Global awareness of disease outbreaks: the experience of ProMED-mail

Google Health Trends performance reflecting dengue incidence for the Brazilian states

Background

Dengue fever is a mosquito-borne infection transmitted by Aedes aegypti and mainly found in tropical and subtropical regions worldwide. Since its re-introduction in 1986, Brazil has become a hotspot for dengue and has experienced yearly epidemics. As a notifiable infectious disease, Brazil uses a passive epidemiological surveillance system to collect and report cases; however, dengue burden is underestimated. Thus, Internet data streams may complement surveillance activities by providing real-time information in the face of reporting lags.

Methods

We analyzed 19 terms related to dengue using Google Health Trends (GHT), a free-Internet data-source, and compared it with weekly dengue incidence between 2011 to 2016. We correlated GHT data with dengue incidence at the national and state-level for Brazil while using the adjusted R squared statistic as primary outcome measure (0/1). We used survey data on Internet access and variables from the official census of 2010 to identify where GHT could be useful in tracking dengue dynamics. Finally, we used a standardized volatility index on dengue incidence and developed models with different variables with the same objective.

Results

From the 19 terms explored with GHT, only seven were able to consistently track dengue. From the 27 states, only 12 reported an adjusted R squared higher than 0.8; these states were distributed mainly in the Northeast, Southeast, and South of Brazil. The usefulness of GHT was explained by the logarithm of the number of Internet users in the last 3 months, the total population per state, and the standardized volatility index.

Conclusions

The potential contribution of GHT in complementing traditional established surveillance strategies should be analyzed in the context of geographical resolutions smaller than countries. For Brazil, GHT implementation should be analyzed in a case-by-case basis. State variables including total population, Internet usage in the last 3 months, and the standardized volatility index could serve as indicators determining when GHT could complement dengue state level surveillance in other countries.

Social media and internet-based data in global systems for public health surveillance: a systematic review

CONTEXT

The exchange of health information on the Internet has been heralded as an opportunity to improve public health surveillance. In a field that has traditionally relied on an established system of mandatory and voluntary reporting of known infectious diseases by doctors and laboratories to governmental agencies, innovations in social media and so-called user-generated information could lead to faster recognition of cases of infectious disease. More direct access to such data could enable surveillance epidemiologists to detect potential public health threats such as rare, new diseases or early-level warnings for epidemics. But how useful are data from social media and the Internet, and what is the potential to enhance surveillance? The challenges of using these emerging surveillance systems for infectious disease epidemiology, including the specific resources needed, technical requirements, and acceptability to public health practitioners and policymakers, have wide-reaching implications for public health surveillance in the 21st century.

METHODS

This article divides public health surveillance into indicator-based surveillance and event-based surveillance and provides an overview of each. We did an exhaustive review of published articles indexed in the databases PubMed, Scopus, and Scirus between 1990 and 2011 covering contemporary event-based systems for infectious disease surveillance.

FINDINGS

Our literature review uncovered no event-based surveillance systems currently used in national surveillance programs. While much has been done to develop event-based surveillance, the existing systems have limitations. Accordingly, there is a need for further development of automated technologies that monitor health-related information on the Internet, especially to handle large amounts of data and to prevent information overload. The dissemination to health authorities of new information about health events is not always efficient and could be improved. No comprehensive evaluations show whether event-based surveillance systems have been integrated into actual epidemiological work during real-time health events.

CONCLUSIONS

The acceptability of data from the Internet and social media as a regular part of public health surveillance programs varies and is related to a circular challenge: the willingness to integrate is rooted in a lack of effectiveness studies, yet such effectiveness can be proved only through a structured evaluation of integrated systems. Issues related to changing technical and social paradigms in both individual perceptions of and interactions with personal health data, as well as social media and other data from the Internet, must be further addressed before such information can be integrated into official surveillance systems.

