Infectious Disease and Climate Change
by Leigh Barrett / MIPJ
“Climate change is not just an environmental issue… it is an all-encompassing threat. It is a threat to health, since a warmer world is one in which infectious diseases such as malaria and yellow fever will spread further and faster.”
- UN Secretary-General Kofi Annan’s address to the Climate Change Conference, as delivered in Nairobi, 15 November, 2006
The earth’s surface has warmed by more than 0.8°C (1.4°F) in the last century, with about two thirds of that occurring in the period since 1980. This dramatic increase, understood and accepted to be largely as a result of human activity, is creating more extreme weather conditions, intense flooding, extended droughts, and more frequent El Nino Southern Oscillations (ENSO) as oceans get warmer. ENSO is the warning signal to the planet — once the upper levels of the oceans have warmed, El Nino activity will probably weaken, but there is little doubt that ENSO is considered a tipping point for the Earth’s climate. These oscillations of the ocean result in devastating hurricanes, tornadoes, and more extreme winters. Projections of an average surface temperature increase from 1.1°C to 6.4°C over the next century will see a shift to long-term drought conditions, melting glaciers which supply fresh water to around 200 million people in large population centers, and sea level increases which are already resulting in salt water intrusions into freshwater aquifers. As that intrusion takes place, the lack of potable water, as well as water available for agricultural irrigation becomes a devastating reality, will have a profound impact on the health of humans, animals, as well as plant life, throughout the world.
Life forms generally had adjusted to climate changes in the past, whether seasonal, or even inter-annual variations, but the rapid pace of change now may be faster than evolution can cope with, leaving many species threatened with extinction, and humans facing dire diseases at a level we are simply not equipped to combat.
Human health is sensitive to geographic and temporal shifts in weather and climate, and studying the effects of those factors on human health, especially considering the rapid changes the world is seeing in terms of climate change, would take decades of empirical study. That time, and the decisions made after those studies have been done, run into the obstacle of the rapidity of change. The world quite simply does not have the time to indulge theories anymore. Early implementation of policies should have been done decades ago, yet attention only started to seriously be paid to the subject in the late 1990’s.
Many working in the infectious diseases field, and the health care community generally, noticed that there was no binding resolution following the 2009 United Nations Climate Change Conference in Copenhagen. In fact, it’s a subject that seems to have largely been ignored by governments, planners and policymakers, even as scientists and health professionals are sending out warning signs, and the increased stress from climate change is starting to have an effect on services provided to their populations.
A healthy population is imperative to productivity, especially in the agricultural sector, ensuring food security for the entire population. Impacts on food production by increased or reduced rainfall patterns leads to a diminished capacity to utilize food effectively, resulting in higher rates of malnutrition and susceptibility to infectious diseases, such as HIV/Aids, cholera, polio, and many others.
It’s not only the “usual suspects” (under-developed and developing nations, historically lacking the health infrastructure to efficiently deal with outbreaks) who are feeling the pressure. In recent years, developed countries like America have been experiencing epidemics of infectious diseases previously unheard of, or at least thought to have long been under control.
THERE’S A BUG IN THE SYSTEM
Mosquitoes are America’s deadliest insect, in terms of actual deaths caused — largely due to the numerous diseases they carry, malaria being only one, and soaring summer temperatures can increase the incidence of vector-borne diseases.
In epidemiology, a vector is an organism that transmits a disease or parasite from one animal or plant form to another. And mosquitoes are possibly the most well-known of the vector-borne carriers. The Natural Resources Defense Council provides a shocking uptick in once contained infectious disease in the United States. Lyme disease from ticks could expand from 4,000 to 10,000 cases, where Dengue Fever increased 6,000 cases from the years 2005 to 2010. West Nile Virus increased to 16,000 plus cases in 2005, from its first appearance in the US in early 1999.
West Nile Virus is now established in New York City after a prolonged drought followed by a heat wave in the summer of 1999 resulted in an outbreak in Queens, New York, which then spread to other northeastern states. In 2012, West Nile Virus was responsible for the deaths of 286 people in the United States, with the worst area being Texas.
In 2013, Dallas County, Texas reported its first fatal incident in September. El Nino-Southern Oscillations create colder winters in Texas with heavier snowfall, resulting in a greater incidence of standing water, essential for mosquitoes, including those carrying the West Nile Virus, to breed.
