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Featured researches published by David C. Swan.


The Journal of Infectious Diseases | 2011

Prevalence of Genital Human Papillomavirus Among Females in the United States, the National Health and Nutrition Examination Survey, 2003–2006

Susan Hariri; Elizabeth R. Unger; Maya Sternberg; Eileen F. Dunne; David C. Swan; Sonya Patel; Lauri E. Markowitz

BACKGROUND Genital human papillomaviruses (HPV) include >40 sexually transmitted viruses. Most HPV infections do not progress to disease, but infection with certain types of HPV can cause cervical and other anogenital and oropharyngeal cancer, and other types of HPV are associated with anogenital warts. HPV vaccines prevent infection with HPV 16 and 18, which account for 70% of cases of cervical cancer, and HPV 6 and 11, which cause 90% of the cases of anogenital warts. METHODS Using data and self-collected cervicovaginal specimens from 4150 females, 14-59 years of age, from consecutive National Health and Nutrition Examination Surveys (2003-2006), we estimated the prevalence of type-specific HPV DNA and examined sociodemographic and sexual determinants. RESULTS The overall prevalence of HPV was 42.5% in females 14-59 years of age and varied significantly by age, race or ethnicity, and number of sex partners. Individual type prevalence was less than 7%, ranging from <0.5% through 6.5%. The most common type was nononcogenic HPV 62 (found in 6.5% of subjects), followed by HPV 53 and HPV 16 (4.7%), both of which are oncogenic types. The most prevalent species was nononcogenic α3. CONCLUSIONS HPV infection is common among US females, with the highest burden of infection found in young females 20-24 years of age. Monitoring trends in HPV type distribution will contribute to our understanding of the early impact of HPV vaccines.


Journal of Clinical Microbiology | 2006

Simultaneous Amplification and Identification of 25 Human Papillomavirus Types with Templex Technology

Jian Han; David C. Swan; Sharon J. Smith; Shanjuan H. Lum; Susan E. Sefers; Elizabeth R. Unger; Yi-Wei Tang

ABSTRACT The majority of existing human papillomavirus (HPV) genotyping assays are based on multiplex PCR using consensus or degenerate primers. We developed a Templex HPV assay that simultaneously detects and identifies 25 common HPV genotypes in a single-tube reaction using type-specific primers for the HPV-specific E6 and E7 genes. The analytical sensitivities of the Templex assay for HPV type 16 (HPV-16), -18, and -56 were 20, 100, and 20 copies per reaction mixture, respectively. The Templex assay provides semiquantitative information on each type when multiple HPV types coexist in one reaction. We tested 109 clinical cervical specimens previously evaluated with the Digene HC2 high-risk HPV DNA test and found 95.4% concordance between the assay results. The Templex assay provided type-specific results and found multiple types in 29.2% (14 of 48) of high-risk HPV-positive samples. The entire Templex procedure, including DNA extraction, can be completed within 5 hours, providing a rapid and reliable diagnostic tool for HPV detection and typing that is amenable to automation.


Sexually Transmitted Diseases | 2010

Human papillomavirus infection and cytologic abnormalities of the anus and cervix among HIV-infected women in the study to understand the natural history of HIV/AIDS in the era of effective therapy (the SUN study).

Erna M. Kojic; Susan Cu-Uvin; Lois Conley; Tim Bush; Juanita Onyekwuluje; David C. Swan; Elizabeth R. Unger; Keith Henry; John Hammer; Edgar Turner Overton; Teresa M. Darragh; Joel M. Palefsky; Claudia Vellozzi; Pragna Patel; John T. Brooks

