In this week’s feature article, we compile the latest research on physical agents, the environment and demographics, and how these factors can impact upon the occupational health of workers in the agricultural sector. This is the 3rd segment of our feature article series on emerging risks.
WORK IN HEAT
In edition 189 of BC Disease News (here) our feature article focused on work in heat. Since climate change is predicted to increase in intensity, duration and frequency in the future, the prevalence of occupational disease, attributed to heat exposure, is likely to rise. As such, although much of the literature on the dangers of heat exposure in agriculture originates from sub-tropical regions, such as India and Central America, increased frequency and intensity of heatwaves, predicted in the UK in the future, may mean that foreign risks soon become directly transferrable.
The National Institute for Occupational Safety and Health (NIOSH) lists farmers as a group of workers at risk of heat stress. In our previous feature article, we discussed US research, which found that between 1992 and 2006, 68 crop production workers died from heat related illness, equating to a figure 20 times greater than the average rate of civilian workers overall.
The feature also included a 2016 study of Latino farmworkers in Northern Carolina, of which 72% had experienced at least one heat related illness symptom, and 27% had experienced 3 or more symptoms. Heat stress risk was found to be typically more common in agricultural occupations, such as sheep shearing.
We have previously indicated that one of the drawbacks of estimating heat illness in agriculture is that many cases are likely to be missed, as surveys often exclude data on workers on small farms.
The Canadian Centre for Occupational Health and Safety, the Occupational Safety and Health Administration in the USA, Work Safe in Australian States, the United States Environmental Protection Agency (EPA) offer the following advice:
- Monitor temperature and humidity and workers’ responses at least hourly in hot environments;
- Schedule heavy work and tasks requiring personal protective equipment (PPE) for the cooler hours of the day;
- Acclimatise workers gradually to hot temperatures;
- Shorten the length of work periods and increase the length of rest periods;
- Give workers shade or cooling during breaks; and
- Halt work altogether under extreme conditions.
In our work in heat feature, we reported on a Farmers Weekly (FW) news story which focused on a farmer, who was suffering with rhabdomyolysis. The condition causes muscle necrosis, which has been linked with heat stroke.[i] According to FW, ‘although doctors were able to identify Mr Cook’s condition, it was hard for them to administer the correct treatment without knowing what had caused it’. Another farmer contracted a similar condition 2 years earlier, in 2014. The young men affected were aged 22 and 33.
Over the past year, publications on work in heat included advice for employers and employees, the effectiveness of interventions to reduce the effects of heat, and the medical effects of working in excess heat. In addition, several UK news outlets reported on legal rights for workers in heatwaves. Several of the new studies on work in the heat were conducted in India, Central American and Malaysia, although these are not included in the present feature.
Medical effects of heat
Researchers found that, among 283 agricultural workers in California, 35 participants (12.3%) demonstrated acute kidney injury (AKI) over the course of a work shift. Male workers, who experienced heat strain (determined by measurements of body temperature and heart rate), were at higher risk of AKI. Those paid on the basis of crop harvesting productivity had an increased risk of AKI, particularly in female workers[ii].
Elsewhere, an Iranian team found that heat stress was associated with increased levels of stress, hormones and decreased cognitive performance scores[iii].
Also, in an Italian study, among agricultural workers, researchers found that the highest risk of occupational injuries occurred on the days with the highest average all-day temperatures, and the highest peak temperatures[iv].
An additional article, in OHS Online, outlined some statistics from the USA, regarding work in heat and worker health and safety. In 2013, there were 16,320 reports of heat illness so serious that the patient took days away from work[v].
Legal rights when working in a heatwave in the UK
In summer of 2017, several UK newspapers reported on workers’ legal rights in hot weather. Though UK employees are not expected to work in temperatures below 16°C (or 13°C for physically demanding jobs), according to a code of practice, there is no legally binding maximum temperature.
As temperatures reached higher than 32°C in some parts of the UK, in June of last year, the Trade Unions Congress (TUC) recommended that employers temporarily relax dress codes so that staff could be more comfortable. They also recommended that alternating work patterns, by which work is done in the cooler parts of the day, should be considered for outdoor workers. Although there are no strict legal protections for workers working in a heatwave, the TUC recommends that employers:
- Ensure that outdoor workers have access to sunscreen;
- Distribute fans to employees;
- Offer flexible working so employees can avoid travelling in rush hour; and
- Allow staff to take regular breaks.