These little midge-like flies also visit upon us Dengue Fever (also called “breakbone fever”), of the same genus as West Nile Virus. While rarely fatal, the incidence of Dengue Fever has increased 30-fold between 1960 and 2010, with cases popping up in Flori- da, west Texas and Hawaii. As the weather warms, especially in humid or tropical regions, the conditions become favorable for mosquitoes. A 2008 report by the Lowy Institute in Sydney, Australia, suggests that by 2085, more than half the world’s population will be living in areas at risk for dengue fever. And, as the world warms, the winters that once prevented the spread of vector-borne diseases by killing carriers, becomes less of a protective barrier.
Wealthy countries, able to spray, clean out stagnant water, and use other efforts like breeding mosquito-eating fish, clearly have an advantage. Global trade and international travel still pave avenues, helping mosquitoes spread the viruses. Global attention to developing vaccines to combat the spread would be helpful, but doesn’t resolve the underlying issue of climate change, the base reason for the spread of infectious viruses.
In an article written by Abdisalan M Noor et al in BioMed Central, called, “The risks of malaria in Kenya in 2009”, reduced risk of infection is found in particularly urban areas where temperatures do not exceed 160C, and in areas where there is less than three continuous months of precipitation less than 60mm in an average year. The change in climate conditions has resulted in areas previously unaffected by malaria, like the East Kenya highlands, now experiencing new outbreaks. High rates of illness and death have been happening because malaria has been introduced into a previously non-immune population. Ironically, Kenya is the world’s largest supplier of pyrethrins, commonly used in malaria and insecticide preparations.
AGRICULTURE AND DISEASE
With the rise of agricultural industrialization around the world, many industries are replacing organic waste with synthetic compounds. Anthony Penna states in his book, The Human Footprint, “nitrogen applied to the soil degrades into gaseous nitrogen oxides that become heat-trapping greenhouse gasses more powerful than carbon dioxide.” By compromising the air and lowering the oxygen levels in the oceans through synthetic compound run-off, we place ourselves at risk from the various infectious microbes carried by farm animals: tetanus, tuberculosis, smallpox, diphtheria, measles and influenza, to name a few.
HIV/AIDS
The HIV/AIDS pandemic across southern Africa has had a devastating effect on every country’s ability to plan for disasters. The strain on resources, the loss of such a large segment of the population’s workforce has profoundly deep implications.
With much of the continent engaged in agricultural activities, able-bodied workers are a necessity to keep food production at a rate that can sustain the continent. The pandemic affects hu- man resources through a loss of labor, increased absenteeism due to illness, and morbidity and the burden falls onto the survivors, who carry the additional work- load usually without an increase in pay or benefits. The entire country of Malawi, with the highest population of HIV-prevalence in the world, is susceptible to climate change: droughts, floods, tropical cyclones have had extremely damaging effects on agriculture, and with climate change, the government’s ability to respond to these disasters as well as the already burdensome HIV-related health of their population, is diminished.
The nutritional requirements of people living with HIV/AIDS is higher than a healthy person’s needs, and the impact of severe weather conditions increases the effect of drought or floods on food production, creating a vicious cycle. The inability to provide adequate nutrition in times of severe weather patterns weakens the immune system, making the person more susceptible to infections, which then undermines the nutritional status.
Accelerating the spread of HIV/AIDS is gender inequality and cultural patterns found in many parts of Africa. It is fairly common in some places to marry young girls off in times of drought, usually to older men who have had numerous sexual partners (including at-risk prostitutes). Women, especially widowed in many cases, may sell sex for money in order to survive, adding to the already overloaded burden of institutions working with these populations.
Disaster management organizations are now facing the additional load of controlling or managing the spread of diseases, both amongst the population they’re assisting, and themselves as they face a lack or shortage of infrastructure. The Red Cross has already mainstreamed climate change considerations into their general disaster-preparedness activities.
Lacking infrastructure, especially but not exclusively, in third world and developing nations, puts up to 3 billion people at risk, with an estimate of 150,000 people already dying each year as a direct result of climate change.
OCEAN STRESS
Climate change effects lead to a variety of ecological destructions. Natural disasters, unsanitary water, and erosion of farm land give light to the ongoing challenges. Rising temperatures are also evident in tropical marine environments such as the coral reef ecosystems of the Caribbean. Warmer water temperatures have promoted infections by pathogenic fungi and bacteria. When corals succumb to disease, other species that depend on them are affected. And it appears that the diseases are spreading.
Some parasitic diseases have severely crippled oyster populations along the US East Coast, moving with the warmer winters both further north and south along the coastline than ever before. After daily water temperatures exceeded 15oC along the New England coast, another shellfish parasite Vibrio parahaemolyticus caused an outbreak of gastrointestinal illness in people eating raw oysters at a local shellfish farm. After Hurricane Katrina, two deaths were reported after humans were infected with V. parahaemolyticus after swimming or working in infected waters.
