples from 102 patients who were previously tested for HBV VL by the Cobas Ampliprep/Taqman or Cobas 4800 (Roche, Pleasanton, CA), were analyzed by the recently introduced Cepheid Xpert HBV Viral Load Assay. Thirty-one of the 102 samples were negative for HBV DNA and 71 out of 102 samples had a detectable VL. HBV DNA loads ranged from <20 to 5E8 IU/mL. HBV genotypes (A, B, C, D, E, and G) were known for 52 of the VL positive samples. Correlation of VL results between both assays was determined by the Pearson correlation coefficient (r2 ). The level of concordance was assessed using the Bland-Altman analysis.

RESULTS

HBV VLs correlated well between both assays, across all genotypes (Pearson correlation coefficient r2  = 0.987). Six samples exceeded a 0.5  log difference between assays. Bland-Altman analysis demonstrated a mean of the difference of -0.107 log and a standard deviation of 0.271 log.

CONCLUSION

High correlation was observed between the Roche Cobas HBV Viral Load tests and the Xpert HBV Viral Load Assay, thus enabling rapid, random access, and accurate HBV VL assessment.

Impact of molecular point-of-care testing on clinical management and in-hospital costs of patients suspected of influenza or RSV infection: a modeling study

Background

At hospital admission, patients suspected of infection with influenza or respiratory syncytial virus (RSV) are placed in isolation, pending the outcome of diagnostics. In a significant number, isolated care proves unnecessary. We investigated the potential impact of molecular point‐of‐care (POC) diagnostics on patient management and in‐hospital costs.

Method

Prospective collection of data on resource utilization within the hospital from consecutive patients 18 years or older presenting at our university medical center with symptoms of respiratory tract infection from December 2016 to April 2017. A cost analysis was conducted using Markov modeling comparing the actual course of events (on the basis of routine diagnostic tests) with two hypothetical scenarios: when POC would impact time to diagnosis only (scenario 1) or on discharge from the hospital, too (scenario 2).

Results

A total of 283 patients were included, of whom 217 (76.7%) were admitted. Influenza and RSV were detected in 31% and 7% of the patients, respectively. Fifty‐four percent of patients tested negative, of which 79% were kept in isolated care waiting for test results, with a median duration of 24 hours. Median length of stay was 6.0 days. Mean total in‐hospital costs per patient were € 5243. Introducing POC would lower mean costs per patient to € 4904 (scenario 1) and € 4206 (scenario 2). At the hospital level, this would result in a total cost reduction of € 95 937 to € 293 471 in a single influenza season.

Conclusions

Introducing POC testing for patients presenting with symptoms of viral respiratory tract infection can reduce time‐to‐diagnosis, hospital stay and, thereby, in‐hospital costs.

Long-Lasting Increased Risk of Human Papillomavirus–Related Carcinomas and Premalignancies After Cervical Intraepithelial Neoplasia Grade 3: A Population-Based Cohort Study

Purpose

The aim of this study was to determine the risk of human papillomavirus (HPV)–related carcinomas and premalignancies in women diagnosed with cervical intraepithelial neoplasia grade 3 (CIN3). Knowledge of this risk is important to preventing the development and progression of other HPV-related premalignancies and carcinomas, by considering prophylactic HPV vaccination and/or by paying increased attention to other HPV-related carcinomas and premalignancies when CIN3 is identified.

Methods

Women diagnosed with a CIN3 between 1990 and 2010 were identified from the Dutch nationwide registry of histopathology and cytopathology (PALGA) and matched with a control group of women without CIN3. Subsequently, all cases of high-risk (hr) HPV–associated high-grade lesions and carcinomas in the anogenital region and oropharynx between 1990 and 2015 were extracted. Incidence rate ratios were estimated for carcinomas and premalignancies of the vulva, vagina, anus, and oropharynx.

Results

A total of 178,036 women were identified: 89,018 with a previous diagnosis of CIN3 and 89,018 matched control subjects without a history of CIN3. Women with a history of CIN3 showed increased risk of HPV-related carcinomas and premalignancies, with incidence rate ratios of 3.85 (95% CI, 2.32 to 6.37) for anal cancer, 6.68 (95% CI, 3.64 to 12.25) for anal intraepithelial neoplasia grade 3, 4.97 (95% CI, 3.26 to 7.57) for vulvar cancer, 13.66 (93% CI, 9.69 to 19.25) for vulvar intraepithelial neoplasia grade 3, 86.08 (95% CI, 11.98 to 618.08) for vaginal cancer, 25.65 (95% CI, 10.50 to 62.69) for vaginal intraepithelial neoplasia grade 3, and 5.51 (95% CI, 1.22 to 24.84) for oropharyngeal cancer. This risk remained significantly increased, even after long-term follow-up of up to 20 years.

Conclusion

This population-based study shows a long-lasting increased risk for HPV-related carcinomas and premalignancies of the anogenital and oropharyngeal region after a CIN3 diagnosis. Studies that investigate methods to prevent this increased risk in this group of patients, such as intensified screening or vaccination, are warranted.

Successful treatment of azole-resistant invasive aspergillosis in a bottlenose dolphin with high-dose posaconazole

Invasive aspergillosis due to azole-resistant Aspergillus fumigatus is difficult to manage. We describe a case of azole-resistant invasive aspergillosis in a female bottlenose dolphin, who failed to respond to voriconazole and posaconazole therapy. As intravenous therapy was precluded, high dose posaconazole was initiated aimed at achieving trough levels exceeding 3 mg/l. Posaconazole serum levels of 3–9.5 mg/l were achieved without significant side-effects. Follow-up bronchoscopy and computed tomography showed complete resolution of the lesions.