Background: Human papillomavirus (HPV) infection of the cervix and related abnormal cervical cytology in HIV-infected women has been well described. Little is known about anal HPV infection in HIV-infected women. Methods: The SUN Study is a prospective cohort study of 700 HIV-infected patients including 167 women. At baseline, patients completed a behavioral questionnaire and provided, among other samples, cervical and anal swabs for HPV detection and genotyping and for cytologic examination. Here, we present the available baseline data on the 167 women in the SUN study. Results: Baseline results were available for 120 women (median age: 38 years, 57% non-Hispanic black, median CD4 cell count 444.5 cells/mm3), of whom, 77% were taking antiretroviral therapy. The prevalences in the anus and cervix of any HPV were 90% and 83%, respectively (P = 0.039), and of high-risk (HR) types 85% and 70%, respectively, (P = 0.001). There was no significant difference in the prevalences of abnormal cytology between the anus and cervix: 38% and 33%, respectively (P = 0.217). Although the presence of abnormal cervical cytology was associated with the presence of abnormal anal cytology (relative risk: 1.7, P = 0.024), its sensitivity (52.5%) and positive predictive value positive (45.6%) for identifying women with abnormal anal cytology were poor. A history of anal sex was not associated with anal HPV infection or abnormal anal cytology. Conclusions: In this cohort of HIV-infected women, anal HPV infection was more prevalent and diverse than cervical HPV infection. Anal cytologic abnormalities were as prevalent as cervical cytologic abnormalities, and although abnormal cervical cytology was predictive of abnormal anal cytology, results were not highly concordant. These data support the need for studies of anal cytologic screening of HIV-infected women.


International Journal of Cancer | 2005

Epidemiologic and viral factors associated with cervical neoplasia in HPV-16-positive women

Mangalathu S. Rajeevan; David C. Swan; Rosane Nisenbaum; Daisy R. Lee; Suzanne D. Vernon; Mack T. Ruffin; Ira R. Horowitz; Lisa Flowers; David Kmak; Talaat Tadros; George G. Birdsong; Mujtaba Husain; Sudhir Srivastava; Elizabeth R. Unger

While infection with high‐risk HPV is the most important risk factor for cervical cancer, HPV alone is insufficient. Our purpose was to identify viral and epidemiologic factors associated with cervical disease in HPV‐16 DNA‐positive women referred to colposcopy. We used a standardized interview to collect epidemiologic data from consenting women. Total nucleic acids from exfoliated cervical cells were used for all viral assays (HPV detection and typing using L1 consensus PCR with line probe hybridization, variant classification by sequencing, viral load and transcript copy determination by quantitative PCR and transcript pattern by nested RT‐PCR). Cervical disease was based on colposcopic biopsy. Logistic regression was used to calculate ORs with 95% CIs. There were 115 HPV‐16 positive women among 839 enrollees. By univariate analyses, age >25 years (OR = 3.05, 95% CI 1.20–7.76), smoking (OR = 3.0, 95% CI 1.19–7.56), high viral load (OR = 5.27, 95% CI 2.05–13.60), detection of both E6 and E6*I transcripts (OR = 10.0, 95% CI 2.1–47.58) and high transcript copies (OR = 5.56, 95% CI 2.05–13.60) were significant risk factors for CIN III with reference to No CIN/CIN I. Less than a third of the women (31.5%) had prototype HPV‐16 detected, and variants showed no association with disease, viral load or transcription. Viral DNA and transcript copies were highly correlated, and the ratio of transcript copies to DNA copies was not changed with disease status. While viral load, transcript copies and transcript pattern were statistically associated with CIN III, none of these measures effectively discriminated between HPV‐16 women with disease requiring treatment and those who could be followed. Cellular proliferation and differentiation pathways affected by HPV should be investigated as biomarkers for cervical cancer screening.


Human Pathology | 1991

Association of human papillomavirus with penile carcinoma: A study using polymerase chain reaction and in situ hybridization

Vijay A. Varma; Mary Sanchez-Lanier; Elizabeth R. Unger; Chris Clark; Ronald Tickman; Karlene Hewan-Lowe; Margie L. Chenggis; David C. Swan

Although carcinoma of the uterine cervix has been shown to be strongly associated with human papillomavirus (HPV) infection, a sexually transmitted disease, similar detailed data are lacking in penile carcinoma. To determine the association of HPV with penile carcinoma, we examined 30 specimens of penile carcinoma from 23 patients by the highly sensitive polymerase chain reaction (PCR) and in situ hybridization assays. We also examined nonneoplastic penile foreskins from 20 adults using the polymerase chain reaction assay. Human papillomavirus type 16 genome was found in 15 patients (65%), HPV type 30 was found in three (13%), and HPV type 6/11 was found in two (9%). These HPV types were not detected in any of the nonneoplastic foreskins. As in cervical carcinoma, HPV, particularly type 16, is strongly associated with penile carcinoma and may play an etiologic role in the development of this neoplasm.


