The dangers of zoonotic diseases
Featured Products Promotional FeaturesPosted by: Dental Design 22nd December 2020
Animals are deeply woven into the fabric of human life. In addition to offering companionship as pets in our homes, they help maintain healthy ecosystems and support our food supply chain. However, animals can also pose significant health risks with their ability to spread zoonotic diseases, otherwise known as zoonoses. It is estimated that zoonoses account for 60% of known infectious diseases and up to 75% of new or emerging pathogens.[i] The impact of zoonoses on both animal and human life can be catastrophic – as the COVID-19 pandemic has sadly demonstrated – which is why the prevention and control of such diseases is vital.
What are zoonoses?
Zoonoses are infectious diseases caused by bacteria, viruses, fungi or parasites that spread from animals (typically vertebrates) to humans. They can be transmitted through direct contact with the bodily fluids of an infected animal such as saliva, blood, mucus, urine or faeces. They can also be transmitted via air, water or food, through indirect contact with contaminated objects, or by way of an intermediate host like an insect.[ii] A wide range of species can carry zoonotic agents – from domestic animals to wild ones – and although some zoonoses are relatively benign, others can be life-threatening.
Zoonotic diseases are thought to be responsible for around 2.5 billion cases of human illness and 2.7 million human deaths a year.[iii] What makes some pathogens especially dangerous to humans is their incredible adaptability and the fact that we do not necessarily have the biological means to deal with the health challenges they pose. An animal virus, for instance, that manages to infect a human can mutate, adapting and improving itself for replication within the host. The human body must then create an immune response – which it must devise rapidly, as it has not been confronted with this threat before and, therefore, has no pre-existing immunity to it. If not dealt with quickly, the risk is that the virus may evolve to replicate faster or even escape the immune system’s retaliation.[iv]
In other words, the zoonotic disease and the human immune system enter an arm’s race – with either one of these two competitors winning, or both reaching a stalemate. If the human immune system loses, the consequences can be devastating. The flu epidemic that killed 400,000 people in 2009 was caused by a strain of flu that originated from pigs, which is also believed to be a descendant of the 1918 Spanish Flu that came from birds and killed up to 50 million people at the time it broke out. Although HIV is now thought of as a human virus, it “jumped” from chimpanzees to humans in the 1930s, and has now infected approximately 75 million people.[v]
Coronaviruses are a large family of viruses that infect birds and mammals. These types of viruses have been responsible for several pandemics, including SARS in 2002–2003 and COVID-19, which – at the time of writing – has killed almost 700,000 people worldwide.[vi] Several coronaviruses are known to infect humans, but not all of them jumped directly from their original host to humans. For instance, precursors to the SARS virus have been found in bats, but it made the leap to civets before infecting humans. The leading theory on the origin of COVID-19 is that it jumped into humans at a wildlife market in Wuhan, China. However, it remains unclear whether the virus originated from bats or another animal.[vii]
A growing concern
As we continue to encroach on animal habitats, the likelihood of coming into contact with wildlife will rise, increasing the risk of zoonotic diseases – viruses, in particular – spilling over into human populations. Moreover, as the world becomes ever more interconnected, new and emerging zoonoses in one country could constitute a threat to global health. Zoonotic diseases remain a growing concern due to their increasing unpredictability, epidemic potential, high case fatality ratio, and the absence of specific treatments and vaccines designed to limit their spread.[viii] Dental professionals play a significant role in reducing the burden of zoonoses on public health by practising stringent infection prevention and control.
This should involve effective decontamination of dental instruments, taking advantage of reliable, proven technologies to optimise the process and reduce the risk of disease transmission. Leading manufacturer, W&H, provides a complete decontamination solution with an innovative range of equipment, including the Teon thermo washer-disinfector and the cutting-edge Lisa vacuum sterilizer. This features Eco Dry+ technology to ensure an S class cycle time of 13 minutes and B class cycles from 28 minutes. W&H also offers the Assistina TWIN automatic reprocessing system, which can oil a handpiece in 10 seconds, whilst efficiently removing aerosols produced during the process with its integrated HEPA filter.
The COVID-19 pandemic has emphasised the detrimental effects zoonotic diseases can have not only on public health and wellbeing, but also on the global economy and society as a whole. As such, it is essential that dental teams take every step they can to reduce the risk of spreading potentially harmful zoonoses and maintain a safe, hygienic environment for themselves and patients.
To find out more visit www.wh.com/en_uk, call 01727 874990 or email office.uk@wh.com
[i] Salyer, S. J., Silver, R., Simone, K. and Barton Behravesh, C. (2017) Prioritizing Zoonoses for Global Health Capacity Building-Themes from One Health Zoonotic Disease Workshops in 7 Countries, 2014–2016. Emerging Infectious Diseases. 23(13): S55–64. DOI: 10.3201/eid2313.170418.
[ii] Walzer, C. (2020) The COVID-19 pandemic has introduced us to a new word: Zoonosis (Op-Ed). LiveScience. Available at: https://www.livescience.com/dangers-of-zoonoses-pandemics.html. [Last accessed: 04.08.20].
[iii] Grace, D. et al. (2012) Mapping of poverty and likely zoonoses hotspots. ILRI, Kenya. 119pp. Available at: https://assets.publishing.service.gov.uk/media/57a08a63ed915d622c0006fd/ZooMapDFIDreport18June2012FINALsm.pdf. [Last accessed: 04.08.20].
[iv] Sandoiu, A. (2020) Zoonotic diseases: Why are infections from animals so dangerous to humans? Medical News Today. Available at: https://www.medicalnewstoday.com/articles/zoonotic-diseases-why-are-infections-from-animals-so-dangerous-to-humans#An-evolutionary-arms-race. [Last accessed: 04.08.20].
[v] Le Page, M. (2020) Viruses from animals. New Scientist. 245(3268): 10. DOI: 10.1016/S0262-4079(20)30236-0.
[vi] European Centre for Disease Prevention and Control. (2020) COVID-19 situation update worldwide, as of 4 August 2020. Available at: https://www.ecdc.europa.eu/en/geographical-distribution-2019-ncov-cases. [Last accessed: 04.08.20].
[vii] Hickok, K. (2020) What are zoonotic diseases? LiveScience. Available at: https://www.livescience.com/zoonotic-disease.html. [Last accessed: 04.08.20].
[viii] World Health Organisation. (2020) Zoonotic disease: emerging public health threats in the Region. Available at: http://www.emro.who.int/about-who/rc61/zoonotic-diseases.html. [Last accessed: 04.08.20].