Respiratory infections in Eñepa Amerindians are related to malnutrition and Streptococcus pneumoniae carriage

OBJECTIVES

High acute respiratory tract infection (ARTI) rates are observed in indigenous populations. We assessed the role of viral infections and nasopharyngeal bacterial carriage in ARTIs in Eñepa Amerindians from Venezuela.

METHODS

In 40 children aged 0-10 years with ARTIs, healthy nearest-age sibling controls and their mothers the presence of Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, Moraxella catarrhalis, Mycoplasma pneumoniae, Chlamydophila pneumoniae/psittachi and 15 respiratory viruses was investigated.

RESULTS

S. pneumoniae was the most frequently detected pathogen, with carriage rates of 75% and 38% in children and mothers respectively. In children, S. pneumoniae carriage was associated with ARTI risk in multivariate analysis (OR 14.1, 95% CI 1.4-137.7). Viral infections were not associated with ARTI risk. S. pneumoniae carriage was common in children of all ages while viral co-infections were more frequently present in children under 4 years compared to older children (46% vs. 17%, p < 0.01). An increase of one unit height-for-age Z score (i.e. improved chronic nutritional status) was associated with decreased odds of S. pneumoniae colonization in multivariate analysis (OR 0.66, 95% CI 0.44-0.99).

CONCLUSIONS

In Eñepa children high S. pneumoniae carriage rates associated with a poor nutritional status contribute to the development of ARTIs.

Microbial profiling does not differentiate between childhood recurrent acute otitis media and chronic otitis media with effusion

OBJECTIVES

Otitis media (OM) is one of the most frequent diseases of childhood, with a minority of children suffering from recurrent acute otitis media (rAOM) or chronic otitis media with effusion (COME), both of which are associated with significant morbidity. We investigated whether the microbiological profiling could be used to differentiate between these two conditions.

METHODS

Children up to five years of age, with rAOM (n = 45) or COME (n = 129) and scheduled for tympanostomy tube insertion were enrolled in a prospective study between 2008 and 2009. Middle ear fluids (n = 119) and nasopharyngeal samples (n = 173) were collected during surgery for bacterial culture and PCR analysis to identify Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis, and to detect 15 distinct respiratory viruses.

RESULTS

The occurrence of bacterial and viral pathogens in middle ear fluids did not significantly differ between patients suffering from rAOM and COME. In both patient cohorts, H. influenzae and rhinovirus were the predominant pathogens in the middle ear and nasopharynx. Nasopharyngeal carriage with two or three bacterial pathogens was associated with the presence of bacteria in middle ear fluid (P = 0.04). The great majority of the bacteria isolated from middle ear fluid were genetically identical to nasopharyngeal isolates from the same patient.

CONCLUSIONS

Based on these results, we propose that the common perception that rAOM is associated with recurrent episodes of microbiologically mediated AOM, whereas COME is generally a sterile inflammation, should be reconsidered.

Human papilloma virus detection by in situ hybridisation signal amplification based on biotinylated tyramine deposition

Aim-To describe a method for amplifying human papilloma virus (HPV) in situ hybridisation (ISH) signals.Methods-Three human cervical cell lines, namely CaSKi, HeLa and SiHa, containing different copy numbers of integrated HPV DNA were studied. Following ISH, catalysed reporter deposition (CARD), based on the deposition of biotinylated tyramine at the location of the DNA probe, was used to amplify the ISH signal.Results-Using CARD-ISH, one to three HPV type 16 copies were detected in situ both in cell suspensions and paraffin wax sections of SiHa cells. CARD-ISH can also be used to detect oncogenic HPV DNA sequences, such as HPV types 16 and 18, in routinely processed formalin fixed, paraffin wax embedded cervical specimens.Conclusions-CARD-ISH is a fast and highly sensitive ISH method for the routine detection of low copy number HPV DNA sequences in cervical cell lines and routinely processed tissue sections. Application of this technology also enables the routine detection and cellular localisation of other viral DNA sequences present at copy numbers below the detection limit of conventional ISH methods.

Histopathologic findings in explanted heart tissue from patients with end-stage idiopathic dilated cardiomyopathy

Explanted hearts were examined to determine whether specific histopathologic features are present in the myocardium of patients with end-stage idiopathic dilated cardiomyopathy (IDC). Extensive histopathologic examination by light microscopy, electron microscopy and immunohistochemistry revealed marked fibrosis in the hearts of 21 of 37 IDC patients and in 26 of 35 patients with heart diseases of known causes. Reactive (interstitial and perivascular) fibrosis predominated in the IDC hearts, whereas both reparative (replacement) fibrosis and reactive fibrosis were found in the comparison group. Endocardial fibroelastosis was found in nine patients with IDC and in 14 patients from the comparison group. Distinct patterns of fibrosis were the sole significant histopathologic difference between myocardial samples from patients with IDC and from those with heart diseases of known causes. The diffuse presence of reactive fibrosis in IDC patients suggests a more generalised dysfunction that affects the composition of the myocardial extracellular matrix.

Enterovirus-induced production of pro-inflammatory and T-helper cytokines by human leukocytes

Enteroviruses are associated with chronic inflammatory and autoimmune diseases in humans. In these conditions, the cytokine network is supposed to have an important role in inflammation and modulation of the (auto)immune response. In the present study, we demonstrate that coxsackie virus B4 and poliovirus type 1 induce production of pro-inflammatory cytokines IL-1 beta and TNF-alpha in freshly isolated human leucocytes. Furthermore, enteroviruses stimulate the production of cytokines belonging to Th(1)pathways (IFN-gamma, IL-2), and IL-10, which play a role in regulation of the cellular and humoral immune response.

Co-factors related to the causal relationship between human papillomavirus and invasive cervical cancer in Honduras

BACKGROUND

A case-control study was conducted in Honduras to identify co-factors in the carcinogenic pathway by which human papillomavirus (HPV) causes invasive cervical cancer.