The Journal of Infectious Diseases | 2011

Human Papillomavirus (HPV) 6, 11, 16, and 18 Prevalence Among Females in the United States—National Health and Nutrition Examination Survey, 2003–2006: Opportunity to Measure HPV Vaccine Impact?

Eileen F. Dunne; Maya Sternberg; Lauri E. Markowitz; Geraldine M. McQuillan; David C. Swan; Sonya Patel; Elizabeth R. Unger

The 2003-2006 National Health and Nutrition Examination Surveys were used to assess human papillomavirus (HPV) types 6, 11, 16, and 18 DNA detection from females aged 14-59 years who self-collected cervicovaginal swab specimens. Prevalence was 8.8% (95% confidence interval [CI], 7.8%-10.0%) and was highest among women aged 20-24 years (18.5%; 95% CI, 14.9%-22.8%). Age group, education, marital status, and sexual behavior were associated with detection. These data provide baseline information before HPV vaccine introduction. Early impact of vaccine in the United States may be determined by a reduction in the prevalence of HPV 6, 11, 16, and 18 infection among young women.


Journal of Clinical Virology | 2008

Type-specific reproducibility of the Roche linear array HPV genotyping test

Martin Steinau; David C. Swan; Elizabeth R. Unger

BACKGROUND Type-specific detection of human papillomavirus (HPV) is increasingly important for monitoring temporal and age-specific changes in type-specific prevalence in support of HPV vaccination efforts. The impact of sampling, extraction and assay characteristics on HPV results is increasingly recognized. Inter-assay comparability studies have been performed, but the robustness of type-specific results has neither been emphasized nor has the degree of intra-assay reproducibility been addressed. OBJECTIVES Here we describe the general and type-specific reproducibility of the linear array HPV genotyping test (Roche Molecular Diagnostics, Indianapolis, IN). STUDY DESIGN Extracts of 276 cervical samples from two ongoing epidemiologic HPV studies were retested while blinded to prior results. The testing involved five different reagent lots and three technologists. RESULTS Concordance for HPV detection (sample positive versus negative for any of the 37 types) was high (98.2%, kappa=0.959). Type-specific concordance for individual HPV types was also high (99.4%, kappa=0.915), and most samples (83.0%) showed complete concordance for all types. CONCLUSIONS Type-specific reproducibility of the linear array HPV genotyping test is good but not perfect. The results suggest that type-specific performance should be included in the evaluation of HPV typing formats.


Cadernos De Saude Publica | 1998

A case-control study of human papillomavirus and cervical squamous intraepithelial lesions (SIL) in Harris County, Texas: differences among racial/ethnic groups

Guillermo Tortolero-Luna; Michele Follen Mitchell; David C. Swan; Ruth Ann Tucker; Louise Wideroff; Joseph Icenogle

We conducted a case-control study of the association between SIL and HPV among whites (W), African Americans (AA), and Hispanics (H) in Harris County, Texas. Cases were identified at M.D. Anderson Cancer Center Colposcopy Clinic. Controls were identified among women obtaining routine Pap screening at two Harris County Health Department Clinics. HPV was detected by a PCR-based fluorescent assay. Dichotomous and polytomous logistic regression models were used to estimate adjusted odd ratios (AOR) and 95% confidence intervals (CI) for SIL among racial/ethnic groups and grade of disease. Prevalence of HPV infection was 64% in low grade SIL (LSIL), 84% in high grade SIL (HSIL), and 19% in controls. Risk of SIL was higher in H than in W and AA, AOR 29.5 (12.4-70.5), 15.3 (6.0-33.8), and 5.8 (2.6-12.6), respectively. Similarly, racial/ethnic differences were observed for both LSIL (AOR = 16.6, 7.7, and 4.3, respectively) and HSIL (AOR = 78.6, 34.6, and 14.2, respectively). Findings support the association between SIL and HPV and differences in the strength of the association with LSILs and HSILs. Data also suggest a higher risk for H and a lower risk for AA.


