@article{Peterson_Greene_2017, title={Spatio-Temporal Cluster Detection for Legionellosis using Multiple Patient Addresses}, volume={9}, url={https://ojphi.org/ojs/index.php/ojphi/article/view/7705}, DOI={10.5210/ojphi.v9i1.7705}, abstractNote={<div style="left: 78.2727px; top: 278.962px; font-size: 12.3207px; font-family: sans-serif; transform: scaleX(1.0823);" data-canvas-width="55.467823232323234">Objective</div><div style="left: 91.3182px; top: 291.965px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01494);" data-canvas-width="331.4639823232323">To improve timeliness and sensitivity of legionellosis cluster</div><div style="left: 78.2727px; top: 306.46px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.02667);" data-canvas-width="342.95796994949495">detection in New York City (NYC) by using all addresses available</div><div style="left: 78.2727px; top: 320.955px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00126);" data-canvas-width="156.0294343434344">for each patient in one analysis.</div><div style="left: 78.2727px; top: 348.538px; font-size: 12.3207px; font-family: sans-serif; transform: scaleX(1.11884);" data-canvas-width="71.86668434343434">Introduction</div><div style="left: 91.3182px; top: 361.541px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.0486);" data-canvas-width="332.63444949494937">The Bureau of Communicable Disease (BCD) at the NYC</div><div style="left: 78.2727px; top: 376.036px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.995986);" data-canvas-width="342.08812803030304">Department of Health and Mental Hygiene performs daily automated</div><div style="left: 78.2727px; top: 390.531px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.0483);" data-canvas-width="345.4134868686869">analyses using SaTScan to detect spatio-temporal clusters for</div><div style="left: 78.2727px; top: 405.026px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.990435);" data-canvas-width="110.66459090909089">37 reportable diseases.</div><div style="left: 188.863px; top: 405.352px; font-size: 7.39242px; font-family: serif;">1</div><div style="left: 192.55px; top: 405.026px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.98587);" data-canvas-width="227.63738383838378">Initially, we analyzed one address per patient,</div><div style="left: 78.2727px; top: 419.521px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.975171);" data-canvas-width="343.6503936868687">prioritizing home address if available. On September 25, 2015, a</div><div style="left: 78.2727px; top: 434.016px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.02338);" data-canvas-width="343.0873373737371">BCD investigator noticed two legionellosis cases with similar work</div><div style="left: 78.2727px; top: 448.511px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00713);" data-canvas-width="342.34193459595963">addresses. A third case was identified in a nearby residential facility,</div><div style="left: 78.2727px; top: 463.006px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.96821);" data-canvas-width="343.5370431818181">and an investigation was initiated to identify a common exposure</div><div style="left: 78.2727px; top: 477.501px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.980658);" data-canvas-width="344.0964032828283">source. Four days later, after additional cases living nearby were</div><div style="left: 78.2727px; top: 491.996px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00154);" data-canvas-width="344.3637626262626">reported, the SaTScan analysis detected a corresponding cluster.</div><div style="left: 78.2727px; top: 506.491px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.975251);" data-canvas-width="341.8417138888886">In response to this signaling delay, we implemented a multiple address</div><div style="left: 78.2727px; top: 520.985px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.983729);" data-canvas-width="341.9279588383838">(MA) analysis to improve upon single address (SA) analyses by using</div><div style="left: 78.2727px; top: 535.48px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00137);" data-canvas-width="260.7554444444444">all location data available on possible exposure sites.</div><div style="left: 338.987px; top: 535.806px; font-size: 7.39242px; font-family: serif;">2</div><div style="left: 78.2727px; top: 563.063px; font-size: 12.3207px; font-family: sans-serif; transform: scaleX(1.07424);" data-canvas-width="50.65042676767676">Methods</div><div style="left: 91.3182px; top: 576.066px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00171);" data-canvas-width="42.78981565656566">Positive</div><div style="left: 134.869px; top: 576.066px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00155);" data-canvas-width="52.69812828282828">Legionella</div><div style="left: 187.569px; top: 576.066px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.03149);" data-canvas-width="233.73613383838384">test results for NYC residents are reported to</div><div style="left: 78.2727px; top: 590.561px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.998312);" data-canvas-width="342.1879257575758">BCD with patient demographic and address data. BCD interviews all</div><div