METHODS

Ninety-nine cases aged 23-65 (median 47) years participated. Two controls were matched to each case by age and clinic where they first presented for cytological screening; controls had no cervical abnormalities. Information on risk factors was obtained by personal interviews in the clinics regarding sociodemographic, reproductive and behavioral characteristics. Human papillomavirus was detected in cervical scrapes by general primer-mediated polymerase chain reaction (PCR) followed by sequence analysis to identify the different types present.

RESULTS

All cases had squamous cell tumours and most were FIGO (International Federation of Gynecologists and Obstetricians) class II or higher; HPV was strongly associated with cervical cancer (odds ratio [OR] = 7.66, 95% CI : 3.88-15.1). Among HPV-positive women, dose-response relationships were observed for education, age at first intercourse and exposure to wood smoke that persisted after adjustment for previous screening. Among HPV-negative women, the number of sexual partners and parity were associated with cervical cancer. The protective effect of previous cytological screening operated independently of HPV.

CONCLUSIONS

Our findings speak for the powerful role that both primary and secondary education plays in fostering a lifestyle that reduces the risk of invasive cervical cancer. The data suggest that important elements of such a lifestyle include later age at first sexual intercourse, a limited number of pregnancies, greater likelihood of undergoing cytological screening and reduced exposure to carcinogens in the household environment.

Acute onset of type I diabetes mellitus after severe echovirus 9 infection: putative pathogenic pathways

Enterovirus infections have been implicated in the development of type I diabetes mellitus. They may cause beta cell destruction either by cytolytic infection in the pancreas or indirectly by contributing to autoimmune reactivity. We sought evidence for these 2 mechanisms in a case of acute-onset diabetes mellitus that occurred during severe echovirus 9 infection. The virus was isolated and administered to cultured human beta cells. No viral proliferation was observed, and no beta cell death was induced, while parallel exposure to Coxsackie B virus serotype 3 resulted in viral proliferation and massive beta cell death. Although the viral protein 2C exhibited a sequence similar to that of the beta cell autoantigen glutamic acid decarboxylase (GAD(65)), no cross-reactive T cell responses were detected. The patient did not develop antibodies to GAD(65) either. Absence of evidence for direct cytolytic action or an indirect effect through molecular mimicry with GAD(65) in the present case raises the possibility of another indirect pathway through which enteroviruses can cause diabetes mellitus.

Cross-talk between orientation-dependent recognition determinants of a complex control RNA element, the enterovirus oriR

The coxsackie B3 virus oriR is an element of viral RNA thought to promote the assembly of a ribonucleoprotein complex involved in the initiation of genome replication. The mutual orientation of its two helical domains X and Y is determined by a kissing interaction between the loops of these domains. Here, a genetic approach was worked out to identify spatial orientation-dependent recognition signals in these helices. Spatial orientation changes (due to linear and rotational shifts) were introduced by appropriate insertions/deletions of a single base pair into one or both of the domains, and phenotypic consequences caused by these mutations were studied. The insertion of a base pair into domain Y caused a defect in viral reproduction that could be suppressed by a base-pair insertion into domain X. Similarly, a defect in viral replication caused by a base-pair deletion from domain X could be suppressed by a base-pair deletion from domain Y. Thus, certain areas of the two domains should cross-talk to one another in the sense that a change of space position of one of them required an adequate reply (change of space position) from the other. Phenotypic effects of the local rotation of one or more base pairs (and of some other mutations) in either domain X or domain Y suggested that the two most distal base pairs of these domains served as orientation-dependent recognizable signals. The results were also consistent with the notion that the recognition of the distal base pair of domain Y involved a mechanism similar to the intercalation of an amino acid residue.

AgarCyto: a novel cell-processing method for multiple molecular diagnostic analyses of the uterine cervix

In diagnostic cytology, it has been advocated that molecular techniques will improve cytopathological diagnosis and may predict clinical course. Ancillary molecular techniques, however, can be applied only if a sufficient number of preparations are made from a single cell sample. We have developed the AgarCyto cell block procedure for multiple molecular diagnostic analyses on a single scraping from the uterine cervix. The optimized protocol includes primary fixation and transport in ethanol/carbowax, secondary fixation in Unifix, and embedding in 2% agarose and then in paraffin according to a standard protocol for biopsies. More than 20 microscopic specimens were produced from a single AgarCyto cell block, and standard laboratory protocols have been successfully applied for H&E staining, immunohistochemistry for Ki-67 and p53, and in situ hybridization for the centromere of human chromosome 1 and human papilloma virus Type 16. In addition, single AgarCyto sections yielded sufficient input DNA for specific HPV detection and typing by LiPA-PCR, and the protocol includes an option for DNA image cytometry. The AgarCyto cell block protocol is an excellent tool for inventory studies of diagnostic and potentially prognostic molecular markers of cervical cancer.

Short fragment polymerase chain reaction reverse hybridization line probe assay to detect and genotype a broad spectrum of human papillomavirus types. Clinical evaluation and follow-up

The purpose of this study was to detect and genotype 16 different human papilloma virus (HPV) types simultaneously using a short fragment polymerase chain reaction (SPF) hybridization line probe assay (LiPA). 152 women who were referred to the gynecologist because of abnormal cervical smear underwent colposcopic examination and repeat cervical smear. In addition, the cervical scrapes were analyzed for the presence of HPV by a novel general HPV polymerase chain reaction assay followed by a single reaction genotyping assay allowing for a simultaneous detection and identification of 16 different HPV types. HPV DNA was detected in 38% of normal follow-up cervical scrapes, 51% of scrapes with atypical squamous cells of undetermined significance, 78% of scrapes with mild dysplasia (low grade squamous intraepithelial lesions), 86% of scrapes with moderate dysplasia (high grade squamous intraepithelial lesions), and in 88% of scrapes with severe dysplasia and carcinoma in situ. One case of invasive squamous cell carcinoma was positive for HPV 16. Overall, a single HPV type was detected in 56% of HPV positive scrapes, with HPV 16 being the most common and accounting for 45% of all single infections. Forty-four percent of the positive scrapes contained multiple HPV types, of which double infections prevailed. Follow-up results proved the reproducibility and reliability of SPF HPV LiPA. In conclusion, we have used and evaluated the SPF-HPV-LiPA system for the detection and genotyping of HPV infections. The combined detection-typing method proved to be sensitive, specific, simple, and fast, making mass screening of cervical scrapes accessible for routine practice and facilitating individual patient management.