Figure: It is recommended that employers distribute fans to workers during hot weather[vi]
The TUC has also asked to impose a maximum indoor temperature of 30°C (27°C for strenuous jobs) and an obligation for employers to use cooling systems when temperatures reach 24°C[vii].
Advice for employers/employees
The United States National Institute for Occupational Safety and Health (NIOSH) has developed a heat safety tool app. The app provides real-time heat index measurements and hourly forecasts, specific to the user’s location, and occupational safety and health recommendations[viii]. The app features:
- A visual indicator of the current heat index and associated risk levels specific to the users’ geographical location;
- Precautionary recommendations specific to heat index-associated risk levels;
- An interactive, hourly forecast of heat index values, risk level, and recommendations for planning outdoor work activities in advance;
- Editable location, temperature and humidity controls for calculation of variable conditions; and
- Signs and symptoms of first aid information for heat-related illness.
PPE and Protective Measures
A study of phase change cooling garments, in simulated work in hot conditions, found that participants wearing the garment had lower physiological strain than those without the garment[ix]. A phase change cooling garment, typically in the form of a vest, maintains a cool temperature.
Figure: Phase change cooling vest[x]
An invention to reduce dehydration and kidney damage among sugarcane workers involved implementation of a water, rest, shade and efficiency program. The workers were provided with portable water reservoirs, mobile shaded tents and scheduled rest periods, and the heat index was recorded each day. The program appeared to reduce the impact of heat stress and acute and harvest-long biomarkers for kidney function.[xi].
EU Horizon 2020 HEAT SHIELD project
A 5-year EU project, known as HEAT SHIELD, is currently underway and will be completed by the end of 2020. The project is part of Horizon 2020, an EU research and innovation programme in the areas of transport and energy[xii]. The objective of the HEAT SHIELD project is to develop strategies to mitigate the detrimental effects of climate change on health and society. Specific aims are to develop:
- Appropriate technical and biophysical research-based solutions to be implemented when the ambient temperature poses a health risk or impairs productivity;
- A weather-based warning system with online open access that anticipates events that may pose a threat to workers’ health; and
- Policies specific to particular scenarios aimed at promoting health and preventing loss of productivity.
Policies will be implemented in due course and their effects on health, productivity and society will be evaluated. The project is coordinated in Denmark[xiii].
WORK IN COLD
In issue 188 of BC Disease News (here), our feature article summarised the occupational risks associated with exposure to cold temperatures. Within that article, we discussed the link between cold indoor work and growing rheumatoid arthritis diagnoses. We disseminated research which showed that those who worked in the cold for 20 years and employees contracted to work for 20 hours or more per week, were at a greater risk of rheumatoid arthritis than those with 10 years of experience and employees who worked 10 hours per week, who were at a ‘non-significant’ risk. Further, workers who performed repetitive hand and finger movements were 1.4 times more likely to develop the condition.
Later, in edition 202 (here), we developed on the rheumatoid arthritis link by unearthing research, conducted by the Karolinska Institute, which showed that participants in the study, who were subjected to a cold working environment, were between 1.5 and 1.7 times more likely to develop rheumatoid arthritis, compared to those who had not experienced cold working.
During 2017, publications about work in the cold encompassed the health effects of cold work, legal rights of workers working in the cold, guidance and precautionary advice.
In one study, the researchers observed that hands and foreheads were found to have the greatest and most frequent fluctuations in temperature.[xiv]
A Swedish study suggested that working in cold environments, both indoors and outdoors, is associated with an increased risk of rheumatoid arthritis (RA). Data, on exposure duration and frequency, was collected from 3659 patients who developed RA, as well as 5925 control subjects. One of the 5 sectors where work in the cold was most frequently reported was the agriculture industry[xv].
In another Swedish study, researchers investigated the effects of cold, in respect of hand-arm vibration on the nerves, nerve function and the vascular (blood vessel) system. The risk of developing Raynaud’s phenomenon was increased for workers who had previously reported having cold hands, but there was no increased risk of paresthesia (a prickling or burning sensation). Identified risk factors for cold sensitivity were frostbite in the hands, rheumatic disease, nerve injury in the upper extremity or neck, migraine and vascular disease[xvi].
Figure: The hands are the coldest body part in cold weather, and cold hands may be associated with Raynaud’s phenomenon[xvii]
Several newspapers have reported on workers’ legal rights in cold weather conditions. For example, the Sun outlined parts of the Personal Protective Equipment at Work Regulations 1992, and briefly described frostbite, chilblains and hypothermia[xviii].
