With the Climate Crisis finally taking centre stage in world discussion, Kate Scheer looks at the changes in various diseases taking place as a result of climate change.
Climate change may be the most pressing issue facing civilisation over the course of this century. While the precise ramifications, feedback loops and responses are somewhat unpredictable, general patterns of cause and effect can be anticipated. Changes to the climate can and do have an effect on many things that can threaten human health, and those changes are progressing right this moment.i Although these large-scale changes may seem removed from everyday dentistry, some of them have the potential to impact the lives of your patients and practice.
Britain’s climate is becoming more extreme, with warmer summers and colder winters that are anticipated to exacerbate many existing health risks and bring new challenges. On the microbial level, one probable threat is the potential for Legionella species to flourish within water reservoirs (the genus which includes the bacteria responsible for Legionnaires’ disease).ii Existing infrastructure (notably evaporative cooling systems) is known to be a risk for propagating Legionella, and health and safety regulations outline a series of steps to combat it.iii However, not only will rising temperatures accelerate the growth of the bacteria, additional cooling and recycling systems are anticipated to be built in response to the changing climate. These will likely include: greywater recycling systems, green roofs, and rainwater collection systems. Many of these are likely to feature in residential properties; where they may not receive the tight maintenance expected of businesses.
The warming climate has seen vector-borne infections, including previously tropical diseases (such as malaria and hantavirus), spread far from the relative few countries they were originally found in. African trypanosomiasis, Lyme disease, tick-borne encephalitis, and yellow fever among others, have spread to formerly unaffected latitudes. Dengue fever infections alone have increased 30 times over in the preceding 50 years.iv Dengue fever is transmitted by the mosquito Aedes aegypti, which also serves as a vector for yellow fever.
Where once these mosquitoes were found in only tropical and subtropical regions, with the planet warming and aided by international trade, these creatures are settling and breeding in more countries than ever before, including within Europe. While they are not yet known to have established themselves in Britain, isolated examples have been found already.v Standing water, as with Legionella, serves as an excellent breeding ground for mosquitoes, and they have been known to take advantage of the same types of infrastructure mentioned earlier, as well as other man-made objects such as plant pots, water butts and tires – just about anywhere that can hold relatively undisturbed water, many examples of which can be found in and around homes.
While not as dangerous a vector as Aedes aegypti, Aedes albopictus, more commonly known as the Asian tiger mosquito, has – in recent years – become established in Europe, with numbers increasing and spreading year on year. It can not only transmit Dengue, but also other infectious diseases including Zika, chikungunya and more than 20 other viruses. Already, well established in France and the Mediterranean, it is predicted that the changing climate will enable the species to colonise the southern regions of the UK in the near future due to increasing warmth and humidity.vi Eggs and larvae have already been found and destroyed in Kent on separate incidents in 2016 and 2017.vii Once spread by mosquitoes, some of these viral threats can also be transmitted from person to person. Zika, for example, can be spread sexually and through breast-feeding. While the virus can be detected in saliva, there is currently no evidence that saliva alone can transmit the infection.viii It is theoretically possible, but the viral load found in saliva is expected to be too low for transmission outside of exceptional circumstances.ix Less theoretical is the ability of Zika to survive on hard, non-porous surfaces for hours, making it a potential threat within a dental environment. Thankfully, the same research determined that commonly used disinfectants (such as bleach and isopropyl alcohol) are effective in cleaning surfaces of the virus, though they are less so when infected blood is present.x
Even more mundane threats, like salmonella poisoning, may be exacerbated by the shifting climate. Salmonella has been found to multiply in direct proportion with increasing temperature, within the range of 7.5-37°C, so greater ambient warmth is projected to see rising rates of food poisoning. The human response to hotter weather is also expected to make this worse, with people predicted to eat more raw foods, which can be riskier due to cross-contamination.xi
In many areas where we still have a far from complete view of how climate change will effect infectious diseases, it is entirely possible unexpected threats could arise.xii What is certain is that robust decontamination and sterilization procedures will help keep people safe from existing and emerging threats.
