When there's an outbreak of an infectious disease like SARS (severe acute respiratory syndrome) or swine flu it seems to come out of nowhere, leaving governments and health agencies scrambling to deal with the threat. But the truth is that many outbreaks can be predicted and quickly extinguished—but stronger public-health programs and planning are needed, says a team of infectious-disease experts.
In reviewing nearly 400 serious, international public health events in recent years, the authors of a new study found that a lack of public health infrastructure—meaning things like robust surveillance, high-quality laboratory testing, and rapid reporting and control of infections—was the main driving factor of infectious disease outbreaks, contributing to about 40 percent of outbreaks overall. Other factors, including climate, weather, war, and famine, had a much smaller role, contributing to less than10 percent of infectious disease outbreaks, according to the study, published in PLoS Medicine.
The analysis points to the need for a comprehensive redesign of how governments and nonprofit public health organizations approach infectious disease, the authors say. The current approach—which is to fund disease-specific global health programs, typically on an emergency basis—should be replaced with a broader strategy aimed at strengthening public health infrastructure and development.
The study found that infectious disease outbreaks could be traced to specific public health failures, including a lack of potable water, poor immunization coverage, the inability to purchase or distribute vaccines, and the inability to control vectorborne diseases (meaning bacterial and viral illnesses transmitted by mosquitoes, fleas, or ticks) or zoonotic diseases (those transmitted to people by animals). The many cholera outbreaks around the world, for example, typically stem from unclean water. "Cholera outbreaks are devastating events, and it's in large part because the infrastructure didn't exist beforehand to prevent outbreaks," Tiffany Bogich, a postdoctoral research fellow at Princeton University and a co-author of the study, told TakePart.
Many outbreaks of infectious disease are limited to particular regions. But while the problems with public health infrastructure are most obvious in poorer nations, developed countries may need to rethink their policies too. "We are worried about developing countries because we often see pandemic threats emerge in these countries, particularly tropical places," Bogich says. "But at some level it's a global problem. Vaccine refusal in the West has become a problem now, and we're seeing outbreaks of illnesses like measles."
Instead of simply reacting to outbreaks of disease, public health agencies need to be fortified to prevent problems, the authors wrote. Agencies and governments should develop policies that deal with different stages of an outbreak, from the first signs of a problem to localized outbreaks to a pandemic. The weakest link? That may the inability to identify an outbreak early, Bogich says. "We know the least about the early stages," she says. "Surveillance is a big problem."
Surveillance would be helped a lot, suggest the authors, by bringing together a wide range of experts to prevent infectious disease, especially veterinary specialists. Many illnesses originate in animals and make the leap to humans. Agencies should implement diverse strategies, such as strengthening animal health diagnostic laboratories, training veterinarians in public health strategies, and promoting biosecurity measures on farms. "If you have vets involved maybe there's a better way to do surveillance," Bogich says. "It takes a lot of effort to get people who don't normally communicate to work together on the ground."
Finally, funding in development agencies needs an overhaul, the authors said. Public health and government leaders typically respond with a request for emergency funds to handle an outbreak but don't have the resources to address why the outbreaks occur in the first place. The value of a development approach can be seen with the recent link between H5N1 influenza and backyard poultry production. Governments and agencies responded to that threat with programs that, the authors wrote: "may have played a role in the lack of sustained human-to-human transmission in the region."
Moreover, in Bangladesh, an international health research organization called icddrb, has established an integrated public-health model to address infectious disease threats, Bogich says. Significant progress has been made in controlling outbreaks of Nipah virus, an illness that causes brain inflammation and is spread by a fruit bat during the winter harvesting of date palm juice. While most commonly spread from bat to human, human-to-human transmission has been reported. There is no treatment or vaccine, and the illness can be fatal. "Nipah virus is a fairly rare event, but it's a major problem when it happens," Bogich says. "If anything were to change, the virus could spread beyond southeast Asia."
Improving the public health infrastructure in places most in need of help gives protection to everyone, the authors of the paper wrote. Not only will a revamped model "address the most significant global health threats, but it will also provide the broad-scale first line of defense against the next unknown contagion," they said.
Should governments and health agencies take a different approach to prevention infectious disease threats? Tell us what you think in the comments.