As the Oxford Journal reports: “Between 1973 and 1998, 40 outbreaks of V. parahaemolyticus infections were reported to the CDC, and these outbreaks included >1000 illnesses. Most of these outbreaks occurred during the warmer months and were attributed to seafood, particularly shellfish”. Forty percent of the inflicted were hospitalized.
THERE’S SOMETHING IN THE WATER
Groundwater aquifers are found at almost every point in the Earth’s subsurface. Sometimes fossilized, and sometimes replenished by rain water, they are critical to human survival. Where aquifers are near coast- lines, instead of being replenished with rain water, suitable for drinking and agricultural irrigation, the rising sea waters are infiltrating these important sources of water, and this intrusion is made worse by extreme weather events, such as hurricane storm surges.
Natural disasters such as the Haitian Earthquake of 2010 often result in a cycle of disease and devastation due to the lack of sanitary water and healthcare infrastructure. As Anthony Penna and Jennifer Rivers discuss in Natural Disasters In A Global Environment, the poorest nation in the western hemisphere, with a life expectancy of 62 years, felt this catastrophe and it’s repercussions at an accelerated rate. Between 46,000 and 85,000 people died as the government ceased to exist. A year after the earthquake, the remaining medical units were hampered by a primitive wastewater system leading to the spread of cholera. Drinking the contaminated water prolongs the spread of disease and, along with the lack of healthcare, paves the road to a torturously painful death. Today, around the world about 80% or 5.6 billion people live in areas where clean water is a scarcity.
The largest waterborne disease in America happened in 1993 in Milwaukie, Wisconsin. Contamination at the Howard Avenue Water Purification Plant, resulted in the deaths of at least 104 people, with around 403,000 becoming ill with stomach cramps, and gastrointestinal symptoms. It was thought that runoff from cattle pastures could have caused the infiltration of Cryptosporidium, a microscopic parasite that is most commonly spread through water, but it was later reported by the Center for Disease Control (CDC) that the source was a sewage plant, 2 miles upstream.
POLIO
Polio is highly contagious, harbored in the intestinal system, and transmitted through coughs, sneezing, or fecal matter. Severe cases can be fatal. Over the last 2 decades, massive efforts to eradicate polio have resulted in the disease only appearing in 4 countries, as recently as 2009: India, Nigeria, Afghanistan and Pakistan. The disease affects the most vulnerable in any population: the poor. For some time, there had been a very real fear that if efforts to completely eradicate the disease failed, that with the increase of waterborne diseases and contamination of freshwater aquifers, the tide will turn and polio will once again spread beyond those 4 countries.
And today, that fear is being realized. As of November, 2013, 22 cases had been confirmed in northern Syria by the World Health Organization and Kurdish Red Crescent. With the difficulty of the situation in Syria, and the Syrian government’s refusal to supply other agencies with the polio vaccine to outside agencies, getting medicine to those infected, is extremely difficult and wastes valuable time as the disease spreads.
Refugees fleeing into Syria’s Kurdistan region have brought with them a strain of the disease found in Pakistan, putting not only that region at risk, but also Turkey and potentially Europe, disease-free for more than 10 years. Surprisingly, genetic sequencing in the strain found in Syria indicates the source is Israel. Since February 2013, more than 100 samples of sewage have been tested positive in areas including Gaza and the West Bank. While most children in Israel, Gaza and the West Bank have been vaccinated, should those without adequate immunity come into contact with children who have the virus it may cause the paralytic disease. Considering most children who are not vaccinated are mobile Bedouins, the chances of spreading the dis- ease throughout Jordan, Egypt and Syria, is entirely possible, if not probable. It isn’t only nomadic tribes that threaten the spread of disease: anti-vaccination lobbies in developed nations like Australia and America, make the transitory nature of swathes of humanity a threat to those susceptible globally.
Somalia has also seen an increase in polio, with 180 cases reported in the areas controlled by the Islamic Al Shabab, which has banned vaccination. That outbreak has already crossed borders into Kenya (14 cases) and Ethiopia (7 cases).
Typhoon Haiyan, (or as it is known in the Philippines, Yolanda), affected more than 9 million people in a tragedy directly at the nexus of climate change and poverty.
Shortages of fresh water, a collapse in sanitation, the destruction of the infrastructure making getting supplies to the affected populations extremely challenging, all increases the risk of spreading cholera, dengue fever, typhoid fever, bacterial dysentery, and many other infectious diseases that thrive when sewage and water supplies mingle.
