Surveillance is key in managing bird flu and other pandemics

Kathleen Blanchard's picture
How viruses that "jump" across species barriers open challenges for humans

Do we have the tools to manage avian influenza, MERS coronavirus and other diseases that can easily spread from animals to humans to cause pandemic?

Advertisement

Dr. Richard A. Stein, research scientist in the Department of Biochemistry and Molecular Pharmacology at New York University School of Medicine and adjunct professor in the Department of Biology at Monmouth University, NJ, shared some thoughts with EmaxHealth about how viruses that jump from other species to humans could pose pandemic threats.

Some of the current difficulties in this area of infectious diseases are the need to perform surveillance in animal species, avian species, and environmental samples, the necessity to promptly recognize human outbreaks and, in case an epidemic or pandemic occurs, the need to not only develop medications and vaccines, but also deliver them in a timely manner, often to remote locations worldwide.

Stein notes that 75 percent of viruses that have emerged in humans over the past 10 years have come from non-human species that were able to “jump” the species barriers.

Most, though not all, are respiratory type viruses such as bird flu, SARS, and the MERS coronavirus.

Public health implications of MERS and other viruses

A recent study by Ge and colleagues, which reported that a SARS-like coronavirus can be directly transmitted from bats to humans, highlights the public health implications of how easily reservoirs may spread pathogens to humans, and potentially cause epidemics and pandemics.

According to Dr. Stein, “this study provides, to date, some of the strongest experimental evidence to support the possibility that certain SARS-like coronaviruses can directly cross from bat species to humans, and the finding has immediate and far-reaching implications for infectious disease surveillance efforts”.

Just as it happened in the case of the SARS virus that was the source of a significant pandemic in 2002-2003, the analysis of an ongoing outbreak of the Middle East respiratory syndrome coronavirus indicates that there may be more cases of MERS than previously recognized.

Advertisement

It’s been more than a decade since the SARS virus outbreak, “and we now have many more tools for performing surveillance, thanks to our ability to gain, analyze, and integrate knowledge from several disciplines, including biochemistry, genetics, ecology, mathematical modeling, bioinformatics, and the -omics sciences”, Stein explains.

Better surveillance needed

But in order to keep humans safe, enhanced focus on timely detection, prompt reporting of new cases, and collaborations among governments are necessary in a consistent and systematic manner, on a global scale.

“An aspect that is often not sufficiently appreciated is the tremendous role that political will and political leadership played in eradicating smallpox, and their contribution to the global, concerted efforts that are currently being made to eradicate poliomyelitis worldwide,” Stein says.

Many viruses that are a public health concern are respiratory viruses like MERS and avian influenza.

A new report in the British Journal Lancet urges for increased surveillance of avian influenza, and this follows the first human infection with a wild avian influenza A H6N1 virus that has been persistently circulating in Taiwan.

The two recent reports demonstrate how important it is to track diseases that infect non-human species and have the potential to easily jump to humans. It was reported several years ago that this phenomenon, which was termed “viral chatter”, occurs quite frequently.

Dr. Stein told EmaxHealth that, as previously reported in the literature, most of those cross-species transmission events do not end up in causing human outbreaks, “…but this process increases the diversity of viruses and, consequently, the likelihood that a virus may successfully become established in the human population.”

In context of the cross-species transmission of pathogens, an important concept is that, as we often continue to infringe on the habitat of other species, pathogens gain more opportunities to spread to humans. “As many zoonotic pathogens taught us, one of their most effective ways to gain access to the human population is when certain species that serve as reservoirs, such as bats, search for food or become displaced as a result of anthropogenic perturbations, making their habitat overlap with human settlements”, Stein says.

Image credit: Wikimedia commons

Advertisement