An investigation of relationships between climate and dengue using a water budgeting technique.

Climatic water budget indicators were used to assess intra- and interannual variations in dengue incidence for San Juan, Puerto Rico. Multivariate stochastic relationships between dengue and the water budget were developed to (1) determine and quantify the particular climatic measures and their associated lag periods related to dengue variations, and (2) assess their use for dengue prediction and initiation of emergency response procedures. Such a predictive model would be advantageous because it is based on reliable, easily obtained, and low-cost weather observations. Daily running averages of water budget variables over an 8-week period were related to daily running averages of unconfirmed dengue totals (1988-1993). Resultant models show that a variety of water budget and traditional climate measures over the full 8-week period are associated with dengue. The mean seasonal variation in dengue is highly related (R2=88.1%) to the mean seasonal climate variation, with those thermal and energy variables immediately preceding the dengue response showing the strongest relationships. However, moisture variables, predominantly in the form of surplus, are more influential many weeks in advance. For the interannual model (R2=44.1%), energy change, thermal change, and moisture variables are significant across the 8-week period, with moisture variables playing a stronger role than in the intraannual model. Standardisation substantially changes the importance and timing of the variables, and suggests that dengue during this period is more associated with the mean annual variation of climate than deviations from mean conditions. A dengue early-warning model (based on 5 weeks of climate data) was also developed to predict dengue incidence 3 weeks later. While this predictive model is not reliable as a sole predictor of dengue in San Juan, it may be useful as part of a multifaceted watch/warning system.

Follow-up evaluation of cervicovaginal human papillomavirus infection in adolescents.

We performed a second examination for human papillomavirus (HPV) DNA on 51 sexually experienced 13- to 21-year-old (mean = 17.8 years) female patients seen at an urban teaching hospital. Cervicovaginal lavages were performed 6 to 36 months apart (median = 13.3 months) to collect cells for HPV DNA detection and typing by Southern blot hybridization. At the first and second visits, 39.2% (20/51) and 25.5% (13/51) of patients, respectively, were infected with HPV. Collectively, 56.9% (29/51) of patients had at least one positive HPV test result. Although 7.8% (4/51) were infected with HPV at both visits, only one patient had infection with the same HPV type. These findings suggest that although HPV infection is a common sexually transmitted disease, genotype-specific HPV infection detected by Southern blot at two visits was rare.

Cervical cytology: the need for routine screening in the sexually active adolescent.

Pelvic examinations, including a Papanicolaou smear of the uterine cervix, were performed on 403 asymptomatic, sexually active adolescent girls aged from 12 to 16 years who were in a youth detention center in New York City. The smears were negative for precancerous abnormalities in 389 girls, but 168 of these had evidence of inflammation or nonspecific atypia. In the remaining 14 smears there was cytologic evidence of early precancerous changes (low-grade cervical intraepithelial neoplasia). The prevalence rate for early neoplastic changes was 35/1,000, far higher than previously reported. Further evaluation of three of these girls, by colposcopy and biopsy, revealed precancerous epithelial abnormalities of varying degrees of severity in two of them. Since all patients screened were sexually active and were asyptomatic, no clinical feature distinguished the 389 with negative cytology from the 14 with intraepithelial neoplasia. Five of the patients with precancerous cellular abnormalities had histories of sexual activity of less than two years. The data suggest that cervical cytologic screening should be incorporated into the routine examination of sexually active female adolescents.