Analysis of antibody responses against coxsackie virus B4 protein 2C and the diabetes autoantigen GAD(65)

Type I diabetes mellitus results from the autoimmune destruction of insulin producing beta cells in the pancreas. Certain viral infections, especially those caused by coxsackie B viruses and related enteroviruses, have been associated with the development of type I diabetes. The sequence homology between the coxsackie B4 virus nonstructural protein 2C (CVB4 p2C) and the major diabetes autoantigen glutamic acid decarboxylase (GAD(65)) provides a basis for the hypothesis of molecular mimicry. In this study, we investigated the prevalence of antibodies directed against nonstructural enterovirus proteins. In addition, a correlation of antibodies against CVB4 p2C and GAD(65) was studied in diabetes patients and in healthy controls. Antibody reactivity against CVB proteins was detected by immunoprecipitation of [(35)S]-methionine-labelled viral proteins and GAD(65) antibodies were measured in a quantitative radio-immunoassay. It was shown that antibodies raised against the nonstructural proteins of CVB4 are very common in the population and a high degree of heterotypic cross-reactivity exists between different enterovirus types. CVB4 p2C-specific antibodies were not only detectable in GAD(65) antibody-positive diabetes patients but also in GAD(65) antibody-negative healthy blood donors. Furthermore, GAD(65) antibodies could not be detected in p2C-positive subjects who had various enterovirus infections, indicating that an antibody response to CVB4 p2C does not necessarily induce a cross-reactive immune response against GAD(65). A correlation was not found between antibodies against GAD(65) and p2C.

Autoimmune markers are undetectable in end stage idiopathic dilated cardiomyopathy

BACKGROUND

Autoreactive humoral and cellular immune responses may be involved in the pathogenesis of idiopathic dilated cardiomyopathy (IDC). Certain human leucocyte antigens (HLA) could also be linked to the development of IDC.

AIM

To determine whether various markers of autoimmunity are present in the final phase of the disease, to substantiate the role of an autoimmune process in IDC.

METHODS

37 patients with end stage IDC were studied, together with 39 patients with end stage heart disease of known aetiology who were included for comparison. Multiple myocardial tissue samples from the explanted heart of each patient were evaluated (immuno)histologically. An indirect immunofluorescence assay was used to screen patient serum samples for the presence of heart specific autoantibodies. HLA class I and II frequencies were determined in each group and compared with HLA frequencies from healthy blood donors.

RESULTS

Only scanty small mononuclear cell infiltrates were present in myocardial tissue of seven patients with IDC and of 11 patients with heart disease of known cause. The majority of these inflammatory cells were negative for T cell markers. All blood specimens were negative for heart specific autoantibodies and there was no apparent association of IDC with particular HLA phenotypes.

CONCLUSIONS

These findings suggest that an active autoimmune process is not involved in the end stage of IDC.

Human papillomavirus infection, cervical dysplasia and invasive cervical cancer in Honduras: a case-control study

A substantial body of evidence has confirmed human papillomavirus (HPV) infection as the central etiological agent in human cervical carcinogenesis. In Honduras, cervical cancer is the most common cancer among women, with a high annual incidence. We conducted a population-based, case-control study of 229 patients with different grades of CIN and invasive cervical cancer and 438 matched controls. A structured questionnaire was used to investigate known and probable risk factors for cervical cancer. Cervical scrapes were tested for the presence of different HPV types using a general primer-mediated PCR followed by PCR-based sequencing. HPV DNA was detected in 87% of all cancer in situ and invasive cancer cases, and 95% of invasive cases could be attributed to high-risk types. In control women, 39% were positive for HPV DNA sequences. HPV 16 prevalence ranked highest in all stages of cervical dysplasias, invasive cancers and controls. A statistically significant association with HPV was observed for CIN II, CIN III and invasive cancer, showing an upward trend to more severe lesions and being more pronounced for HPV 16 and related types. The OR for HPV 16- and 18-related invasive cancer cases was 14.88 (95% CI 5.12-43.25) and 74.66 (95% CI 7.77-717.62), respectively. Our results confirm a central role of HPV as the cause of cervical cancer in Honduras and provide information as to the type distribution of HPVs in the country.

Study on microbial persistence in end-stage idiopathic dilated cardiomyopathy

Microbial persistence may be involved in the pathogenesis of idiopathic dilated cardiomyopathy (IDC). Therefore, we evaluated the role of various cardiopathogenic microorganisms in patients with end-stage IDC. In a previous study, we did not find evidence for the persistence of enterovirus RNA in end-stage IDC. In the present study, we looked for other microorganisms that are frequently associated with heart disease, including cytomegalovirus, hepatitis B virus, hepatitis C virus, Borrelia burgdorferi, Chlamydia species, mycoplasmata, and Toxoplasma gondii. Serology, polymerase chain reaction (PCR) analysis specific for detection of microbial genomic sequences, or both investigations were performed on myocardial samples from 37 patients with end-stage IDC. PCR analysis was performed on multiple myocardial samples per patient. Thirty-nine patients with end-stage heart disease of known cause were included as controls. On the basis of our serological data and PCR analyses, we did not find any evidence that microbial persistence in the heart is involved in the end-stage disease process of IDC.