Another article reported on the code of practice, which requires workplaces to be heated to 16°C or higher, or 13°C, if work is strenuous. What is more, employers are not obliged to pay employees if they do not go to work because the weather is too cold[xix]. The Independent reported that groups of workers should raise the issue with their managers if they are too cold[xx]. In addition, the Mirror ran an article, encouraging those who believe they have suffered a cold-weather injury, at the fault of their employer, to seek compensation[xxi].
Various articles in online health and safety publications have offered advice for employers and employees when working in cold weather,[xxii] [xxiii] [xxiv] including the best fabrics for insulation purposes[xxv].
EXPOSURE TO INTERMEDIATE FREQUENCY AND EXTREMELY LOW FREQUENCY AND THZ FIELDS
In agricultural settings, electromagnetic field (EMF) exposure can often be generated by mobile telephone radio base stations (RBS) situated on rural-agricultural lands. As such, EMF are exposed to the public. Research on health conditions caused by EMF is therefore of potential relevance to causation disputes.
In edition 212 of BC Disease (here), we reported on a new study of exposure to non-ionising radiation in pregnant women, which found a significantly higher rate of miscarriage amongst those with higher exposure levels. The rate of miscarriage among the quarter of women with the lowest exposures was 10.4% and among the three-quarters of women with the highest exposures, 24.2% miscarried. According to the researchers, the rate of miscarriage in the general population is between 10% and 15%. The data therefore suggests that there is a significant increase in risk in the women with the highest non-ionising radiation exposure compared to the women with the lowest exposure.
In edition 180 (here), we covered a study which linked Amyotrophic Lateral Sclerosis (ALS), a rare neurodegenerative disorder with extremely low frequency magnetic fields (ELF-MF). ‘Men who were occupationally exposed to high levels of ELF-MFs were 2.19 times more likely to develop ALS than those who had never been exposed to them. Additionally, those in the top tertile (or the top 30 percent) of cumulative exposure were almost twice as likely to develop ALS.’
In issue 117 of BC Disease News, we discussed Directive 2013/35/EU, which specified the minimum health and safety requirements for workplace exposure to the risks arising from EMFs. The directive was adopted in June of 2013 and had to be transposed into domestic legislation by Member States before 1 July 2016. It covers EMFs with frequencies up to 300 gigahertz (GHz) and requires that duty holders assess the levels of EMF to which their workers may be exposed, against a set of specific Action Levels (ALs) and Exposure Limit Values (ELVs). Different frequency ranges have different ALs and ELVs. In the UK, the Directive was implemented by the Control of Electromagnetic Fields at Work Regulations (CEMFAW) 2016.
Over the past year, a range of scientific and medical, studies relating to the health effects of these electromagnetic field types, were published. The studies include observational studies of health effects in humans, such as brain tumours, ALS, dementia, MS, epilepsy, and pregnancy effects. There have also been controlled studies in mice and cell cultures to investigate areas such as fertility and memory, as well as studies quantifying human exposure.
Results from the INTEROCC, 7-country (including the UK) study showed no clear evidence of interaction between occupational exposure to extremely low magnetic fields and chemical exposures, in relation to glioma (brain tumour) or meningioma risk. The researchers noted the need for future research with more refined estimates of occupational exposure[xxvi] [xxvii].
In a study by Lennart Hardell’s research group (the only group to report links between mobile phones and brain cancer) researchers reported an increased risk of late stage astrocytoma (a type of brain cancer) with occupational exposure to extremely low frequency electromagnetic fields[xxviii].
A positive association between occupational exposure to extremely low frequency magnetic fields and amyotrophic lateral sclerosis (ALS), the most common form of motor neurone disease, was reported by a large study from the Netherlands[xxix]. New Scientist[xxx] and the NHS[xxxi] also reported on this study, and pointed out that motor neurone disease has a wide range of possible triggers. However, the fact that only a small number of people developed the disease means that the increased risk may be a ‘false positive’, or due to chance alone.
Animal and cell studies
Mice exposed to intermediate frequency magnetic fields showed no adverse fertility effects. During this study, sperm were analysed for motility, total sperm counts and head abnormalities. Sperm motility actually increased in the group with the highest exposure[xxxii].