Journal of Virological Methods | 2012

Patterns of Cellular and HPV 16 Methylation as Biomarkers for Cervical Neoplasia

Divya A. Patel; Laura S. Rozek; Justin A. Colacino; Adrienne Van Zomeren-Dohm; Mack T. Ruffin; Elizabeth R. Unger; Dana C. Dolinoy; David C. Swan; Juanita Onyekwuluje; Cecilia R. DeGraffinreid; Electra D. Paskett

Aberrant promoter methylation of biologically relevant genes in cervical cancer and uneven CpG distribution within the human papillomavirus 16 (HPV 16) enhancer region have been reported. Cervical samples and questionnaires from 151 women screened for cervical cancer in Appalachian Ohio were analyzed. Methylation was measured by bisulfite sequencing in candidate gene sites in ESR1, DCC, p16, and LINE1 elements. Among 89 HPV 16-positive women, CpG sites in the E6 promoter and enhancer regions and the L1 region of the HPV 16 genome were measured. Methylation levels were compared by cervical cytology and HPV 16 status. HPV methylation was low regardless of cytology status, however E6 methylation was significantly higher in women with normal cytology. ESR1 and DCC methylation were significantly higher in HPV 16-positive women. Increased methylation at sites in the E6 promoter region was associated with lower odds of abnormal cytology. Increased methylation in candidate genes was associated with higher odds of abnormal cytology, particularly DCC region 2.4, DCC region 2.6, ESR1 region 3.2, and LINE1 site 1.2. HPV 16 genome CpG methylation was low except for the L1 region. In general, lower HPV 16 methylation and higher candidate gene methylation levels were associated with higher odds of abnormal cytology.


Pediatrics | 2011

Anogenital Human Papillomavirus in Sexually Abused and Nonabused Children: A Multicenter Study

Elizabeth R. Unger; Nancy N. Fajman; Elizabeth M. Maloney; Juanita Onyekwuluje; David C. Swan; Laurie A. Howard; Consuelo M. Beck-Sague; Mary K. Sawyer; Rebecca G. Girardet; Robert L. Sautter; Margaret R. Hammerschlag; Carolyn M. Black

OBJECTIVES: To characterize the epidemiology of genital human papillomavirus (HPV) infection in children without previous consensual sexual activity, comparing HPV prevalence by certainty of child sexual abuse (CSA). PATIENTS AND METHODS: Patients presenting for evaluation of CSA in 8 sites in Atlanta, Houston, Harrisburg, and New York City were recruited along with patients presenting for unrelated health visits. CSA certainty was classified as definite, probable, possible, or no evidence following published guidelines and the results of history, physical examination, and laboratory tests. Urine and swabs of external genitalia were tested for HPV using L1 consensus polymerase chain reaction. RESULTS: The study included 576 participants (89.9% female) aged 6 months to 13 years (mean: 7.9); 534 of whom were evaluated for CSA and 42 for unrelated reasons. Of those evaluated for CSA, 14 had genital warts. One or more HPV types were detected in 11.8% (61 of 517) of participants with adequate samples. HPV detection was more likely among abused participants (definite, probable, or possible) than among participants without evidence of CSA (13.7% and 1.3%, respectively; P < .0001) and increased with certainty of abuse (8.4%, 15.6%, and 14.5% in participants with possible, probable, and definite CSA, respectively; P < .0001). Participants aged 10 years or older had a higher prevalence of HPV (20.6%) than others (5.6%) (P < .0001). CSA, anogenital warts, and age were independently associated with HPV detection. CONCLUSIONS: HPV detection was associated with CSA and increased with CSA certainty. In this population, genital HPV seemed to behave as a sexually transmitted infection.

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Elizabeth R. Unger

Centers for Disease Control and Prevention

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Martin Steinau

Centers for Disease Control and Prevention

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Ruth Ann Tucker

Centers for Disease Control and Prevention

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Daisy R. Lee

Centers for Disease Control and Prevention

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Juanita Onyekwuluje

Centers for Disease Control and Prevention

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Joseph Icenogle

Centers for Disease Control and Prevention

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Lauri E. Markowitz

National Center for Immunization and Respiratory Diseases

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Louise Wideroff

National Institutes of Health

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Maya Sternberg

Centers for Disease Control and Prevention

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