There is also discussion that polio may return under these difficult conditions. Aid groups have already exhausted their supply of tetanus, adding to the list of other acute muscular and respiratory diseases.
The watery geography of the island nation makes it a natural host to all waterborne diseases, and with that comes mosquitoes and flies. Sporadic outbreaks of cholera in the Philippines over the last few years makes vigilance necessary in this case, and much depends on the swift response and delivery of key services, as well as child immunization to prevent diseases like measles becoming a factor.
However, we should remain aware that frightening projections have been made before: after the 2004 Indonesian tsunami, aside from a cluster outbreak of tetanus affecting just over 100 people, none of the projections panned out.
The same optimistic outcome reversed in Haiti, with the deaths of over 8,000 people due to cholera following the 2010 earthquake. In that situation, the slow restoration of clean water and sanitation infrastructure could be blamed.
CLIMATE CHANGE ON THE PLAYGROUND
Harvard School of Public Health (HSPH): “For the first time since the Industrial Revolution, we are on the cusp of transforming the energy sources that supplies our lives”. What we do today dictates how we live in the future. The HSPH elaborates on how we are seeing the effects of climate change on our children. With ground level Ozone on the rise, inhaling it is harmful to their lungs, triggering asthma attacks and chronic lung disease. Our effort to mine the earth’s natural gas, by fracking, is leading to poisonous waters entering our houses via the kitchen sink, weakening children’s immune systems potentially leading to a variety of cancerous disease in their future. Other symptoms reported by residents in areas that are heavily fracked include itchy eyes, nosebleeds, and scratchy throats.
However, reports definitively linking the sourcing of natural gas to any specific illness are still probably two decades away, and with the powerful energy lobbies resistance to any such reports, perhaps longer.
Some scientists have estimated an increase of 10% in diarrheal diseases by 2030, than if there was no climate change occurring. This always hits the younger children the hardest, and in poorer areas, where their immune system is already compromised by malnutrition and lack of access to primary healthcare.
Wildfires in North America are increasing in occurrence and intensity, emitting fine particulate matter which then contributes to respiratory illnesses — and, again, children are more vulnerable to asthma, bronchitis, and other impacts on their underdeveloped or developing immune system.
The EPA estimates that 16% of the world’s children already live in countries that exceed the annual fine particulate standard. The long term effects on their health and by extension the economy, will be severe, and limit any government’s ability to lift living standards.
Extreme weather and disasters also affect children, dependent on adults for care, but also requiring specialized medical and psychological care due to their development and physical size. They are far more vulnerable to extreme weather conditions, and the current heat waves are resulting in more heat-related illnesses and mortality.
Bangladesh, United States of America, Sudan, Australia… countries of vastly different cultures, socio-economic strata, geographic regions, and yet every single one is deeply affected by what climate change is already bringing to their populations. Discussing climate change in terms such as “greenhouse gas emissions”, or loss of sea ice, or deforestation, lends a distance to the majority of people. It allows us to think of climate change as something happening “scientifically”, rather than a threat to every family.
And yet, just the very act of sending a child to school on a hot, summer day, or a weather event, can launch humanity into a disease spiral that can be largely avoided by paying better attention to those “scientific” vagaries.
The sheer expense of ignoring a mosquito, or not willing to update infrastructure, or having an inadequate healthcare system can ultimately lead to far worse problems than simply not having bugspray available.
Sources:
Natural Resources Defence Council — www.nrdc.org “Infectious Disease: Dengue Fever, West Nile Virus, and Lyme Disease” - 2009
Abdisalan M Noor, et al — BioMedCentral, Noor et al, 2009
Anthony N Penna, “The Human Footprint: A Global Environmental
History”, Wiley-Blackwell: 1 ed (Aug 31, 2009) P 81
Environmental Protection Agency, www.epa.gov: “Climate Change Indicators in the United States”, Aug 2013
The Journal of Infectious Diseases, Vol 181, Issue 5, Pp 1661–1666
Anthony N Penna and Jennifer S Rivers, “Natural Disasters in a Global Environment”, Wiley-Blackwell, 2013, P56
Harvard School of Public Health, Center for Health and Global Environment, 2012
Health Poverty Action website: Climate Change and Health: The Cycle of Poverty and Health
Center of Disease Control: Travel Alert, October 7, 2013
This essay was first published in MIPJ: Climate Change, Resource Conflict, the Environment and Human Security.
Leigh Barrett is a South African veteran broadcast journalist, MIPJ contributor, and the host and producer of MIPJ Online Radio.
Contact: perspective.editorial@gmail.com
