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ISDS 2012 Conference Abstracts

A Binational Influenza Surveillance Network –
California/Baja California
Esmeralda Iniguez-Stevens*, Sarah Marikos and Karen Ferran

EWIDS, California Department of Public Health, San Diego, CA, USA

Objective
To enhance cross-border surveillance for Influenza-Like-Illness

(ILI) in the California/Baja California (CA/BC) border region
through the formation of a border binational surveillance network.

Introduction
In response to the 2009 H1N1 pandemic, the Early Warning In-

fectious Disease Surveillance Program (EWIDS) Office of Binational
Border Health in the California Department of Public Health sought
to strengthen outpatient ILI surveillance along the CA/BC border by
creating the first binational influenza surveillance network in the re-
gion. The establishment of this network was crucial for enhancing
cross-border situational awareness of influenza activity, especially in
a region characterized by high levels of population mobility.

Methods
During summer of 2009, an assessment of current ILI surveillance

activities in the CA/BC border region was conducted. Findings were
utilized to guide recruitment efforts and build a cross-border surveil-
lance network. In CA the assessment revealed that sentinel sites in
the border region participating in CDC’s ILINet surveillance program
were primarily pediatric or school-based clinics and that family prac-
tice patients were not equally represented. In BC the need to enhance
surveillance among the private sector was identified, particularly
among patients belonging to binational healthcare service plans.
These plans offer care to US workforce individuals who seek medical
care in BC. Other needs identified included the need to enhance sur-
veillance among underserved populations such as farm workers and
tribal communities which were not currently being represented.
Working together with partners from both sides of the border EWIDS
initiated efforts to address identified gaps. Over a three-year period
EWIDS recruited private and public sector clinics to participate in
the network.

Results
As a result of the assessment recruitment efforts were focused on

inviting family practice clinics, private clinics, tribal health centers
and clinics that provide care to underserved populations to partici-
pate in the network. These efforts led to the establishment of the Cal-
ifornia/Baja California Border Outpatient Provider ILI Surveillance
Network, which monitors syndromic and virologic influenza activity.
In total EWIDS recruited 22 (13 in CA, 9 in BC) sentinel sites to par-
ticipate; of these, 17 are family practice sites and 5 are pediatric sites.
Additionally, prior to the EWIDS enhancement local tribal health
clinics were not represented in the surveillance system. EWIDS ef-
forts resulted in the inclusion of 8 tribal sites in CA and 1 in BC. Fig-
ure 1 shows the geographical location of network sites, which
includes sites recruited by EWIDS post-assessment as well as pre-

existing sites. Over the past three influenza seasons (2009-2012)
EWIDS recruited sites have constituted 47% of all network sites.
Since the 2009-2010 influenza season 483,772 individuals have been
screened for ILI by participating sites; of these, 65.8% (n=318,295)
were screened by EWIDS recruited sites. Since the establishment of
the network EWIDS has focused on sentinel site retention, logistical
support, data collection, and dissemination of surveillance results. A
weekly report summarizing syndromic and virologic activity is dis-
tributed to public health officials throughout the influenza season.

Conclusions
The network serves as an example of a successful binational co-

ordinated effort to establish an early warning system for enhancing
situational awareness of influenza activity in a cross-border setting.
Next steps include conducting a formal evaluation of the existing sur-
veillance system, enhancing specimen collection for virologic test-
ing, and continuing to foster and build public/private partnerships.

Figure 1. Surveillance Network

Keywords
influenza; surveillance; syndromic; virologic; binational

Acknowledgments

We gratefully acknowledge all our border partners for their contributions
and support including: Border Infectious Disease Surveillance Program,
Imperial County Public Health Department, County of San Diego Public
Health Services Epidemiology & Immunization Services Branch, Naval
Health Research Center Laboratory, California Department of Public
Health Center for Infectious Diseases, Laboratorio Estatal de Salud Pub-
lica de Baja California, Departamento de Epidemiologia Estatal Baja Cal-
ifornia, and our medical partners.

*Esmeralda Iniguez-Stevens
E-mail: einiguez@cdph.ca.gov

Online Journal of Public Health Informatics * ISSN 1947-2579 * http://ojphi.org * 5(1):e3, 2013