OPINION | Environmental surveillance needed for clearer picture in public health
A national wastewater surveillance programme can offer key benefits such as an early warning system which will enable future spikes of diseases to be brought under control quickly, writes Eunice Ubomba-Jaswa and Nonhlanhla Kalebaila.
If there was any doubt, the coronavirus pandemic (Covid-19) has clearly revealed that we inhabit a world where people, animals and environments are interconnected and interdependent.
This mutuality brings with it new challenges and opportunities in controlling not only infectious diseases, but also chemical substances (often man-made) that have a negative impact on human, animal and environmental health.
External pressures on our environment, such as climate change, unplanned urbanisation and poverty also exacerbate the spread of disease, while global connections linked to international trade and tourism means that diseases are only a few flights away from being transported to the next location.
Through a deliberate focus on the human-animal-environment interface, and using an integrated (one-health) and sustainable approach, there is an opportunity to improve and maintain health within these three sectors.
Human health is inextricably linked to environmental health
On the 26 September, World Environmental Health Day allows us to focus on how environmental dynamics are affecting the well-being of humans and our ecosystem as a whole.
In light of the Covid-19 pandemic, this year’s theme, as declared by the International Federation of Environmental Health (IFEH) is “Environmental Health, A Key Public Health Intervention in Disease Pandemic Prevention”.
Based on estimates provided by the World Health Organisation (WHO) and other institutions, the global disease burden attributed to environmental factors is approximately 24% while 23% of all deaths globally are due to some environmental factor with children experiencing the highest death rates; and of the 102 disease groupings covered in a 2004 WHO report, 85 of these disease categories had some environmental factor associated with it.
Some of the commonly known and wide-spread environmentally related diseases occurring include diarrhoea, respiratory infections and malaria.
In some cases, non-communicable diseases such as cancers and cardiovascular diseases have also been shown to be environmentally related.
Improved water, sanitation and hygiene (WASH) measures, better management of harmful chemical substances as well as the existence and implementation of occupational policy around environmentally related work has seen a reduction in the environmental disease burden.
Environmental surveillance: A complementary tool for clinical disease prevention
It is often a difficult task to link an environmental factor to the occurrence or spread of a disease and as a result it is sometimes necessary to determine indirect health effects and investigate widespread or prominent environmental incidents to understand the progression or likelihood of a disease in a human population or ecosystem.
Furthermore, with certain infectious diseases such as polio, very few individuals will exhibit symptoms (approximately 1 in 200) and therefore a clinical monitoring programme is unlikely to pick up the presence of a disease which can then begin to circulate quietly in a community.
Environmental surveillance, through the continuous monitoring and profiling of water and wastewater sources for substances that can serve as indicators or biomarkers of the collective status of environmental health is increasingly being used worldwide for detecting and avoiding emerging and unrecognised hazards that may cause health disparities and for guiding forensic investigations of cause-effect linkages involving communities and stressors.
This approach is based on the fact that any substance (e.g. infectious agents, illicit drugs, food or environmental toxicants) that may be present in the environment will be washed into the aquatic system, either directly through the draining…