PubMed · 10448355
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
S Rashid, R S Morton. 1999. Contact tracing.. https://pubmed.ncbi.nlm.nih.gov/10448355/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Phylodynamics bridges the gap between classical epidemiology and pathogen genome sequence data by estimating epidemiological parameters from time-scaled pathogen phylogenetic trees. The models used in phylodynamics typically assume that the sampling procedure is independent between infected individuals. However, this assumption does not hold for many epidemics, in particular for such sexually transmitted infections as HIV-1, for which contact tracing schemes are included in health policies of many countries. We extended phylodynamic multi-type birth-death (MTBD) models with contact tracing (CT), and developed a simulator to generate trees under MTBD and MTBD-CT models. We proposed a non-parametric test for detecting contact tracing in pathogen phylogenetic trees. Its application to simulated data showed that it is both highly specific and sensitive. For the simplest representative of the MTBD-CT family, the BD-CT(1) model, where only the last contact can be notified, we solved the differential equations and proposed a closed form solution for the likelihood function. We implemented a maximum-likelihood program, which estimates the BD-CT(1) model parameters and their confidence intervals from phylogenetic trees. It performed accurate parameter inference on BD and BD-CT(1) simulated data, and detected contact tracing in HIV-1 B epidemics in Zurich and the UK. Importantly, we showed that not accounting for contact tracing when it is present, leads to bias in parameter estimation with the BD model (overestimation of the becoming-non-infectious rate). This bias is also present, but greatly reduced, when the BD-CT(1) model is used on data where multiple contacts can be notified. Our CT test, MTBD-CT tree simulator and BD-CT(1) parameter estimator are freely available at GitHub (evolbioinfo/treesimulator and evolbioinfo/bdct).
OBJECTIVE: The objective of this study was to assess the impact of syphilis control activities in King County, Washington. STUDY DESIGN: We calculated rates of early syphilis and trends in numbers of persons tested and diagnosed through screening and partner notification from 1998 to 2005. RESULTS: Early syphilis cases increased from 38 in 1998 to 188 in 2005 with 92% occurring among men who have sex with men (MSM). Our health department conducted public awareness campaigns, increased publicly financed syphilis screening among MSM by 179%, and intensified partner notification efforts. Despite these efforts, the prevalence of syphilis among screened populations was only 1.1%, and 71% syphilis cases were diagnosed after seeking care for symptoms. The proportion of cases diagnosed through screening and partner notification did not significantly change during the evaluation period. Early syphilis incidence among MSM more than doubled between 2003 and 2005. CONCLUSIONS: New, innovative approaches to syphilis control are needed.
OBJECTIVE: The objective of this study was to estimate the effectiveness of partner notification (PN) by linking measures of PN with the gonorrhea incidence rate in New York State exclusive of New York City. STUDY DESIGN: Gonorrhea cases were identified from the Communicable Disease Confidential Case Reports system. Case interview data were obtained from the case management database. Gonorrhea incidence data and interview data were aggregated from individual records and then linked at the county level. RESULTS: From 1992 to 2002, 100,756 gonorrhea cases were reported and 37% were interviewed. A total of 34,807 partners were elicited from 37,393 index cases: 18,291 (52.5%) partners sought medical evaluation, 10,159 (29.2%) received preventive treatment, and 7,474 (21.5%) were infected and treated. The gonorrhea incidence rate was inversely correlated with the percent of partners given preventive treatment and positively related to the percent of infected partners. CONCLUSIONS: Our study adds new evidence that PN is an effective mechanism to detect new cases and interrupt disease transmission within communities.