Changing climate could be good news for disease spreading fungus
By Kirsten Dall Hjøllund
She could hardly lift her head off her pillow. Excruciating pain was causing tears to stream down her face involuntarily. She had been working away in the garden of her home the day before, determined to get it ready for a season of heavy Seattle rain. Now, it felt as if her brain was trying to burst out of her skull. Coughing and choking, she could barely breathe, she felt as though she was dying, and she did not know why. It took several weeks before Sharon Filip of Seattle, Washington, got an answer. A call from her doctor taught her the name of her disease. She had contracted valley fever.
Sharon Filip, 68, got the diagnosis in the fall of 2001, a week after she had arrived home from a trip to visit her son in Tuscon, Arizona. At some point during her stay, she took a breath of the fungus causing the disease.
The fungus is called Coccidioides Immits. It grows in the ground and spreads through airborne spores. Carried by the dry, dusty desert wind, the spores can travel over hundreds of miles. Small, but not insignificant, this fungus is posing a substantial threat to the health of the individual American, a challenge to the health-care system, and an economic burden to society at large. It is a burden which might increase, as the climate changes towards an even more friendly habitat for the microscopic perpetrators.
A fever on the rise, possibly spreading
The known symptoms of valley fever can vary greatly from person to person. Coughing, chest pains, chills, night sweats, headaches, fatigue, joint aches, red spotty rashes and, as the name suggests, fever, are some of the initial symptoms. For around 60 percent of the people who take a breath of the fungus, the guarding immune system stands alert, catching the fungus before any symptoms develop. For others, the fungus results in illness similar to the flu, which clears on its own. But for about five percent, especially elders, pregnant women, or people with an already crippled immune system, the valley fever can develop into a chronic pneumonia, and for some, spread through the bloodstream to skin, bones, liver, brains, heart or spinal cord. Without proper and timely treatment, this spread will most likely lead to a fatal outcome.
Data on how many people die due to the fever is limited, but a study from 2012 found that from 1990 to 2008, 3000 people across the US had died because of the disease – twice as many cases as tuberculosis. Taking the population growth into account, the Centers for Disease Control and Prevention (CDC) still found an eightfold increase. However, this does not even give a full picture of the problem, as the total number of cases is believed to be hugely underreported. Further, the fungus now seems to be expanding out of the known endemic areas. Recently, a soil sample from Benton County, Washington, detected the fungus. The sample was taken after two boys and a middle-aged man had been diagnosed with valley fever, without having recently traveled elsewhere. Research found that there was a genetic match between fungus in the soil and fungus in one of the patient's lungs, and concluded that all three had most likely caught the fungus in their home state. This could mean that the fungus is now capable of growing much further north than previously thought. A press release from Washington State University providing information about the detection stated that scientists have become quite certain that the fungus has indeed moved beyond its normal geographical area, which might mean that the scope of the disease is even bigger than initially suspected.
Climate changes could boost valley fever fungus
Answers as to why we see spikes in cases and a possibly expanded footprint of the fungus are complex and not yet fully developed. However, a proper amount of evidence correlating climate conditions and the fungus has been established. There is a correlation, because the success of the fungus is tied to certain climatic conditions. A study from 2005 found drought, rainfall, wind, dust and average temperature to be the most statistically significant variables when explaining developments in valley fever-cases. Several other studies have found similar correlations between the disease and climate patterns.
First off, the fungus is designed to survive in semi-arid areas. It needs a bit of moisture in the soil to grow, and then a dry period in order to develop the spores which can break off and spread.
The number of people contracting valley fever has been increasing over time, with huge spikes in certain years. For instance, the numbers rose tremendously between 1998 and 2011. Data from the states where the disease is endemic, California, Arizona, Nevada, New Mexico and Utah, showed an 850 percent increase, with over 20.000 cases diagnosed in the latter year.
Doctor and professor John Galgiani, director of Valley Fever Center For Excellence in Arizona, has studied valley fever for more than 35 years. He has studied the link between rain and dryness, and says that “we have seen a clear pattern showing that rainfall followed by a long, dry period is linked to spikes in valley fever cases”. Studies suggest that the timing of the rainfall is important. The fungus prefers rain during winter and fall, and dryness during summer.
A dry period with high temperatures are a benefit for the fungus, not only because it dries the spores: “In drought and high temperatures, competing organisms die, which leaves fungus such as the Coccidioides to dominate,” says Antje Lauer, microbiologist from California State University. She studies the earth of California, trying to determine which sorts of soil are likely to host the fungus.
When the spores are dry enough to break off, the fungus needs the air to carry them, which is why wind and particularly dust storms play a role. For instance, back in 1977, a strong dust storm hit the San Joaquin Valley in California, carrying spores outside of the endemic region, leading to an unexpectedly high number of people catching valley fever.
All these climatic conditions are boosted or constrained by the interplay with people. For instance, microbiologist Antje Lauer notes that construction work and farming is responsible for a lot of the soil disturbance which could whirl spores into the air and make people sick. However, studies have found that though there is a correlation between human disturbance of the soil and spikes in cases, climate variables are more significant.