In another study of mice, exposed to intermediate frequency magnetic fields, memory impairment and inflammation were observed in the group with the highest exposure. No effects on body weight, spontaneous activity, motor coordination, anxiety, or aggression were observed[xxxiii].
Figure: There are numerous sources of exposure to EM fields[xxxiv]
ENVIRONMENTAL AND DEMOGRAPHIC FACTORS
Climate change brings about the risk of disease-transmitting pests. Species of concern for the UK are culex modestus mosquitoes, which transmit West Nile Virus (already reported in the UK), aedes albopictus mosquitoes, which transmit dengue fever, and chikungunya (established in temperature parts of Europe, but not the UK - though it has been found in the UK[xxxv]), and ixodes ticks, which carry the Lyme disease bacterium.
West Nile Virus has previously been associated with farming activity[xxxvi] [xxxvii], while outdoor workers, in regular contact with animals in rural settings, are at risk of contracting these conditions.
Public Health England (PHE), over the past year, has updated its advice regarding West Nile virus[xxxviii]. It noted that no-one has been infected with West Nile virus in the UK, though there have been cases diagnosed in the UK in those who have traveled overseas. Nonetheless, the mosquito which transmits the disease is now established on the land adjoining either side of the Thames Estuary. The known distribution includes parts of Kent and Essex. Precautionary PHE advice includes information about symptoms, treatment and prevention of West Nile virus. A study of the frequency and types of mosquitoes biting humans in southern England found that culex modestus can be a major human-biting species in the UK[xxxix]. Another paper, published in 2017, reported that culex modestus bites birds in the UK. Feeding on both resident and migratory birds means that there is potential for transmission of viruses between birds too[xl].
Figure: Known distribution of culex modestus in South East England (Source: Public Health England, from Veterinary Record)[xli]
PHE has also published guidance on distinguishing aedes albopictus from native British mosquitoes, because it received a number of specimens incorrectly reported to be aedes albopictus, or Asian tiger mosquitoes[xlii]. PHE conducts surveillance for mosquitoes, and it was reported, in August 2017, that Asian tiger mosquito larvae were found in Kent[xliii]. These mosquitoes have been responsible for outbreaks of Chikungunya disease in France and Italy, where several people died.
Figure: aedes albopictus[xliv]
Another new review, in 2017, reported on vector-borne diseases, additional to those discussed above. These may appear in the UK as a result of climate change, and the review made suggestions to reduce their impact. Other vector-borne diseases that have appeared in Europe in recent years include vivax malaria, leishmaniasis and tick-borne encephalitis. The vectors of these diseases, as was the case with the other vector-borne diseases, are mosquitoes, sand flies and ticks.
Lyme disease is a bacterial infection, which usually resolves with antibiotic treatment, but in some cases, lingering symptoms, known as post-treatment Lyme disease, can persist. Lyme disease can also result in various health complications in 10% to 20% of those affected[xlv]. The notion of chronic Lyme disease (distinct from post-treatment Lyme disease) is controversial, particularly as it is sometimes used to describe symptoms in people who have no evidence of a current or past infection with the bacteria that cause Lyme disease. Chronic Lyme disease is not recognized by experts[xlvi], though some medics and alternative practitioners offer diagnoses and treatments, which can have harmful side effects[xlvii]. However, studies published in late 2017 showed that in primates, Lyme bacteria could persist months after infection, even when treated with antibiotics, and their presence may not be detected by standard testing for Lyme disease[xlviii] [xlix] [l].
Agricultural and outdoor workers are at increased risk of Lyme disease, spread by ticks. In September of 2017, some areas in southern England and the Scottish Highlands were named as being high risk regions for Lyme disease[li]. It has been suggested that tick populations grow significantly two years after a season in which large numbers of oak acorns are produced[lii].
Figure: ixodes tick[liii]
Figure: The bullseye rash typically associated with Lyme disease[liv]
WOMEN IN AGRICULTURE
The number of women working in agriculture is increasing. This is consistent with trends over the past few years. A growth in the proportion of women in agricultural workforces could lead to an increase in the number of claims for diseases specific to women. Such diseases include hormone and endocrine effects and reproductive and pregnancy effects, resulting from exposure to chemical agents, such as pesticides. One new study has found a weak link between exposure to temperatures of 30°C in expectant mothers and neural tube defects in offspring[lv].
