Smartphone Use for Cervical Cancer Screening in Low-Resource Countries: A Pilot Study Conducted in Madagascar.

BACKGROUND: Visual inspection of the cervix after application of 5% acetic acid (VIA) is a screening technique for cervical cancer used widely in low and middle-income countries (LMIC). To improve VIA screening performance, digital images after acid acetic application (D-VIA) are taken. The aim of this study was to evaluate the use of a smartphone for on- and off-site D-VIA diagnosis. MATERIALS AND METHODS: Women aged 30-65 years, living in the city of Ambanja, Madagascar, were recruited through a cervical cancer screening campaign. Each performed a human papillomavirus (HPV) self-sample as a primary screen. Women testing positive for HPV were referred for VIA followed by D-VIA, cervical biopsy and endocervical curettage according to routine protocol. In addition, the same day, the D-VIA was emailed to a tertiary care center for immediate assessment. Results were scored as either D-VIA normal or D-VIA abnormal, requiring immediate therapy or referral to a tertiary center. Each of the three off-site physicians were blinded to the result reported by the one on-site physician and each gave their individual assessment followed by a consensus diagnosis. Statistical analyses were conducted using STATA software. RESULTS: Of the 332 women recruited, 137 (41.2%) were HPV-positive and recalled for VIA triage; compliance with this invitation was 69.3% (n = 95). Cervical intraepithelial neoplasia was detected in 17.7% and 21.7% of digital images by on-site and off-site physicians, respectively. The on-site physician had a sensitivity of 66.7% (95%CI: 30.0-90.3) and a specificity of 85.7% (95%CI: 76.7-91.6); the off-site physician consensus sensitivity was 66.7% (95%CI: 30.0-90.3) with a specificity of 82.3% (95%CI: 72.4-89.1). CONCLUSION: This pilot study supports the use of telemedicine for off-site diagnosis of cervical intraepithelial neoplasia, with diagnostic performance similar to those achieved on-site. Further studies need to determine if smartphones can improve cervical cancer screening efficiency in LMIC.

Index cluster study of dengue virus infection in Nicaragua.

Traditional study designs do not identify acute asymptomatic or pre-symptomatic dengue virus (DENV) infections, thus limiting our understanding of immunologic and viral factors that modulate infection outcome. In the 2006 and 2007 dengue seasons, we conducted a pilot index cluster study in Managua, Nicaragua, in which 442 persons living within 50 meters of 22 index cases identified through an ongoing pediatric cohort study were evaluated for DENV infection. Post-enrollment and pre-enrollment DENV infections were confirmed in 12 (2.7%) and 19 (4.3%) contacts, respectively. Five (42%) post-enrollment infections were asymptomatic, and DENV-2 was identified in 9 (75%) infections. Phylogenetic analysis with full-length DENV genomic sequence from contacts, index cases, and cohort dengue cases indicated focal transmission and infection outside the local area. We demonstrate the feasibility of identification of acute asymptomatic and pre-symptomatic cases in urban Latin America, the first report of such a study in the Americas, and identify age and concomitant immunity to DENV of contacts as a key factor in index cluster study design.

Trends in patterns of dengue transmission over 4 years in a pediatric cohort study in Nicaragua.

BACKGROUND: Dengue is the most prevalent mosquito-borne viral disease in humans and a major urban public health problem worldwide. METHODS: A prospective cohort study of approximately 3800 children initially aged 2-9 years was established in Managua, Nicaragua, in 2004 to study the natural history of dengue transmission in an urban pediatric population. Blood samples from healthy subjects were collected annually prior to the dengue season, and identification of dengue cases occurred via enhanced passive surveillance at the study health center. RESULTS: Over the first four years of the study, seroprevalence of anti-dengue virus (DENV) antibodies increased from 22%-40% in the 2-year-old cohort and 90%-95% in the 9-year-old cohort. The incidence of symptomatic dengue cases and the ratio of inapparent to symptomatic DENV infection varied substantially from year to year. The switch in dominant transmission from DENV-1 to DENV-2 was accompanied by an increase in disease severity but, paradoxically, a decrease in transmission. Phylogeographic analysis of full-length DENV-2 sequences revealed strong geographic clustering of dengue cases. CONCLUSIONS: This large-scale cohort study of dengue in the Americas demonstrates year-to-year variation of dengue within a pediatric population, revealing expected patterns in transmission while highlighting the impact of interventions, climate, and viral evolution.

Feasibility of cytology-based cervical cancer screening in rural Cameroon.

OBJECTIVE: To determine the prevalence of cervical cancer and its precursors in a rural population in Cameroon and to evaluate the feasibility of a cytology-based screening program in such areas. STUDY DESIGN: A prospective study was conducted in the rural town of Bafang. Following an advocacy campaign, 750 women were recruited. After a clinical examination, all women had a Pap smear with the Cervex Brush. Each sample had two preparations, conventional and liquid based. The conventional smears were interpreted in Bafang. Cytologically abnormal cases, those with clinical inflammation and/or macroscopic cervical lesions, had a colposcopic examination and directed biopsy. HSIL and colposcopically abnormal cases were treated with large loop excision of the transformation zone (LLETZ). The liquid-based preparations and histopathology were performed in Geneva and the results sent to Cameroon for patient follow-up. RESULTS: Mean age and parity of the women screened were 43.7 years and 7.8, respectively. The conventional smears showed 3.6% cervical abnormalities: 2% (15/740) ASCUS/LSIL and 1.6% (12/740) HSIL. The liquid-based preparations showed 12.6% (91/722) cervical abnormalities: 10.1% (73/722) ASCUS/LSIL and 2.5% (18/722) HSIL. Fifty percent of samples in both preparations showed evidence of inflammation. Histology was performed on 64 colposcopically directed punch biopsies and LLETZ specimens. The histologic diagnoses agreed with the cytologic findings in 60% (14/23) of conventional smears and 85% (12/14) of liquid-based preparations. CONCLUSION: There is a high rate of cervical intraepithelial neoplasia in the unscreened rural population of Cameroon. The situation is complicated by a high rate of cervical infection. A population-based cytologic screening program for cervical cancer would not be feasible in rural Cameroon because of high cost, low quality and limited technical facilities. Rural Africa requires an algorithm using a simple, low-cost technique of mass screening and an improved cytology service only to triage selected patients.