With links between climate and the fungus, climate changes would seem to be an important factor in determining the extent of the fungus's growth. Studies on the link between climate changes and the growth of the fungus have not yet been carried out, but both John Galgiani and Antje Lauer, along with other scientists, have noted the possibility that it has or will have an impact.“If we for instance continue to see longer periods of drought it will benefit the fungus,” says Antje Lauer. Taking a closer look at the nature of current climate changes, things could be moving in a favorable direction for the fungus. In the Southwestern part of the states, the average yearly temperature has risen about 1,5 °Fahrenheit over the last century. Scientists project a further 100 2.5-8 degree increase by the end of this century, and heat waves are projected to become longer and hotter. According to the United States Environmental Protection Agency, the Southwestern states are particularly sensitive to changes in temperature, as even small decreases in available water, and the resulting droughts, can have huge impacts. Water scarcity is already a problem in the Southwest, as warming is reducing the spring snowpack and the Colorado River flows, which is an important source of water. Droughts are a part of life in the southwest, but they are predicted to become more frequent and severe. According to the US Geological Survey, the dry conditions will most likely accelerate dust storms. At interplay with the way humans disturb the soil, this is good news for the fungus. Antje Lauer notes that scarcity of water in California means that some farmers abandon fields, leaving large parts of disturbed soil to dry up, creating huge dust storms when wind sweeps over it. If the dust storms sweep over land where the fungus grows, it is likely that the spread of the spores will accelerate.
If we take a look at the changing climate in Washington, we also see conditions that are becoming beneficial for growth of the fungus. Just as in the Southwest, this region has seen temperatures rise about 1,5 ° Fahrenheit. Climate scientists project the temperature will have risen 2 degrees by the 2020's. The rising temperatures will results in water scarcity, as Washington relies on water stored in snowpack and glaciers that melt into rivers. According to the Department of Ecology in Washington, the average snowpack of Washington's Cascade mountain range has already declined by about 25 percent between 1950 and 2006.
Droughts have always been a part of the climate of eastern Washington, but with increasing temperatures and water scarcity, they now seem to be happening more frequently. Between 2000 and 2005, the state experienced two drought emergencies, one of them the second worst in history. In May this year, the US Department of Agriculture declared drought in five counties in eastern Washington, including Benton County where the fungus was detected. The Department of Ecology estimates that the evidently higher temperatures could result in stronger winds, which along with droughts could increase the potential for dust storms in Washington as well. Further, climate models project that less rain will fall during summers in Washington, and more rain will fall during autumn and winter, aligning with the conditions studies have found fertile for the fungus.
To know the impacts of climate change for sure, more studies have to be carried out. “Long term environmental studies should be done in order to find out what exactly the changes mean to the growth of the fungus”, Antje Lauer says.
However, that type of study requires a lot of funding, and valley fever as a research area has not been prioritized.“Valley fever is a neglected problem, and it is partly because it is considered a regional disease,” says John Galgiani.
A billion-dollar fever
In Washington, Sharon Filip went to the doctor. He examined her and prescribed antibiotics for what he believed was a severe case of bacterial pneumonia. The diagnosis was mistaken, and mistaken diagnoses are one of the reasons why valley fever is taking a significant toll on the US health care system. People often have to wait several weeks, some even months, before they get the proper diagnosis. This leads to the need for more extensive and expensive treatment. Moreover, proper treatment of the disease is costly, as those infected are in need of tests, surgeries and often expensive anti-fungal medication, and risk missing several weeks of work and school.
The cost of the disease is not only a burden to the people fighting it. Valley fever is also a burden to the health care system and society at large. According to the CDC, more than 40 percent of patients who get ill from valley fever require hospitalization at some point, with an average cost of nearly $50.000 per hospital visit. A study looking at the cost of valley fever in California revealed that the total charges of hospital stays related to the disease reached the substantial amount of 2,2 billion US dollars in the period of 2000 to 2011. Most of these expenses were covered by government funding, and the costs were for hospitalizations alone. Taking into consideration the cost of treating patients both in hospitals and outside, along with their lost days of work, John Galgiani estimates the total cost to be 0,4 billion dollars per year for the whole US.
One reason why the valley fever is not spotted earlier, and therefore requires extensive medical attention, is because doctors' awareness of the disease is fairly low. This is true even in areas like Arizona where valley fever has been challenging the health care system for several decades. In a survey carried out by the Arizona Department of Health Services, 40 percent of the Arizona doctors that were asked said that they lacked confidence in diagnosing valley fever.
A valley fever survivor
On antibiotics, Sharon went from bad to worse. She did not want to go to the hospital, because as she says, “if I was going to die, I wanted to die in my own home.” The doctor convinced her to see a pulmonary doctor, who took a sample from her lungs. While waiting for the results, Sharon Filip was in bed, in pain. “It felt as though something was sucking the life out of me,” she says. But while lying there, waiting for the results, something happened. Her immune system kicked in and started fighting back. When the results where in weeks later and she got the diagnosis of valley fever, she was back on her feet, and her doctor decided not to put her on anti-fungal medication, as the harsh side effects could have made her worse off.
Along with her son Dave, she decided to found the group Valley Fever Survivor, with the aim of informing the general public about the disease. Such awareness-promoting groups can prove very beneficial, as studies show that people who know about valley fever before contracting it have a higher chance of getting the correct diagnosis.
Sharon Filip survived her encounter with the microscopic perpetrators. Most of her joint problems have now vanished, and she is back working as a hypnotherapist. However, her recovery was anything but swift. Her lung capacity has been permanently damaged due to the fungus, and so has the optic nerve in her left eye, which means she has issues with her sight. It took six months until she was able to walk up the stairs again. Working away on her patch of Seattle soil is something she can no longer do.
Kirsten Dall Hjølland is a 26-year old journalist, educated from the Danish School of Media and Journalism, Denmark, with a specialism in radio reporting. Currently freelancing for the Danish Broadcasting Corporation, DR.
Photo copyright © 2011 Nephron via Wiki Commons