The Lisa sterilizer from W&H is an efficient and easy-to-use Type B vacuum sterilizer featuring integrated traceability. As preventing cross-contamination is vitally important to patient safety, Lisa will help ensure your instruments are sterilized with minimal effort.
Whether driven by macro scale climatic change or not, there are innumerable pathogens that can harm patients and your dental staff. Either way, there are fundamental protocols that can help keep them safe from infection, and by observing best practice and using high quality equipment, you will be ready – whatever the future brings.
i Altizer S., Ostfeld R., Johnson P., Kutz T., Harvell C. Climate change and infectious diseases: from evidence to a predictive framework. Science. 2013; 341(6145): 514-519. http://science.sciencemag.org/content/341/6145/514 Accessed November 23, 2018.
ii Vardoulakis S., Dimitroulopoulou C., Thornes J., Lai K., Taylor J., Myers I., Heaviside C., Mavrogianni A., Shrubsole C., Chalabi Z., Davies M., Wilkinson P. Impact of climate change on the domestic indoor environment and associated health risks in the UK. Environment International. 2015; 85: 299-313. https://www.sciencedirect.com/science/article/pii/S0160412015300507 Accessed November 23, 2018.
iii HSE. Legionnaires’ disease: Technical guidance. Health and Safety Executive. 2013. http://www.hse.gov.uk/pubns/priced/hsg274part1.pdf Accessed November 23, 2018.
iv Wu X., Lu Y., Zhou S., Chen L., Xu B. Impact of climate change on human infectious diseases: empirical evidence and human adaptation. Environment International. 2016; 86: 14-23. https://www.sciencedirect.com/science/article/pii/S0160412015300489 Accessed November 22, 2018.
v Dallimore T., Hunter T., Medlock J., Vaux A., Harbach R., Strode C. Discovery of a single male Aedes aegypti (L.) in Merseyside, England. Parasites & Vectors. 2017; 10: 309. https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-017-2251-0 Accessed November 23, 2018.
vi ECDC. Aedes albopictus – Factsheet for experts. European Centre for Disease Prevention and Control. 2016. https://ecdc.europa.eu/en/disease-vectors/facts/mosquito-factsheets/aedes-albopictus Accessed November 23, 2018.
vii Public Health England. Mosquito: nationwide surveillance. Gov.UK. 2017. https://www.gov.uk/government/publications/mosquito-surveillance/mosquito-nationwide-surveillance Accessed November 23, 2018.
viii CDC. Clinical guidance for healthcare providers for prevention of sexual transmission of zika virus. Centers for Disease Control and Prevention. 2018. https://www.cdc.gov/zika/hc-providers/clinical-guidance/sexualtransmission.html Accessed November 23, 2018.
ix Newman C., Dudley D., Aliota M., Weiler A., Barry G., Mohns M., Breitbach M., Stewart L., Buechler C., Graham M., Post J., Schultz-Darken N., Peterson E., Newton W., Mohr E., Capuano III S.,O’Connor D., Friedrich T. Oropharyngeal mucosal transmission of zika virus in rhesus macaques. Nature Communications. 2017; 8(16): 169. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5539107/ Accessed November 23, 2018.
x American Association of Pharmaceutical Scientists. Zika virus can live for hours on hard, non-porous surfaces. ScienceDaily. 2016. www.sciencedaily.com/releases/2016/11/161115164220.htm
xi Lake I., Gillespie I., Bentham G., Nichols G., Lane C., Adak G., Threlfall E. A re-evaluation of the impact of temperature and climate change on foodborne illness. Epidemiology and Infection. 2009; 137(11): 1538-1547. https://www.ncbi.nlm.nih.gov/pubmed/19371450 Accessed November 23, 2018.
xii Liang L., Gong P. Climate change and human infectious disease: a synthesis of research findings from global and spatio-temporal perspectives. Environment International. 2017; 103: 99-108. https://www.ncbi.nlm.nih.gov/pubmed/28342661 Accessed November 23, 2018.