HLA DOA1 and DOB1 loci in Honduran women with cervical dysplasia and invasive cervical carcinoma and their relationship to human papillomavirus infection

Molecular and epidemiological studies have demonstrated that certain types of human papillomavirus (HPV), mainly HPV-16 and HPV-18, are the primary causes of cervical cancer and its precursor lesions; there is now evidence for a clear association with specific HLA class I and class II loci contributing independently to the expression of cervical cancer. Among Honduran women carcinoma of the cervix is the most common type of cancer, and infections with high-risk HPV types are highly prevalent. To study the interactive role of viral-host genetics, we performed PCR amplification of DNA and sequence-specific oligonucleotide probe typing on cervical scrapes from 49 women [24 with cervical intraepithelial neoplasia stage III or cervical cancer (severe cases) and 25 with stage I or II cervical intraepithelial neoplasia (mild cases)] and 75 control subjects to look for possible associations between HPV and HLA class II DQA1 and DQB1 alleles in the development of dysplasias and invasive cancer. This analysis revealed a predominance of HLA-DQA1*0301 among severe-case patients [relative risk (RR) = 3.45, p = 0.008), whereas DQA1*0501 was negatively associated (RR = 0.30, p = 0.03), suggesting a protective effect of this allele. HPV typing showed a decreased relative risk among the HPV-16 or HPV-18 carrying patients and other HPV-related positive patients in the presence of DQB1*0602 compared with positive control subjects (p = 0.04). No statistically significant allele frequency difference was observed between mild dysplasia cases and control subjects. The results suggest that DQA1*03011, which is in linkage desequilibrium with all HLA-DR4 alleles, confers an increased risk for severe cervical dysplasia and invasive cancer, whereas DQA1*0501, which is in several DR52 haplotypes, has a protective effect. Furthermore, specific HLA-DQB1 sequences may be important in determining the immune response to HPV peptides and may affect the risk for cervical cancer after HPV infection in mestizo Honduran women.

Neuroinvasion by human herpesvirus type 7 in a case of exanthem subitum with severe neurologic manifestations

A 19-month-old girl presented with severe neurologic symptoms associated with exanthem subitum. Human herpesvirus type 7 (HHV-7) DNA was detected in the CSF and serum, and supported by serologic studies. The patient was diagnosed with encephalopathy due to an acute HHV-7 infection. Neuron-specific enolase in the CSF was strongly elevated during the acute stage of infection, suggesting that the encephalopathy was due to viral invasion of the brain.

[Genotyping of human papillomavirus genotyes in cervical scrapes by line probe assay]

OBJECTIVE

To pursue the further development of a practical HPV genotyping system applicable for mass screening.

METHODS

Cervical scrapes from 155 women were tested for the presence of HPV using a general-primer based PCR. A reverse hybridization assayor, the line probe assay (LiPA) was used for genotyping 16 different HPV types(HPV 6, 11, 16, 18, 31, 33, 35, 40, 42, 43, 44, 45, 51, 52, 56, 58) simultaneously.

RESULTS

93(60%) out of 155 specimens tested were positive for HPV DNA by PCR. The HPV positivity amongst the group of women with no cervical abnormality was 43%, while that in women with cervical dysplasia and cervical cancer was 81.2% PCR products from 89 HPV positive cases were genotyped by LiPA, of which 49 cases were single HPV infected concerning 11 different HPV types and the commonest type was HPV-16, occurring in 25(51%) of all single HPV infected cases. The other 40 specimens contained multiple HPV types comprising 16 different HPV types. Although double infections(n = 25) prevailed, triple(n = 9), quadruple(n = 3) and quintuple (n = 3) infections were also found. PCR products of four HPV positive cases failed to be classified by LiPA. Sequencing analysis revealed that these 4 cases were HPV-66 which was not included in LiPA probes. Follow-up data of 12 cases confirmed the HPV genotyping results.

CONCLUSION

The LiPA for HPV genotyping is easy to perform. It allows accurate and rapid identification of 16 different HPV types in cervical scrapes and will facilitate HPV detection as well as genotyping in cervical cancer screening programs.

Structural requirements of the higher order RNA kissing element in the enteroviral 3'UTR

The origin of replication ( oriR ) involved in the initiation of (-) strand enterovirus RNA synthesis is a quasi-globular multi-domain RNA structure which is maintained by a tertiary kissing interaction. The kissing interaction is formed by base pairing of complementary sequences within the predominant hairpin-loop structures of the enteroviral 3' untranslated region. In this report, we have fully characterised the kissing interaction. Site-directed mutations which affected the different base pairs involved in the kissing interaction were generated in an infectious coxsackie B3 virus cDNA clone. The kissing interaction appeared to consist of 6 bp. Distortion of the interaction by mispairing of each of the base pairs involved in this higher order RNA structure resulted in either temperature sensitive or lethal phenotypes. The nucleotide constitution of the base which gaps the major groove of the kissing domain was not relevant for virus growth. The reciprocal exchange of the complete sequence involved in the kissing resulted in a mutant virus with wild type virus growth characteristics arguing that the base pair constitution is of less importance for the initiation of (-) strand RNA synthesis than the existence of the tertiary structure itself.

