Ebola and Ecology

Emerging infectious diseases

Emerging infectious diseases (EID) may have a lot to do with changing environmental conditions and human-wildlife interaction. EID are either new types of pathogens or old ones that have mutated to become novel, as the flue does every year. Most known human EID are shared with animals meaning they are zoonotic. There is an excellent map over hot spots for EIDs in the world that was published in the New York Times back in 2012 that can be found here. While the research field, ecology-infectious diseases, is relatively new and crosses disciplinary boundaries I believe it should get more attention. Especially since it may tell us more about why EIDs have become so prevalent over the last couple of decades.

While Ebola is a really scary disease because of its high fatality rate (50-90 %) its just one of nearly 1,000 known human diseases that have originated from animals. The specific source of the Ebola outbreak is not known, however, Ebola is thought to be naturally harboured in some species of bats. Initial transmission to humans may thus have come about via butchering or consuming bats or other infected species. VICE News made a great short documentary about bushmeat in the time of Ebola. While Ebola has had a devastating impact in west African countries it is unlikely that Ebola becomes a global pandemic since the infection pathway requires direct contact with bodily fluids. That said, the illegal bushmeat trade could potentially act as a transfer of the disease in to other countries around the world. Anyway, the Ebola outbreak serves as a reminder of the linkages between disrupted ecosystems and human illness.

The more we humans expand our footprint and population, altering habitats and moving animals (and the pathogens they carry), the greater potential for infection and spread of pathogens novel to humans. For example, overfishing in an area could lead to an increase in bushmeat consumption due to subsistence standards which in turn could increase the prevalence of EIDs. Similarly deforestation forces animals to move into closer proximity to humans leading to closer contact, conflicts and loss of biological diversity. Moreover warming temperatures due to climate change may also change habitats and create new ones suitable for species and their pathogens. Examples range from mosquitoes to fruit bats.

Ebola Outbreak
Source: Future Earth
Some international groups such as WHO, Future Earth, Diversitas have come together and created the ecoHEALTH project, bringing together researchers from different fields to investigate connections between health and environmental change to generate policy outputs. Hopefully this crisis may shed some new light on prevention methods that include a better care for the worlds ecosystems and biodiversity. For example; combating illegal wildlife trade, improving sanitation, halting deforestation and securing more eco-friendly food production. At the moment many international help organizations are are instead struggling to keep up with all the emerging health crises. Doctors without borders (MSF) have their work cut out for them, combating both disease outbreaks and humanitarian crises, from outbreaks of MERS, Ebola and the Avian Flue to conflicts in South Sudan, Central African Republic and Syria. The organisations spokesperson begged the UN for more resources to combat the Ebola Outbreak, as many countries have not responded quickly enough to the crisis. One should understand that these are costly ways of trying to handling public health issues, much more can be done and to a lower cost on the side of prevention. We have the tools, now we only need foresight.

The complex dynamics of EID has become a hot topic. Hopefully more countries will start taking into account the overlapping drivers of disease and environmental change. Thinking of human health as separate from animal health and their determinants should be a thing of the past. Understanding the underlying parameters, such as human-wildlife proximity and habitat change, of disease outbreak could help organizations set up global monitoring services and look for early warnings of new outbreaks.


Out of the ashes into the fire

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