Publications by authors named "Nadia Duffy"

5 Publications

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Ebola Patient Virus Cycle Threshold and Risk of Household Transmission of Ebola Virus.

J Infect Dis 2020 02;221(5):707-714

Division of Preparedness and Emerging Infections, National Center for Emerging and Zoonotic diseases, Centers for Disease Control and Prevention, Anchorage, Alaska, USA.

Background: Identifying risk factors for household transmission of Ebola virus (EBOV) is important to guide preventive measures during Ebola outbreaks.

Methods: We enrolled all confirmed persons with EBOV disease who were the first case patient in a household from December 2014 to April 2015 in Freetown, Sierra Leone, and their household contacts. Index patients and contacts were interviewed, and contacts were followed up for 21 days to identify secondary cases. Epidemiologic data were linked to EBOV real-time reverse-transcription polymerase chain reaction cycle threshold (Ct) data from initial diagnostic specimens obtained from enrolled index case patients.

Results: Ct data were available for 106 (71%) of 150 enrolled index patients. Of the Ct results, 85 (80%) were from blood specimens from live patients and 21 (20%) from oral swab specimens from deceased patients. The median Ct values for blood and swab specimens were 21.0 and 24.0, respectively (P = .007). In multivariable analysis, a Ct value from blood specimens in the lowest quintile was an independent predictor of both increased risk of household transmission (P = .009) and higher secondary attack rate among household contacts (P = .03), after adjustment for epidemiologic factors.

Conclusions: Our findings suggest the potential to use Ct values from acute EBOV diagnostic specimens for index patients as an early predictor of high-risk households and high-risk groups of contacts to help prioritize EBOV disease investigation and control efforts.
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http://dx.doi.org/10.1093/infdis/jiz511DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8423484PMC
February 2020

Household Transmission of Ebola Virus: Risks and Preventive Factors, Freetown, Sierra Leone, 2015.

J Infect Dis 2018 07;218(5):757-767

Division of Preparedness and Emerging Infections, National Center for Emerging and Zoonotic Diseases, Centers for Disease Control and Prevention, Anchorage, Alaska.

Background: Knowing risk factors for household transmission of Ebola virus is important to guide preventive measures during Ebola outbreaks.

Methods: We enrolled all confirmed persons with Ebola who were the first case in a household, December 2014-April 2015, in Freetown, Sierra Leone, and their household contacts. Cases and contacts were interviewed, contacts followed prospectively through the 21-day incubation period, and secondary cases confirmed by laboratory testing.

Results: We enrolled 150 index Ebola cases and 838 contacts; 83 (9.9%) contacts developed Ebola during 21-day follow-up. In multivariable analysis, risk factors for transmission included index case death in the household, Ebola symptoms but no reported fever, age <20 years, more days with wet symptoms; and providing care to the index case (P < .01 for each). Protective factors included avoiding the index case after illness onset and a piped household drinking water source (P < .01 for each).

Conclusions: To reduce Ebola transmission, communities should rapidly identify and follow-up all household contacts; isolate those with Ebola symptoms, including those without reported fever; and consider closer monitoring of contacts who provided care to cases. Households could consider efforts to minimize risk by designating one care provider for ill persons with all others avoiding the suspected case.
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http://dx.doi.org/10.1093/infdis/jiy204DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6508068PMC
July 2018

Notes from the Field: Ebola Virus Disease Response Activities During a Mass Displacement Event After Flooding--Freetown, Sierra Leone, September-November, 2015.

MMWR Morb Mortal Wkly Rep 2016 Feb 26;65(7):188-9. Epub 2016 Feb 26.