[i] Heytens, K. et al. Exertional rhabdomyolysis and heat stroke: Beware of volatile anesthetic sedation World J Crit Care Med. 2017 Feb 4; 6(1): 21–27 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5295166/ (Accessed 22 March 2018).
[ii] Moyce, S. et al. Heat strain, volume depletion and kidney function in California agricultural workers. Occup Environ Med 74, 402–409 (2017). http://oem.bmj.com/content/74/6/402 (Accessed 2 January 2018)
[iii] Mazlomi, A. et al. The influence of occupational heat exposure on cognitive performance and blood level of stress hormones: a field study report. International Journal of Occupational Safety and Ergonomics 23, 431–439 (2017). http://www.tandfonline.com/doi/abs/10.1080/10803548.2016.1251137 (Accessed 2 January 2018)
[iv] Riccò, M. Air temperature exposure and agricultural occupational injuries in the Autonomous Province of Trento (2000–2013, North-Eastern Italy). Int J Occup Med Environ Health 31, 317–331 (2017). http://ijomeh.eu/Air-temperature-exposure-nand-agricultural-occupational-injuries-nin-the-Autonomous,74594,0,2.html (Accessed 2 January 2018)
[v] The Dangers of Heat Stress OHS Online. 1 March 2017 https://ohsonline.com/articles/2017/03/01/the-dangers-of-heat-stress.aspx (Accessed 2 January 2018)
[vi] Image from: Wikimedia Commons contributors, "File:Kawasaki-Electric Fan.jpg," Wikimedia Commons, the free media repository, https://commons.wikimedia.org/w/index.php?title=File:Kawasaki-Electric_Fan.jpg&oldid=236307989 (accessed January 29, 2018).
[vii] Working in a heatwave: your legal rights. The Guardian. 21 June 2017 https://www.theguardian.com/careers/2017/jun/21/working-in-a-heatwave-your-legal-rights (Accessed 2 January 2018)
[viii] OSHA-NIOSH Heat Safety Tool App. NIOSH. 25 April 2017 https://www.cdc.gov/niosh/topics/heatstress/heatapp.html (Accessed 2 January 2018)
[ix] Butts, C. L., Smith, C. R., Ganio, M. S. & McDermott, B. P. Physiological and perceptual effects of a cooling garment during simulated industrial work in the heat. Applied Ergonomics 59, 442–448 (2017). http://www.sciencedirect.com/science/article/pii/S0003687016302149 (Accessed 2 January 2018)
[x] Figure from https://www.safetyandbootcenter.com/TechNiche_TechKewl_Phase_Change_Cooling_Vest_p/4531.htm
[xi] Wegman, D. H. et al. Intervention to diminish dehydration and kidney damage among sugarcane workers. Scand J Work Environ Health 44, 16–24 (2018). https://www.ncbi.nlm.nih.gov/pubmed/28691728 (Accessed 2 January 2018)
[xiii] HEAT-SHIELD. Horizon 2020. http://cordis.europa.eu/project/rcn/200678_en.html (Accessed 2 January 2018
[xiv] Arezes, P. M. et al. Occupational Safety and Hygiene V: Selected papers from the International Symposium on Occupational Safety and Hygiene (SHO 2017), April 10-11, 2017, Guimarães, Portugal. (CRC Press, 2017). https://books.google.co.nz/books?hl=en&lr=&id=0syEDgAAQBAJ&oi=fnd&pg=PA23&dq=occupational+cold&ots=YPbiDnhp6V&sig=DhPCxqNg9c7LW2O4MtvLdasMX9o#v=onepage&q=occupational%20cold&f=false (Accessed 2 January 2018)
[xv] Zeng, P., Bengtsson, C., Klareskog, L. & Alfredsson, L. Working in cold environment and risk of developing rheumatoid arthritis: results from the Swedish EIRA case–control study. RMD Open 3, e000488 (2017). http://rmdopen.bmj.com/content/3/2/e000488 (Accessed 2 January 2018)
[xvi] Carlsson, D. Effects of cold and hand-arm vibration on the peripheral neurosensory and vascular system : an occupational perspective. DIVA (2017). http://umu.diva-portal.org/smash/record.jsf?pid=diva2%3A1151024&dswid=646 (Accessed 2 January 2018)
[xvii] Image from http://maxpixel.freegreatpicture.com/Frost-Cold-Hand-Winter-1927461
[xviii] SITTING CHILLY Working outside in cold, snow or icy weather? Your employment rights explained. The Sun 12 December 2017 https://www.thesun.co.uk/money/2652709/snow-cold-weather-temperature-employment-rights/ (Accessed 2 January 2018)