Occurrence of verocytotoxin-producing Escherichia coli O157 on Dutch dairy farms

During the period from September 1996 through November 1996, 10 Dutch dairy farms were visited to collect fecal samples from all cattle present. The samples were examined for the presence of verocytotoxin (VT)-producing Escherichia coli (VTEC) of serogroup O157 (O157 VTEC) by immunomagnetic separation following selective enrichment. Cattle on 7 of the 10 dairy farms tested positive for O157 VTEC, with the proportion of cattle infected varying from 0.8 to 22.4%. On the seven farms positive for O157 VTEC, the excretion rate was highest in calves ages 4 to 12 months (21.2%). In a follow-up study, two O157 VTEC-positive farms and two O157 VTEC-negative farms identified in the prevalence study were revisited five times at intervals of approximately 3 months. Cattle on each farm tested positive at least once. The proportion of cattle infected varied from 0 to 61.0%. Excretion rates peaked in summer and were lowest in winter. Again, the highest prevalence was observed in calves ages 4 to 12 months (11.8%). O157 VTEC strains were also isolated from fecal samples from horses, ponies, and sheep and from milk filters and stable flies. O157 VTEC isolates were characterized by VT production and type, the presence of the E. coli attaching-and-effacing gene, phage type, and pulsed-field gel electrophoretic genotype. No overlapping strain types were identified among isolates from different farms except one. The predominance of a single type at each sampling suggests that horizontal transmission is an important factor in dissemination of O157 VTEC within a farm. The presence of more than one strain type, both simultaneously and over time, suggests that there was more than one source of O157 VTEC on the farms. Furthermore, this study demonstrated that the O157 VTEC status of a farm cannot be ascertained from a single visit testing a small number of cattle.

Lack of consistent short sequence repeat polymorphisms in genetically homologous colonizing and invasive Candida albicans strains

Short sequence repeats (SSRs), potentially representing variable numbers of tandem repeat (VNTR) loci, were identified for the human-pathogenic yeast species Candida albicans by computerized DNA sequence scanning. The individual SSR regions were investigated in different clinical isolates of C. albicans. Most of the C. albicans SSRs were identified as genuine VNTRs. They appeared to be present in multiple allelic variants and were demonstrated to be diverse in length among nonrelated strains. As such, these loci provide adequate targets for the molecular typing of C. albicans strains. VNTRs encountered in other microbial species sometimes participate in regulation of gene expression and function as molecular switches at the transcriptional or translational level. Interestingly, the VNTRs identified here often encode polyglutamine stretches and are frequently located within genes potentially involved in the regulation of transcription. DNA sequencing of these VNTRs demonstrated that the length variability was restricted to the CAA/CAG repeats encoding the polyglutamine stretches. For these reasons, paired C. albicans isolates of similar genotype, either found as noninvasive colonizers or encountered in an invasive state in the same individual, were studied with respect to potentially invasion-related alterations in the VNTR profiles. However, none of the VNTRs analyzed thus far varied systematically with the transition from colonization to invasion. In contrast to the situation described for some prokaryotic species, this finding suggests that VNTRs of C. albicans may not simply function as contingency loci related to straightforward on/off regulation of invasion-related gene expression.

No evidence for persistent enterovirus infection in patients with end-stage idiopathic dilated cardiomyopathy

Persistence of enteroviruses in heart tissue has been implicated in the etiology of idiopathic dilated cardiomyopathy (IDC). Therefore, we determined the prevalence of enterovirus RNA in heart tissue from patients with end-stage IDC. During heart transplantation, 287 transmural biopsy specimens were aseptically collected from the explanted hearts of 38 patients with IDC and of 39 patients with cardiac failure of known cause. A nested polymerase chain reaction with general specificity for enteroviruses was used to screen for the presence of enterovirus RNA in the heart tissue samples. No enterovirus RNA was detected in any of the 287 heart biopsy specimens. These findings lead to a conclusion that enteroviruses do not persist in heart tissue from patients with end-stage IDC, nor with other heart diseases of known cause.

In situ localisation of Yersinia enterocolitica by catalysed reported deposition signal amplification

AIM

The sensitive detection of pathogenic Yersinia enterocolitica in paraffin embedded tissue sections by in situ hybridisation (ISH).

METHODS

Y enterocolitica infected cell lines, rat spleens, and patient biopsy specimens were used to compare conventional ISH, immune fluorescence assay (IFA) detection, and catalysed reporter deposition (CARD) signal amplification ISH.

RESULTS

CARD-ISH was shown to be more sensitive then conventional ISH and had a comparable sensitivity to IFA. In contrast to IFA, CARD-ISH preserved good tissue morphology.

CONCLUSIONS

CARD-ISH appeared to be a fast and sensitive ISH method for detecting Y enterocolitica in routinely processed tissue sections. Application of this method allows the combination of routine detection and cellular localisation of the pathogen within the infected tissue.

Nosocomial outbreak of colonization and infection with Stenotrophomonas maltophilia in preterm infants associated with contaminated tap water

Between March and May 1996 Stenotrophomonas maltophilia was cultured from endotracheal aspirate samples from five preterm infants in a neonatal intensive care unit (NICU). Four infants were superficially colonized, but a fifth died due to S. maltophilia septicaemia. S. maltophilia was cultured from tap water from three outlets in the NICU including one with a previously unnoticed defective sink drain. Water from these outlets was used to wash the preterm infants. Environmental and clinical S. maltophilia isolates yielded identical banding patterns on random arbitrary polymorphic DNA (RAPD) PCR analysis. The outbreak was controlled by reinforcement of hand disinfection, limitation of the use of tap water for hand washing and by using sterile water to wash the preterm infants. We conclude that tap water should not be used for washing preterm infants in the NICU, unless steps are taken to prevent microbial growth in the outlets.

Characterization of pathogenetic determinants of Candida albicans strains

The study was an attempt to correlate phenotypic pathogenetic determinants of clinical Candida albicans strains with their genotype as determined by PCR fingerprinting. A total of 25 C. albicans strains was tested. Adherence capacity, hydrophobicity and proteinase production were compared with the genotypes of the particular Candida strains. The fungal strains represented eleven genotypes. No correspondence relationship was found between genotype and the markers of pathogenicity.

