Public Health Surveillance Using Emergency Medical Service Logs --- U.S.--Mexico Land Border, El Paso, Texas, 2009

Public Health Surveillance Using Emergency Medical Service Logs --- U.S.--Mexico Land Border, El Paso, Texas, 2009
Weekly
June 4, 2010 / 59(21);649-653


In 2008, approximately 358 million travelers entered the United States, of whom 206 million arrived via land ports of entry (POEs) on the U.S.--Mexico border (1). Effective response to infectious diseases of public health importance among travelers requires timely identification and reporting to state and federal health authorities. Currently, notifications are made primarily by U.S. Customs and Border Protection (CBP) officers to CDC quarantine stations. However, CBP personnel have competing priorities and limited public health training (2). To evaluate the utility of monitoring emergency medical service (EMS) dispatch and response logs for ill travelers with symptoms or signs suggestive of infectious diseases, CDC screened medical records of patients transported by EMS during 2009 from the four POEs in El Paso, Texas. The screening was conducted using commercial software that monitors EMS logs and sends alerts in real time based on preestablished criteria (i.e., records containing keywords suggesting infectious diseases). Records that met the criteria were forwarded to El Paso Quarantine Station personnel and reviewed within 24 hours. If a reportable infectious disease was suspected, the final diagnosis was requested from the receiving hospital. This report summarizes the results of the evaluation, which found that, of 50,779 EMS responses in the city of El Paso, 455 (0.9%) records met alert criteria, 86 (0.2%) needed diagnostic confirmation, and nine (<0.1%) were for reportable infectious diseases. Monitoring EMS logs can enhance detection of travelers with serious infections at POEs but requires additional screening and follow-up by CDC.

CDC's Division of Global Migration and Quarantine (DGMQ) is responsible for responding to communicable diseases in arriving international travelers that might pose a public health threat. Effective and timely detection of travelers with reportable infectious diseases is necessary for disease prevention and control measures, such as outbreak and contact investigations (i.e., for infectious tuberculosis and many vaccine preventable diseases) and monitoring of POEs for mass disease events with bioterrorism potential. CDC's El Paso Quarantine Station has one medical officer and one public health advisor who are responsible for responding to these public health threats at 29 POEs spread over 1,200 miles of the U.S.--Mexico border. At POEs, CBP has agreed* to report to CDC quarantine stations any traveler who might have any of a number of clinical syndromes suggestive of an infectious disease of public health importance. However, CBP officers also must screen travelers rapidly for immigration requirements, criminal histories, terrorism intent, and illicit drug trafficking, as well as public health threats, while also permitting entry of persons engaged in commerce, tourism, or other lawful pursuits (2). Because screening and reporting of health threats might be limited by CBP's broad mandate and need for rapid processing of travelers, the Institute of Medicine has suggested that new strategies be pursued to identify travelers for signs of communicable diseases (2).

Use of EMS dispatch and response and emergency department chief complaint data is an efficient way to detect conditions of clinical and public health interest (3,4). The four urban POEs that join El Paso, Texas, and Ciudad Juarez, Chihuahua, Mexico (Bridge of the Americas, Paso Del Norte, Ysleta, and Stanton) are particularly suited to such use because of the large numbers of crossings (31.5 million per year) and because the El Paso Fire Department's computer-assisted dispatch and response system integrates both 911 call center data and EMS clinical findings into a single electronic patient record.

In this study, CDC evaluated the utility of monitoring El Paso Fire Department patient records using commercial software (FirstWatch, FirstWatch Solutions Corporation, Encinitas, California) that monitors EMS records in real time and sends an alert if the record meets the following criteria: 1) EMS response to one of the four POEs and 2) at least one keyword suggesting infection.† When EMS records matched these criteria, they were sent automatically by e-mail to the quarantine station medical officer, who reviewed the information in the alert (date, location of patient, chief complaint, and a brief summary of medical clinical) within 24 hours. If an infection reportable to the city of El Paso, Texas, or New Mexico health departments was considered possible, the El Paso Quarantine Station contacted the relevant hospital to obtain the final diagnosis. A final diagnosis was not requested for patients primarily transported for intentional or unintentional injuries, or for labor and obstetric conditions. These diagnoses were received within 24 hours for most patients. The primary diagnosis was then coded by CDC using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) (Table). To determine whether any of these patients had been reported previously to CDC by CBP, information was extracted from CDC's Quarantine and Activity Reporting System (QARS), in which all illnesses, deaths, and other port-related public health events reported to quarantine station staff members are recorded.

During 2009, El Paso EMS made 50,779 calls, of which 898 (1.8%) were to the four border crossings. Of these 898 calls, 455 (50.7%%) met the alert criteria. Review of the alerts led to final diagnoses being requested for 86 (9.6%) patients. Reportable infectious diseases were identified in nine (10.5%) of the 86 patients, including pandemic influenza A (H1N1) (five cases), coccidiodomycosis, Legionnaires disease, and invasive Streptococcus pneumoniae; nonreportable infectious diseases (e.g., urinary tract infection, bronchitis, osteomyelitis) were identified in 31 (36.0%); and a noninfectious condition in 46 (53.5%) (Table). Reportable infectious diseases were clustered in the fall, coinciding with the H1N1 epidemic (Figure).

During the same period, 295 notifications in QARS involved the jurisdiction of the El Paso Quarantine Station. Of these, 27 (9.1%) were from CPB officers at the four POEs covered by El Paso EMS. Among those 27 patients, two (7.4%) had reportable infectious diseases (tuberculosis, Hansen disease), 15 (55.6%) had nonreportable infectious diseases, and 10 (37.0%) had noninfectious conditions. Only two (2.3%) of the 86 travelers for whom a final diagnosis was requested and none of the nine patients with reportable infectious diseases were reported to the El Paso Quarantine Station by CBP.

Reported by
D Fishbein, MD, M Sandoval, MPH, C Wright, MPH, S Herrera, MPH, S Reese, MPH, T Wilson, MS, M Escobedo, MD, S Waterman, MD, S Modi, MD, J Keir, MPH, H Lipman, PhD, Div of Global Migration and Quarantine, National Center for Emerging and Zoonotic Infectious Diseases; D Sugerman, MD, EIS Officer, CDC.

open here to see the full-text:
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5921a1.htm?s_cid=mm5921a1_e