Since the start of the Ebola virus disease (Ebola) outbreak in West Africa, Sierra Leone has reported 8,706 confirmed Ebola cases and 3,956 deaths. During September 15-16, 2015, heavy rains flooded the capital, Freetown, resulting in eight deaths, home and property destruction, and thousands of persons in need of assistance. By September 27, approximately 13,000 flood-affected persons registered for flood relief services from the government. On September 17, two stadiums in Freetown were opened to provide shelter and assistance to flood-affected residents; a total of approximately 3,000 persons stayed overnight in both stadiums (Sierra Leone Ministry of Health and Sanitation, personal communication, September 2015). On the same day the stadiums were opened to flood-affected persons, the Ministry of Health and Sanitation (MoHS) and Western Area Ebola Response Center (WAERC) staff members from CDC, the World Health Organization (WHO), and the African Union evaluated the layout, logistics, and services at both stadiums and identified an immediate need to establish Ebola response activities. The patient in the last Ebola case in the Western Area, which includes Freetown, had died 37 days earlier, on August 11; however, transmission elsewhere in Sierra Leone was ongoing, and movement of persons throughout the country was common.
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http://dx.doi.org/10.15585/mmwr.mm6507a4DOI Listing
February 2016

Oral cancer preventive practices of South Carolina dentists and physicians.

J Cancer Educ 2010 Jun;25(2):166-73

Department of Craniofacial Biology, Medical University of South Carolina, 173 Ashley Avenue, MSC 507, Charleston, SC 29425-5070, USA.

The purpose of this study was to assess the South Carolina (SC) dentists' and physicians' oral cancer knowledge and practices and interest in training in oral cancer screening and tobacco cessation counseling. Method used was a cross-sectional survey of SC dentists and selected physician specialties with responses to mailed questionnaires summarized by descriptive statistics and chi-square tests for comparisons. Overall response rates were 58%for dentists and 44% for physicians. Dentists (81%) and 13% of the physicians reported conduct of oral cancer examinations at least half of the time over the past 12 months. Dentists (41%) and 83% of physicians assisted patients to quit smoking. Few dentists (19%) and 53% of physicians were aware of SC tobacco cessation resources. Dentists (40%) and physicians (37%) were interested in receiving training in oral cancer screening, and 36% and 49%, respectively, in training in tobacco cessation counseling. Results support the development of tailored education for SC dentists and physicians to achieve Healthy People 2010 Oral Health Objectives for Oral Cancer.
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http://dx.doi.org/10.1007/s13187-009-0025-xDOI Listing
June 2010

Oral cancer knowledge and experience: a survey of South Carolina medical students in 2002.

J Cancer Educ 2005 ;20(3):136-42

Medical University of South Carolina, Charleston 29425, USA.

Background: Compared to the U.S. states and District of Columbia, the adult population in South Carolina ranks in the high five in oral cavity and pharynx cancer mortality rate and top ten for incidence rate. Previous studies revealed a lack of knowledge related to the diagnosis of oral cancer among health professionals in the USA. This study assessed the oral cancer knowledge and experience of medical students in an academic setting.

Methods: This IRB approved cross-sectional survey used a self-administered pilot-tested questionnaire and the census of the Medical University of South Carolina medical students. Data were summarized by frequencies and chi-square comparisons of pre-clinical (first and second year) and clinical (third and fourth year) students.

Results: The overall response rate was 79% (450/571 students), range 61-91% by year. Significant (p < 0.001) differences were found between pre-clinical and clinical students for knowledge of risk factors, signs and symptoms of oral cancer, and tobacco cessation techniques; with clinical students more knowledgeable but at less than 78% accuracy. All students were in high agreement of the role and responsibility of physicians in tobacco cessation, and in medical history taking. Four students had seen or been instructed on how to perform an oral biopsy. Most (75%) of fourth year students felt adequately trained to palpate neck lymph nodes. However, less than 7% of all students perceived they were adequately trained to examine patients for oral cancers.

Conclusions: Results suggest that these students may not receive adequate exposure to oral cancer prevention and detection knowledge and practices. Additional training to increase knowledge of risk factors and cessation counseling, and knowledge of signs and symptoms and examination skills may improve oral cancer prevention and detection. The implication is that additional education for the medical students in prevention and detection may lead to improvements in South Carolina oral cavity and pharyngeal cancer incidence and mortality rates.
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http://dx.doi.org/10.1207/s15430154jce2003_6DOI Listing
April 2006
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