Biology Reference
In-Depth Information
resources, and a greater availability of electronic communication infrastruc-
ture (Brownstein et al. 2008). Surveillance capacity for infectious disease
outbreak detection can be costly, and many countries lack the public health
infrastructure to even identify outbreaks at their earliest stages (Wilson and
Brownstein 2009). Critical gaps exist, for example, in media reporting in
tropical and lower-latitude areas, including major parts of Africa and South
America—the very regions that have the greatest burden and risk of emerg-
ing infectious diseases (Brownstein et al. 2008).
Another limitation with HealthMap's current system is in its use of a dic-
tionary of known locations and diseases. This dictionary limits the system
to what is already known. Enhancing the system consists of augmenting the
database by capturing correct locations and disease names, often involv-
ing careful manual data entry. The system must also be manually updated
to reflect new geography, albeit infrequently, as national borders shift and
names of places change (Freifeld et al. 2008).
One final important limitation is HealthMap's use of unstructured, free
text information. While Web-based electronic information sources are
potentially useful, information overload and occasional difficulties in dis-
tinguishing “signal from noise” pose substantial barriers to fully utilizing
this information. In addition, public awareness of these “signals,” if they are
openly accessible, could create problems in terms of risk communication for
public health officials. While HealthMap works to address the computational
challenges of utilizing such unstructured data by generating meta-alerts
of disease outbreaks, further in-depth evaluation is required with respect
to false positives and gaps in coverage (Brownstein et al. 2008; Wilson and
Brownstein 2009).
6.8 System Utilization during a Disease
outbreak (Novel Influenza A (H1N1))
In early April 2009, HealthMap's Spanish-language system collected and
disseminated a local media report describing evidence of an epidemic of
acute respiratory infections in La Gloria, Veracruz, Mexico (April 1, 2009, see
Figure 6.5) (Brownstein, Freifeld, and Madoff 2009). It was estimated in the
report that 60% of the town's 3000 inhabitants had been infected and that
two had died since early March 2009 (Morales 2009). This was followed by a
second report on April 2, 2009, which discussed the possible role of a United
States-owned pig farm in the epidemic (Martinez 2009). Reports of this out-
break did not appear in English-language media until weeks later (April 21,
2009) when two unrelated children in California were confirmed to have
Influenza A, H1N1 without prior exposure to pigs. The timeline of reports of
this emerging novel infection emphasizes the importance of surveillance of