The new International Health Regulations: considerations for global public health surveillance

Global public health surveillance is critical for the identification and prevention of emerging and reemerging infectious diseases. The World Health Organization recently released revised International Health Regulations (IHR) that serve as global legislation and provide guidelines for surveillance systems. The IHR aim to identify and prevent spread of these infectious diseases; however, there are some practical challenges that limit the usability of these regulations. IHR requires Member States to build necessary infrastructure for global surveillance, which may not be possible in underdeveloped countries. A large degree of freedom is given to each individual government and therefore different levels of reporting are common, with substantial emphasis on passive reporting. The IHR need to be enforceable and enforced without impinging on government autonomy or human rights. Unstable governments and developing countries require increased assistance in setting up and maintaining surveillance systems. This article addresses some challenges and potential solutions to the ability of national governments to adhere to the global health surveillance requirements detailed in the IHR. The authors review some practical challenges such as inadequate surveillance and reporting infrastructure, and legal enforcement and maintenance of individual human rights.

Extending the event calculus for tracking epidemic spread

OBJECTIVE

The email reporting system has been recognized as a key tool for early warning of disease outbreaks and surveillance of emerging diseases. The aim of the work reported here was to develop a formal language for building an event-centered representation of outbreak histories, described by outbreak reports, which could be used for tracking the spread of epidemics.

METHODS

The SpatioTemporal Extended Event Language (STEEL) we have built is an extension of the Event Calculus that is based on joint spatial and temporal location of event occurrences and structured conglomeration of events. This language allows us to represent and build aggregates of events, according to their spatiotemporal location.

MATERIAL AND RESULTS

In a proof of concept study, this language was implemented in Prolog. A trial corpus of 35 outbreak reports from a PROMED-Mail diffusion list was hand coded in an experimental implementation of STEEL. The performances of this language were compared with three human experts during a question and answer task on this corpus. The experiment showed agreement between responses of the experts and the system.

CONCLUSION

STEEL ensures the spatial and temporal location of event occurrence. The resulting representation is very close to the narrative. Further work must be made to develop a system capable of automatically modeling outbreak reports.

The Global Public Health Intelligence Network and early warning outbreak detection: a Canadian contribution to global public health

The recent SARS epidemic has renewed widespread concerns about the global transmission of infectious diseases. In this commentary, we explore novel approaches to global infectious disease surveillance through a focus on an important Canadian contribution to the area--the Global Public Health Intelligence Network (GPHIN). GPHIN is a cutting-edge initiative that draws on the capacity of the Internet and newly available 24/7 global news coverage of health events to create a unique form of early warning outbreak detection. This commentary outlines the operation and development of GPHIN and compares it to ProMED-mail, another Internet-based approach to global health surveillance. We argue that GPHIN has created an important shift in the relationship of public health and news information. By exiting the pyramid of official reporting, GPHIN has created a new monitoring technique that has disrupted national boundaries of outbreak notification, while creating new possibilities for global outbreak response. By incorporating news within the emerging apparatus of global infectious disease surveillance, GPHIN has effectively responded to the global media's challenge to official country reporting of outbreak and enhanced the effectiveness and credibility of international public health.

An outbreak of Plasmodium vivax malaria in Far North Queensland, 2002

OBJECTIVE

To describe an outbreak of Plasmodium vivax malaria in Far North Queensland in 2002.

DESIGN

Epidemiological and entomological investigations; molecular analyses of the infecting parasites.

MAIN OUTCOME MEASURES

Case characteristics, adult and larval mosquito counts at the outbreak location, haplotyping of parasites in blood samples from different cases determined through sequencing of AMA1 and MSP1 genes.

RESULTS

A man with imported P. vivax malaria stayed at a camping ground 95 km north of Cairns in late September 2002. This led to an outbreak of P. vivax malaria in 10 adults who stayed at the camping ground in October. Large numbers of Anopheles farauti sensu lato larvae were present in stagnant pools in a creek at the camping ground, and many adult mosquitoes were collected nearby. Not only had most of the infected patients been exposed to mosquitoes at night, they were also less likely than other campers to have used insect repellents appropriately (odds ratio, 0.01; P < 0.001). Two different haplotypes of P. vivax, only one of which was detected in the imported case, were involved in the outbreak.

CONCLUSIONS

Although local transmission of malaria is rare in Far North Queensland, the risk is probably higher in the dry season (September to December). Campers need to be aware of the increased risk of mosquito-borne diseases. Sexual recombination of multiple gametocytes in mosquitoes infected by the imported case may have resulted in the two haplotypes of P. vivax involved in the outbreak.