[xix] AN ICE THOUGHT Is it too cold to work today, how cold does it have to be to get sent home and what’s the minimum temperature for schools to shut? The Sun 15 December 2017 https://www.thesun.co.uk/money/2314627/too-cold-work-today-temperature-laws-rights-schools-shut/ (Accessed 2 January 2018)
[xx] How cold it needs to be before British workers should be sent home by employers Independent 7 November 2017 http://www.independent.co.uk/news/uk/home-news/how-cold-work-sent-home-employees-workers-temperature-office-employer-boss-a8041971.html (Accessed 2 January 2018)
[xxi] Working in cold temperatures? Your rights, the law and how to claim compensation if you’ve been mistreated http://www.mirror.co.uk/lifestyle/your-rights-working-cold-temperatures-7113462 (Accessed 2 January 2018)
[xxii] Out in the cold. How to avoid injuries and illnesses when temperatures plummet. Safety and Health. 25 November 2017 http://www.safetyandhealthmagazine.com/articles/16353-out-in-the-cold (Accessed 2 January 2018)
[xxiii] Cold Stress Guide. OSHA United States Department of Labour. https://www.osha.gov/SLTC/emergencypreparedness/guides/cold.html (Accessed 2 January 2018)
[xxiv] Cold (Work) Comforts OHS Online 25 December 2017 https://ohsonline.com/articles/2017/12/25/cold-comforts.aspx (Accessed 2 January 2018)
[xxv] 3 Safety Considerations for Cold Weather Work. Incident Prevention Magazine. 19 December 2017 https://incident-prevention.com/ip-articles/3-safety-considerations-for-cold-weather-work (Accessed 2 January 2018)
[xxvi] Turner, M. C. et al. Interactions between occupational exposure to extremely low frequency magnetic fields and chemicals for brain tumour risk in the INTEROCC study. Occup Environ Med 74, 802–809 (2017). http://oem.bmj.com/content/74/11/802 (Accessed 3 January 2018)
[xxvii] Vila, J. et al. 0363 Occupational exposure to high frequency electromagnetic fields and risk of brain tumours in the interocc study. Occup Environ Med 74, A113–A114 (2017). http://oem.bmj.com/content/74/Suppl_1/A113.2 (Accessed 3 January 2018)
[xxviii] Carlberg, M., Koppel, T., Ahonen, M. & Hardell, L. Case-control study on occupational exposure to extremely low-frequency electromagnetic fields and glioma risk. Am. J. Ind. Med. 60, 494–503 (2017). https://www.ncbi.nlm.nih.gov/pubmed/28394434 (Accessed 3 January 2018)
[xxix] Koeman, T. et al. Occupational exposure and amyotrophic lateral sclerosis in a prospective cohort. Occup Environ Med 74, 578–585 (2017). http://oem.bmj.com/content/74/8/578 (Accessed 3 January 2018)
[xxx] ALS linked to occupational exposure to electromagnetic fields. New Scientist 29 March 2017. https://www.newscientist.com/article/2126263-als-linked-to-occupational-exposure-to-electromagnetic-fields/ (Accessed 3 January 2017)
[xxxi] Electromagnetic fields link to motor neurone disease ‘weak’. NHS Choices. 30 March 2017 https://www.nhs.uk/news/neurology/electromagnetic-fields-link-to-motor-neurone-disease-weak/ (Accessed 3 January 2017)
[xxxii] Kumari, K. et al. Effects of intermediate frequency magnetic fields on male fertility indicators in mice. Environmental Research 157, 64–70 (2017). https://www.sciencedirect.com/science/article/pii/S0013935117303705 (Accessed 3 January 2018)
[xxxiii] Kumari, K. et al. Behavioral testing of mice exposed to intermediate frequency magnetic fields indicates mild memory impairment. PLOS ONE 12, e0188880 (2017). http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0188880 (Accessed 3 January 2018)
[xxxiv] Image from http://www.axiuminspections.com/emf-testing-colorado/
[xxxv] Golding, Nick, Miles A. Nunn, Jolyon M. Medlock, Bethan V. Purse, Alexander GC Vaux, and Stefanie M. Schäfer. “West Nile Virus Vector Culex Modestus Established in Southern England.” Parasites & Vectors 5 (2012): 32. doi:10.1186/1756-3305-5-32.
