Storms Ahead: Predicting And Responding To Infectious Disease

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In 1918, an influenza pandemic swept the globe, killing more than 50 million people. At least 20% of the world’s population was infected, and entire villages in Alaska and Africa were wiped out. Without our modern understanding of viruses or experience with anything of this scale, the US Public Health Service could do little to prevent spread or treat those affected, leading to more than 600,000 American deaths.

Fortunately, since 1918, the world has learned much about the nature of disease and how it spreads. We’ve developed a system for analyzing and responding to threats that far surpasses any sort of coordination we may have had 90 years ago, both nationally and globally. Two groups, the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC), work together to ensure that the public is kept safe and informed. The latest threat they have to face is the H1N1 influenza virus, also known as the swine flu. H1N1 was recently declared a pandemic by the WHO, meaning that there have been large outbreaks in multiple regions of the globe.

One key to containing infectious diseases like H1N1 is the early detection of outbreaks, requiring a great deal of seamless cooperation to analyze illness patterns over a vast area in real-time. To recognize any out-of-the-ordinary statistics as they develop at the local level, the CDC has an established network of outpatient care centers, hospitals, and city statistics offices that submit data including illness, mortality, and hospitalization figures to headquarters for scrutiny on a weekly basis. In Mexico, a 300% spike in influenza cases alerted authorities that there was a problem, but it was attributed to a rebound of the normal seasonal flu.

Had the Mexican officials been aware that the virus was different, they would have treated the outbreak with much more care and urgency. Learning the biological nature of a disease is another essential step in determining the best course of action to prevent spread and treat victims. For this reason, all CDC state public health laboratories and some county and academic labs have united as “WHO collaborating laboratories” to characterize the diseases in question and send results back to the WHO. These labs allow scientists to identify new strains of disease and determine ways to fight them. Today’s H1N1 virus was first identified as a new viral combination after it was sent to CDC labs when a Border Infectious Disease Surveillance program facility in California found it “untypable.” It has since been determined that the disease is a new blend of four distinct viral subtypes.

The statistics from the CDC’s local network partners are coupled with this biological information for analysis. Regional illness levels and the frequencies of different classes of virus are compiled by place and combined with hospitalization figures, mortality rates, and other data to track the spread of infection. If the percentage of patients seeking help from healthcare providers due to influenza-like symptoms exceeds that area’s calculated regional baseline, extra vigilance is necessary.

This information is then disseminated to local CDC and WHO partners – in return for their patient statistics, healthcare centers receive guidance from huge knowledge banks. The CDC presents weekly influenza surveillance reports through a site called FluView, which provides detailed statistics for healthcare professionals so they can assess the risk in their area. On the global level, the WHO makes information available through its website, providing daily updates regarding the worldwide health situation. Locally, clinics and hospitals make use of any new strategies developed by either governing body.

Perhaps most importantly, information about outbreaks and what precautions can be taken is then communicated to the general population. The recent media storm surrounding the H1N1 virus occurred largely because the disease was new and its capabilities were unknown. "Early on," said Dr. Gary Noskin, professor of medicine at Northwestern University's Feinberg School of Medicine, "it was important to get the message out that there was a new flu virus and that there were things people could do to protect themselves."

The CDC newsroom works with major media outlets and holds press conferences to keep the media and general public informed of both the disease’s status and any strategies, like hand-washing and encouraging the infected to remain home, that ordinary people can employ to prevent the spread. Immunization is another accessible and important method of protection—if you’ve ever gotten a flu shot, you’ve been given precautionary treatment based on analysis of disease data.

As in the case of H1N1, preventing an outbreak is not always possible, so measures must be in place to contain infectious disease once it begins to spread. The CDC’s National Center for Immunization and Respiratory Diseases is in charge of immunizing the public, but also helms measures toward controlling existing outbreaks, ensuring that transport equipment and medical supplies are readily available to quick-response teams.

Similarly, the WHO’s Global Outbreak Alert and Response Network (GOARN) unites more than 130 partner institutions to monitor both major cities and remote areas. These organizations utilize WHO resources when necessary to treat and educate about infectious diseases. For example, this community influenza mitigation packet details recommended courses of action in the event of infection – isolation, non-pharmaceutical intervention, and so on.

When recognition, data analysis, publicity, and response teams work together, they can have great success. Consider the summer of 2004, when the WHO was alerted of possible Ebola cases in Yambio, Sudan. Ebola, which has a 50-90% fatality rate, is extremely contagious, spreading through contact with bodily fluids. GOARN quickly created a crisis response team comprised of organization members and volunteers from local healthcare groups. The team used the WHO’s prior knowledge of the disease – vital when dealing with something so virulent – to take action, educating the locals and constructing a specialized clinic. Precautions such as the burning of all potentially contaminated articles were employed, and after the development of new cases ceased, they were able to declare that the outbreak had ended after the previously determined incubation period of 42 days had passed. The organization’s collaboration with local workers produced truly incredible results: the extremely contagious disease was restricted to 17 individuals.

H1N1 continues to spread. Fortunately, the current cases are generally mild. But there is no reason to discontinue vigilance. "Over time, there will be another pandemic, says Dr. Noskin. "Over time, there will be more virulent strains of flu. The problem is, it's impossible to predict." There will always be outbreaks: outbreaks of influenza, of Ebola, and of diseases as of yet unknown. Not every catastrophe can be prevented, not every crisis can be averted. But by maintaining a modern public health system, we're giving ourselves a fighting chance.

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