style="left: 78.2727px; top: 605.056px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.983869);" data-canvas-width="341.9599926767677">cases to elicit additional locations of potential exposure and enters the</div><div style="left: 78.2727px; top: 619.551px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.968885);" data-canvas-width="343.4212285353531">addresses into a disease surveillance database (Maven). Addresses</div><div style="left: 78.2727px; top: 634.046px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00709);" data-canvas-width="342.4602133838384">are assigned X/Y coordinates in near real-time via integration with a</div><div style="left: 78.2727px; top: 648.541px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00139);" data-canvas-width="112.90695959595959">geocoding webservice.</div><div style="left: 91.3182px; top: 663.036px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.03113);" data-canvas-width="329.8746111111113">We used the prospective space-time permutation scan statistic in</div><div style="left: 78.2727px; top: 677.531px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.9885);" data-canvas-width="46.261790909090905">SaTScan,</div><div style="left: 124.517px; top: 677.857px; font-size: 7.39242px; font-family: serif;">3</div><div style="left: 128.166px; top: 677.531px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.965876);" data-canvas-width="291.80732247474737">enabling the advanced input feature on the spatial neighbors</div><div style="left: 78.2727px; top: 692.026px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00573);" data-canvas-width="342.3665760101011">tab to “include location ID in the scanning window if at least one set</div><div style="left: 78.2727px; top: 706.521px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.988542);" data-canvas-width="341.88730050505046">of coordinates is included.” This option considered a case as included</div><div style="left: 78.2727px; top: 721.016px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.963992);" data-canvas-width="94.56758712121213">in a given cluster if</div><div style="left: 172.811px; top: 721.016px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.990973);" data-canvas-width="17.6062904040404">any</div><div style="left: 190.417px; top: 721.016px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.976557);" data-canvas-width="229.62101767676768">of the case’s addresses were within the cluster.</div><div style="left: 78.2727px; top: 735.511px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.9864);" data-canvas-width="341.8367856060607">The case file included: unique case ID (as the location ID), number of</div><div style="left: 78.2727px; top: 750.006px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.993824);" data-canvas-width="342.0080434343433">cases, onset date, and day of week. The coordinate file included: case</div><div style="left: 78.2727px; top: 764.501px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.997212);" data-canvas-width="342.17683712121203">ID and X/Y coordinates for each address per case, resulting in one or</div><div style="left: 78.2727px; top: 778.996px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.0321);" data-canvas-width="342.89759848484823">more rows per case. We searched for alive clusters with a temporal</div><div style="left: 78.2727px; top: 793.491px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.987739);" data-canvas-width="341.98833030303024">range of 2 to 30 days and a maximum spatial size of 50% of observed</div><div style="left: 78.2727px; top: 807.985px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.983338);" data-canvas-width="341.8737477272726">cases. The study period was 1 year. Monte Carlo simulations (N=999)</div><div style="left: 78.2727px; top: 822.48px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00433);" data-canvas-width="229.94135606060607">were used to determine statistical significance.</div><div style="left: 91.3182px; top: 836.975px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00019);" data-canvas-width="331.3136696969695">We mimicked prospective surveillance to determine when the</div><div style="left: 78.2727px; top: 851.47px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.02652);" data-canvas-width="343.09719393939406">September 2015 cluster would have been detected had this analysis</div><div style="left: 78.2727px; top: 865.965px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01228);" data-canvas-width="345.01799217171697">been in place, by performing daily SA and MA analyses from</div><div style="left: 78.2727px; top: 880.46px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.98631);" data-canvas-width="343.8770946969696">September 21 (when the first outbreak-linked case was reported)</div><div style="left: 78.2727px; top: 894.955px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.03178);" data-canvas-width="343.0824090909091">to September 29 (when the initial SaTScan analysis signaled). Any</div><div style="left: 78.2727px; top: 909.45px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00491);" data-canvas-width="189.57625555555555">cluster with a recurrence interval (RI)</div><div style="left: 