[xxxix] Brugman, V. A. et al. How often do mosquitoes bite humans in southern England? A standardised summer trial at four sites reveals spatial, temporal and site-related variation in biting rates. Parasites & Vectors 10, 420 (2017). https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-017-2360-9 (Accessed 19 January 2018)
[xl] Brugman, V. A. et al. Blood-feeding patterns of native mosquitoes and insights into their potential role as pathogen vectors in the Thames estuary region of the United Kingdom. Parasites & Vectors 10, 163 (2017). https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-017-2098-4 (Accessed 19 January 2018)
[xli] Image from (Cull B, Vaux AGC, Medlock JM, Abbott A, Gibson G. Expansion of the range of the West Nile virus vector in Essex. Veterinary Record 179: 363-364 October 8 2016)
[xlii] Distinguishing Aedes albopictus, the Asian Tiger mosquito, form native British mosquitoes. Public Health England, 10 August 2017. https://www.gov.uk/government/publications/mosquito-surveillance/distinguishing-aedes-albopictus-the-asian-tiger-mosquito-from-native-british-mosquitoes (Accessed 19 January 2018)
[xliii] Confirmed: Invasive Asian tiger mosquitoes in UK. British Pest Control Association, 4 August 2017. https://bpca.org.uk/News-and-Blog/confirmed-invasive-asian-tiger-mosquitos-in-uk (Accessed 19 January 2018)
[xliv] By James Gathany, CDC [Public domain], via Wikimedia Commons https://commons.wikimedia.org/wiki/File%3ACDC-Gathany-Aedes-albopictus-1.jpg
[xlv] Rizzoli, A. et al. Lyme borreliosis in Europe. Eurosurveillance 16, 19906 (2011). http://www.eurosurveillance.org/content/10.2807/ese.16.27.19906-en (Accessed 19 January 2018)
[xlvii] Marzec, N. S. Serious Bacterial Infections Acquired During Treatment of Patients Given a Diagnosis of Chronic Lyme Disease — United States. MMWR Morb Mortal Wkly Rep 66, (2017). https://www.cdc.gov/mmwr/volumes/66/wr/mm6623a3.htm (Accessed 19 January 2018)
[xlviii] Embers, M. E. et al. Variable manifestations, diverse seroreactivity and post-treatment persistence in non-human primates exposed to Borrelia burgdorferi by tick feeding. PLOS ONE 12, e0189071 (2017). http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0189071 (Accessed 19 January 2018)
[xlix] Crossland, N. A., Alvarez, X. & Embers, M. E. Late Disseminated Lyme Disease: Associated Pathology and Spirochete Persistence Posttreatment in Rhesus Macaques. The American Journal of Pathology (2017). doi:10.1016/j.ajpath.2017.11.005 https://www.sciencedirect.com/science/article/pii/S0002944017308945 (Accessed 19 January 2018)
[l] Lyme bacteria survive 28-day course of antibiotics months after infection. ScienceDaily, 13 December 2017. https://www.sciencedaily.com/releases/2017/12/171213143613.htm (Accessed 19 January 2018)
[li] Health body warns many UK areas have high Lyme disease risk. New Scientist, 25 September 2017. https://www.newscientist.com/article/2148357-health-body-warns-many-uk-areas-have-high-lyme-disease-risk/
[lii] Bogdziewicz, M. & Szymkowiak, J. Oak acorn crop and Google search volume predict Lyme disease risk in temperate Europe. Basic and Applied Ecology 17, 300–307 (2016). http://iranarze.ir/wp-content/uploads/2016/10/E402.pdf (Accessed 19 January 2018)
[liii] Image from Fritz Flohr Reynolds https://www.flickr.com/photos/fritzflohrreynolds/8550674860
[liv] By Photo Credit: James Gathany Content Providers(s): CDC/ James Gathany [Public domain], via Wikimedia Commons https://commons.wikimedia.org/wiki/File%3AErythema_migrans_-_erythematous_rash_in_Lyme_disease_-_PHIL_9875.jpg
[lv] Auger, N., Fraser, W. D., Arbour, L., Bilodeau-Bertrand, M. & Kosatsky, T. Elevated ambient temperatures and risk of neural tube defects. Occup Environ Med 74, 315–320 (2017). http://oem.bmj.com/content/74/5/315 (Accessed 19 January 2018)