Isolation and characterization of verocytotoxin-producing Escherichia coli O157 strains from Dutch cattle and sheep

In the periods from July to November 1995 and 1996, fecal samples from Dutch cattle and sheep were collected at the main slaughterhouses of The Netherlands, located at different geographic sites. The samples were examined for the presence of verocytotoxin (VT)-producing Escherichia coli (VTEC) of serogroup 0157. E. coli O157 strains could be isolated from 57 (10.6%) of 540 adult cattle, 2 (0.5%) of 397 veal calves, 2 (3.8%) of 52 ewes, and 2 (4.1%) of 49 lambs. Immunomagnetic separation with O157-specific-antibody-coated beads appeared to be significantly more sensitive than conventional plating for detection of the organism in feces. With the exception of two isolates from adult cattle which appeared to be negative for VT genes, all animal isolates were positive for both VT (VT1 and/or VT2) and E. coli attaching-and-effacing gene sequences, and therefore, they were regarded as potential human pathogens. Although genomic typing by pulsed-field gel electrophoresis revealed a wide variety of distinct restriction patterns, comparison of the 63 animal isolates with 33 fecal O157 VTEC strains previously isolated from humans with the diarrhea-associated form of the hemolytic-uremic syndrome by their phage types and VT genotypes showed a marked similarity between animal and human isolates: 30 (90.9%) of the 33 human isolates appeared to be of E. coli O157 strain types also isolated from cattle and sheep. It was concluded that Dutch cattle and sheep are an important reservoir of E. coli O157 strains that are potentially pathogenic for humans.

Local expression of cytokine mRNA in spleen and Peyer's patches of rats is involved in resistance against infection with Yersinia enterocolitica

The immune-response against infection with Yersinia enterocolitica was studied in a rat model which resembles yersiniosis in humans. Lewis, Fischer and Brown Norway rats were inoculated with Y. enterocolitica and the cytokine mRNA expression in spleen and Peyer's patches was determined. In Brown Norway rats the infection was mild and Yersinia enterocolitica was fully cleared. In these rats the highest anti-inflammatory cytokine expression was found probably resulting in a protective host defence against the infection. In both the Lewis and Fischer rats Y. enterocolitica persisted. The anti-inflammatory cytokine expression was less pronounced in these two rat strains. The authors conclude that progression of disease, persistence of infection and development of reactive arthritis, may be related to the local expression of specific cytokines.

Evaluation of the discriminatory power of pulsed-field gel electrophoresis and PCR fingerprinting for epidemiologic typing of Candida species

OBJECTIVE: To evaluate the discriminatory power of genotyping methods (PCR fingerprinting and pulsed-field gel electrophoresis) validated for Candida albicans in other Candida species. METHODS: Molecular typing methods are increasingly being applied for studies where the interpretation of data essentially relies on the typing results rather than epidemiologic data. In this situation, the discriminatory power (ability to identify differences among epidemiologically unrelated strains) of the typing method is important in allowing one to draw valid conclusions. By applying PCR fingerprinting, electrophoretic karyotyping, and restriction fragment endonuclease analysis using standard restriction enzymes and primers proven to be useful in previous studies, we evaluated whether the use of multiple genotyping methods is sufficient to delineate known unrelated strains among seven Candida species. RESULTS: All three methods identified individual genotypes for each of the seven Candida species studied. However, optimal strain delineation required the combined use of all three typing methods and was observed only within the small number of C. albicans and C. tropicalis isolates tested in this study. CONCLUSION: Typing assays that are able to delineate a certain Candida species may not be used blindly for other species of that genus. Regarding the limited number of strains tested, further validation of the discriminative power of genotyping methods (including in C. tropicalis) should be done.

Molecular mimicry in diabetes mellitus: the homologous domain in coxsackie B virus protein 2C and islet autoantigen GAD65 is highly conserved in the coxsackie B-like enteroviruses and binds to the diabetes associated HLA-DR3 molecule

It has been proposed that molecular mimicry between protein 2C (p2C) of coxsackie virus B4 and the autoantigen glutamic acid decarboxylase (GAD65) plays a role in the pathogenesis of insulin-dependent diabetes mellitus (IDDM). In this study we show that the amino acid sequence of p2C which shares homology with a sequence in GAD65 (PEVKEK), is highly conserved in coxsackie virus B4 isolates as well as in different viruses of the subgroup of coxsackie B-like enteroviruses. These are the most prevalent enteroviruses and therefore exposure to the mimicry motif will be a frequent event throughout life. Presentation of the homologous peptides by HLA molecules is essential for T-cell reactivity. Therefore, we tested whether the PEVKEK motif can bind to the IDDM-associated HLA-DR1, -DR3 and -DR4 molecules. Synthetic peptides with sequences derived from p2C and GAD65 did bind to HLA-DR3 but not to HLA-DR1 or -DR4. Replacement of amino acids within the motif showed that the PEVKEK motif binds specifically to HLA-DR3. Moreover, both p2C and GAD65 peptides bind in the same position within the peptide binding groove of the DR3 molecule which is an essential requirement for T-cell cross-reactivity. The results support molecular mimicry between p2C of coxsackie B-like enteroviruses and GAD65. However, this molecular mimicry may be limited to the HLA-DR3 positive subpopulation of IDDM patients.