267.848px; top: 911.79px; font-size: 12.3207px; font-family: sans-serif;">≥</div><div style="left: 274.61px; top: 909.45px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00545);" data-canvas-width="146.04226919191922">100 days was summarized in</div><div style="left: 78.2727px; top: 923.945px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.03879);" data-canvas-width="343.2672196969694">a map and linelist. Prospective, automated analyses were launched</div><div style="left: 78.2727px; top: 938.44px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.956022);" data-canvas-width="343.482832070707">in April 2016 and run daily using Microsoft Task Scheduler, SAS</div><div style="left: 78.2727px; top: 952.935px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.991767);" data-canvas-width="339.21740328282823">9.4, and SaTScan 9.4.1. Signals through July 2016 were summarized.</div><div style="left: 78.2727px; top: 980.518px; font-size: 12.3207px; font-family: sans-serif; transform: scaleX(1.08542);" data-canvas-width="44.50239393939395">Results</div><div style="left: 91.3182px; top: 993.521px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01689);" data-canvas-width="331.96297095959585">In mimicked prospective analysis, the SA and MA SaTScan</div><div style="left: 78.2727px; top: 1008.02px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01871);" data-canvas-width="342.6758257575758">analyses identified clusters of 13 and 11 cases, respectively, starting</div><div style="left: 78.2727px; top: 1022.51px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.972445);" data-canvas-width="343.71076515151503">September 27, 2015. The MA cluster was more spatially focused</div><div style="left: 78.2727px; top: 1037.01px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.04041);" data-canvas-width="343.00725277777764">(2.11 km vs. 5.42 km) and more unlikely to occur by chance alone</div><div style="left: 78.2727px; top: 1051.5px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.04417);" data-canvas-width="342.9222398989899">(RI of 16,256 days vs. 8,758 days). In prospective analyses, a MA</div><div style="left: 443.545px; top: 277.47px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.950664);" data-canvas-width="343.5382752525253">cluster of 6 cases was identified on July 5, 2016 with a radius of</div><div style="left: 443.545px; top: 291.965px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00324);" data-canvas-width="344.7789704545453">1.69 km (RI=100 days). On July 6, the MA cluster case count</div><div style="left: 443.545px; top: 306.46px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01462);" data-canvas-width="342.6881464646464">increased to 7 and maintained the same radius (RI=685 days), while</div><div style="left: 443.545px; top: 320.955px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.02544);" data-canvas-width="342.77069520202014">a cluster of the same 7 cases was identified by the SA analysis with</div><div style="left: 443.545px; top: 335.45px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.03715);" data-canvas-width="342.8975984848486">a larger radius (1.97 km) and lower RI (292 days). The RI for both</div><div style="left: 443.545px; top: 349.945px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00129);" data-canvas-width="287.4544166666666">clusters peaked on July 7 (MA: 2348 days, SA: 713 days).</div><div style="left: 443.545px; top: 377.528px; font-size: 12.3207px; font-family: sans-serif; transform: scaleX(1.10408);" data-canvas-width="73.93656313131314">Conclusions</div><div style="left: 456.591px; top: 390.531px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01148);" data-canvas-width="331.56378005050504">In preliminary evaluation, the MA analysis facilitated cluster</div><div style="left: 443.545px; top: 405.026px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.02268);" data-canvas-width="344.999511111111">detection using non-residential possible exposure sites, such as</div><div style="left: 443.545px; top: 419.521px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.981439);" data-canvas-width="341.78627070707057">workplaces. Timeliness was slightly improved, but the larger practical</div><div style="left: 443.545px; top: 434.016px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01364);" data-canvas-width="344.72106313131303">benefit was identifying more spatially focused clusters. Smaller</div><div style="left: 443.545px; top: 448.511px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.994422);" data-canvas-width="341.99818686868696">clusters are useful for more precisely targeting legionellosis infection</div><div style="left: 443.545px; top: 463.006px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.03201);" data-canvas-width="343.14401262626274">source identification and remediation activities, especially in urban</div><div style="left: 443.545px; top: 477.501px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00156);" data-canvas-width="287.1463989898989">environments with high population and building densities.</div>}, number={1}, journal={Online Journal of Public Health Informatics}, author={Peterson, Eric R. and Greene, Sharon K.}, year={2017}, month={May} }