Sick as a Dog

 
 


With many of today’s most lethal human viruses and diseases originating in the animal kingdom, Emily Longworth examines the greater impact of interspecies illnesses

In the last week, news of an emerging killer respiratory infection around the Middle East has been dominating headlines and worrying world health agencies. Most closely resembling the SARS virus, this new strain of coronavirus has infected 11 people in total, and killed 5 of those diagnosed. But no one has been yet able to confirm exactly where it came from; the leading theory is that the virus has jumped from animals to humans, along with many of the most threatening infections in the history of human health.

If the interspecies hypothesis is true for the new coronavirus strain, it will be added to the growing list of zoonotic infections that have been destructive to human health. Zoonosis is the transmission of disease and infectious agents from animals to humans. In 2001, a comprehensive review of all identified known human pathogens was carried out, listing 61% of the 1415 species in the review as zoonotic in their origin. Not only this, but zoonosis has also been the source of some of the most lethal and catastrophic pandemics ever experienced; AIDs, ebola, Spanish influenza and the Black Plague among them.

Even in our own time, the Avian H5N1 virus, foot and mouth disease and swine flu have reached pandemic status, threatening the world over and amassing fatalities. So how much of a threat will zoonotic diseases become in the future? The recent novel coronavirus scare has reawakened the threat of viruses that evolve faster than our vaccinations can contain them; infections that seemingly come from nowhere but can potentially spread everywhere.

The most important factor in the tracking of the virus is whether or not it has the ability to spread easily between humans.  Belonging to the same family as SARS (Severe Acute Respiratory Syndrome) has caused healthcare officials to be on high alert, but until last month, there was little evidence of its human-to-human transmission. In late January, the two men diagnosed with the virus in the UK were father and son, where only the father had been travelling in the Middle East immediately prior to his illness. His son has become the first person of the 11 known cases who has not been a resident of Saudi Arabia, Qatar or Jordan, leaving the Health Protection Agency (HPA) to conclude that he must have caught the virus from his father.

This is a serious concern for many healthcare professionals, who were among the chief victims of the SARS virus in 2003. In cases like this, where little to nothing in known of a virus before its outbreak, there is a scarcity of funding going towards their research. This leaves everybody in limbo over the severity of the threat until it’s too late. Or at least, that was the case for SARS. Since 2003, the European Union have set up the EMPERIE programme, which aims to catch the next epidemic before it goes too far.

“If we had known about SARS when it had only infected a few people, we might have stopped it then” says Ab Osterhaus from the Erasmus Medical Centre in Rotterdam, who was one of the founding contributors to the EMPERIE project.

With an emphasis on the rapid recognition of new diseases, identification of cause, and development of treatment and long-term prevention, it seems as though EMPERIE have the ideal strategy for targeting zoonotic diseases before they reach an outbreak status in human populations. But it is crucially dependant on international collaboration, and the combined expertise of specialist researchers, which was absent at the beginning of the SARS, Bird flu and swine flu pandemics.

In fact, the efforts to ultimately eradicate Bird Flu through in-depth research suffered huge drawbacks from lack of transparency. In early 2012, after labs started to develop strains that could mutate naturally to become highly transmissible between humans while remaining lethal, a moratorium was introduced on all publications on avian flu study.

This was a response to the widespread fears of bioterrorism or unintended outbreak. For many scientists, the moratorium was a huge step backwards “Understanding how the avian virus is adapted to mammals will lead to better surveillance and vaccines” said Yoshihiro Kawaoka, influenza researcher in Tokyo.  In January of this year, the moratorium was lifted. But with no standard of international research regulations, and poor public understanding through misrepresentation in the media, the battle against potentially lethal zoonoses may continue to struggle.

It is proposed that the new coronavirus came from bats, in the same way that SARS did. But this is still debatable among its researchers. Ab Osterhaus believes that it did come from bats, but we haven’t really seen the full extent of its transmission from animals to humans. “It could be spreading at very low levels in the Middle East, but mostly causing mild disease we don’t see. Or it could be only occasionally spilling over into people from bats.”

In the hopes that we will learn from the counter-intuitive introduction of the moratorium for bird flu research, the fight against any future threats will hopefully remain unhindered and transparent. In the meantime, scientists are still focused on tracking the coronavirus before it could infect more numbers. Tracking the early stages of viruses is a meticulous process though, according to Osterhaus: “It’s like stamp collecting, you don’t know when something is going to turn out to be interesting”. Except with pathogens, we’re all hoping they won’t turn out to be interesting in the slightest.

Advertisements