Genetic analysis of mengovirus protein 2A: its function in polyprotein processing and virus reproduction

To examine the functional requirements of mengovirus 2A for virus reproduction, a series of mutants with overlapping deletions within the 2A region of mengovirus, and two chimeric constructs in which 2A is replaced either by Theiler's murine encephalomyelitis virus (TMEV) 2A or by coxsackie B3 virus (CBV3) 2Apro were generated. In vitro polyprotein synthesis showed that in both deletion mutants and the TMEV 2A chimeric construct, viral 3C protease (3Cpro)-mediated cleavage at the VP1-2A junction was disturbed, which resulted in decreased formation of mature capsid proteins and accumulation of the P1-2A precursor. 2Apro-mediated processing of the chimeric VP1-2Apro junction was highly efficient. Although the resulting L-P1 precursor was cleaved at the L-VP4 junction, further processing of the P1 precursor was abrogated. Two deletion mutant viruses and a TMEV 2A chimeric virus were obtained after transfection. The CBV 2Apro construct did not result in viable virus. Deletion mutant virus production was less than 3% compared to wild-type virus production, whereas chimeric virus production was reduced to 25%. Although inhibition of host-cell translation was identical in wild-type and mutant virus-infected cells, viral protein and RNA synthesis were reduced in cells infected with mutant virus, independently of the impaired P1-2A processing. It is concluded that mengovirus 2A may play a functional role in either virus translation or replication, and that the functional aspects of mengovirus and TMEV 2A cannot be exchanged. The results also confirm that the processing cascade of L-P1-2A occurs sequentially and is probably regulated by subsequent conformational transitions of the cleavage products after each proteolytic event. The sequential release of L and 2A may be essential in the context of their function in virus replication.

A sero-epidemiological study of the relationship between sexually transmitted agents and cervical cancer in Honduras

To investigate a possible cause-and-effect relationship between sexually transmitted diseases and cervical cancer, we performed a sero-epidemiological study on the presence of antibodies against a number of sexually transmitted agents (STAs) in patients with cervical cancer and their matched controls. In this study, we used serological techniques to investigate the presence of antibodies to cytomegalovirus, herpes simplex virus type 2, human immunodeficiency virus, Chlamydia trachomatis, Treponema pallidum and human papillomavirus (HPV) early protein E7 in sera from patients with cervical cancer, cervical intra-epithelial neoplasia and individually matched, healthy controls. The presence of antibodies to infectious agents other than HPV appeared not to be associated with risk of cervical neoplasia in either univariate or multivariate analysis. After adjustment for cytology, schooling and presence of HPV DNA in cervical scrapes, there was a significantly higher prevalence of antibodies to HPV-16 E7 protein in sera from patients with cervical cancer (OR = 3.6, 95% CI 1.0-12.9) than in healthy controls. The highest antibody prevalence was found among HPV-16 DNA-positive cervical cancer patients (33%). Our results indicate that in these study groups past infections with the STA considered seems to be of no apparent relevance for cervical carcinogenesis and that the HPV-16 anti-E7 response appears to be associated with cervical cancer.

Prenatal diagnosis and treatment of congenital Toxoplasma gondii infections: an experimental study in rhesus monkeys

The efficacy of treatment in fetuses in whom congenital Toxoplasma gondii infection has ben established has been investigated using rhesus monkeys as a model for humans. A polymerase chain reaction has been developed for the detection of Toxoplasma gondii. Using this polymerase chain reaction congenital infection can be established within 2 days of receiving an amniotic fluid sample. The polymerase chain reaction has subsequently been used to monitor the effect of treatment on fetal infection. The results show that early treatment with the combination of pyrimethamine and sulfadiazine was clearly effective in reducing the number of parasites in the infected fetus. The parasite was no longer detectable in the amniotic fluid 10 to 13 days after treatment was started. Spiramycin, on the other hand, has to be administered for at least 3 weeks to achieve the same effect. Moreover, pharmacokinetic studies revealed that spiramycin does not reach the brain. Pyrimethamine and sulfadiazine are able to pass the blood-brain barrier. Pyrimethamine appears to accumulate in the brain tissue and reaches concentrations which are also effective in vitro.

Chimeric coxsackie B3 virus genomes that express hybrid coxsackievirus-poliovirus 2B proteins: functional dissection of structural domains involved in RNA replication

The 2B proteins of coxsackievirus and poliovirus (PV) share significant structural similarity and exhibit similar biochemical activities, namely inhibition of protein secretion and modification of membrane permeability. Both proteins contain two hydrophobic domains in the carboxy-terminal two-thirds of their sequence, of which one has the potential to form a cationic amphipathic alpha-helix. To gain more insight into the structural requirements of enterovirus protein 2B for its functioning in viral RNA replication, a chimeric cDNA approach was used. Chimeric coxsackie B3 virus (CBV3) genomes were constructed that expressed either the entire PV 2B protein or hybrid proteins in which specific segments of CBV3 2B were substituted by their corresponding PV counterparts. In vitro synthesis and processing of the chimeric polyproteins showed no abnormalities. CBV3 genomes carrying the entire PV 2B gene failed to replicate. A chimeric genome that expressed a hybrid 2B protein consisting of the amino-terminal one-third of PV and the remainder of CBV3 yielded viable viruses. In contrast, a 2B protein consisting of the amino-terminal one-third of CBV3 and the remainder of PV failed to drive replication. These data imply that a sequence-specific interaction with another viral protein is required to drive RNA replication and suggest that the proposed sites of contact reside in the carboxy-terminal two-thirds of 2B. Hybrid genomes in which either the amphipathic alpha-helix or the other hydrophobic domain was replaced failed to replicate. The potential contribution of these domains to the structure and functioning of protein 2B are discussed.

Association of infections with human immunodeficiency virus and human papillomavirus in Honduras

The etiologic role of the oncogenic types of human papillomavirus (HPV) in the development of cervical cancer has been widely proven. Since this cancer occurs more frequently in immunosuppressed individuals, we sought to evaluate the prevalence of HPV infection among human immunodeficiency virus (HIV)-infected and HIV-noninfected prostitutes in Tegucigalpa, Honduras. Cervical scrapes were collected from 23 HIV-seropositive and 28 HIV-seronegative prostitutes for HPV DNA detection by the polymerase chain reaction. Fifty-six percent of the HIV-seropositive women and only 18% of the seronegative women were HPV DNA positive (odds ratio = 6.0). In addition, there was a significant association between seropositivity for HIV with a history of sexually transmitted diseases (P < 0.01). Our data confirm the association between infections with HIV and HPV.